Y2S2 P2 - Head and Neck (1)
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Questions and Answers

What type of ossification is primarily responsible for the formation of the skull?

  • Metaplastic ossification
  • Intramembranous ossification (correct)
  • Endochondral ossification
  • Appositional ossification

    • Which bones are included in the neurocranium?

  • Frontal, maxilla, zygomatic, sphenoid
  • Frontal, mandible, maxilla
  • Frontal, ethmoidal, nasal, parietal
  • Frontal, occipital, parietal, temporal (correct)

    • What is the primary function of the ethmoid bone?

  • Supports the structure of the jaw
  • Protects the optic nerve
  • Forms the floor of the cranium
  • Contributes to the roof of the nasal cavity (correct)

    • At what stage does the skull's sutures fuse together?

    <p>In adulthood</p> Signup and view all the answers

    What are the bilateral pairs of bones in the neurocranium?

    <p>Temporal and parietal</p> Signup and view all the answers

    The glabella is a part of which bone?

    <p>Frontal bone</p> Signup and view all the answers

    Which bone is found between the two orbital cavities?

    <p>Ethmoid bone</p> Signup and view all the answers

    Which of the following components make up the roof and floor of the neurocranium?

    <p>Frontal, parietal, and temporal for the roof; frontal, sphenoid, and temporal for the floor</p> Signup and view all the answers

    What structure provides attachment for the falx cerebri?

    <p>Crista galli</p> Signup and view all the answers

    Which of the following structures is associated with the sphenoid bone?

    <p>Optic canal</p> Signup and view all the answers

    What is the primary function of the foramen rotundum?

    <p>Transmits V2 (maxillary nerve)</p> Signup and view all the answers

    What feature of the temporal bone is associated with the temporomandibular joint (TMJ)?

    <p>Zygomatic process</p> Signup and view all the answers

    Which part of the sphenoid bone houses the pituitary gland?

    <p>Sella turcica</p> Signup and view all the answers

    What is the purpose of the pterygoid hamulus?

    <p>Acts as a pulley for tensor veli palatini</p> Signup and view all the answers

    How does a CSF leak relate to the cribriform plate?

    <p>It causes nasal drip.</p> Signup and view all the answers

    Which structure is formed by the fusion of the medial and lateral sheets of the ethmoidal labyrinth?

    <p>Cribriform plate</p> Signup and view all the answers

    Which anatomical structure separates the middle cranial fossa from the posterior cranial fossa?

    <p>Petrous part of temporal bone</p> Signup and view all the answers

    What is the consequence of trauma at the pterion?

    <p>Extradural haematoma due to meningeal artery damage</p> Signup and view all the answers

    Which cranial foramina is associated with cranial nerve VII?

    <p>Internal acoustic meatus</p> Signup and view all the answers

    Which bones compose the roof of the neurocranium?

    <p>Frontal, two parietal, and occipital bones</p> Signup and view all the answers

    Which structure does the cribriform plate contain, facilitating the passage of sensory information?

    <p>Olfactory nerves (CN I)</p> Signup and view all the answers

    What bones make up the basicranium?

    <p>Frontal, temporal, sphenoid, and occipital bones</p> Signup and view all the answers

    Which process does the zygomatic bone articulate with?

    <p>Frontal, maxillary, and temporal processes</p> Signup and view all the answers

    The jugular foramen is associated with which cranial nerves?

    <p>IX, X, XI</p> Signup and view all the answers

    What forms the temporomandibular joint (TMJ)?

    <p>Head of the condylar process of the mandible and the tubercle of the tympanic part of the temporal bone</p> Signup and view all the answers

    Which nerve supplies the inferior alveolar nerve as it travels through the mandibular canal?

    <p>Mental nerve</p> Signup and view all the answers

    Which of the following muscles is responsible for retracting the jaw?

    <p>Temporalis</p> Signup and view all the answers

    What structure serves as the attachment point for the soft palate at the back of the maxilla?

    <p>Posterior nasal spine</p> Signup and view all the answers

    Which foramen is responsible for supplying the hard palate?

    <p>Greater palatine foramen</p> Signup and view all the answers

    What is the role of the lateral pterygoid muscle?

    <p>Moves the jaw side to side and protracts</p> Signup and view all the answers

    The mylohyoid line is associated with which anatomical feature of the mandible?

    <p>Presence of the mylohyoid groove</p> Signup and view all the answers

    What covers the articular surfaces of the TMJ?

    <p>Fibrocartilage</p> Signup and view all the answers

    Which bones are primarily responsible for forming the basicranium?

    <p>Frontal, sphenoid, ethmoid, occipital</p> Signup and view all the answers

    What type of joint forms the suture connections between the bones of the skull?

    <p>Fibrous joint</p> Signup and view all the answers

    Which of the following bones does not contribute to the neurocranium?

    <p>Maxilla</p> Signup and view all the answers

    Which bone is specifically located at the roof of the nasal cavity and between the two orbital cavities?

    <p>Ethmoid bone</p> Signup and view all the answers

    What is the primary anatomical function of the glabella region of the frontal bone?

    <p>Location for a reflexive response in Parkinson's patients</p> Signup and view all the answers

    Which of the following best describes the composition of the neurocranium?

    <p>Eight distinct bones including four midline and two bilateral pairs</p> Signup and view all the answers

    Which cranial bone contains significant features that are associated with the eye socket?

    <p>Ethmoid bone</p> Signup and view all the answers

    Which of the following statements is true regarding the bones of the skull?

    <p>The bones of the skull are joined by sutures that become fused in adulthood.</p> Signup and view all the answers

    What anatomical feature serves as an attachment point for the falx cerebri?

    <p>Crista galli</p> Signup and view all the answers

    During a CSF leak, which structure's damage could result in nasal dripping?

    <p>Cribriform plate</p> Signup and view all the answers

    Which feature is located on the greater wing of the sphenoid bone?

    <p>Foramen rotundum</p> Signup and view all the answers

    What is the function of the pterygoid hamulus?

    <p>Pulley for tensor veli palatini</p> Signup and view all the answers

    Which foramen is responsible for transmitting the middle meningeal vessels?

    <p>Foramen spinosum</p> Signup and view all the answers

    Which anatomical structure divides the anterior cranial fossa from the middle cranial fossa?

    <p>Lesser wing of sphenoid</p> Signup and view all the answers

    What feature is located at the base of the sella turcica?

    <p>Tuberculum sellae</p> Signup and view all the answers

    Which of the following correctly describes the articulation of the zygomatic process?

    <p>Articulates with the zygomatic bone</p> Signup and view all the answers

    What is the significance of the pterion in cranial anatomy?

    <p>It is a common site for extradural hematoma due to underlying arterial structures.</p> Signup and view all the answers

    Which of the following bones does NOT contribute to the formation of the floor of the neurocranium?

    <p>Parietal bone</p> Signup and view all the answers

    What anatomical structures pass through the jugular foramen?

    <p>Glossopharyngeal nerve (CN IX), vagus nerve (CN X), and accessory nerve (CN XI)</p> Signup and view all the answers

    Which cranial foramen is associated with the passage of the internal carotid artery?

    <p>Carotid canal</p> Signup and view all the answers

    The zygomatic bone articulates with which of the following processes?

    <p>Maxillary process</p> Signup and view all the answers

    Which bone forms a crucial part of the boundary between the middle and posterior cranial fossa?

    <p>Temporal bone</p> Signup and view all the answers

    What is the primary anatomical significance of the cribriform plate?

    <p>It supports the olfactory bulbs for the sense of smell.</p> Signup and view all the answers

    Which of the following foramina allows for the passage of the facial nerve?

    <p>Internal acoustic meatus</p> Signup and view all the answers

    What is the primary function of the lingual nerve in relation to the mandibular fossa?

    <p>Supplies sensory innervation to the floor of the mouth</p> Signup and view all the answers

    Which muscles are innervated by the mandibular nerve (V3)?

    <p>Masseter, temporalis, and medial/lateral pterygoid</p> Signup and view all the answers

    Which foramen provides passage for the lesser palatine nerve and vessels?

    <p>Lesser palatine foramen</p> Signup and view all the answers

    What anatomical feature is associated with the mental foramen?

    <p>Allows passage for the mental nerve and vessels</p> Signup and view all the answers

    Where does the temporomandibular joint (TMJ) articulate with the temporal bone?

    <p>Articular tubercle</p> Signup and view all the answers

    What is the role of the greater palatine vessels in relation to the palatine canal?

    <p>To supply the hard palate</p> Signup and view all the answers

    Which anatomical structure does the coronoid process of the mandible primarily serve?

    <p>Attachment of the temporalis muscle</p> Signup and view all the answers

    What is the significance of the articular disc in the temporomandibular joint (TMJ)?

    <p>It divides the joint into two compartments</p> Signup and view all the answers

    Which structure does not lie above the anterior scalene?

    <p>Subclavian vein</p> Signup and view all the answers

    What structure is found between the anterior and middle scalene muscles?

    <p>Brachial plexus</p> Signup and view all the answers

    Which muscle attaches to the second rib?

    <p>Posterior scalene</p> Signup and view all the answers

    Which component is found within the carotid sheath?

    <p>Vagus nerve</p> Signup and view all the answers

    What is a true statement about the deep cervical fascia?

    <p>It splits into several layers, including the prevertebral fascia.</p> Signup and view all the answers

    What is a significant consequence of goitre compression on the larynx?

    <p>Dysphonia</p> Signup and view all the answers

    Which cervical plexus branch is responsible for innervating the diaphragm?

    <p>Phrenic</p> Signup and view all the answers

    What anatomical structures are associated with the posterior triangle of the neck?

    <p>Axillary inlet structures</p> Signup and view all the answers

    Which section of the pharynx connects with the oral cavity?

    <p>Oropharynx</p> Signup and view all the answers

    Which condition is characterized by injuries to the cervical muscles and ligaments?

    <p>Cervical strain/sprain</p> Signup and view all the answers

    What is the role of the connective tissue fascia in the cervical region?

    <p>Serves as the first barrier before reaching vertebrae</p> Signup and view all the answers

    Which muscles are primarily involved with the ansa cervicalis in cervical plexus innervation?

    <p>Sternohyoid and omohyoid</p> Signup and view all the answers

    What structural barriers separate the nasal cavity from the oral cavity?

    <p>Hard and soft palate</p> Signup and view all the answers

    Which nerve innervates the posterior belly of the occipitofrontalis muscle?

    <p>Posterior auricular branch of the facial nerve [VII]</p> Signup and view all the answers

    What is the effect of tone in the aponeurosis of the scalp on scalp lacerations?

    <p>Inhibits blood vessel closing, causing wounds to gape</p> Signup and view all the answers

    Which artery provides anterior arterial supply to the scalp?

    <p>Supratrochlear artery</p> Signup and view all the answers

    What is the role of the buccinator muscle in facial function?

    <p>Compress cheek against teeth</p> Signup and view all the answers

    Which muscle is responsible for the downward movement of the eyebrows?

    <p>Procerus</p> Signup and view all the answers

    Which muscle is innervated by branches of the cervical plexus?

    <p>Sternocleidomastoid</p> Signup and view all the answers

    At which cervical level does the common carotid artery bifurcate into its branches?

    <p>C3-C4</p> Signup and view all the answers

    What type of anatomical structure is formed by the combined actions of the longus capitis and longus colli muscles?

    <p>Lateral cervical muscle group</p> Signup and view all the answers

    Which structure connects the middle ear to the nasopharynx?

    <p>Eustachian tube</p> Signup and view all the answers

    What is the function of the infrahyoid muscles?

    <p>Depress the hyoid bone</p> Signup and view all the answers

    What distinguishes the splenius capitis muscle from other posterior cervical muscles?

    <p>It is a superficial muscle</p> Signup and view all the answers

    Which muscle is found beneath the platysma in the anterior cervical region?

    <p>Longus colli</p> Signup and view all the answers

    Which muscle is referred to as the 'pouter' of the lip?

    <p>Mentalis</p> Signup and view all the answers

    Which cervical joint is involved in nodding the head?

    <p>Occipitoatlantal joint</p> Signup and view all the answers

    Which structure is located above the anterior scalene muscle?

    <p>Phrenic nerve</p> Signup and view all the answers

    What do the anterior and middle scalenes attach to?

    <p>First rib</p> Signup and view all the answers

    Which vessel does the subclavian artery specifically branch from?

    <p>Aorta</p> Signup and view all the answers

    Which structures are enclosed within the carotid sheath?

    <p>Common carotid artery, internal jugular vein, vagus nerve</p> Signup and view all the answers

    From which layer of deep cervical fascia does the prevertebral fascia originate?

    <p>Deep cervical fascia</p> Signup and view all the answers

    What complication arises from the compression of the larynx?

    <p>Dysphonia</p> Signup and view all the answers

    Which injury is characterized by damage to the muscles, tendons, and ligaments of the cervical spine from trauma?

    <p>Cervical strain/sprain</p> Signup and view all the answers

    What connects the middle ear to the nasopharynx?

    <p>Eustachian tube</p> Signup and view all the answers

    Which cervical plexus branch is primarily responsible for innervating the diaphragm?

    <p>Phrenic nerve</p> Signup and view all the answers

    Which structure separates the nasopharynx from the oropharynx?

    <p>Palatoglossal folds</p> Signup and view all the answers

    Which of the following is NOT a boundary of the anterior triangle of the neck?

    <p>Clavicle</p> Signup and view all the answers

    What is a potential complication of compression of the superior vena cava?

    <p>Superior vena cava syndrome</p> Signup and view all the answers

    Which neck structure is primarily associated with axillary inlet structures?

    <p>Posterior triangle</p> Signup and view all the answers

    Which nerve innervates the frontal belly of the occipitofrontalis muscle?

    <p>Temporal branches of facial nerve</p> Signup and view all the answers

    What is the arterial supply to the scalp from the external carotid artery?

    <p>Superficial temporal artery</p> Signup and view all the answers

    Which muscle is involved in wrinkling the forehead?

    <p>Frontalis</p> Signup and view all the answers

    Which scalene muscle attaches to the first rib?

    <p>Anterior scalene</p> Signup and view all the answers

    Which muscle acts as a depressor of the corners of the mouth?

    <p>Depressor anguli oris</p> Signup and view all the answers

    What structure is primarily responsible for the connection between the nasopharynx and the middle ear?

    <p>Eustachian tube</p> Signup and view all the answers

    Which artery supplies the posterior part of the scalp?

    <p>Occipital artery</p> Signup and view all the answers

    Which muscle is responsible for closing the eyelids?

    <p>Orbicularis oculi</p> Signup and view all the answers

    What is the primary function of the buccinator muscle?

    <p>Compress the cheeks against the teeth</p> Signup and view all the answers

    Which component of the cervical muscles is NOT considered part of the superficial anterior cervical muscles?

    <p>Longus colli</p> Signup and view all the answers

    Which layer does the aponeurosis of the scalp lie within?

    <p>Third layer</p> Signup and view all the answers

    Which muscle originates from the styloid process of the temporal bone?

    <p>Stylohyoid</p> Signup and view all the answers

    Which branch of the facial nerve innervates the muscles of the lower lip?

    <p>Mandibular branch</p> Signup and view all the answers

    Which spinal levels provide innervation to the lesser occipital nerve?

    <p>C2-3</p> Signup and view all the answers

    What is the primary function of the external carotid artery?

    <p>Supply blood to the head and neck</p> Signup and view all the answers

    Which branch of the internal carotid artery is specifically associated with the face?

    <p>Ophthalmic artery</p> Signup and view all the answers

    At what anatomical landmark does the carotid artery bifurcate?

    <p>C4 vertebra</p> Signup and view all the answers

    Which of the following arteries branches off the maxillary artery?

    <p>Middle meningeal artery</p> Signup and view all the answers

    What is the course of the ophthalmic artery as it enters the orbit?

    <p>Via the optic canal</p> Signup and view all the answers

    Which artery curves around the inferior border of the mandible?

    <p>Facial artery</p> Signup and view all the answers

    What area does the transverse facial artery primarily supply?

    <p>Temple and side of the face</p> Signup and view all the answers

    What is the primary reason for the increased infection risk in facial and cranial veins?

    <p>Valveless nature of the veins</p> Signup and view all the answers

    Which condition is characterized by inflammation of the temporal arteries and may lead to optic nerve ischemia?

    <p>Temporal arteritis</p> Signup and view all the answers

    Which lymph node is associated with drainage from the chin area?

    <p>Submental node</p> Signup and view all the answers

    In the context of lymphatic drainage, which statement is true regarding the structure's proximity to the midline?

    <p>The closer to the midline, the more likely it has bilateral drainage.</p> Signup and view all the answers

    What is a common clinical association with Virchow’s Node?

    <p>Intra-abdominal/thoracic organ drainage</p> Signup and view all the answers

    Which laboratory findings are considered indicative of inflammation in patients suspected of having temporal arteritis?

    <p>High ESR, increased C-reactive protein, and elevated platelets</p> Signup and view all the answers

    Which vein serves as the primary anterior drainage route for venous blood from the head and neck?

    <p>Internal jugular vein</p> Signup and view all the answers

    What is a classic symptom of temporal arteritis experienced by patients during jaw movement?

    <p>Jaw pain and claudication</p> Signup and view all the answers

    What anatomical structure significantly contributes to the drainage of intra-abdominal or thoracic organs?

    <p>Virchow’s Node</p> Signup and view all the answers

    Which of the following is a common symptom associated with temporal arteritis?

    <p>Throbbing headache and jaw pain</p> Signup and view all the answers

    Which lymphatic node is typically associated with tonsillar enlargement in children?

    <p>Jugulodigastric lymph node</p> Signup and view all the answers

    What is the hallmark laboratory finding indicative of inflammation in temporal arteritis?

    <p>Elevated C-reactive protein</p> Signup and view all the answers

    Which of the following veins primarily drains the facial region anteriorly?

    <p>Internal Jugular Vein</p> Signup and view all the answers

    What clinical sign is most indicative of cavernous sinus thrombosis?

    <p>Reduced vision acuity</p> Signup and view all the answers

    Which factor is a likely risk for developing temporal arteritis?

    <p>Old age and female gender</p> Signup and view all the answers

    Which important aspect of the facial and cranial veins contributes to increased infection risk?

    <p>Valveless structure</p> Signup and view all the answers

    What are the primary branches of the external carotid artery that supply the face and scalp?

    <p>Facial artery and superficial temporal artery</p> Signup and view all the answers

    Which artery is known to be an exception among the branches of the internal carotid artery that supplies the face?

    <p>Ophthalmic artery</p> Signup and view all the answers

    At which anatomical location do the carotid arteries bifurcate?

    <p>C4 vertebra</p> Signup and view all the answers

    Which artery runs in the infratemporal fossa before entering the pterygopalatine fossa?

    <p>Maxillary artery</p> Signup and view all the answers

    Which artery branches off the internal carotid artery and supplies the scalp?

    <p>Ophthalmic artery</p> Signup and view all the answers

    Which of the following arteries does NOT branch from the external carotid artery?

    <p>Ophthalmic artery</p> Signup and view all the answers

    What is the main function of the internal carotid arteries?

    <p>Supply blood to the brain and central nervous system</p> Signup and view all the answers

    What unique feature is associated with the middle meningeal artery?

    <p>It is associated with a blow to the pterion.</p> Signup and view all the answers

    What is the primary source of sensory innervation to the head and neck region?

    <p>Cranial nerves</p> Signup and view all the answers

    Which autonomic nervous system component supplies the lacrimal glands in the head?

    <p>Parasympathetic fibers from cranial nerves</p> Signup and view all the answers

    What is the pathway of sympathetic fibers to the head and neck region?

    <p>Exit via T1 superior cervical ganglion</p> Signup and view all the answers

    Which cranial nerve is primarily responsible for the sensory innervation to the oral cavity?

    <p>Cranial Nerve V (Trigeminal)</p> Signup and view all the answers

    What is the role of the cervical plexus in the head and neck?

    <p>It provides cutaneous and muscular innervation.</p> Signup and view all the answers

    Which of the following statements is true regarding the innervation of glands in the head and neck?

    <p>Autonomic innervation includes both PNS and SNS components.</p> Signup and view all the answers

    Which cranial nerve is associated with the parasympathetic innervation of salivary glands?

    <p>Cranial Nerve IX (Glossopharyngeal)</p> Signup and view all the answers

    What anatomical structure is predominantly responsible for cutaneous sensation in the neck?

    <p>Cervical plexus</p> Signup and view all the answers

    Which cranial nerve provides parasympathetic innervation to the lacrimal gland?

    <p>Facial nerve</p> Signup and view all the answers

    What is the destination of the post-ganglionic fibers that originate from the inferior salivatory nucleus?

    <p>Parotid gland</p> Signup and view all the answers

    Which target organs are innervated by the dorsal vagal motor nucleus?

    <p>Smooth muscle of the gastrointestinal tract</p> Signup and view all the answers

    Which ganglion does the pre-ganglionic fiber from the oculomotor nerve synapse in?

    <p>Ciliary ganglion</p> Signup and view all the answers

    What is the primary function of the vagus nerve?

    <p>Control heart rate and lung function</p> Signup and view all the answers

    Which of the following target organs is innervated by the post-ganglionic fibers from the submandibular ganglion?

    <p>Sublingual gland</p> Signup and view all the answers

    Which nerve carries sensory information from the anterior part of the tongue?

    <p>Facial nerve</p> Signup and view all the answers

    From which nucleus do the pre-ganglionic fibers that innervate the smooth muscle of the trachea originate?

    <p>Dorsal vagal motor nucleus</p> Signup and view all the answers

    What is the primary role of the ossicles in the middle ear?

    <p>To amplify sound waves</p> Signup and view all the answers

    Which structure connects the middle ear to the nasopharynx?

    <p>Eustachian tube</p> Signup and view all the answers

    What is the primary function of the semicircular canals in the inner ear?

    <p>Maintaining balance and spatial orientation</p> Signup and view all the answers

    How do sound waves initially interact with the ear's anatomy?

    <p>They are trapped by the auricle</p> Signup and view all the answers

    Which part of the ear is primarily involved in detecting sound vibrations?

    <p>Inner ear</p> Signup and view all the answers

    Which condition is typically characterized by inflammation and swelling of the mucous membrane in the tympanic cavity leading to blockage of the pharyngotympanic tube?

    <p>Otitis Media</p> Signup and view all the answers

    What anatomical structure separates the middle ear from the internal carotid artery?

    <p>Anterior wall</p> Signup and view all the answers

    Which age group is most commonly affected by Otitis Media due to factors like a shorter and more horizontal eustachian tube?

    <p>Infants and small children (6-24 months)</p> Signup and view all the answers

    Which of the following pathogens is NOT commonly associated with Otitis Media infections?

    <p>Mycobacterium tuberculosis</p> Signup and view all the answers

    Which symptoms are commonly observed in a patient with Otitis Media?

    <p>Fever, earache, and irritability</p> Signup and view all the answers

    What is the primary function of the pharyngotympanic tube?

    <p>To equalize pressure across the tympanic membrane</p> Signup and view all the answers

    Which structures communicate with the middle ear posteriorly?

    <p>Mastoid area via the mastoid antrum</p> Signup and view all the answers

    Which cranial nerve is primarily responsible for the innervation of the mucous membranes in the middle ear?

    <p>Glossopharyngeal nerve (IX)</p> Signup and view all the answers

    What structure provides attachment for the tensor tympani muscle within the middle ear?

    <p>Handle of the malleus</p> Signup and view all the answers

    Which artery provides arterial supply to the middle ear?

    <p>Maxillary artery</p> Signup and view all the answers

    What is the anatomical significance of the tympanic plexus in the middle ear?

    <p>It provides sympathetic nerve supply to the otic ganglion</p> Signup and view all the answers

    Which nerve is responsible for innervating the outer surface of the tympanic membrane?

    <p>Auriculotemporal nerve</p> Signup and view all the answers

    Which of the following statements accurately describes the position of the epitympanic recess?

    <p>It is situated superiorly to the tympanic membrane</p> Signup and view all the answers

    What anatomical feature allows the tensor veli palatini muscle to open the pharyngotympanic tube?

    <p>Cartilage surrounding the tube</p> Signup and view all the answers

    What is the primary arterial supply to the auricle?

    <p>Anterior auricular branches of the superficial temporal artery</p> Signup and view all the answers

    Which part of the tympanic membrane is characterized by being thick and taut?

    <p>Pars tensa</p> Signup and view all the answers

    What is the primary function of cerumen in the external ear?

    <p>Provide lubrication</p> Signup and view all the answers

    Which function is primarily associated with the stapedius muscle in the middle ear?

    <p>Pulls the stapes posteriorly to reduce motion</p> Signup and view all the answers

    Where does the external acoustic meatus change from cartilage to bone?

    <p>In the medial third</p> Signup and view all the answers

    Which structure of the incus articulates with the head of the stapes?

    <p>Lenticular process</p> Signup and view all the answers

    Which node is responsible for lymphatic drainage from the auricle?

    <p>Both anterior and posterior auricular nodes</p> Signup and view all the answers

    What is the location of the entrance of the tympanic branch of the glossopharyngeal nerve?

    <p>Jugular wall</p> Signup and view all the answers

    What is the primary role of the tensor tympani muscle in the middle ear?

    <p>Tenses the tympanic membrane to enhance vibration transmission</p> Signup and view all the answers

    What causes fainting during ear washing via the external acoustic meatus?

    <p>Stimulation of the auricular branch of the vagus nerve</p> Signup and view all the answers

    Which structure can facilitate drainage from the tympanic membrane for conditions like glue ear?

    <p>Grommets tube</p> Signup and view all the answers

    What is the anatomical significance of the tegmen tympani?

    <p>It demarcates the middle ear from the middle cranial fossa</p> Signup and view all the answers

    Which of the following best describes the relationship between the malleus and the incus?

    <p>The head of the malleus articulates with the body of the incus</p> Signup and view all the answers

    Which wall of the middle ear houses the stapedius muscle attachment?

    <p>Mastoid wall</p> Signup and view all the answers

    What is the primary function of the two limbs of the stapes?

    <p>Attach to the oval window for sound transmission</p> Signup and view all the answers

    What structure drains into the nasal cavity from the nasal sinuses?

    <p>Eustachian tube</p> Signup and view all the answers

    Which ossicle in the middle ear is directly connected to the tympanic membrane?

    <p>Malleus</p> Signup and view all the answers

    What anatomical feature separates the oral cavity from the nasal cavity?

    <p>Hard palate</p> Signup and view all the answers

    Which component of the ear is primarily responsible for balancing?

    <p>Semicircular canals</p> Signup and view all the answers

    Which structure is attached to the stapes and serves to transmit sound to the inner ear?

    <p>Cochlea</p> Signup and view all the answers

    What is the most common pathogen responsible for otitis media as indicated in the pathophysiology?

    <p>Respiratory Syncytial Virus (RSV)</p> Signup and view all the answers

    Which statement accurately describes the anatomical feature known as the labyrinthine wall?

    <p>It houses the round and oval windows.</p> Signup and view all the answers

    What is a common symptom of otitis media in infants and small children?

    <p>Ear discharge and irritability</p> Signup and view all the answers

    Which factor contributes to the increased incidence of otitis media in infants and small children?

    <p>More horizontal orientation of the eustachian tube</p> Signup and view all the answers

    What is the primary consequence of inflammation in the tympanic cavity due to otitis media?

    <p>Partial or complete blockage of the pharyngotympanic tube</p> Signup and view all the answers

    What structure is formed by the auricle and its associated components?

    <p>Tragus and antitragus</p> Signup and view all the answers

    Which of the following nerves innervates the external acoustic meatus?

    <p>Auricular branch of vagus nerve</p> Signup and view all the answers

    What component differentiates the pars flaccida from the pars tensa of the tympanic membrane?

    <p>Thickness and tension</p> Signup and view all the answers

    Which artery supplies the auricle?

    <p>Anterior auricular branches of the superficial temporal artery</p> Signup and view all the answers

    What is the primary cause of fainting during ear washing?

    <p>Stimulation of the auricular branch of the vagus nerve</p> Signup and view all the answers

    What anatomical feature is associated with the malleus in the tympanic membrane?

    <p>Handle of malleus attachment</p> Signup and view all the answers

    What is the primary function of the pharyngotympanic tube?

    <p>To equalize pressure across the tympanic membrane</p> Signup and view all the answers

    Which anatomical structure is located posteriorly and communicates with the middle ear?

    <p>Mastoid area via mastoid antrum</p> Signup and view all the answers

    What are the auditory ossicles in the middle ear?

    <p>Malleus, incus and stapes</p> Signup and view all the answers

    Which structure provides a connection between the body of the incus and the stapes?

    <p>Lenticular process</p> Signup and view all the answers

    Which muscle contracts to open the pharyngotympanic tube during swallowing?

    <p>Tensor veli palatini muscle</p> Signup and view all the answers

    What is the primary function of the tensor tympani muscle in the middle ear?

    <p>To tense the tympanic membrane</p> Signup and view all the answers

    What is the primary role of the tympanic plexus in the middle ear?

    <p>Provide sensory innervation to the mucous membranes</p> Signup and view all the answers

    Which wall of the middle ear is composed of thin bone and lies above the internal jugular vein?

    <p>Jugular wall</p> Signup and view all the answers

    What is the role of the stapedius muscle in the auditory system?

    <p>To prevent over-oscillation of the stapes</p> Signup and view all the answers

    Which nerve is part of the tympanic plexus and provides sympathetic fibers to the otic ganglion?

    <p>Glossopharyngeal nerve</p> Signup and view all the answers

    What is the function of the auditory ossicles in the middle ear?

    <p>Transmit sound vibrations to the inner ear</p> Signup and view all the answers

    Which part of the stapes articulates with the oval window?

    <p>Oval base</p> Signup and view all the answers

    What separates the middle ear from the middle cranial fossa?

    <p>Tegmen tympani</p> Signup and view all the answers

    Which structure is associated with the upper posterior wall of the middle ear?

    <p>Short limb of the incus</p> Signup and view all the answers

    Which bone houses the entrance of the tympanic branch of the glossopharyngeal nerve?

    <p>Temporal bone</p> Signup and view all the answers

    Which branch of the maxillary artery enters through the sphenopalatine foramen?

    <p>Sphenopalatine artery</p> Signup and view all the answers

    What type of innervation do the glands in the nasal cavity primarily receive?

    <p>Both sympathetic and parasympathetic</p> Signup and view all the answers

    Which nerve primarily supplies sensory information to the nasal cavity?

    <p>Infraorbital nerve (V2)</p> Signup and view all the answers

    What is the primary exit point for the nasopalatine nerve?

    <p>Incisive canal</p> Signup and view all the answers

    Which artery is associated with the medial wall of the pterygopalatine fossa?

    <p>Sphenopalatine artery</p> Signup and view all the answers

    What does the cribriform plate primarily facilitate?

    <p>Olfactory nerve (CNI) transmission</p> Signup and view all the answers

    Which of the following nerves join the maxillary nerve (V2) in the pterygopalatine fossa?

    <p>Greater petrosal nerve</p> Signup and view all the answers

    Which structure does the nasolacrimal duct drain into?

    <p>Inferior nasal meatus</p> Signup and view all the answers

    Which arteries are involved in the anastomosis at Kiesselbach’s Area, contributing to epistaxis?

    <p>Ophthalmic a. and facial a.</p> Signup and view all the answers

    What is the primary drainage route for the frontal sinus?

    <p>Middle meatus through the semilunar hiatus.</p> Signup and view all the answers

    Which nerve provides sensory innervation to the anterior part of the nasal cavity?

    <p>Ophthalmic branch (V1)</p> Signup and view all the answers

    Which foramina allow for the passage of veins from the nasal cavity to the cavernous sinus?

    <p>Foramen cecum</p> Signup and view all the answers

    Which branches of the internal carotid artery contribute to the vascular supply of the nasal cavity?

    <p>Anterior/posterior ethmoidal a. and ophthalmic a.</p> Signup and view all the answers

    What role does the cribriform plate play in the anatomy of the nasal cavity?

    <p>Serves as the site for olfactory nerve passage.</p> Signup and view all the answers

    Which structure is NOT a component of the nasal cavity's venous drainage?

    <p>Inferior alveolar vein</p> Signup and view all the answers

    Which area of the nasal cavity is most susceptible to infection that might reach the CNS?

    <p>Cavernous sinus</p> Signup and view all the answers

    What structure exits the incisive canal to reach the oral cavity?

    <p>Nasopalatine nerve</p> Signup and view all the answers

    Which of the following arteries supplies the nasal cavity via its inferior nasal branches?

    <p>Maxillary artery</p> Signup and view all the answers

    What is primarily transmitted through the sphenopalatine foramen?

    <p>Sphenopalatine artery</p> Signup and view all the answers

    Which nerve is specifically associated with olfaction and passes through the cribriform plate?

    <p>Olfactory nerve (CNI)</p> Signup and view all the answers

    Which structure communicates the pterygopalatine fossa with the lateral walls of the nasal cavity?

    <p>Sphenopalatine foramen</p> Signup and view all the answers

    What primary function does the greater palatine artery serve in the nasal cavity?

    <p>Vascular supply to the hard palate</p> Signup and view all the answers

    Which anatomical feature surrounds the nerves at the medial wall of the pterygopalatine fossa?

    <p>Posterior lateral nasal nerves</p> Signup and view all the answers

    Which structure carries the nasal vein to the superior sagittal sinus?

    <p>Foramen Cecum</p> Signup and view all the answers

    Which nerve exits the incisive canal into the oral cavity?

    <p>Nasopalatine nerve</p> Signup and view all the answers

    What does the sphenopalatine foramen primarily communicate with?

    <p>Pterygopalatine fossa</p> Signup and view all the answers

    Which artery enters the incisive canal?

    <p>Greater palatine artery</p> Signup and view all the answers

    What is the anatomical significance of the cribriform plate?

    <p>Contains the olfactory nerve pathways</p> Signup and view all the answers

    Which of the following structures is associated with the foramen cecum?

    <p>Nasal veins</p> Signup and view all the answers

    Which of these nerves is a branch of the maxillary division (V2)?

    <p>Nasopalatine nerve</p> Signup and view all the answers

    Which structure is primarily responsible for the olfactory function?

    <p>Olfactory nerve (CNI)</p> Signup and view all the answers

    Which bones form the boundary between the nasal cavity and the nasopharynx?

    <p>Vomer, sphenoid, palatine</p> Signup and view all the answers

    What is one function of the branches from the superior nasal branches of the infraorbital nerve?

    <p>Sensory innervation of the nasal cavity</p> Signup and view all the answers

    Which of the following statements about the lateral wall of the nasal cavity is correct?

    <p>The inferior nasal concha is a separate bone.</p> Signup and view all the answers

    What is the primary function of the nasal conchae?

    <p>Increase surface area for filtration and humidification.</p> Signup and view all the answers

    Which anatomical structure does the cribriform plate primarily facilitate?

    <p>Transmission of olfactory nerves.</p> Signup and view all the answers

    What is the role of the incisive canal in the context of the nasal cavity?

    <p>It exits into the oral cavity, facilitating airflow.</p> Signup and view all the answers

    Which components make up the external nasal skeleton?

    <p>Septal cartilage, major/minor alar cartilages, fibrofatty tissue.</p> Signup and view all the answers

    Which artery communicates with the nasal cavity through the sphenopalatine foramen?

    <p>Maxillary artery</p> Signup and view all the answers

    Which statement describes the central point of the internal nasal septum?

    <p>It includes the vomer as a key component.</p> Signup and view all the answers

    Which sinuses drain into the middle meatus via the semilunar hiatus?

    <p>Frontal sinus, anterior ethmoidal cells</p> Signup and view all the answers

    Which structure is associated with the drainage of the maxillary sinus?

    <p>Semilunar hiatus</p> Signup and view all the answers

    What is the function of the sphenoethmoidal recess?

    <p>It drains the sphenoid sinus.</p> Signup and view all the answers

    Which of the following structures does NOT open into the superior meatus?

    <p>Sphenoid sinus</p> Signup and view all the answers

    Which anatomical feature serves as a pathway for the drainage of the middle ethmoidal cells?

    <p>Ethmoidal bulla</p> Signup and view all the answers

    What artery communicates with the pterygoid fossa?

    <p>Sphenopalatine artery</p> Signup and view all the answers

    Which nerves primarily transmit sensory information in the nasal region?

    <p>Olfactory nerve (CNI)</p> Signup and view all the answers

    Which of the following is NOT a branching pathway for arterial supply to the nasal cavity?

    <p>Internal carotid artery</p> Signup and view all the answers

    Which structure exits through the incisive canal?

    <p>Nasopalatine nerve</p> Signup and view all the answers

    What is the pathway for the sympathetic fibers innervating the nasal glands?

    <p>From T1 through the superior cervical sympathetic ganglion</p> Signup and view all the answers

    Which nerve is responsible for olfaction?

    <p>Olfactory nerve (CNI)</p> Signup and view all the answers

    The entry point of the greater palatine artery is through which structure?

    <p>Greater palatine foramen</p> Signup and view all the answers

    Which of the following arteries contributes to the anterior nasal supply?

    <p>Anterior ethmoidal artery</p> Signup and view all the answers

    What is a potential consequence of venous drainage from the nasal cavity posteriorly?

    <p>Cavernous sinus thrombosis</p> Signup and view all the answers

    Which nerve innervates the anterior ethmoidal area to provide sensory input?

    <p>Ophthalmic nerve (V1)</p> Signup and view all the answers

    What anatomical feature serves as a drainage pathway for the frontal sinuses?

    <p>Middle meatus</p> Signup and view all the answers

    What is the relationship between Kiesselbach's Area and epistaxis?

    <p>It has a high vascular supply, making it prone to bleeding.</p> Signup and view all the answers

    Where does the nasal vein drain in individuals who possess it?

    <p>Superior sagittal sinus</p> Signup and view all the answers

    What part of the skull is formed by the development of air-filled spaces known as sinuses?

    <p>Frontal bone</p> Signup and view all the answers

    Study Notes

    Skull

    • Formed by intramembranous ossification, joined by sutures which fuse in adulthood
    • Composed of neurocranium (brain) and viscerocranium (face)

    Neurocranium

    • Composed of 8 bones : 4 midline (frontal, ethmoidal, sphenoidal, occipital), 2 bilateral pairs (temporal, parietal)
    • Roof/calvarium (frontal, occipital, parietal), floor/basicranium (frontal, sphenoid, ethmoid, occipital, parietal, temporal)
    • Frontal Bone:
      • Glabella tap is used to test for Parkinson's (normal reflex is blinking, but patients with Parkinson's continue to blink)
    • Ethmoid Bone:
      • Forms roof of nasal cavity, between 2 orbital cavities
      • Forms ethmoidal labyrinths which are composed of: lateral sheet (orbital plate) and medial sheet (superior and middle conchae)
      • Labyrinths unite at cribriform plate: holds olfactory nerve (CNI) fibers, crista galli for attachment of falx cerebri, foramen caecum (emissary veins)
      • Perpendicular plate forms part of nasal septum
      • Provides link between cranial & nasal (cribriform plate/foramen caecum) - CSF leak can cause nasal drip
      • Provides link between nasal & orbit - air causing orbital emphysema
    • Sphenoid Bone:
      • Located in middle cranial fossa around back of nasal cavity/orbit/temple
      • Composed of body, greater/lesser wings, pterygoid process
      • Body: Sella turcica (depression) contains hypophyseal fossa (where pituitary gland sits), tuberculum sellae (anterior) and dorsum sellae (posterior), anterior/posterior clinoid processes x2, chiasmatic groove/sulcus formed by optic chiasm
      • Lesser Wing: Forms division between anterior/middle cranial fossa, borders optic canal with body
      • Greater Wing: Foramen rotundum (V2), foramen ovale (V3), foramen spinosum (middle meningeal vessels), spine provides attachment for sphenomandibular l. and tensor veli palatini
      • Pterygoid Processes: Medial pterygoid plate (contains pterygoid hamulus which acts as a pulley for tensor veli palatini and attachment for pterygoidmandibular raphe)
      • Pterygoid Canal: Runs horizontally through root of pterygoid process, opens into pterygopalatine fossa
    • Temporal Bone:
      • Squamous: temporalis muscle, petrotympanic fissure (chorda tympani), zygomatic process articulates with zygomatic bone (contains lateral surface/masseter m., tympanic, external auditory meatus)
      • Styloid Process: Stylomandibular l. of TMJ, styloglossus m., petromastoid
      • Mastoid Process: Sternocleidomastoid, posterior belly of digastric, splenius capitis, mastoid air cells
      • Petrous Part: Inner ear, boundary between middle/posterior cranial fossa
    • Neurocranium Roof: Mainly made up of frontal, 2x parietal, and occipital bones, sutures: coronal, sagittal, lambdoid, bregma (front), lambda (back)
    • Pterion: Point between sphenoid (greater wing), temporal, frontal, parietal bones, anterior division of middle meningeal a. runs under here so trauma can cause extradural haematoma
    • Neurocranium Floor/Basicranium: Made up of frontal, ethmoidal, sphenoid, temporal, parietal, occipital bones
    • Cranial Foramena:
      • Cribriform Plate: CN 1
      • Optic Canal: CN 2, Ophthalmic a.
      • Superior Orbital Fissure: CN 3, 4, 5(1), 6, Sup ophthalmic v.
      • Foramen Rotundum: CN 5(2)
      • Foramen Ovale: CN 5(3)
      • Foramen Spinosum: Middle meningeal a./v.
      • Carotid Canal: Internal carotid a.
      • Internal Acoustic Meatus: CN 7 & 8
      • Jugular Foramen: CN 9, 10 & 11, Inferior petrosal and sigmoid sinus → IJV
      • Hypoglossal Canal: CN 12
      • Foramen Magnum: Medulla oblongata, meninges, vertebral a.

    Viscerocranium

    • Nasal Bone:
    • Vomer:
    • Lacrimal Bone:
    • Zygomatic Bone: Contains maxillary, frontal, and temporal processes where it articulates
      • Zygomaticofacial foramen: contains zygomaticofacial n. and vessels
    • Maxilla:
      • Forms roof of palate
        • Anterior: Incisive canals on either side, greater palatine vessels & nasopalatine nerves travel between oral/nasal cavities
        • Posterior: Posterior nasal spine & posterior margin of horizontal palates, attachment of soft palate
      • Palatine canal: (from pterygopalatine fossa) forms: greater palatine foramen (greater palatine n. & vessels to supply hard palate) and lesser palatine foramen (lesser palatine n. & vessels to supply the soft palate)
    • Mandible:
      • Made up of body and ramus
      • Condylar Process: forms temporomandibular joint (TMJ) with temporal bone
      • Coronoid Process: attachment of temporalis m.
      • Mandibular Foramen: forms mandibular canal that finishes as mental foramen
        • Inferior alveolar n. (from V3) supplies teeth as travels through and turns into the mental n. as it exits to supply the skin of the chin
        • Inferior alveolar vessels also travel through
      • Mylohyoid Line: forms mylohyoid groove, houses lingual n. and n. to mylohyoid
      • Other Bits: Alveolar border (where teeth are), mandibular symphysis (midline, encloses mental protuberance), superior/inferior mental spines, sublingual and submandibular fossa, retromolar triangle, neck of condylar process (lateral pterygoid), lingula (sphenomandibular l)
    • Temporomandibular Joint (TMJ): Synovial joint formed by: head of condylar process (mandible) and tubercle of tympanic part of (temporal bone), ligaments: Lateral, sphenomandibular, stylomandibular, articular surfaces are covered with fibrocartilage and divided into 2 by articular disc

    Muscles of Mastication

    • Masseter, temporalis, medial/lateral pterygoid
    • Develop from 1st pharyngeal arch
    • ALL INNERVATED BY mandibular nerve (V3)
    • All muscles elevate EXCEPT:
      • Lateral Pterygoid: Oriented horizontally onto pterygoid process, moves jaw side to side and protracts
      • Temporalis: (deep temporal n.) also retracts jaw by attaching to condylar process

    Temporal, Infratemporal, Pterygopalatine Fossa

    • Temporal Fossa: Temporalis m., deep temporal n. and artery, middle temporal a.

    Skull

    • Formed by intramembranous ossification
    • Joined by sutures (fibrous joints) that fuse in adulthood
    • Divided into neurocranium (houses the brain) and viscerocranium (the face)

    Neurocranium

    • Composed of 8 bones: 4 midline (frontal, ethmoid, sphenoid, occipital) and 2 bilateral pairs (temporal, parietal)
    • Roof/calvarium: frontal, occipital, parietal
    • Floor/basicranium: frontal, sphenoid, ethmoid, occipital, parietal, temporal

    Frontal Bone

    • Glabella tap: normal reflex is blinking, but in Parkinson’s patients they continue to blink.

    Ethmoid Bone

    • Forms part of the roof of the nasal cavity and lies between the two orbital cavities.
    • Forms ethmoidal labyrinths, which are composed of two sheets:
      • Lateral sheet (orbital plate)
      • Medial sheet (superior and middle conchae)
    • Labyrinths unite at the cribriform plate, which has holes for the olfactory nerve fibers and the crista galli, for attachment of the falx cerebri (dura mater).
    • Provides a link between:
      • Cranial and nasal (cribriform plate/foramen caecum) - CSF leak causes nasal drip
      • Nasal and orbit - air can cause orbital emphysema

    Sphenoid Bone

    • Located in the middle cranial fossa around the back of the nasal cavity, orbit, and temple.
    • Composed of a body, greater/lesser wings, and pterygoid process.
    • Body:
      • Sella turcica (depression) contains the hypophyseal fossa, where the pituitary gland sits, bound by the tuberculum sellae (anterior) and dorsum sellae (posterior).
      • Anterior/posterior clinoid processes x2
      • Formed by the optic chiasm
    • Lesser wing:
      • Forms the division between anterior and middle cranial fossa.
      • Borders the optic canal with the body
    • Greater wing:
      • Foramen rotundum (V2)
      • Foramen ovale (V3)
      • Foramen spinosum (middle meningeal vessels)
      • Spine provides attachment for the sphenomandibular ligament and tensor veli palatini.
    • Pterygoid processes:
      • Medial pterygoid plate (contains the pterygoid hamulus, which acts as a pulley for tensor veli palatini and attachment for the pterygoidmandibular raphe)
      • Lateral pterygoid plate (attachment for the medial/lateral pterygoid muscles)
      • Pterygoid canal (runs horizontally through the root of the pterygoid process, opening into the pterygopalatine fossa)

    Temporal Bone

    • Squamous: temporalis muscle, petrotympanic fissure (chorda tympani)
    • Zygomatic process: articulates with the zygomatic bone
    • Lateral surface: masseter muscle, tympanic
    • External auditory meatus (ear)
    • Articulates with the head of the mandible to form the temporomandibular joint (TMJ)
    • Styloid Process: stylohyoid ligament of TMJ, styloglossus muscle
    • Petromastoid: mastoid process (sternocleidomastoid, posterior belly of digastric, splenius capitis), mastoid air cells
    • Petrous part: inner ear and boundaries between the middle/posterior cranial fossa

    Neurocranium: Roof

    • Primarily made up of the frontal, parietal x2, and occipital bones.
    • Sutures: coronal, sagittal, lambdoid
    • Bregma (front), lambda (back)
    • Pterion: a point where the sphenoid (greater wing), temporal, frontal, and parietal bones meet, the anterior division of the middle meningeal artery runs under here, so trauma can cause an extradural hematoma.

    Neurocranium: Floor/Basicranium

    • Made up of the frontal, ethmoid, sphenoid, temporal, parietal, and occipital bones.
    • Divided into three fossae: anterior, middle, and posterior cranial fossa
      • Lesser wing of the sphenoid
      • Petrous part of the temporal bone
    • Contains cranial foramina

    Cranial Foramena

    • Foramen | CN | Others
    • Cribriform Plate | I
    • Optic canal | II | Ophthalmic artery
    • Superior orbital fissure | III, IV, V(1), VI | Superior ophthalmic vein
    • Foramen rotundum | V(2)
    • Foramen ovale | V(3)
    • Foramen spinosum | | Middle meningeal artery/vein
    • Carotid canal | | Internal carotid artery
    • Internal acoustic meatus | VII, VIII
    • Jugular foramen | IX, X, XI | Inferior Petrosal Sinus and Sigmoid Sinus → Internal Jugular Vein
    • Hypoglossal canal | XII
    • Foramen magnum | | Medulla oblongata, meninges, vertebral artery

    Viscerocranium

    • Bones | Key Features
    • Nasal |
    • Vomer |
    • Lacrimal |
    • Zygomatic | Zygomaticofacial foramen - zygomaticofacial nerve and vessels
    • Maxilla | Forms the roof of the palate, incisive canals, posterior nasal spine, palatine canal
    • Mandible | Body, ramus, condylar process, coronoid process, mandibular foramen, mylohyoid line, alveolar border, mandibular symphysis, sublingual and submandibular fossa

    Mandible

    • Important Parts
      • Body
      • Ramus
      • Condylar process - forms temporomandibular joint (TMJ)
      • Coronoid process - attachment of temporalis muscle
      • Mandibular foramen - forms the mandibular canal (inferior alveolar nerve supplies teeth and turns into the mental nerve as it exits to supply the skin of the chin), inferior alveolar vessels also travel through.
      • Mylohyoid line - forms mylohyoid groove (lingual nerve, nerve to mylohyoid)
    • Other Bits
      • Alveolar border = where teeth are
      • Mandibular symphysis = midline, encloses the mental protuberance
      • Superior/inferior mental spines on the inside of the chin
      • Sublingual and submandibular fossa
      • Retromolar triangle
      • Neck of condylar process - lateral pterygoid
      • Lingula - sphenomandibular ligament

    Temporomandibular Joint (TMJ)

    • Synovial joint
    • Formed by: head of condylar process (mandible) and tubercle of the tympanic part of the temporal bone.
    • Ligaments: lateral, sphenomandibular, stylomandibular.
    • Articular surfaces covered with fibrocartilage and divided into two by the articular disc.

    Muscles of Mastication

    • Masseter, temporalis, medial/lateral pterygoid
    • Develop from the first pharyngeal arch
    • All are innervated by the mandibular nerve (V3)
    • All muscles elevate the mandible EXCEPT:
      • Lateral pterygoid (oriented horizontally onto the pterygoid process) which moves the jaw side to side and protracts.
      • Temporalis muscle (deep temporal nerve) also retracts the jaw by attaching to the condylar process

    Scalp

    • The scalp moves as a single unit on top of the pericranium.
    • Arteries are found between the first and second layers.
    • The aponeurosis is comprised of the occipitofrontalis muscle.
    • The scalp's tone prevents blood vessels and skin from closing in deep lacerations, causing gaping wounds.
    • Superficial wounds that don't go through the entire scalp don't gape.
    • The occipitofrontalis muscle moves the scalp, wrinkles the forehead, and raises the eyebrows.
    • The frontal belly is innervated by temporal branches, and the posterior belly is innervated by the posterior auricular branch of the facial nerve (VII).

    Scalp Innervation

    • The trigeminal nerve (V) innervates the scalp.
    • The supra trochlear and supraorbital nerves are supplied by V1.
    • The zygomatictemporal and auriculotemporal nerves are supplied by V2.
    • The cervical plexus also innervates the scalp.
    • The lesser occipital (C2-3) and greater occipital (C2) nerves provide innervation.

    Scalp Arterial Supply

    • The internal carotid artery supplies blood to the scalp anteriorly.
    • The supra trochlear and supraorbital arteries are supplied by the internal carotid artery.
    • The external carotid artery supplies blood to the scalp in all other regions.
    • The superficial temporal, posterior auricular, and occipital arteries are supplied by the external carotid artery.

    Facial Muscles

    • Facial expression muscles develop from the second pharyngeal arch.
    • All facial expression muscles are innervated by the facial nerve (VII).

    Orbital Group

    • The orbicularis oculi closes the eyes.
    • The corrugator supercilli draws the eyebrows together.

    Nasal Group

    • The procerus pulls the eyebrows downward.
    • The nasalis compresses the nares transversely and the alar opens the nares.
    • The depressor septi nasi opens the nostrils.

    Other Facial Muscles

    • The platysma, anterior/superior/posterior auricular, and occipitofrontalis muscles also contribute to facial expression.
    • The buccinator muscle lies underneath and sucks the cheek towards the teeth.

    Oral Group

    • The levator labii superioris alaeque nasi, levator anguli oris, levator labii superioris, zygomaticus minor/major, risorius, depressor labii inferioris, depressor anguli oris, and mentalis are all involved in oral expressions.
    • These muscles work together to control lip movement and expressions like pouting.

    Facial Nerve Innervation

    • The facial nerve (VII) arises from the posterior cranial fossa
    • The facial nerve traverses the internal acoustic meatus (temporal bone) and exits via the stylomastoid foramen to deliver motor branches to the facial expression muscles.

    Nasal Cavities and Connections

    • Nasal sinuses drain into the nasal cavity.
    • The middle ear connects to the nasopharynx through the Eustachian tube.
    • The oral and nasal cavities are separated by the hard and soft palate.
    • The pharynx connects to the esophagus.
    • The nasopharynx opens to the nasal cavity via the choanae.
    • The oropharynx opens to the oral cavity via the palatoglossal folds.
    • The larynx connects to the trachea.

    The Neck

    • The neck connects to the thorax via the thoracic inlet.
    • The neck connects to the upper limbs via the axillary inlet.

    Cervical Vertebrae

    • The occipitoatlantal joint connects the occipital bone to the atlas (C1).
    • The atlas (C1) has anterior and posterior arches, but no vertebral body.
    • The atlantoaxial joint connects the atlas (C1) to the axis (C2).
    • The axis (C2) has a dens (odontoid process).
    • Typical cervical vertebrae (C3-7) have:
      • Transverse processes with foramina that house vertebral arteries and veins (except for C7)
      • A rectangular vertebral body and a triangular foramen
      • A bifid spinous process with the nuchal ligament in between

    Jefferson Fracture

    • This fracture involves the anterior and posterior arches of the atlas (C1).
    • 50% of cases are associated with other cervical spine injuries.
    • 33% are associated with C2 fractures.
    • There is a risk of vertebral artery injury.

    Cervical Muscles

    • Neck muscles are divided into anterior, lateral, and posterior groups.
    • All muscles in the neck are paired.

    Anterior Cervical Muscles

    • The platysma is a superficial muscle, covering most of the anterior neck.
    • The sternocleidomastoid (SCM) runs from the sternum and clavicle to the mastoid process, hence its two heads.
    • The subclavius is another superficial muscle.
    • Suprahyoid muscles:
      • Digastric: two bellies, anterior and posterior
      • Mylohyoid: from the mandible to the hyoid bone
      • Geniohyoid: from the chin to the hyoid bone
      • Stylohyoid: from the styloid process to the hyoid bone

    Infrahyoid Muscles

    • Sternohyoid
    • Sternothyroid
    • Thyrohyoid
    • Omohyoid: wraps around the internal jugular vein and attaches to the scapula

    Lateral Cervical Muscles

    • Rectus capitis

    • Longus capitis

    • Longus colli

    • Scalenes:

      • Originate from the transverse processes and insert into:
        • First rib: anterior and middle scalenes
        • Second rib: posterior scalene
      • Structures found above the anterior scalene:
        • Phrenic nerve
        • Branches of the thyrocervical trunk (suprascapular and transverse cervical arteries)
        • Subclavian vein
      • Structures found between the anterior and middle scalenes:
        • Brachial plexus
        • Subclavian artery

    Posterior Cervical Muscles

    • These muscles have a lower yield in terms of clinical relevance.
    • Superficial:
      • Splenius capitis
      • Splenius cervicis scalene
    • Suboccipital:
      • Rectus capitis posterior major and minor
      • Obliquus capitus superior and inferior
      • Transversospinalis
      • Semispinalis capitis and cervicis
      • Rotatores cervicis
      • Interspinalis
      • Intertransversarii

    Cervical Fascias

    • Superficial cervical fascia: covers the neck.
    • Deep cervical fascia has three compartments.
      • Prevertebral fascia: connects to the endothoracic fascia and axillary sheath.
      • Pretracheal fascia: connects to the pericardium.
        • Contains:
          • Pharynx, larynx, esophagus, trachea
          • Thyroid and parathyroid glands
          • Recurrent laryngeal nerve
          • Strap muscles
      • Carotid sheath:
        • Contains:
          • Common carotid artery
          • Internal jugular vein
          • Vagus nerve (CNX)
        • Pierced by the glossopharyngeal nerve (CNIX) and the ansa cervicalis.
        • Connected by the alar fascia.
    • Investing layer: encases trapezius and the sternocleidomastoid (SCM).
    • Note: the prefix "pre" in some fascias refers to the proximity to the vertebrae, meaning that you would encounter these fascias first if you were to try and reach the vertebrae.

    Goitre Complications

    • Compression of:
      • Larynx: dysphonia (hoarseness)
      • Trachea: cough and dyspnea (difficulty breathing)
      • Esophagus: dysphagia (difficulty swallowing)
      • Superior vena cava (SVC): superior vena cava syndrome (Pemberton's sign)

    Cervical Connective Tissue Injury

    • Referred to as cervical strain or sprain.
    • Involves injury to muscles, tendons, and ligaments of the cervical spine.
    • Characterized by whiplash injury.

    Thyroid Gland

    • The thyroid gland is located in the anterior neck, below the cricoid cartilage and above the trachea.
    • It is a butterfly-shaped gland that secretes hormones essential for metabolic regulation.
    • It is surrounded by the pretracheal fascia.

    Cervical Plexus

    • Found in the posterior triangle of the neck.

    • Cutaneous branches:

      • Anterior rami:
        • Lesser occipital (C2)
        • Great auricular (C2-3)
        • Transverse cervical (C2-3)
        • Supraclavicular (C3-4)
      • Posterior rami:
        • Greater occipital (C2)
        • Dorsal rami of C3, 4, 5

    • Muscular branches:

      • C1 (travels with the hypoglossal nerve): suprahyoids
      • Ansa Cervicalis (C1-3): strap muscles (sternohyoid, sternothyroid, omohyoid)
      • Phrenic (C3-5): diaphragm and pericardium
      • Segmental branches (C1-4): anterior/middle scalenes
      • Other branches: other cervical muscles

    Triangles of the Neck

    • Anterior Triangle:
      • Boundaries: mandible, sternocleidomastoid (SCM), midline
      • Contains structures between the head and thorax.
    • Posterior Triangle:
      • Boundaries: clavicle, sternocleidomastoid (SCM), trapezius
      • Contains structures related to the axillary inlet (upper limb structures).

    Structures within the Anterior Triangle

    • Midline structures:
      • Hyoid bone
      • Larynx
      • Thyroid/parathyroid glands
      • Esophagus
    • Carotid sheath:
      • Common carotid artery
      • Internal jugular vein
      • Vagus nerve (CNX)

    Scalp

    • The scalp moves as a singular unit over the pericranium.
    • Arteries are found between the first and second layers of the scalp.
    • The aponeurosis is made up of the occipitofrontalis muscle.
    • The tone of the occipitofrontalis muscle inhibits the closure of blood vessels and skin in scalp lacerations leading to gaping wounds.
    • Superficial scalp wounds that do not lacerate the entire depth of the scalp do not gape.
    • The occipitofrontalis muscle moves the scalp, wrinkles the forehead, and raises the eyebrows.
    • The frontal belly of the occipitofrontalis muscle is innervated by the temporal branches of the facial nerve, while the posterior belly is innervated by the posterior auricular branch of the facial nerve.

    Scalp Innervation

    • The scalp is innervated by the trigeminal nerve (CN V) and the cervical plexus.
    • The trigeminal nerve innervates the scalp via its branches:
      • V1: Supratrochlear and supraorbital nerves
      • V2: Zygomaticotemporal nerve
      • V3: Auriculotemporal nerve
    • The cervical plexus innervates the scalp via the lesser occipital nerve (C2-3) and the greater occipital nerve (C2).

    Scalp Arterial Supply

    • The scalp receives blood supply from both the internal and external carotid arteries.
    • The internal carotid artery supplies the anterior part of the scalp:
      • Supratrochlear artery
      • Supraorbital artery
    • The external carotid artery supplies the rest of the scalp:
      • Superficial temporal artery
      • Posterior auricular artery
      • Occipital artery

    Facial Muscles Development and Innervation

    • Facial muscles of expression develop from the second pharyngeal arch.
    • All facial muscles are innervated by the facial nerve (CN VII).

    Facial Muscle Groups

    • Orbital Group:
      • Orbicularis oculi: Closes the eyes.
      • Corrugator supercilii: Draws eyebrows medially.
    • Nasal Group:
      • Procerus: Depresses the eyebrow.
      • Nasalis: Compresses the nostrils transversely and opens the nostrils.
      • Depressor septi nasi: Opens the nostrils.
    • Other Facial Muscles:
      • Platysma
      • Anterior/superior/posterior auricular muscles
      • Occipitofrontalis muscle
    • Oral Group (12 to 6 o’clock):
      • Levator labii superioris alaeque nasi: Elevates the upper lip and ala of the nose.
      • Levator anguli oris: Elevates the angle of the mouth.
      • Levator labii superioris: Elevates the upper lip.
      • Zygomaticus minor/major: Elevates the angle of the mouth.
      • Risorius: Draws the corner of the mouth laterally.
      • Buccinator: Compresses the cheek against the teeth, aiding in sucking and chewing.
      • Depressor labii inferioris: Depresses the lower lip.
      • Depressor anguli oris: Depresses the angle of the mouth.
      • Mentalis: Wrinkles the chin and protrudes the lower lip (pouting).

    Facial Nerve VII

    • The facial nerve arises from the posterior cranial fossa.
    • It travels through the internal acoustic meatus of the temporal bone.
    • It exits the skull through the stylomastoid foramen.
    • It gives off motor branches to all the muscles of facial expression.

    Neck Relations and Key Features

    • The neck connects the thorax via the thoracic inlet.
    • The neck connects to the upper limbs via the axillary inlet.
    • The carotid artery bifurcates at the level of C3-4.
    • The transition between the larynx/trachea and pharynx/oesophagus occurs at the level of C5-6.
    • The transition between the cricoid cartilage and the first tracheal ring occurs at the level of C5-6.

    Bony Structures of the Neck

    • Cervical Vertebrae:

      • Occipitoatlantal Joint: Articulation between the occipital bone and C1.
      • C1 (Atlas):
        • Anterior and posterior arches (no vertebral body).
        • Lacks a spinous process.
      • Atlantoaxial Joint: Articulation between C1 and C2.
      • C2 (Axis):
        • Dens (odontoid process).
      • Typical Cervical Vertebrae (C3-7):
        • Transverse processes with a transverse foramen housing the vertebral arteries and veins (except for C7).
        • Rectangular vertebral body and triangular vertebral foramen.
        • Bifid spinous process with the nuchal ligament between them.

    • Radiological Evaluation of C1 & C2:

      • An open mouth AP projection X-ray can visualize C1 and C2.

    Jefferson Fracture

    • A fracture of the atlas (C1) through the anterior and posterior arches.
    • In 50% of cases, it is associated with other cervical spine injuries.
    • In 33% of cases, it is associated with a C2 fracture.
    • It can lead to vertebral artery injury.

    Cervical Muscles Overview

    • Cervical muscles are divided into anterior, lateral, and posterior groups. All are paired.
    • Anterior:
      • Superficial: Platysma, Sternocleidomastoid (SCM), Subclavius.
      • Suprahyoids: Digastric, Mylohyoid, Geniohyoid, Stylohyoid.
      • Infrahyoids: Sternohyoid, Sternothyroid, Thyrohyoid, Omohyoid.
    • Lateral:
      • Anterior, Middle, and Posterior Scalenes:
      • Rectus capitus: Longus capitus, Longus colli
    • Posterior:
      • Superficial: Splenius capitis, Splenius cervicis, Scalene.
      • Suboccipital: Rectus capitis posterior major and minor, Obliquus capitis superior and inferior, Transversospinalis, Semispinalis capitis, Semispinalis cervicis, Rotatores cervicis, Interspinalis, Intertransversarii.

    Anterior Cervical Muscles

    • Superficial:
      • Platysma: Covers the neck like a sheet.
      • Sternocleidomastoid (SCM): Attaches from the sternum and clavicle to the mastoid process, having two heads.
      • Subclavius: Located below the clavicle.
    • Suprahyoid Muscles (Inferior to Superior):
      • Digastric: Has anterior and posterior bellies.
      • Mylohyoid: Extends from the mandible to the hyoid bone.
      • Geniohyoid: Extends from the chin to the hyoid bone.
      • Stylohyoid: Attaches to the styloid process of the temporal bone.
    • Infrahyoid Muscles (Inferior to Superior):
      • Sternohyoid:
      • Sternothyroid:
      • Thyrohyoid:
      • Omohyoid: Wraps around the internal jugular vein and attaches to the scapula.

    Lateral Cervical Muscles

    • Rectus Capitis:
    • Longus Capitis:
    • Longus Colli:
    • Scalenes:
      • All originate from the transverse processes of cervical vertebrae.
      • Anterior and Middle Scalenes: Insert into the first rib.
      • Posterior Scalene: Inserts into the second rib.
    • Structures Located Above the Anterior Scalene:
      • Phrenic nerve.
      • Branches of the thyrocervical trunk (suprascapular and transverse cervical arteries).
      • Subclavian vein.
    • Structures Located Between the Anterior and Middle Scalenes:
      • Brachial plexus.
      • Subclavian artery.

    Posterior Cervical Muscles

    • Superficial:
      • Splenius capitis.
      • Splenius cervicis
      • Scalene.
    • Suboccipital:
      • Rectus capitis posterior major and minor.
      • Obliquus capitis superior and inferior.
      • Transversospinalis.
      • Semispinalis capitis and cervicis.
      • Rotatores cervicis.
      • Interspinalis.
      • Intertransversarii.

    Cervical Cross Section and Fascias

    • Superficial Cervical Fascia:

    • Deep Cervical Fascia:

      • Prevertebral Fascia:
        • Continues as the endothoracic fascia and axillary sheath.
      • Pretracheal Fascia:
        • Continues as the pericardium.
        • Encloses the pharynx, larynx, oesophagus, trachea, thyroid and parathyroid glands, and recurrent laryngeal nerve.
        • Covers the strap muscles.
      • Carotid Sheath:
        • Encloses the common carotid artery, internal jugular vein, and vagus nerve (CN X).
        • Pierced by the glossopharyngeal nerve (CN IX) and the ansa cervicalis.
        • Connected by the alar fascia.
      • Investing Layer:
        • Covers the trapezius and SCM muscles.

    • Note: "Pre-" in fascia refers to the fact that the fascia is located anterior to the vertebra.

    Goitre Complications

    • Compression of Structures:
      • Larynx: Dysphonia (hoarseness).
      • Trachea: Cough and dyspnea.
      • Oesophagus: Dysphagia (difficulty swallowing).
      • Superior Vena Cava (SVC): Superior vena cava syndrome (Pemberton’s sign - facial plethora and distension of the neck veins on elevation of the arms).

    Cervical Connective Tissue Injury

    • Also called cervical strain/sprain.
    • Injuries to muscles, tendons, and ligaments of the cervical spine resulting from trauma.
    • Characteristic of whiplash injury.

    Neck Structures & Connections

    • Nasal Sinuses: Drain into the nasal cavity.
    • Middle Ear: Connected to the nasopharynx through the eustachian tube.
    • Oral Cavity and Nasal Cavity: Separated by the hard and soft palates.
    • Pharynx Connected to the Oesophagus:
      • Nasopharynx: Connects to the nasal cavity through the choanae.
      • Oropharynx: Connects to the oral cavity through the palatoglossal folds.
    • Larynx Connected to the Trachea:

    Cervical Plexus

    • Located in the posterior triangle of the neck.
    • Cutaneous Branches:
      • Anterior Rami (Curling Around the SCM):
        • Lesser occipital nerve (C2).
        • Great auricular nerve (C2-3).
        • Transverse cervical nerve (C2-3).
        • Supraclavicular nerve (C3-4).
      • Posterior Rami:
        • Greater occipital nerve (C2).
        • Dorsal rami of C3, C4, C5.
    • Muscular Branches:
      • C1 (Travels with Hypoglossal Nerve): Innervates the suprahyoid muscles.
      • Ansa Cervicalis (C1-3): Innervates the strap muscles (sternohyoid, sternothyroid, omohyoid).
      • Phrenic Nerve (C3-5): Innervates the diaphragm and pericardium.
      • Segmental Branches (C1-4): Innervate the anterior and middle scalene muscles.
      • Other Branches: Innervate other cervical muscles.

    Triangles of the Neck

    • Anterior Triangle:
      • Boundaries: Mandible, SCM, midline of the neck.
      • Structures within:
        • Midline structures: Hyoid bone, larynx, thyroid/parathyroid glands, oesophagus.
        • Carotid sheath: Contains the carotid artery.
    • Posterior Triangle:
      • Boundaries: Clavicle, SCM, trapezius.
      • Structures within: Associated with the axillary inlet (structures related to the upper limbs).

    Carotid Arteries

    • The carotid arteries originate from the right brachiocephalic trunk and the left aortic arch.
    • They bifurcate at the level of C4, at the upper border of the thyroid cartilage.
    • The bifurcation results in the external carotid arteries, supplying the head and neck, and the internal carotid arteries, supplying the brain and CNS.
    • The vertebral arteries, originating from the thyrocervical trunk, also contribute to brain supply along with the internal carotid arteries.
    • The ophthalmic artery is the only branch of the internal carotid artery that supplies structures outside of the CNS, including the face.

    External Carotid Artery

    • Key branches:
      • Facial artery: supplies structures around the inferior border of the mandible, including the medial corner of the eye, and the upper and lower lips.
      • Superficial temporal artery: supplies the scalp and temporal region.
      • Maxillary artery: located in the infratemporal fossa, then the pterygopalatine fossa. Important branches include:
        • Middle meningeal artery: passes through the foramen spinosum, and may be damaged in a blow to the pterion.
        • Inferior alveolar artery: supplies the lower teeth.
        • Branches in the pterygopalatine fossa: supply the orbit, palate, nasal cavity and upper teeth.

    Internal Carotid Artery

    • Primarily supplies the CNS, with the exception of the ophthalmic artery.
    • Ophthalmic artery:
      • Enters the orbit through the optic canal along with the optic nerve.
      • Branches supply the lacrimal gland, zygomatic bone, dorsal nasal region, and the scalp.

    Venous Drainage

    • All venous drainage in the head and neck eventually flows into the subclavian vein.
    • External jugular vein (posteriorly): receives drainage from the retromandibular vein (formed by the maxillary and superficial temporal veins), and the posterior auricular vein.
    • Internal jugular vein (anteriorly): receives drainage from the facial vein.
    • Facial vein communicates with the superior ophthalmic vein, which connects to the cavernous sinus, highlighting the potential for Cavernous Sinus Thrombosis.
    • Emissary veins connect the pterygoid plexus to intracranial venous structures.

    Lymphatics

    • Half of the body's lymph nodes are located in the head and neck.
    • Structures closer to the midline are more likely to have bilateral lymphatic drainage.
    • Enlarged and hard lymph nodes may indicate cancer, while enlarged and tender nodes may indicate infection.
    • Lymphatic drainage patterns:
      • Submental nodes: drain the chin.
      • Submandibular nodes: drain the middle portion of the face.
      • Pre-auricular/parotid nodes: drain the eyes, nose, and lateral cheek.
      • All of these nodes drain into the deep cervical lymph nodes.
    • Virchow's node (supraclavicular node): drains intra-abdominal and thoracic organs.
    • Jugulodigastric lymph node (upper cervical): drains the tonsils, often permanently enlarged in children.

    Temporal Arteritis

    • Definition: inflammation of the temporal arteries.
    • Cause: unknown.
    • Risk factors:
      • Female gender.
      • Older age.
      • Frequent association with polymyalgia rheumatica (PMR), characterized by pain and stiffness in proximal joints.
    • Symptoms:
      • Throbbing headache and tenderness in the temples, often exacerbated by combing hair.
      • Jaw pain, possibly associated with chewing (claudication).
      • Fever and night sweats.
      • Unintentional weight loss.
      • Optic nerve ischemia, leading to double vision, sudden, or permanent vision loss in one eye.
    • Diagnosis:
      • Physical examination: prominent temporal arteries, tenderness over the temporal area, decreased pulses throughout the body.
      • Blood tests:
        • Elevated ESR (erythrocyte sedimentation rate), indicating inflammation.
        • Elevated C-reactive protein, indicating inflammation.
        • Increased platelet count.
      • Biopsy of the artery: gold standard for diagnosis.
    • Treatment:
      • High-dose corticosteroids to reduce inflammation.

    Carotid Arteries

    • The carotid arteries originate from the brachiocephalic trunk (right) and aortic arch (left).
    • They bifurcate at the level of the superior border of the thyroid cartilage (C4) into the external and internal carotid arteries.
    • The external carotid arteries supply the head and neck.
    • The internal carotid arteries supply the brain and central nervous system (CNS) along with the vertebral arteries (from the thyrocervical trunk).
    • The ophthalmic artery is an exception and branches from the internal carotid artery, supplying the face.

    External Carotid Artery

    • The facial artery curves around the inferior border of the mandible.
    • It supplies the medial corner of the eye (angular artery), lips (superior and inferior labial arteries) and anastomoses around the lip.
    • The superficial temporal artery and transverse facial artery are also branches of the external carotid artery.
    • The maxillary artery is located in the infratemporal fossa and pterygopalatine fossa.
    • It gives rise to the middle meningeal artery (enters through the foramen spinosum, associated with trauma to the pterion), inferior alveolar artery and supplies the temporomandibular joint (TMJ).
    • In the pterygopalatine fossa, it branches into the infraorbital, greater palatine, pharyngeal, sphenopalatine, and posterior superior alveolar arteries.

    Internal Carotid Artery

    • The internal carotid artery primarily supplies the CNS, except for its branch, the ophthalmic artery which contributes to facial blood supply.

    Ophthalmic Artery

    • The ophthalmic artery enters the orbit through the optic canal with the optic nerve.
    • Its branches include:
      • Lacrimal branch which contributes to the zygomatic bone, zygomaticofacial artery and zygomaticotemporal artery.
      • Dorsal nasal artery.
      • Supraorbital and supratrochlear arteries that supply the scalp.
      • Anterior and posterior ethmoidal arteries that supply the nasal cavity.

    Venous Drainage

    • All venous drainage eventually flows into the subclavian vein.
    • The external jugular vein (posteriorly) receives drainage from the retromandibular vein (from the maxillary and superficial temporal veins) and posterior auricular vein.
    • The internal jugular vein (anteriorly) receives drainage from the facial vein.

    Intracranial Venous Connections

    • The facial vein communicates with the superior ophthalmic vein, which leads to the cavernous sinus.
    • Emissary veins from the pterygoid plexus contribute to intracranial venous drainage.
    • Facial and cranial veins lack valves, posing a risk for infection.

    Lymphatics

    • Half of the body’s lymph nodes are located in the head and neck.
    • Structures closer to the midline tend to have bilateral lymphatic drainage.
    • Cancerous lymph nodes are enlarged and hard, while infected lymph nodes are enlarged and tender.

    Lymphatic Drainage

    • The submental lymph nodes drain the chin.
    • The submandibular lymph nodes drain the middle of the face.
    • The pre-auricular/parotid lymph nodes drain the eyes, nose, and lateral cheek.
    • All of these lymph nodes ultimately drain into the deep cervical group.

    Virchow’s Node (Supraclavicular node)

    • Drains intra-abdominal and thoracic organs.

    Jugulodigastric lymph node (upper cervical)

    • Drains the tonsils. Often permanently enlarged in children.

    Temporal Arteritis

    • Involves inflammation of the temporal arteries.
    • The cause is unknown.
    • It is more prevalent in females and older individuals.
    • It is frequently associated with polymyalgia rheumatica (PMR), characterized by pain and stiffness in proximal joints.

    Symptoms of Temporal Arteritis

    • Throbbing headache and tenderness in the temples, particularly when combing hair.
    • Jaw pain, especially with chewing (claudication).
    • Fevers and night sweats.
    • Unintentional weight loss.
    • Optic nerve ischemia leading to double vision, sudden or permanent loss of vision in one eye.

    Diagnosis of Temporal Arteritis

    • Physical examination: Prominent temporal arteries, tenderness over the temporal area, decreased pulses throughout the body.
    • Blood tests:
      • High erythrocyte sedimentation rate (ESR) indicating inflammation.
      • Elevated C-reactive protein indicating inflammation.
      • Increased platelets.
    • Artery biopsy (gold standard).

    Treatment of Temporal Arteritis

    • High dose corticosteroids (to reduce inflammation).

    Head and Neck Innervation

    • Head and neck innervation is primarily controlled by cranial nerves.
    • Glands in the head and neck receive autonomic innervation.
      • Parasympathetic (PNS) roots originate from cranial nerves.
      • Sympathetic (SNS) roots originate from the thoracic region.
        • They travel through the sympathetic chain.
        • They exit via the T1 superior cervical ganglion.
        • They reach their destination via plexuses on blood vessels.
    • The cervical plexus (C1-C5) contributes to cutaneous and muscular innervation of the neck.

    Cranial Nerve Summary

    • The 12 cranial nerves can be remembered by Roman numerals.
    • Common mnemonic for cranial nerve functions is "Some Say Money Matters But My Brother Says Big Brains Matter More."
    • Sensory (S), Motor (M), and Both (B).

    Foramina and Associated Structures

    • Cribriform Plate: CN I (olfactory nerve)
    • Optic Canal: CN II (optic nerve), Ophthalmic artery
    • Superior Orbital Fissure: CN III (oculomotor nerve), CN IV (trochlear nerve), CN V(1) (ophthalmic division of trigeminal nerve), CN VI (abducens nerve), Superior ophthalmic vein
    • Foramen Rotundum: CN V(2) (maxillary division of trigeminal nerve)
    • Foramen Ovale: CN V(3) (mandibular division of trigeminal nerve)
    • Foramen Spinosum: Middle meningeal artery/vein
    • Carotid Canal: Internal carotid artery
    • Internal Acoustic Meatus: CN VII (facial nerve), CN VIII (vestibulocochlear nerve)
    • Jugular Foramen: CN IX (glossopharyngeal nerve), CN X (vagus nerve), CN XI (accessory nerve), Inferior petrosal and sigmoid sinus, Internal Jugular Vein (IJV)
    • Hypoglossal Canal: CN XII (hypoglossal nerve)
    • Foramen Magnum: Medulla oblongata, Meninges, Vertebral artery

    Autonomics

    • Autonomics innervate glands in the head and neck such as salivary, mucous, and lacrimal glands.

    Parasympathetic Innervation Overview

    • The parasympathetic nervous system is responsible for "rest and digest" functions.
    • Parasympathetic innervation primarily targets smooth muscle, cardiac muscle, and glands, allowing for precise and localized control of these organs.

    Cranial Nerve Summary

    • Edinger-Westphal Nucleus:

      • Located in the midbrain, this nucleus controls the pupillary sphincter muscle and ciliary muscles of the eye.
      • The preganglionic fibers travel within the oculomotor nerve (CN III) to the ciliary ganglion.
      • Postganglionic fibers innervate the ciliary muscles, causing lens accommodation for near vision, and the sphincter pupillae, causing constriction of the pupil to allow more light into the eye in low-light conditions.

    • Superior Salivatory Nucleus:

      • Located in the pons, this nucleus controls lacrimal glands, nasal cavity, palate, and salivary glands.
      • Pre-ganglionic fibers travel within the facial nerve (CN VII) to the pterygopalatine ganglion, where they synapse with postganglionic fibers.
      • These postganglionic fibers then innervate the lacrimal gland for tear production, the nasopharynx, the palate, and the nasal cavity.

    • Facial Nerve:

      • Also contributes to salivary gland innervation.
      • Pre-ganglionic fibers travel within the chorda tympani nerve, a branch of the facial nerve, to the submandibular ganglion, which innervates the sublingual and submandibular glands.

    • Inferior Salivatory Nucleus:

      • Located in the medulla, this nucleus controls the parotid gland.
      • Pre-ganglionic fibers travel within the glossopharyngeal nerve (CN IX) to the otic ganglion.
      • Postganglionic fibers then hitchhike on the auriculotemporal nerve to reach the parotid gland.

    • Dorsal Vagal Motor Nucleus:

      • Located in the medulla oblongata, this nucleus is responsible for parasympathetic innervation of the heart, lungs, bronchi, and the gastrointestinal tract.
      • Pre-ganglionic fibers travel within the vagus nerve (CN X) to ganglia located within the target organs, where they synapse with postganglionic fibers.
      • These postganglionic fibers then innervate the smooth muscle of the trachea, bronchi, and gastrointestinal tract, contributing to digestion, respiration, and heart rate control.

    Cranial Nerve Functions

    • Olfactory Nerve (CN I): Sensory, responsible for smell.
    • Optic Nerve (CN II): Sensory, responsible for vision.
    • Oculomotor Nerve (CN III): Motor, responsible for eye movement, pupil constriction, and maintaining an open eyelid.
    • Trochlear Nerve (CN IV): Motor, responsible for controlling the superior oblique muscle of the eye, which moves the eye downward and laterally.
    • Trigeminal Nerve (CN V): Sensory for facial sensation, and motor for chewing muscles.
    • Abducent Nerve (CN VI): Motor, responsible for controlling the lateral rectus muscle of the eye, which abducts the eye laterally.
    • Facial Nerve (CN VII): Motor for facial expression and some glands, sensory for anterior tongue and palate.
    • Vestibulocochlear Nerve (CN VIII): Sensory, responsible for balance and hearing.
    • Glossopharyngeal Nerve (CN IX): Motor for pharynx muscles involved in swallowing, sensory for posterior tongue, tonsil, and pharynx.
    • Vagus Nerve (CN X): Motor for the heart, lungs, and digestive tract, and sensory for the same areas, as well as parts of the pharynx, larynx, external ear.
    • Accessory Nerve (CN XI): Motor, responsible for controlling the sternocleidomastoid and trapezius muscles, which are involved in head and shoulder movement.
    • Hypoglossal Nerve (CN XII): Motor, responsible for controlling tongue muscles, essential for speech and swallowing.

    Upper Respiratory Tract and Pharynx

    • Nasal sinuses drain into the nasal cavity.
    • The middle ear is connected to the nasopharynx via the eustachian tube.
    • Oral cavity and nasal cavity are separated by the hard and soft palate.
    • Pharynx connects to the oesophagus (C3-4).
      • The nasopharynx connects to the nasal cavity via the choanae.
      • The oropharynx connects to the oral cavity via the palatoglossal folds.
    • Larynx connects to the trachea (C3-4).

    Ear

    • Relationships
      • Nasal cavity: pharyngotympanic tube
      • External: external acoustic meatus
      • Cranial cavity: temporal bone (internal acoustic meatus)

    The Ear

    • The ear is divided into the external/outer, middle, and inner ear.
    • The bony part of the ear is part of the temporal bone.
    • Sound transmission:
      • Sound is trapped by the external ear and travels through the external acoustic meatus.
      • Sound waves move the tympanic membrane, which is attached to the ossicles (malleus, incus, stapes) in the middle ear, amplifying the sound.
      • The stapes are attached to the inner ear and move fluid in the cochlea, detected by the vestibulocochlear nerve [VII].
      • The semicircular canals in the inner ear also contain fluid that functions in balance and is the reason why you are dizzy.

    External Ear

    • Consists of the auricle and external acoustic meatus (from concha to tympanic membrane).
    • Auricle:
      • Skin cancers often present at the helix.
      • Darwin’s tubercle is a normal feature.
      • Components: Helix, antihelix, tragus, antitragus, intertragic notch, fossas (triangular and scaphoid), lobule, and concha.
    • External Acoustic Meatus:
      • Lateral ⅓ is cartilage, the other ⅔ is temporal bone.
      • Not straight, for examination pull upward, posteriorly, and outward.
      • Travels upward anteriorly, upward posteriorly, and downward anteriorly.
      • Contains cerumen (wax).
      • Innervation:
        • Auricle: Auriculotemporal branch of mandibular nerve [V3], lesser occipital nerve (C2), greater auricular nerve (C2-C3) of cervical plexus.
        • External acoustic meatus: Auricular branch of vagus nerve [X] (can cause fainting during ear washing) and facial nerve [VII] (sends a branch to the auricular branch of [X]).
      • Arterial supply/Venous drainage:
        • External carotid artery: — posterior auricular artery.
        • Superficial temporal artery: — anterior auricular branches.
        • Occipital artery.
      • Lymphatic drainage: Anterior/posterior auricular nodes draining into upper deep cervical nodes.

    Tympanic Membrane

    • Parts: Pars flaccida (thin and slack) and pars tensa (thick and taut).
    • The handle of malleus is in the tympanic membrane, tubes need to go through the lower part.
    • Grommets: Tubes through the membrane allow fluid to drain - used for glue ear/otitis media.
    • Innervation:
      • Outer surface: Auriculotemporal nerve (mandibular nerve [V3]), auricular branch of vagus nerve [X], branch of facial nerve [VII] to auricular branch of vagus nerve [X], glossopharyngeal nerve [IX].
      • Inner surface: Glossopharyngeal nerve [IX] via tympanic plexus.

    Middle Ear - Where?

    • Situated between the external ear and inner ear in an air-filled mucous membrane lined space in the temporal bone.
    • Components: Tympanic cavity (directly next to the tympanic membrane) and epitympanic recess (superiorly).
    • Communications:
      • Mastoid area (posteriorly): Consists of mastoid air cells via the mastoid antrum. This is part of the temporal bone. Infections can spread from the middle ear to the mastoid process because the mucous membranes are continuous.
      • Nasopharynx (anteriorly and medially): Via the pharyngotympanic (eustachian) tube. This is why you can make your ears pop by blocking your nose and blowing out air. It functions to equalize pressure across the tympanic membrane. The tube is surrounded by cartilage and tensor veli palatini muscle (which contracts when you swallow), opening up the tube.

    Middle Ear - Neurovasculature

    • Arterial supply: External carotid artery: Tympanic branch of maxillary artery and Mastoid branch of occipital/posterior auricular arteries (as well as other small branches).
    • Venous drainage: Pterygoid plexus.
    • Innervation of mucous membranes: Tympanic plexus formed by tympanic nerve (branch of glossopharyngeal nerve [IX]) and branches of internal carotid plexus. The plexus gives off the lesser petrosal nerve, which supplies the sympathetic nervous system to the otic ganglion.

    Middle Ear - Contents

    • Auditory Ossicles: Malleus, incus, and stapes form a chain from the tympanic membrane to the oval window of the internal ear.
      • Malleus: Handle (attached to the tympanic membrane and tensor tympani muscle), lateral process (anterior/posterior malleolar folds of tympanic membrane), anterior process (anterior wall via a ligament), head (articulates with incus).
      • Incus: Body (articulates with head of malleus), long limb with a lenticular process (articulates with head of stapes), short limb (ligament to upper posterior wall of the middle ear).
      • Stapes: Two limbs attach to the oval base, which articulates with the oval window on the labyrinth wall, associated with the stapedius muscle.

    Middle Ear - Contents

    • Muscles: Involved in modulating movement during vibration transmission.
      • Tensor tympani: Attached to the handle of malleus to tense the tympanic membrane, branches from V3.
      • Stapedius: From the mastoid wall to the neck of stapes, pulls the stapes posteriorly to prevent excessive oscillation in response to loud noises, [VII].

    Middle Ear - The Room (learn)

    • Lateral view: Looking into the ear (tympanic membrane removed, back = the wall between middle/internal ear).

    Middle Ear - The Room (Learn)

    • Tegmental wall (roof): Separated from the middle cranial fossa by tegmen tympani, located on the petrous part of temporal bone.
    • Jugular wall (floor): Composed of a thin layer of bone and mastoid air cells, the internal jugular vein is located right underneath. Entrance of the tympanic branch of the glossopharyngeal nerve [IX] to later form the tympanic plexus.
    • Membranous wall (lateral): Tympanic membrane.
    • Mastoid wall (posterior): Lower part composed of bone (mastoid air cells), superiorly forms the mastoid antrum. Stapedius muscle attachment (to stapes). Entry of the chorda tympani, branch of facial nerve [VII] that later supplies taste to the anterior ⅔ of the tongue.
    • Anterior wall: Separates from the internal carotid artery. Exit of the chorda tympani, pharyngotympanic tube, tensor tympani muscle attachment (to malleus).
    • Labyrinthine wall (medial): Also the lateral wall of the inner ear. Round and oval window (attachment of stapes). Promontories for: cochlea (on which lies the tympanic plexus), facial canal (containing facial nerve [VII]), and lateral semicircular canal. Lesser petrosal nerve from the tympanic plexus enters the otic ganglion via foramen ovale.

    Otitis Media

    • Definition: Infection of the middle ear.
    • Epidemiology: Common in infants and small children (6-24 months), as the eustachian tube is more horizontal, shorter, has less cartilage, and is more patent, in addition to immunological immaturity.
    • Pathophysiology: Most often viral (RSV), also S. pneumoniae, H. influenzae, Moraxella catarrhalis. Ascending infection often secondary to upper respiratory tract infection (URTI). Inflammation and swelling of the mucous membrane of the tympanic cavity causes partial or complete pharyngotympanic tube blockage.
    • Symptoms: Fever, lethargy, irritability, earache, ear discharge, hearing loss, bulging ear drum. Usually self-resolving, symptoms last...

    Upper Respiratory Tract & Pharynx

    • Nasal Sinuses: Drain into the nasal cavity
    • Middle Ear: Connected to the nasopharynx via the Eustachian tube
    • Oral & Nasal Cavities: Separated by the hard and soft palate
    • Pharynx: Connects to the esophagus at C3-4
      • Nasopharynx: Connects to the nasal cavity via choanae
      • Oropharynx: Connects to the oral cavity via palatoglossal folds
    • Larynx: Connects to the trachea at C3-4

    Ear

    • Relations:
      • Nasal cavity - pharyngotympanic tube
      • External - external acoustic meatus
      • Cranial cavity - temporal bone (internal acoustic meatus)

    Ear Overview

    • Structure: Divided into external, middle, and inner ear
    • Bony structure: Part of the temporal bone
    • Function:
      • External ear traps sound and directs it through the external acoustic meatus.
      • Sound waves vibrate the tympanic membrane (ear drum) which is connected to the ossicles (malleus, incus, stapes) in the middle ear. Ossicles amplify the sound.
      • Stapes connects to the inner ear and vibrates fluid in the cochlea, this vibration is detected by the vestibulocochlear nerve (VIII).
      • Semicircular canals in the inner ear contain fluid which functions in balance.

    External Ear

    • Structure: Composed of auricle and external acoustic meatus (extends from concha to tympanic membrane).
    • Skin Cancers: Often present at the helix (the outer rim of the ear)
    • Darwin's Tubercle: A small bump on the helix, considered normal.
    • Auricle Structures:
      • Helix (w/ crux) and antihelix (w/ crura)
      • Tragus and antitragus with intertragic notch
      • Fossas: triangular and scaphoid
      • Lobule and concha

    External Ear: External Acoustic Meatus

    • Structure: Cartilage for lateral ⅓ and temporal bone for the remaining ⅔
    • Examination: Pull upward, posteriorly, and outward for examination.
    • Course: Travels upward, anteriorly then upward, posteriorly then downward, anteriorly.
    • Cerumen: Ear wax
    • Associated Muscles: Innervated by facial nerve (VII).
    • Innervation:
      • Auricle:
        • Auriculotemporal branch of the mandibular nerve (V3),
        • Lesser occipital nerve (C2),
        • Greater auricular nerve (C2-C3) of cervical plexus
      • External Acoustic Meatus:
        • Auricular branch of vagus nerve (X) (causes fainting during ear washing)
        • Facial nerve (VII) which sends a branch to the auricular branch of the vagus nerve (X)
    • Arterial Supply/Venous Drainage:
      • External Carotid Artery:
        • Posterior auricular artery
        • Superficial temporal artery → anterior auricular branches
        • Occipital artery
    • Lymphatic Drainage: Anterior/posterior auricular nodes draining into upper deep cervical nodes.

    Tympanic Membrane

    • Structure:
      • Pars flaccida: Thin and slack
      • Pars tensa: Thick and taut
    • Malleus: Handle is embedded in the membrane. Grommets (small tubes) are placed through this area to aid draining fluid.
    • Grommets: Used for glue ear or otitis media (middle ear infection)
    • Innervation:
      • Outer Surface:
      • Auriculotemporal nerve (branch of mandibular nerve [V3])
        • Auricular branch of vagus nerve (X)
        • Branch of facial nerve (VII) to the auricular branch of vagus nerve (X)
        • Glossopharyngeal nerve (IX)
      • Inner Surface:
        • Glossopharyngeal nerve (IX) via tympanic plexus

    Middle Ear

    • Location: Air-filled space in the temporal bone, between external and inner ear
    • Structure:
      • Tympanic cavity: Directly next to the tympanic membrane
      • Epitympanic recess: Superiorly.

    Middle Ear: Connections

    • Mastoid process: Connects posteriorly via mastoid air cells and the mastoid antrum. ( Infections can spread from middle ear to mastoid process).
    • Nasopharynx: Connects anteriorly and medially via the pharyngotympanic (eustachian) tube.

    Middle Ear: Eustachian Tube

    • Function: Equalizes pressure across the tympanic membrane.
    • Structure: Cartilage and tensor veli palatini muscle. When you swallow, this muscle contracts and opens the tube.

    Middle Ear: Neurovasculature

    • Arterial Supply: External carotid artery →:
      • Tympanic branch of maxillary artery
      • Mastoid branch of occipital/posterior auricular arteries (as well as other small branches).
    • Venous Drainage: Pterygoid plexus
    • Innervation of Mucous Membranes: Tympanic plexus formed by tympanic nerve (branch of glossopharyngeal nerve [IX]) and branches of internal carotid plexus (gives off lesser petrosal nerve which supplies SNS to the otic ganglion).

    Middle Ear Contents

    • Auditory Ossicles:
      • Malleus, incus, and stapes. Connects from the tympanic membrane to the oval window of the inner ear.
      • Malleus:
        • Handle: Attached to the tympanic membrane and tensor tympani muscle
        • Lateral process: Anterior/posterior malleolar folds of the tympanic membrane
        • Anterior process: Attaches to anterior wall via a ligament
        • Head: Articulates with incus
      • Incus:
        • Body: Articulates with the head of the malleus
        • Long limb: with a lenticular process (articulates with the head of the stapes)
        • Short limb: Attaches via ligament to the upper posterior wall of middle ear
      • Stapes:
        • Two limbs attach to the oval base which articulates with the oval window on the labyrinth wall
        • Associated with stapedius muscle

    Middle Ear Contents: Muscles

    • Tensor Tympani: Attached to the handle of the malleus to tense the tympanic membrane (Innervated by V3).
    • Stapedius: Attached from the mastoid wall to neck of the stapes. Pulls the stapes posteriorly to prevent excessive oscillation in response to loud noises (innervated by VII).

    Otitis Media

    • Definition: Middle ear infection
    • Epidemiology: Common in infants and small children (age 6 - 24 months). Due to:
      • More horizontal eustachian tube
      • Shorter tube
      • Less cartilage
      • More patent tube
      • Immunological immaturity
    • Pathophysiology: Viruses (RSV) most common. Also bacteria like:
      • S. pneumoniae,
      • H. influenzae,
      • Moraxella catarrhalis.
      • Ascending infection often secondary to URTI.
      • Inflammation and swelling of the mucous membrane of the tympanic cavity causes partial or complete pharyngotympanic tube blockage
    • Symptoms: Fever, lethargy, irritability, earache, ear discharge.
      • Possible hearing loss, bulging ear drum
      • Usually self-resolving, symptoms last 1-2 weeks.

    Nasal Cavity - Anatomy and Physiology

    • Foramen Cecum: Allows drainage for the nasal vein, in 1% of people, the vein travels through this foramen into the superior sagittal sinus
    • Cribriform Plate:
      • Houses the olfactory nerve (CNI) and sensory fibers from the anterior ethmoidal nerve, a branch of V1
      • Allows for the passage of the anterior and posterior ethmoidal arteries, which come from the internal carotid artery
    • Kiesselbach's Area: (also known as Little's Area)
      • A highly vascular area and site of frequent nosebleeds (epistaxis) due to the connection between the internal carotid artery and external carotid artery
      • Key arteries contributing include:
        • Anterior and posterior ethmoidal arteries (from the internal carotid)
        • Greater palatine artery and sphenopalatine artery (from the maxillary artery, which is a branch of the external carotid)
    • Nasal Sinuses: Air-filled spaces in the skull that develop during childhood and make the skull lighter
      • Frontal Sinus:
        • Drains into the middle meatus via the semilunar hiatus
        • Nerve supply from supra-orbital nerve (from V1)
        • Receives blood supply from anterior ethmoidal artery
      • Ethmoidal Sinus:
        • Anterior Ethmoidal: Drains into the middle meatus passing through the ethmoidal infundibulum and semilunar hiatus; Receives innervation from anterior and posterior ethmoidal branches of the nasociliary nerve
        • Posterior Ethmoidal: Drains into the superior meatus; Innervated via anterior/posterior ethmoidal branches of the nasociliary nerve
    • Nasal Vein Drainage:
      • Anteriorly drains into the facial vein
      • Posteriorly drains into the pterygoid plexus
      • Superiorly drains into the ethmoidal vein, then into the superior ophthalmic vein, and finally the cavernous sinus
    • Lymphatic Drainage:
      • Anteriorly, lymph travels to the submandibular nodes
      • Posteriorly, lymph travels to the upper deep cervical nodes
    • Innervation of the Nasal Cavities:
      • Mostly sensory nerves, with the exception of CNI (olfactory nerve)
      • CNI provides the sense of smell
      • Around the Naris: Internal nasal branches of the infraorbital nerve (from V2) provide sensory innervation
      • Nasal Glands
        • Sympathetic innervation comes from the superior cervical sympathetic ganglion via the T1 spinal cord
        • Parasympathetic innervation comes from the facial nerve (CNVII), via the greater petrosal nerve. The greater petrosal nerve joins the V2 in the pterygopalatine fossa.

    Structures and Functions of Nasal Foramina

    • Sphenopalatine Foramen
      • Provides passage for the sphenopalatine artery (a branch of the maxillary artery) into the nasal cavity and contributes to blood supply to the posterior portion of the nasal cavity
      • Also allows for entry of the maxillary (V2) branches: nasopalatine nerve (medially) and posterior nasal nerves (laterally) into the nasal cavity
    • Incisive Canal:
      • Allows greater palatine artery to enter and the nasopalatine nerve to exit for communication between the nasal cavity and oral cavity.

    Nasal Cavity Relations

    • The nasal cavity connects to the nasopharynx through the choanae, which is formed by the vomer, sphenoid and palatine bones.
    • The ethmoid bone connects the nasal cavity to the cranial cavity via its cribriform plate and foramen cecum.
    • The maxilla connects the nasal cavity to the oral cavity through the incisive canal.
    • The pharyngotympanic tube connects the middle ear to the nasal cavity.
    • The nasal cavity is also connected to the nasal sinuses and the external environment through the nares.

    External Nasal Skeleton

    • The external nasal skeleton is composed of nasal, maxilla bones, septal and lateral cartilages, major/minor alar cartilages, and fibrofatty tissue.
    • The nares can be flared by the nasalis, depressor septi nasi, and levator labii superioris alaeque nasi muscles.

    Internal Nasal Septum

    • The internal nasal septum separates the nasal cavity into two chambers.
    • Starting from the top and moving clockwise, the internal nasal septum is made up of the frontal, ethmoid, sphenoid, palatine, maxilla, septal cartilage, and nasal bones.
    • The vomer is located in the central point of the septum.
    • The palatine and maxilla form the hard palate.

    Nasal Septum

    • The lateral wall of the nasal cavity is formed by the frontal, ethmoid, sphenoid, palatine, maxilla, septal cartilage, and nasal bones.
    • The central bones of the lateral wall are the lacrimal and inferior nasal concha.
    • There are three (or four) nasal conchae: the highest, superior, middle and inferior. The inferior nasal concha is separate bone.
    • The nasal conchae increase the surface area of the nasal cavity, which helps to warm and humidify inhaled air.
    • The space underneath each concha is called a meatus: the superior, middle and inferior meatus.

    Nasal Cavity Entrances and Exits

    • The sphenopalatine foramen connects the nasal cavity to the pterygopalatine fossa.
      • This foramen is important because it provides a passage for:
        • The sphenopalatine artery (from the maxillary artery)
        • The nasopalatine nerve (branch of the maxillary nerve [V2]) that innervates the medial wall.
        • The posterior lateral nasal nerves (branch of the maxillary nerve [V2]) that innervate the lateral wall.
    • The incisive canal allows for the passage of the greater palatine artery entering the nasal cavity and the nasopalatine nerve exiting into the oral cavity.
    • The foramen cecum allows for the passage of the nasal vein, which connects to the superior sagittal sinus.
    • The cribriform plate allows for the passage of the olfactory nerve (CN I), anterior ethmoidal nerve (branch of the ophthalmic nerve [V1]), anterior and posterior ethmoidal arteries.
    • Around the nares:
      • There are internal nasal branches of the infraorbital nerve (from V2).
      • There are alar branches of the nasal artery arising from the facial artery.
    • The nasal cavity also has small foramina that allow for the passage of inferior nasal branches of the greater palatine nerve (from V2).

    Nasal Cavity Innervation

    • Sensory innervation:
      • Olfactory nerve (CN I) - olfaction (special sensory):
      • Anterior ethmoidal nerve (branch of the ophthalmic nerve [V1])
      • Internal nasal branches of the infraorbital nerve (from V2)
      • Alar branches of the nasal artery arising from the facial artery
      • Inferior nasal branches from the greater palatine branch of V2
    • Autonomic innervation:
      • Glands receive SNS via T1 → superior cervical sympathetic ganglion → travel with V2
      • Glands receive PNS via facial n.(CNVII) via greater petrosal n.Joining V2 in pterygopalatine fossa

    Nasal Cavity Arterial Supply

    • Sphenopalatine foramen:
      • Sphenopalatine artery (from the maxillary artery)
    • Incisive canal:
      • Greater palatine artery
    • Cribriform plate:
      • Anterior and posterior ethmoidal arteries
    • Around the nares:
      • Alar branches of the nasal artery arising from the facial artery
    • Small foramina:
      • Inferior nasal branches from the greater palatine branch of V2

    Kiesselbach’s Area/ Little’s Area

    • This area is located on the nasal septum and is a common site of epistaxis (nosebleeds).
    • It is a significant area of anastomosis between the internal and external carotid arteries.
    • The arteries that anastomose within Kiesselbach’s area are:
      • From the internal carotid artery: ophthalmic artery → anterior/posterior ethmoidal arteries.
      • From the external carotid artery: maxillary artery → greater palatine artery, sphenopalatine artery.

    Nasal Cavity – Venous and Lymphatic Drainage

    • Venous drainage:
      • Anteriorly: facial vein (note the risk of CNS infection)
      • Posteriorly: pterygoid plexus
      • Superiorly: ethmoidal veins → superior ophthalmic vein → cavernous sinus
      • Some individuals (1%) have a nasal vein that passes through the foramen cecum into the superior sagittal sinus.
    • Lymphatic drainage: -
      • Anteriorly: submandibular nodes
      • Posteriorly: upper deep cervical nodes

    Nasal Sinuses

    • The nasal sinuses are air-filled spaces within the bones of the skull that form during childhood. They lighten the skull.
    • Each nasal sinus drains into the nasal cavity.
    • Sinus: | Drainage: | Innervation: | Arterial Supply:
    • -------- | -------- | -------- | --------
    • Frontal | Middle meatus: Semilunar hiatus. | Supra-orbital nerve (from V1) | Anterior ethmoidal artery.
    • Ethmoidal: |
      • anterior: Middle meatus: ethmoidal infundibulum/ semilunar hiatus. | Anterior/posterior ethmoidal branches of nasociliary nerve (from V1). | Anterior/posterior ethmoidal artery.
      • middle: Middle meatus: ethmoid bulla.| Orbital branches from pterygopalatine ganglion (from V2). | Anterior/ posterior ethmoidal arteries.
      • posterior: Superior meatus | Orbital branches from pterygopalatine ganglion (from V2). | Anterior/ posterior ethmoidal arteries.
    • Sphenoidal: | Sphenoethmoidal recess | Pharyngeal nerve (from V2) | Sphenopalatine artery
    • Maxillary: | Middle meatus: Semilunar hiatus | Infraorbital and alveolar branches of V2 | Intraorbital and superior alveolar artery.

    Nasal Sinuses Drainage Summary (High Yield)

    • Sinus: | Drainage:
    • -------- | --------
    • Frontal | Semilunar hiatus of middle meatus.
    • Ethmoidal:
      • anterior: Middle meatus: ethmoidal infundibulum/ semilunar hiatus.
      • middle: Middle meatus: ethmoid bulla
      • posterior: Superior meatus
    • Sphenoidal | Sphenoethmoidal recess
    • Maxillary | Semilunar hiatus
    • Ethmoidal cells drain into the superior and middle meatus through the semilunar hiatus and ethmoidal bulla opening, respectively.

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