Gross Anatomy: Head and Neck PDF

GROSS ANA: HEAD AND NECK Lateral View of the Skull The Head ▪ Frontal bone. ▪ Parietal bone. ▪ Skull....

GROSS ANA: HEAD AND NECK Lateral View of the Skull The Head ▪ Frontal bone. ▪ Parietal bone. ▪ Skull. ▪ Occipital bone. ▪ Brain. ▪ Temporal bone. ▪ 12 cranial nerves. o Squamous. o All distributing to the head except for the o Tympanic. 10th cranial nerve (Vagus Nerve). o Mastoid process. o Vagus nerve exits the skull and travels down o Styloid process. the neck. o Zygomatic process. Bones of the Skull o Greater wing of the sphenoid. ▪ Coronal sutures – fusion of frontal & parietal bones. ▪ Several bones joined together in the sutures. ▪ Lambdoid sutures – fusion of parietal and occipital ▪ Only temporomandibular joint is mobile. bones. ▪ Vault is the upper part of the cranium. ▪ Sagittal sutures – fusion of the 2 parietal bones in the ▪ Base of the skull is the lower part. midline. ▪ Each bone is made up of external and internal tables. ▪ Pterion – the thinnest part of the cranial vault. o Diploe is the spongy bone in between the o Articulation of: tables. ▪ Squamous temporal. o Both sides are covered with periosteum. ▪ Greater wing of sphenoid. Cranium Facial bones ▪ Anterior inferior corner of parietal ▪ Frontal bone: 1 ▪ Zygomatic bones: 2 bone. ▪ Parietal bones: 2 ▪ Maxillae: 2 o Anterior division of the middle meningeal ▪ Occipital bone: 1 ▪ Nasal bones: 2 artery. ▪ Temporal bones: 2 ▪ Lacrimal bones: 2 Posterior View of the Skull ▪ Sphenoid bone: 1 ▪ Vomer: 1 ▪ Ethmoid bone: 1 ▪ Palatine bones: 2 ▪ Parietal bone. ▪ Inferior conchae: 2 o Sagittal sutures. ▪ Mandible: 1 ▪ Occipital bone. Anterior View of the Skull o Lambdoid suture. o External occipital protuberance. ▪ Frontal bone – upper margins of orbit. ▪ Attachment for ligamentum nuchae. o Superciliary arches. o Superior nuchal lines. o Supraorbital notch or foramen. o Orbital margin: ▪ Superior – frontal bone. ▪ Lateral – zygomatic bone. ▪ Inferior – maxilla. ▪ Medial – maxilla. o Frontal Air sinuses – hollow space above the orbital margins within the frontal bone. ▪ Nasal bones – bridge the nose. o Anterior nasal aperture – lower border of nasal bone plus maxilla. o Vomer – divides the anterior nasal aperture. o Conchae – shelves of bones projecting in to nasal cavity. ▪ Superior and middle conchae – from ethmoid bone. Superior View of the Skull ▪ Frontal bone. ▪ Coronal suture. ▪ Parietal bones. ▪ Sagittal suture. Inferior View of the Skull (Anterior Part) ▪ Maxilla. o Hard Palate. ▪ Palatine bone. o Choanae – posterior nasal aperture. o Separated by vomer. ▪ Sphenoid bone. o Medial Pterygoid plates. o Lateral Pterygoid plates.  - Slit in the middle for anterior ethmoid nerve. ▪ Middle cranial fossa. o Houses the temporal lobes of cerebrum. o Boundaries: ▪ Anterior – lesser wings of sphenoid. ▪ Posterior – superior border of petrous part of temporal bone. ▪ Lateral – squamous part of the temporal bone, greater wings of Inferior View of the Skull (Middle Part) sphenoid and parietal bones. ▪ Petrous part of temporal bone. ▪ Floor – greater wing of sphenoid, o External auditory canal. petrous and squamous part of o Carotid canal. temporal bone. o Foramen spinosum. o Sphenoid bone – central body with greater o Jugular foramen. and lesser wings. ▪ Tympanic part of temporal bone. ▪ Body contains sphenoidal air sinuses. o Sphenoparietal venous sinus – posterior border of lesser wing. ▪ Drains into the cavernous sinus. ▪ Posterior cranial fossa. o Lodges the hindbrain. ▪ Cerebellum, pons and medulla. Inferior View of the Skull (Posterior Part) o Boundaries: ▪ Occipital bone. ▪ Anterior – superior border of o Occipital condyles – articulates with the C1 petrous part of temporal bone. bone (Atlas). ▪ Posterior – internal surface of the o Foramen magnum. squamous part of occipital bone. o External occipital crest. ▪ Floor – formed by basilar, condylar o Nuchal lines. and squamous part of the occipital bone and mastoid part of the temporal bone. ▪ Roof – tentorium cerebelli. Vault of the Skull ▪ Coronal sutures. ▪ Sagittal sutures. ▪ Lambdoid sutures. ▪ Grooves for the middle meningeal artery. Mandible Base of the Skull ▪ Consists of body and rami. ▪ Angle of the mandible – where body and rami meet. ▪ Anterior cranial fossa. ▪ Outer surface of body: o For frontal lobes of the cerebrum. o Symphysis menti. o Crest for falx cerebri. o Mental foramen. o Boundaries: ▪ Inner surface: ▪ Anterior – inner surface of frontal o Mental spines – genioglossus muscle origin. lobe. o Mylohyoid line – from mental spine to below ▪ Posterior – lesser wing of sphenoid. the 3rd molar. Articulates w/ pterion. o Submandibular fossa – below the mylohyoid Anterior clinoid process – line. given rise to tentorium o Sublingual fossa – above the mylohyoid line cerebelli. on the anterior part of mylohyoid line. ▪ Median part – groove for optic o Mandibular foramen – for alveolar nerves chiasm. and vessels. ▪ Floor – orbital plates (laterally) and ▪ Alveolar part – upper part. cribriform plate (medially). o 16 sockets for teeth. Crista galli – upward ▪ Base – lower part. projection of ethmoid bone o Digastric fossa on either side of symphysis for falx cerebri. menti. o For belly of digastric muscle. ▪ Markings for attachment of masseter. o Cerebrum. o Diencephalon. Temporomandibular Joint ▪ Thalamus (dorsal). ▪ Articulation between articular tubercle and anterior ▪ Hypothalamus (ventral). portion of mandibular fossa of the temporal bone ▪ Midbrain. and condyloid process of the mandible. ▪ Hindbrain. ▪ Synovial joint with articular disc. o Pons. ▪ Encapsulated. o Medulla oblongata. ▪ Articular disc divides joint into upper and lower o Cerebellum. cavities. ▪ Synovial membrane. ▪ Nerve supply – auriculotemporal and masseteric branches of the mandibular nerve. ▪ Movement: o Depression – as mouth is opened, mandible is pulled forward by lateral pterygoid muscle. Depression is due to digastrics, geniohyoids, and mylohyoids. o Elevation – elevation by temporalis, masseter and medial pterygoids. Retraction is by the posterior fibers of the temporalis. ▪ Ligaments: o Lateral temporomandibular ligament – tubercle on the root of the zygoma to lateral surface on the neck of mandible. ▪ Limits posterior movement thus protecting the external auditory. o Sphenomandibular ligament – medial side of the joint. Runs from spine of sphenoid bone to lingula of mandible foramen. o Stylomandibular ligament – thickened deep cervical fascia from apex of styloid process to *Note: Left-side of the brain is associated with logic, angle of mandible. reasoning and science. Right side is associated with ▪ Movement: creativity. So left-handed people are generally more o Protrusion – lateral pterygoid. artistic. o Retraction – posterior fibers of the temporalis. Meninges of the Skull o Lateral chewing movement – alternate ▪ Falx cerebri – between two cerebrums. protruding and retracting mandible on each o From crista galli to the tentorium cerebelli. side. o Sagittal sinus runs on superior edge. ▪ Relationships: o Inferior edge is free. o Anteriorly: The mandibular notch and the ▪ Tentorium cerebelli – between cerebrum and masseteric nerve and artery. cerebellum. o Posteriorly: The tympanic plate of the o Tentorial notch – for the passage of external auditory meatus and the glenoid midbrain. process of the parotid gland. o Borders: Posterior clinoid process, superior o Laterally: The parotid gland, fascia and skin. border of petrous bone and grooves for o Medially: The maxillary artery and vein and transverse sinuses. the auriculotemporal nerve. ▪ Falx cerebelli – between the hemispheres of Neonatal Skull cerebellum. o Posterior margin is occipital sinus. ▪ Disproportionate large cranium. ▪ Diaphragmatic Sellae – covers the sella turcica. ▪ Smooth and unilaminar bones. o Small opening in the center for the pituitary ▪ Fontanelles – interval between skull bones. gland stalk. o Anterior fontanelle – diamond shaped. ▪ Between frontal and parietal bones. Dural Nerve Supply ▪ Closes by 18 months old. ▪ From trigeminal, vagus and first 3 cervical nerves. o Posterior fontanelle – triangular shaped. ▪ Sensitive to stretching → headache. ▪ Between parietal and occipital o Above the tentorium cerebelli, ipsilateral bones. headache. ▪ Closes by 12 months old. o Below the tentorium cerebelli to the neck ▪ Tympanic part of temporal bone. and scalp. o Cartilaginous at birth and ossified in adults. o Tympanic membrane is near the surface. Dural Arterial Supply ▪ No mastoid process – forms with the pull of SCM. ▪ Internal carotid, maxillary, ascending pharyngeal, ▪ Fusion of symphysis menti at 12 months old. occipital and vertebral arteries. Brain ▪ Forebrain. ▪ Most important: middle meningeal artery – from Muscles of the Eyelid maxillary artery in infratemporal fossa → foramen spongiosum. Meninges of the Brain ▪ Arachnoid mater. o Impermeable. o Between dura and pia mater. o Potential spaces: ▪ Subdural space – above the arachnoid mater. ▪ Subarachnoid space – below the arachnoid mater. o Arachnoid granulation – projections into sinuses. Orbit ▪ Pia mater. o Adherent to the tissue of the brain. ▪ Pyramidal cavity. o Continuous with the epineurium of the o Base in front (orbital margin). cranial nerves. o Apex behind. ▪ Boundaries: o Roof – frontal bone. o Lateral wall – zygomatic bone and greater wing of sphenoid. o Floor – orbital plate of maxilla. o Medial wall – frontal process of maxilla, lacrimal bone, orbital plate of ethmoid and bony of sphenoid. ▪ Opening: o Orbital opening: Lies anteriorly about one- sixth of the eye is exposed. o Supraorbital notch (foramen): Situated on the superior orbital margin. It transmits supraorbital nerve and blood vessels. o Infraorbital groove and canal: Situated on Arterial Supply to the Brain the floor of the orbit in the orbital plate of the maxilla; they transmit the infraorbital ▪ Comes from 4 major vessels, 2 internal carotid nerve (a continuation of the maxillary nerve) arteries, and 2 vertebral arteries. and blood vessels. ▪ The 2 internal carotid arteries will enter the skull to o Nasolacrimal canal: Located anteriorly on form the Anterior Communicating Artery. the medial wall; it communicates with the ▪ The 2 vertebral arteries will form the Basilar Artery, inferior meatus of the nose. It transmits the and terminate into the Posterior Meningeal Artery. nasolacrimal duct. o Inferior orbital fissure: Located posteriorly between the maxilla and the greater wing of the sphenoid; it communicates with pterygopalatine fossa. It transmits the maxillary nerve and its zygomatic branch, the inferior ophthalmic vein, and sympathetic nerves. o Superior orbital fissure: Located posteriorly between the greater and lesser wings of the sphenoid. It communicates with the middle cranial fossa. It transmits the lacrimal nerve, the frontal nerve, the trochlear nerve, the oculomotor nerve (upper and lower divisions), the abducent nerve, the nasociliary nerve, and the superior The Eye (Orbital Region) ophthalmic vein. o Optic canal: Located posteriorly in the lesser ▪ Upper skin and lower eyelids. wing of the sphenoid; it communicates with o Skin and conjunctiva (mucous membrane). the middle cranial fossa. It transmits the o Eyelashes on the free edges. optic nerve and the ophthalmic artery. o Sebaceous glands (of Zeis), ciliary glands (of Molls). o Tarsal gland (sebaceous glands). ▪ Secretes into the margins and allows airtight seal. ▪ Medial and lateral angles. ▪ Palpebral fissure (Opening).  o Accommodation reflex – constriction of pupils when suddenly focusing on near object. The Ear ▪ External ear. o Auricle – collects air vibrations. ▪ Made of elastic cartilage covered by skin. ▪ Has extrinsic and intrinsic muscle, supplied by facial nerve. Contents of Eyeball o External auditory meatus – auricle to tympanic membrane. ▪ Aqueous humor. o Lined with hairs, sebaceous glands and o Fills anterior and posterior chamber. ceruminous glands. Cerumen prevents o From ciliary processes, drained at the entrance of foreign bodies into canal. iridocorneal angle into the canal of o Sensory – auriculotemporal nerve and Schlemm. auricular branch of vagus. o Obstruction results into glaucoma. o Lymph drainage – superficial parotid, o Function – support eyeball by internal mastoid and superficial cervical lymph pressure. nodes. ▪ Nourish eyeball. ▪ Middle ear. ▪ Remove products of metabolism. o Petrous part of temporal bone. ▪ Vitreous body. o Contains auditory ossicles. o Transparent gel behind the lens. o Transmits vibrations from tympanic o Hyaloid canal runs from lens to optic disc. membrane to the perilymph of the internal o Contains hyaloid artery which disappears ear. before birth. o Communicates with the nasopharynx and o Function: auditory tube and behind with the mastoid ▪ Magnifying power of eye. antrum. ▪ Supports the posterior surface of o Roof: tegmen tympani. lens. o Floor: thin plate of bone. ▪ Assist in holding the neural part of o Anterior wall – thin wall separating the canal the retina against the pigmented from the internal carotid artery. part. o Posterior wall – upper part has the aditus to ▪ Lens. the mastoid antrum, lower part has a o Biconvex structure in transparent capsule. pyramid, whose apex emerges into the o Behind iris and in front of vitreous body. tendon of stapedius muscle. o Encircled by ciliary process. o Lateral wall – tympanic membrane. o Elastic lens capsule is under tension thus ▪ Umbo – small depression. assuming globular shape than disc. ▪ Concavity produces a cone of light – o Equatorial region is attached to the ciliary anterior and inferior from umbo. processes of the ciliary body by suspensory o Medial wall – inner ear. ligament. o Auditory ossicles. o Pull on the suspensory ligament keeps the ▪ Malleus – attached to the tympanic elastic lens flattened to focus on the distant membrane by the handle and to the object. incus by the head. ▪ Incus – body articulates with the malleus. Long process is parallel to the hand of malleus and articulates with stapes. ▪ Stapes. o Muscles. ▪ Tensor tympani. ▪ Stapedius muscle. o Movements: ▪ Medial movement of the tympanic Accommodation of the Eye membrane pushes the handle of ▪ Ciliary body constriction – focus closer. malleus medially. ▪ Pupils constriction – ensures light passes thru center ▪ This results in lateral movement of of eye. the head of the malleus and body of ▪ Convergence of eye – focus on the closer object. incus. ▪ Pupillary reflex: ▪ The long process of the incus then o Direct light reflex – constriction of pupils due movement medially within the to light. stapes. o Consensual light reflex – constriction of ▪ Then the base of the stapes is moved pupils due to light on the other eye. medially pushing on the fenestra vestibuli medially.  ▪ The fluid then causes an outward o The nasalis is the largest of the nasal bulging on the fenestra cochlea. muscles. It is split into two parts; transverse ▪ Inner ear. and alar. o In the petrous part of the temporal bone. o Attachments: Both portions of the muscle o Bony labyrinth. originate from the maxilla. The transverse ▪ Vestibule. part attaches to an aponeurosis across the Central part. dorsum of the nose. The alar portion of the Fenestra vestibuli and muscle attaches to the alar cartilage of the fenestra cochlea on the nasal skeleton. lateral wall. o Actions: The two parts have opposing ▪ Semicircular canals (responsible for functions. The transverse part compresses balance and sense of movement. the nares, and alar part opens the nares. Most posterior. o Innervation: Facial nerve. Superior (vertical/sagittal). ▪ Procerus. Posterior (vertical/coronal). o The procerus is the most superior of the Lateral nasal muscles. It also lies superficially to the (horizontal/transverse other muscles of facial expression. semicircular canal). o Attachments: It originates from the nasal With one ampulla for each. bone, inserting into the lower medial Semicircular ducts are lodge forehead. in each canal. o Actions: Contraction of this muscle pulls the 5 orifices open to 2. eyebrows downward to produce transverse ▪ Cochlea wrinkles over the nose. o Innervation: Facial nerve. Most anterior. ▪ Depressor Septi Nasi. Contains perilymph. o This muscle assists the alar part of the nasali Resembles snail shell. in opening the nostrils. Modiolus is the central pillar o Attachments: It runs from the maxilla (above making 2.5 turns. the medial incisor tooth) to the nasal Spiral lamina with the septum. basilar membrane divides o Actions: It pulls the nose inferiorly, opening the canal into the nares. o Scala vestibuli. o Innervation: Facial nerve. o Scala tympani. ▪ Membranous labyrinth. Oral Group Lodge within the bony ▪ Orbicularis Oris. labyrinth. o The fibres of the orbicularis oris enclose the Contains endolymph. opening to the oral cavity. Utricle (larger) and saccule o Attachments: Arises from the maxilla and (smaller) vestibular sacs. from the other muscles of the cheek. It o Vestibulocochlear nerve. inserts into the skin and mucous membranes ▪ Internal acoustic meatus. of the lips. Facial Muscles: Orbital group o Action: Purses the lips. o Innervation: Facial nerve. ▪ Orbicularis oculi. ▪ Buccinator. o This muscle surrounds the eye socket and o This muscle is located between the mandible extends into the eyelid. It can be functionally and maxilla, deep to the other muscles of the split into two parts; the outer orbital part face. and inner palpebral part. o Attachments: It originates from the maxilla o Actions: The palpebral part of the muscle and mandible. The fibres run in an performs gentle closure of the eyelid, inferomedial direction, blending with the whereas the orbital portion closes more orbicularis oris and the skin of the lips. forcefully. o Actions: The buccinator pulls the cheek o Innervation: Facial nerve. inwards against the teeth, preventing ▪ Corrugator Supercilii. accumulation of food in that area. o The corrugator supercilii is a much smaller o Innervation: Facial nerve. muscle, and is located posteriorly to the ▪ Other oral muscles. orbicularis oculi muscle. ▪ The lower group contains the depressor anguli oris, o Attachments: It originates from the depressor labii inferioris and the mentalis. superciliary arch, running in a superolateral ▪ The upper group contains the risorius, zygomaticus direction. It inserts into the skin of the major, zygomaticus minor, levator labii superioris eyebrow. alaeque nasi and levator anguli oris. o Actions: It acts to draw the eyebrows together, creating vertical wrinkles on the bridge of the nose. o Innervation: Facial nerve. Nasal Group ▪ Nasalis. The Neck ▪ Occipital artery. ▪ Posterior auricular artery. ▪ Superficial temporal artery. Palpable in front of auricle. ▪ Maxillary artery. Jaws, muscles for mastication, nose, palate and meninges of the skull. Middle meningeal artery. ▪ Internal Carotid Artery. o Supplies brain, eye, forehead and part of nose. *Platysma is most superficial. o Embedded in carotid sheath, with internal jugular vein and vagus nerve. o Goes into the carotid foramen to give off the ophthalmic artery before joining the circle of Willis. ▪ Subclavian Artery. o First part. ▪ Left from aortic arch, right from brachiocephalic artery. ▪ Give rise to vertebral artery, ascends thru the cervical transversalis foramen, unite as the basilar artery. ▪ Basilar artery courses along anterior groove on Pons and then splits into posterior cerebral artery. Veins of the Brain ▪ Facial vein. o Union of supraorbital and supratrochlear veins. o Descends on the lateral side of the mouth. o Joined by anterior division of the retromandibular vein and drains into the internal jugular vein. ▪ Common Carotid Artery. ▪ Superficial temporal vein. o Arise from the brachiocephalic artery (right) o Side of the scalp. and arch of aorta (left). o Follows the superficial temporal artery and o At anterior border of SCM, bifurcates into auriculotemporal nerve. internal and external carotid. o Enters the parotid salivary gland. o Carotid sinus – localized dilation at the o Joins the maxillary vein to become the beginning of internal carotid. retromandibular vein. ▪ Reflex pressoreceptor mechanism. ▪ Maxillary vein. o Carotid body – posterior to the point of o Formed in the infratemporal fossa from bifurcation. pterygoid plexus. ▪ Chemoreceptor for CO2 and O2. ▪ Retromandibular vein. o Divides into the anterior branch. ▪ External Carotid Artery. ▪ Joins the facial vein. o One of the terminal branches of common o And posterior branch. carotid artery. ▪ Joins the auricular vein to form the o Supplies the neck, face, scalp, tongue and external jugular vein. maxilla. ▪ External jugular vein. o Terminates as superficial temporal and o Descends across the SCM beneath the maxillary arteries. platysma and drains into the subclavian vein. o Anterolateral – SCM, facial nerves. Internal o Tributaries: jugular lies lateral then posterior to it. ▪ Posterior external jugular vein. o Medially – wall of pharynx and internal ▪ Transverse cervical vein. carotid artery. ▪ Suprascapular vein. o Branches: ▪ Anterior jugular vein. ▪ Superior thyroid artery. ▪ Anterior jugular vein. Accompanied by external o Descends in front of the neck above the laryngeal artery. sternum. ▪ Ascending pharyngeal artery. ▪ Internal jugular vein. ▪ Lingual artery. o Receives blood from the brain, face and ▪ Facial artery. neck. Supplies the tonsils, o Continuation of the sigmoid sinus and leave submandibular gland and the skull thru the jugular foramen. muscles and skin of face.  o Joins the subclavian vein at the middle of the Digestive System of the Head and Neck: The Mouth clavicle to form the brachiocephalic vein. o Anterolateral: ▪ Lips. ▪ Skin, fascia, sternocleidomastoid o Fleshy fold on the orifice. and parotid salivary gland. o Skin on outer side, mucous membrane in the ▪ Lower part covered by insides. sternothyroid, sternohyoid and o Philtrum is the shallow groove on the middle omohyoid. of the upper lip. o Posterior: o Labial Frenulae on midline of the upper lip. ▪ Transverse process of the cervical ▪ The mouth cavity. vertebrae, levator scapulae, o Lips to pharynx. scalenus medius, scalenus anterior, o Oropharyngeal isthmus. cervical plexus, phrenic nerve, ▪ On each side of the palatoglossal thyrocervical trunk, vertebral vein fold. and first part of the subclavian o Vestibule. artery. ▪ Between lips and cheeks externally. o Medial: ▪ Between teeth internally. ▪ Internal carotid artery, CN 9 to 12. ▪ Lateral wall – cheek. o Inferior petrosal sinus. ▪ Duct of the parotid salivary gland – o Facial vein. small papilla into the vestibule o Pharyngeal vein. opposite the upper second molar o Lingual vein. tooth. o Superior thyroid vein. o Mouth proper. o Middle thyroid vein. ▪ Roof – hard palate and soft palate. ▪ Subclavian vein. ▪ Floor – anterior two thirds of the o Continuation of the axillary vein at outer tongue and sides of tongue to border of 1st rib. mandible. o Forms the brachiocephalic vein. Frenulum of the tongue – o Receives the external jugular vein. underside of the tongue. o Thoracic duct on the left. Plica fimbriata – mucous o Right lymphatic duct on the right. membrane folds lateral to o Anterior: clavicle. the frenulum. o Posterior: scalenus anterior muscle and Submandibular ducts – on phrenic nerve. the side of the frenulum. o Inferior: upper surface of 1st rib. Sublingual folds – due to projections of the sublingual Peripheral Nerves glands. o Sensory innervation. ▪ Roof: greater palatine and nasopalatine from maxillary division of the trigeminal nerve. ▪ Floor: Lingual nerve, from mandibular division of the trigeminal nerve. Taste fibers in the chorda tympani nerve of facial nerve. ▪ Cheek: Buccal nerve, from mandibular division of the trigeminal nerve. The Teeth ▪ Deciduous teeth. o 20 teeth: 4 incisors, 2 canines, 4 molars in each jaw. o 6 months to 2 years. o Lower teeth appears first. ▪ Permanent teeth. Brachial plexus o 32 teeth: 4 incisors, 2 canines, 4 premolars, and 6 molars in each jaw. o 6 years to 17-30 years (third molar). o Lower teeth appears first. The Tongue ▪ Muscles attached to the styloid process and soft palate above and mandible and hyoid muscle below. ▪ Divided into right and left by median fibrous septum. ▪ Mucous membrane.  o Divided into the by sulcus terminalis (apex at ▪ Funnel shaped, wider under the skull and lower ends back) into: is continuous with the esophagus at C6 level. ▪ Anterior – 2/3, covered by filiform ▪ Muscles: papilla, fungiform papillae and o Superior, middle and inferior constrictor vallate papillae. muscles (circular). ▪ Posterior – 1/3, devoid of papillae, o Stylopharyngeus and salpingopharyngeal has lingual tonsils. muscles (longitudinal). ▪ Muscles: ▪ Nasal pharynx. o Intrinsic – longitudinal, transverse and o Above the soft palate and behind the nasal vertical fibers. cavities. ▪ Nerve – hypoglossal nerve. o Roof is composed of pharyngeal tonsils. ▪ Action – alter the shape of the o Floor is the pharyngeal isthmus. tongue. o Lateral wall has the auditory tube opening. o Extrinsic – genioglossus, hypoglossus, o Pharyngeal recess – depression in the styloglossus, and palatoglossus. pharyngeal wall. ▪ Nerve – hypoglossal nerve. o Salpinopharyngeal fold covers the salpinopharyngeal muscle. ▪ Oral pharynx. o Floor is formed by posterior one third of tongue and interval between tongue and epiglottis. o Median glossoepiglottic folds. ▪ Vallecula – depression on each side of medial glossopharyngeal fold. o Lateral glossoepiglottic folds. ▪ Laryngeal pharynx. The Palate o Behind the opening of the larynx. o Lateral wall formed by thyroid cartilage and ▪ Hard palate. thyrohyoid membrane. ▪ Soft palate. ▪ Nerve supply: o Mobile fold with uvula on the midline. o Maxillary nerve. o Closes the pharyngeal isthmus during o Glossopharyngeal nerve. speech. o Internal branch of the vagus nerve. o Tensor veli palatini – tenses the soft palate. ▪ Blood supply: o Levator veli palatini – raises the soft palate. o Ascending pharyngeal, tonsillar branch of o Palatoglossus – pulls root of tongue upward facial arteries and branches of the maxillary and backward. and lingual arteries. o Palatophryngeus – elevates the wall of the ▪ Lymph nodes: pharynx. o Retropharyngeal or patatracheal nodes into o Musculus uvulae – elevates the uvula. the deep cervical nodes. Salivary Gland Palatine tonsils ▪ Parotid gland. ▪ 2 masses of lymphoid tissue one the lateral walls of o Largest salivary gland. the oral pharynx. o Location: below the external auditory ▪ Surface is pitted to form the tonsillar crypts. meatus behind the mandibular rami. ▪ Blood supply: tonsillar branch of facial artery. o Composed mostly of serous acini. ▪ Drains into the deep cervical lymph nodes below and o Divided into superficial and deep lobes. behind the angle of the mandible. o Ducts emerge on anterior border and rains ▪ Waldeyer’s Ring of Lymphoid tissue. opposite the second molar. o Lymphoid tissue surrounding the opening of o Nerve supply: glossopharyngeal nerve. the respiratory and oral cavities. ▪ Submandibular gland. o Composed of palatine tonsils and tubal o Location: lower border of mandible. tonsils (Lateral), palatine tonsils (above) and o Serous and mucous acini. lingual tonsils (lower part). o Divided into superficial and deep parts by the mylohyoid muscle. The Respiratory System of the Head and Neck: External o Duct emerges from deep part and drain into Nose the sides of the frenulum. ▪ Nostrils – elliptical orifices. o Nerve supply: chorda tympani from facial ▪ Nasal septum – separates the orifices. nerve. ▪ Ala nasi – lateral margin of orifices. ▪ Sublingual gland. ▪ Blood supply – ophthalmic and maxillary arteries. Ala o Located at floor of mouth. nasi supplied by facial artery. o Contains serous and mucous acini. ▪ Nerve supply – infratrochlear and external nasal o Drains into the mouth on the summit of branch of the ophthalmic nerve and infraorbital sublingual folds. branch of the maxillary nerve. o Nerve: chorda tympani via facial nerve. Nasal Cavity The Pharynx ▪ From nostrils to posterior nasal aperture or choanae. ▪ Divided into nasal, oral and laryngeal parts. ▪ Nasal vestibule – cavity inside the nostril divided by ▪ Cartilages: the septum. o Thyroid cartilage. ▪ Septum is made up of septal cartilage, vertical plate o Cricoid cartilage. of ethmoid and vomer. o Arytenoid cartilage. ▪ Walls: o Corniculate cartilage. o Floor – palatine process of maxilla and o Cuneiform cartilage. horizontal plate of palatine bone. o Epiglottis. o Roof – nasal and frontal bones, middle of cribriform plate of ethmoid (anterior) and Muscles of the Larynx body of sphenoid (posterior). ▪ Extrinsic muscles. o Lateral wall – Superior, middle and inferior o These muscles move the larynx up and down nasal conchae. during swallowing. ▪ Sphenoethmoidal recess – above the o Elevation: The digastric, the stylohyoid, the superior conchae, receives opening mylohyoid, the geniohyoid, the of sphenoid air sinus. stylopharyngeus, the salpingopharyngeus ▪ Superior meatus – below the and the palatopharyngeus muscles. superior conchae, receives opening o Depression: The sternothyroid, the of posterior ethmoid sinuses. sternohyoid, and the omohyoid muscles. ▪ Middle meatus – below the middle ▪ Intrinsic muscles. conchae. o Two muscles modify the laryngeal inlet: Bulla ethmoid – swelling ▪ Narrowing the inlet: The oblique formed by the middle arytenoid muscle. ethmoidal air sinuses. ▪ Widening the inlet: The Hiatus semilunaris – opens thyroepiglottic muscle. below the bulla, receives o 5 muscles move the vocal folds (cords): opening of maxillary sinus. ▪ Tensing the vocal cords: The Infundibulum – anterior end cricothyroid muscle. of hiatus, continuous with ▪ Relaxing the vocal cords: The frontal sinus. thyroarytenoid (vocalis) muscle. o Medial wall – nasal septum. ▪ Abducting the vocal cords: The ▪ Area above ethe superior conchae is sensitive to posterior cricoarytenoid muscle. smell. ▪ Approximates the arytenoid ▪ Lower part lined by mucous membrane. cartilages: The transverse arytenoid ▪ Warm blood – heats up the air. muscle ▪ Mucus – traps foreign particles which is then swallowed and destroyed by gastric acid. ▪ Nerve supply: o Olfactory nerves – thru the cribriform plate (smell). o Opthalmic and maxillary division of trigeminal nerve (for ordinary extension). ▪ Blood supply – maxillary artery and sphenopalatine artery. o Venous drainage by submucous venous plexus. Paranasal sinus ▪ Function: resonators of voice. o Reduce weight of skull. Sinus Site of Drainage Maxillary sinus Middle meatus through hiatus semilunaris. Frontal sinuses. Middle meatus via infundibulum. Sphenoidal sinuses. Sphenoethmoidal sinuses. Ethmoidal sinuses. --- Anterior group. Infundibulum and into middle meatus. Middle group. Middle meatus on or above bulla ethmoidalis. Posterior group. Superior meatus. Larnyx ▪ Protective sphincter at the inlet. ▪ Responsible for the voice production. ▪ Below the tongue and hyoid bone at the level of C4 to C6.