Questions and Answers
Contraction of the ________ muscle, innervated by____ produces the blink.
orbicularis oculi, facial nerve
Parasympathetic innervation to the pupil is done by what nerve?
oculomotor (CN3)
Which of the following is a cranial nerve injury associated with anosmia?
Which cranial nerve injury is associated with unilateral blindness?
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Cranial nerve injury causes ophthalmoplegia, which nerve is involved?
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What is the result of injury to V3 in the context of cranial nerve injuries?
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Inability to abduct the eye is a result of damage to cranial nerve _____.
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Loss of gag and carotid reflexes is associated with cranial nerve _____ .
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Cranial nerve _______ is associated with facial paralysis.
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Which cranial nerve is responsible for auditory and vestibular deficits?
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Cranial nerve _______ is responsible for the loss of cough reflex.
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Lack of shoulder shrug is indicative of injury to cranial nerve _____ .
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Paralysis of the tongue muscles leads to lingual deviation toward the side of injury of cranial nerve _____.
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What muscle is the chief muscle of facial expression?
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Infection may spread from the nasal cavity to the meninges along the olfactory nerves via which structure?
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Blood supply to the vestibular region of the nasal cavity is from branches of all the following vessels EXCEPT which one?
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Which of the following paranasal sinuses drains by gravity with the body in the erect position?
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Injury to the motor root of V3 would incur paralysis of all of the following EXCEPT which muscle?
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The Pterygomandibular Raphe marks the juncture of two muscles that are innervated by which cranial nerves?
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A lesion involving the inferior salivatory nucleus would affect?
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Which of the following structures is found in the lateral wall of the tonsillar fossa?
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The palatine tonsils are located between the anterior and posterior faucial folds. The muscles that form these folds are respectively?
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Which muscle is responsible for preventing the tongue from falling backward and obstructing respiration?
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Deviation of the tongue toward the right indicates impairment of which structure?
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Which cranial nerve paralysis results in internal strabismus (deviation of the eye medially)?
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Which of the following nerves innervates the muscles originating from the styloid process?
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If nerves passing through the jugular foramen were severed, which muscle would remain functional?
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During examination of the mouth, if the palate is observed to deviate to the normal side with no loss of the gag reflex, which muscles are paralyzed on the injured side?
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What muscle normally abducts the vocal folds?
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The superior laryngeal branch of the vagus nerve provides sensory innervation to which of the following structures?
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The thyroid gland receives its blood supply in part from branches of which artery?
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Which laryngeal ossicle forms a complete ring?
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Which region is NOT affected by a lesion in the medulla involving the nucleus ambiguus?
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Internal carotid arteries have significant anastomotic connections with tributaries of all the following arteries EXCEPT?
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What brings about accommodation?
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Which cell bodies innervate the pupillary dilator muscles?
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Which cell bodies convey pain, touch, and temperature from the posterior third of the tongue?
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Which cell bodies are responsible for the cough reflex?
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Which cell bodies regulate lacrimal secretion?
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Which cell bodies supply sensation from the nasal mucosa?
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Which cell bodies supply the parotid gland?
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Which cell bodies convey taste from the anterior third of the tongue?
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Which cell bodies regulate sublingual gland secretion?
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Select the appropriate nerve for the afferent limb of the blink reflex.
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What nerve contains the afferent component of the cardiac reflex responsible for slowing the heart?
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Which nerve has a branch that constitutes the efferent component of the cardiac reflex that slows the heart?
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Which nerve's excessive activity may contribute to tachycardia?
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The contents of the carotid sheath include all of the following except:
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The internal carotid arteries have significant anastomic connections with tributaries of all the following arteries EXCEPT the:
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All of the following correctly pertain to the retrovisceral space EXCEPT that:
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Infection of the retrovisceral (retropharyngeal) space:
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All of the following statements correctly pertain to the sternocleidomastoid EXCEPT that:
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All of the following correctly pertain to the descendens hypoglossi (superior root) of the ansa cervicalis EXCEPT that:
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Characteristics of the cervical sympathetic chain include all of the following EXCEPT:
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Characteristics of Horner's syndrome that provide the diagnosis include all of the following on the affected side EXCEPT:
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Cerebrospinal fluid is produced in all of the following locations EXCEPT the:
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Arachnoid Villi allow CSF to pass between which of the following two spaces:
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Which of the following statements best characterizes the carotid reflex (hypersensitive)?
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Afferent component of the cardiac reflex that slows the heart is carried by:
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Efferent component of the cardiac reflex that slows the heart is carried by:
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A patient's epicranial aponeurosis is penetrated, which results in severe gaping of the wound. The structure underlying the aponeurosis is?
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Forehead and scalp bleed profusely. All of the following statements correctly pertain to the blood supply to the scalp EXCEPT:
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A pituitary adenoma, which produces visual field deficits, that expands superiorly and compresses the central portion of the optic chiasm will result in?
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Inability to close the right eye is the result of involvement of the:
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The difficulty with mastication is the result of paralysis of:
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The pain in the external auditory meatus is due to involvement of sensory neurons that have their cell bodies in the:
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The branch of the facial nerve that conveys secretomotor neurons involved in lacrimation is the:
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Which of the following statements concerning the lacrimal apparatus is correct?
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Small tumor of the orbit that involves the orbital foramen will produce which of the following signs and symptoms?
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Infection in the region drained by the angular vein may result in venous thrombosis of the cavernous sinus via the:
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All of the following signs could result from infection within the right cavernous sinus EXCEPT:
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Tic Douloureux (trigeminal neuralgia) is characterized by sharp pain over the distribution of the trigeminal nerve. This syndrome involves neurons that have their cell bodies in the:
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A cranial fracture through the foramen rotundum that compresses the enclosed nerve results in?
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In addition to hearing loss and balance disturbances, a tumor in the internal acoustic meatus may be responsible for all the following signs and symptoms EXCEPT:
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Which of the following statements concerning opening the jaw is correct?
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In dislocation of the jaw, displacement of the articular disk beyond the articular tubercle of the TMJ results from spasm or excessive contraction of which of the following muscles?
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Study Notes
Carotid Sheath Contents
- Contains common carotid artery, internal carotid artery, external carotid artery, internal jugular vein, and vagus nerve.
- Sympathetic chain is located posterior to the carotid sheath.
Internal Carotid Artery Anastomoses
- Internal carotid artery lacks connections to the lingual artery.
- Anastomoses occur with facial, superficial temporal, and internal maxillary arteries.
Retrovisceral Space
- Considered a potential space until fascial layers are separated.
- Lies deep to the pretracheal fascia and is posterior to the oropharynx.
Infection Spread in Retrovisceral Space
- Infection can extend into the posterior mediastinum, presenting a life-threatening scenario.
- Pretracheal space infections lead to conditions down to the superior mediastinum.
Sternocleidomastoid Muscle
- Divides neck into anterior and posterior triangles.
- Innervated by the spinal accessory nerve (CN XI).
- Simultaneous contraction results in flexion of the head, not extension.
Ansa Cervicalis
- Superior root (descendens hypoglossi) is not functionally part of the hypoglossal nerve.
- Innervates infrahyoid muscles, and injury can cause swallowing difficulties.
Cervical Sympathetic Chain
- Does not receive a white ramus from cervical nerves, as that comes from lower thoracic levels.
- Supplies sympathetic innervation to the head.
Horner's Syndrome Symptoms
- Characterized by ptosis, anhidrosis, miosis, and slight enophthalmos on the affected side.
- Mydriasis (dilated pupil) does not occur in Horner's syndrome.
Cerebrospinal Fluid (CSF) Production
- Produced at choroid plexuses in the lateral ventricles, third ventricle, and fourth ventricle.
- The cerebral aqueduct does not produce CSF due to its narrow structure.
Arachnoid Villi Function
- Allow CSF to flow between the subarachnoid space and the superior sagittal sinus.
- Important for CSF absorption.
Carotid Reflex
- Initiated in the carotid sinus by changes in arterial pressure.
- Contains baroreceptors that respond to blood pressure fluctuations.
Cardiac Reflex Components
- Afferent signals carried by the carotid branch of the glossopharyngeal nerve.
- Efferent signals that slow the heart are transmitted via the vagus nerve.
Epicranial Aponeurosis and Underlying Structures
- Penetration leads to severe gaping, underlying blood vessels present, not bone or dura mater.
Scalp Blood Supply
- Bleeding beneath the epicranial aponeurosis spreads widely; above it leads to localized bleeding.
- Contralateral anastomotic connections are abundant.
Visual Field Deficits from Pituitary Adenoma
- Compresses optic chiasm resulting in loss of left and right temporal fields of vision.
- Produces bitemporal hemianopsia.
Eye Closure Inability
- Caused by paralysis of the palpebral portion of the orbicularis oculi muscle.
- Innervated by the zygomatic branch of the facial nerve.
Mastication Difficulty
- Result of buccinator muscle paralysis; this muscle helps keep food in place during chewing.
Pain in External Auditory Meatus
- Sensory innervation from neurons located in the geniculate ganglion, associated with the facial nerve.
Lacrimation and Facial Nerve
- Greater superficial petrosal nerve carries secretomotor fibers to the lacrimal gland.
Lacrimal Apparatus Anatomy
- Lacrimal gland is located in the upper lateral orbit.
- Nasolacrimal duct ends in the inferior meatus of the nose.
Orbit Tumor Effects
- Can cause blindness due to compression of the optic nerve and ophthalmic artery.
Infection Spread to Cavernous Sinus
- May occur through the superior ophthalmic vein from the angular vein; connects to the cavernous sinus.
Cavernous Sinus Infection Signs
- Loss of corneal reflex and ocular paralysis due to involvement of cranial nerves within the sinus.
Tic Douloureux (Trigeminal Neuralgia)
- Involves sensory neurons in the trigeminal ganglion, leading to sharp pain distribution.
Impact of Fracture at Foramen Rotundum
- Compression of maxillary division of trigeminal nerve (V2) leads to loss of the sneeze reflex.
Acoustic Meatus Tumors and Symptoms
- Can cause dry eye and facial paralysis but not loss of secretion from the parotid gland.
Jaw Opening Mechanism
- Involves rotation in the inframeniscal compartment and gliding in the suprameniscal compartment of the TMJ.
Jaw Dislocation Cause
- Resulting from lateral pterygoid muscle spasm or excessive contraction.
Infection Spread Along Olfactory Nerves
- Through the cribiform plate, allowing potential transmission of pathogens to the meninges.
Blood Supply to Nasal Cavity
- Supplied by anterior, posterior ethmoidal branches, and additional vessels; the posterior branch of the ophthalmic artery is not involved.
Paranasal Sinuses Gravity Drainage
- Maxillary sinuses do not drain by gravity when the body is upright, unlike others like frontal and inferior ethmoidal sinuses.
Injury to V3 Motor Root Effects
- Results in paralysis of the anterior belly of digastric and mylohyoid muscle, but not buccinator muscle.### Innervation of Muscles
- Buccinator muscle is innervated by the Facial nerve (CN 7), alongside the posterior belly of the digastric muscle.
- Muscles associated with mastication, anterior belly of digastric, mylohyoid, tensor tympani, and tensor veli palatini are motor innervated by the mandibular branch of the trigeminal nerve (V3).
Pterygomandibular Raphe
- Located in the oral cavity, important landmark indicating the junction of the Buccinator and Superior Constrictor muscles.
- Innervation from Facial nerve (CN 7) for Buccinator and pharyngeal branch of Vagus nerve (CN 10) for Superior Constrictor.
Inferior Salivatory Nucleus Lesion
- Affects activation of neurons in the otic ganglion, impacting parotid gland secretion.
- Notably, innervation of superior tarsal muscle (sympathetic) and other glands is mediated by different nuclei.
Lateral Wall of Tonsillar Fossa
- Glossopharyngeal nerve is found here, making it a critical area during tonsillectomy due to risk of injury.
Muscles of the Folds
- Anterior and posterior faucial folds formed by Palatoglossus and Palatopharyngeus, both innervated by the Vagus nerve.
Tongue Muscles and Functions
- Genioglossus muscle protrudes the tongue, innervated by the Hypoglossal nerve (CN 12).
- Hyoglossus muscle, innervated by CN 12, assists in retracting and depressing the tongue.
- Anterior belly of digastric lowers the jaw and is also innervated by V3.
Eye Movements
- Internal strabismus arises from paralysis of the Abducens nerve (CN 6), affecting the lateral rectus muscle.
- Ophthalmoplegia results from dysfunction in Oculomotor nerve (CN 3).
Cranial Nerve Functions
- CN 9 (Glossopharyngeal) provides sensory input for the gag reflex.
- CN 5 (Trigeminal) is involved in afferent pathways for the sneezing reflex and sensation in the conjunctiva.
Blood Supply to Thyroid Gland
- Inferior thyroid artery, arising from the thyrocervical trunk (branch of subclavian artery), supplies part of the thyroid gland.
Hematomas and Associated Risks
- Epidural hematoma results from tearing the middle meningeal artery.
- Subdural hematoma is associated with cerebral vein rupture.
- Subarachnoid hemorrhage often results from a ruptured aneurysm of the middle cerebral artery.
Cerebrospinal Fluid (CSF) Production
- CSF is produced by the choroid plexuses, circulating through brain ventricles and into the subarachnoid space for absorption via arachnoid villi.
Reflex Arcs and Associated Nerves
- Afferent limb of the cough reflex is processed through vagal pathways.
- Cardiac reflexes involve glossopharyngeal and vagus nerves, influencing heart rate and rhythm.
Clinical Considerations
- Damage to CN can result in specific deficits such as facial paralysis (CN 7), hearing loss (CN 8), and loss of gag reflex (CN 9).
- Each cranial nerve has distinct functions impacting various physiological responses, including muscle movement and sensory feedback.
Summary of Cranial Nerve Injuries
- Includes symptoms ranging from anosmia, unilateral blindness, to facial paralysis and tongue deviation toward the injured side.
Key Ganglia Involved
- Ciliary ganglion regulates accommodation; Pterygopalatine ganglion is responsible for lacrimal secretion; and Otic ganglion supplies the parotid gland.
These notes provide a concise yet comprehensive overview of cranial nerves, their innervations, and clinical implications, aiding in understanding their functions and relationships within cranial anatomy.
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Test your knowledge on the anatomical structures contained within the carotid sheath. This quiz focuses on identifying components of the carotid sheath and understanding their locations. Challenge yourself to differentiate between included and excluded structures!