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Flashcards in CRANIAL NERVES Deck (26)
1

1. A 50 year old family physician has vertical diplopia; the feels unsure when descending stairs. He can eliminate the double vision by tilting his chin toward the paretic side. Which of the following extra ocular muscles is responsible for the ocular malalignment?
A. Superior rectus D. Lateral rectus
B. Inferior rectus E. Superior oblique
C. Inferior oblique

1-E The superior oblique muscle depresses, abducts, and intorts the eye. Paralysis of this muscle results in extorsion and weakness of downward gaze. Head tilting compensates for extorsion

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2. A chemodectoma of the glomus jugulare comprises all of the eranial nerves passing through the jugular foramen. All of the following functions would be ipsilaterally impaired as a result of this tumor EXCEPT
A. the gag reflex D. swallowing
B. parotid gland secretion E. normal movement of the tongue
C. phonation

2-E The hypoglossal nerve (CN XII) passes through the hypoglossal canal, not through the jugular foramen. It innervates the intrinsic and extrinsic muscles of the tongue (genioglossus, styloglossus, and hyoglossus).

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3. The cavernous sinus contains all of the following structures EXCEPT the
A. ophthalmie nerve
B. mandibular nerve
C. abdocent and trochlear nerves
D. postganglionie sympathetic fibers
E. preganglionic parasympathetic fibers

3-B The mandibular nerve (CV V-3) does not pass through the cavernous sinus : it exits the skull via the foramen ovale.

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4. The superior orbital fissure contains all of the following structures EXCEPT the
A. ophthalmic veins D. abducent nerve
B. ophthalmic nerve E. optic nerve
C. trochlear nerve

4-E The optic nerve (CN II) enters the skull via the optic canal. The optic canal also contains the ophthalmic artery.

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5. Transection of the left oculomotor nerve results in all of the following conditions EXCEPT
A. diplopia when attempting to adduct the left eye
B. a fixed dilated pupil on the side
C. no consensual reaction when light is shone in the left eye
D. a normal bilateral corneal reflex
E. a left eye that “looks down and out”

5-C Transection of the oculamotor nerve (CN III) does not interrupt the afferent limb of the pupillary reflex, which is bilateral. Light shone into the left eye results in constriction of the contralateral pupil, the consensual reaction

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6. A glioma destroying the right trochlear nucleus would result in all of the following conditions EXCEPT
A. extorsion of the affected eye
B. diplopia when looking down
C. head tilt
D. paralysis of the right superior oblique muscle
E. unaffected pupillary light reflexes

6-D The right trochlear nucleus of CN IV projects to the left superior oblique muscle. Diplopia occurs when an image falls on disparate parts of the retina. The pupillary light reflex is mediated by the parasympathetic fibers of the oculomotor nerve.

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7. All of the following statements concerning the vestibulacochlear nerve are correct EXCEPT
A. it exits the brainstem in the corebellopontine (CP) angle
B. the vestibular ganglion is located in the internal auditory meatus
C. irritative lesions cause tinnitus and nystagmus
D. destructive lesions cause ipsilateral deafness
E. it is a special visceral afferent (SVA) nerve

7-E The vestibulacochlear nerve (CN VIII) is classified as a special somatic afferent (SSA) nerve, as is the optic nerve (CN II).

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8. All of the following statements concerning the geniculate ganglion are correct EXCEPT
A. it is found within the temporal bone
B. it receives taste fibers from the anterior
C. it gives rise to the greater petrosal nerve
D. it contains postganglionic parasympathetic neurons
E. it contains sensory neurons than innervate the outer ear

8-D The geniculate ganglion contains all of the first-order sensory neurons of the facial nerve (CN VII) general somatic afferent (GSA) and special visceral afferent (SVA). It is found within the temporal bone and gives rise to he greater petrosal nerve. Sensory neurons in the geniculate ganglion innervate tste buds from the anterior two-thirds of the tongue . taste fibers from the posterior third of the tongue belong to the glossopharyngeal nerve (CV IX). Pseudounipolar ganglion cells of the geniculate ganglion innervate part of the outer ear.

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9. All of the following statements concerning the olfactory nerve are correct EXCEPT
A. it projects directly to the forebrain
B. it synapses with mitral cells
C. its cells of origin are found in the masal mucosa
D. it is a special somatic afferent (SSA) nerve
E. it enters the skull via the cribriform plate of the ethmoid bone

9-D The olfactory nerve (CN I), a special visceral afferent (SVA), consists of the unmyelinated axons of bipolar neurons found in the olfactory epithelium of the upper nasal cavity. There are 25 million neurosensory cells on each side. These axons synapse with mitral cells in the olfactory bulb, a rchinencephalic structure of the forebrain. Mitral cells project directly via the olfactory tract to the primary olfactory cortex of the uncus.

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10. All of the following statements concerning the optic nerve are correct EXCEPT
A. it enters the skull via the superior orbital fissure
B. it is the afferent limb of the pupillary light reflex
C. There is no regeneration after injury
D. It lies within the subarachnoid space
E. its axons are myclinated by oligodendrocytes

10-A The optic nerve (CN II) enters the skull via the optic canal of the sphenoid bone (the ophthalmic artery is also found in the optic canal). Efferent retinal fibers the afferent limb of the pupillary light reflex. The efferent limb is the oculomotor nerve (CN III). The optic nerve is invested with meninges and lies in the subarachnoid space. The optic nerve is a tract of the central nervous system (CNS) and not a peripheral nerve. There is no regeneration after transection. The axons of the nerve are myclinated by oligodendrocytes; peripheral nerve axons are myclinated by Schwann cells.

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11. All of the following statements concerning the oculomotor nerve correct EXCEPT
A. it originates in the rostral midbrain
B. it traverses the cavernous sinus
C. it exits the cranial vault via the superior orbital fissure
D. it has a sympathetic component
E. transection results in ptosis

11-D The oculamotor nucleus is found in the rostral midbrain at the level of the superior colliculus, Ptosis results after transection of the fibers to the lovator palpehrae muscle. The oculomotor nerve (CN III) traverses the wall of the cavernous sinus with CN IV, CN VI, CN V-1, and CN V-2. The oculamotor nerve has a general visceral efferent (GVE) parasympathetic component, which arises from the Edinger. Westphal nucleus. CN III exits the cranium via the superior orbital fissure.

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12. All of the following statements concerning the accessory nerve are correct EXCEPT
A. it exits the skull via the jugular foramen
B. it contains fibers from the nucleus ambiguous
C. it contains fibers from the dorsal motor nucleus
D. it contains fibers from cervical spinal cord levels
E. it innervates two muscles of branchiomeric origin

12-C The accessory (spinal) nerve (CN XI) exits the skull via the jugular foramen (with CN IX and CN X). The spinal part of the spinal accessory nerve enters the skull via the foramen magnum. CN XI contains SVE fibers from the nucleus ambiguous that innervate intrinsic muscles of the larynx; CN XI contains special visceral efferent (SVE) fibers from the cervical spinal cord that innervate two muscles of branchiomeric origin the trapezius and the sternocleidomastoid. The dorsal motor nucleus is the general visceral efferent (GVE) nucleus of the vagal nerve (CN X).

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13. All of the following statements concerning the facial nerve are correct EXCEPT
A. it innervates the lacrimal gland
B. it innervates the stapedius muscle
C. it innervates the posterior belly of the digastric muscle
D. it provides the efferent limb for the corneal reflex
E. it projects to the etic ganglion

13-E The facial (CN VII) provides the preganglionic parasympathetic innervation for the lacrimal, sublingual, and submandibular glands and innervates the stapedius muscle of the tympanic cavity and the posterior belly of the digastric muscle. The otic ganglion receives preganglionic parasympathetic input from the glossopharyngeal nerve (CN IX) and projects postganglionic parasympathetic fibers to the parotid gland.

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14. All of the following statements concerning the trigeminal nerve are correct EXCEPT
A. it contains special visceral efferent (SVE) and general somatic afferent (GSA) fibers
B. it innervates the sensor tympani muscle
C. it innervates the anterior belly of the digastric muscle
D. it innervates the supratentorial dura
E. it innervates the skin over the angle of the jaw

14-E The trigeminal nerve (CN V) [generalsomatic afferent (GSA) and special visceral efferent (SVE)] innervates the tensor tympani muscle, the anterior belly of the digastric muscle, and the supratentorial dura. The skin over the angle of the jaw and the scalp of the back of the head are innervated by the second and third cervical nerves.

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15. Transection of the glossopharyngeal nerve results in all of the following deficits EXCEPT
A. loss of the gag reflex
B. loss of neurons in the superior salivatory nucleus
C. loss of taste and pain sensation from the posterior third of the tongue
D. loss of the carotid sinus reflex
E. loss of neurons in the nucleus ambiguous

15-B Transection of the glossopharyngeal nerve (CN IX) results in degeneration of neurons in the rostral part of the nucleus ambiguous and in the inferior salivatory nucleus, loss of the gag reflex, loss of sensation from the tonsillar bed, loss of taste and pain sensation from the posterior third of the tongue, and loss of the carotid sinus reflex. The superior salivatory nucleus is a general visceral efferent (GVE) nucleus of CN VII.

16

A. Glossopharyngeal nerve
B. Accessory nerve
C. Trigeminal nerve
D. Facial nerve
E. Vagal nerve

16. Innervates
the parotid gland

16-A The glossopharyngeal nerve (CN IX) innervates the parotid gland via the tympanic and lesser petrosal nerves, the otic ganglion, and the auriculotemporal nerve.

17

A. Glossopharyngeal nerve
B. Accessory nerve
C. Trigeminal nerve
D. Facial nerve
E. Vagal nerve

17. Is the efferent limb of
the corneal reflex

17-D The facial nerve (CN VII) provides the efferent limb of the corneal reflex (orbicularis oculimuscle)

18

A. Glossopharyngeal nerve
B. Accessory nerve
C. Trigeminal nerve
D. Facial nerve
E. Vagal nerve

18. Is the efferent limb of
the gag reflex

18-E The vagal nerve (CN X) provides the efferent limb of the gag reflex (muscles of the soft palate). The glossopharyngeal nerve provides the afferent limb of the gag reflex.

19

A. Glossopharyngeal nerve
B. Accessory nerve
C. Trigeminal nerve
D. Facial nerve
E. Vagal nerve

19. Innervates
the infratentorial dura

19-E The vagal nerve (CN X) innervates, via the recurrent meningeal ramus, the infratentorial dura (the dura of the posterior cranial fossa).

20

A. Glossopharyngeal nerve
B. Accessory nerve
C. Trigeminal nerve
D. Facial nerve
E. Vagal nerve

20. Is a pure motor nerve

20-B The accessory nerve (CN XI) is a pure special visceral efferent (SVE) motor nerve. The cranial division innervates, via the recurrent laryngeal nerve, the intrinsic muscles of the larynx; the spinal division innervates, via motor branches, the sternocleidomastoid muscle and upper parts of the trapezius muscle.

21

A. Foramen jugular
B. Innominate canal
C. Foramen magnum
D. Foramen ovale
E. Foramen rotundum
F. Foramen spinosum
G. Foramen stylomastoidum
H. Superior orbital fissure

21. A branch of
the maxillary artery

21-F The middle meningeal artery, a branch of the maxillary artery, traverses the foramen spinosum

22

A. Foramen jugular
B. Innominate canal
C. Foramen magnum
D. Foramen ovale
E. Foramen rotundum
F. Foramen spinosum
G. Foramen stylomastoidum
H. Superior orbital fissure

22. The nerve innervates
the buccinators muscle

22-G The facial nerve (CN VII) exits the base of the skull via the stylomastoid foramen; CN VII innervates the muscles of facial expression, including the buccinators muscle.

23

A. Foramen jugular
B. Innominate canal
C. Foramen magnum
D. Foramen ovale
E. Foramen rotundum
F. Foramen spinosum
G. Foramen stylomastoidum
H. Superior orbital fissure

23. The nerve that innervates the skin
of the upper lip

23-E The maxillary nerve (CN V-2) exits the skull via the foramen rotundum

24

A. Foramen jugular
B. Innominate canal
C. Foramen magnum
D. Foramen ovale
E. Foramen rotundum
F. Foramen spinosum
G. Foramen stylomastoidum
H. Superior orbital fissure

24. Cranial nerves
IX, X, and XI

24-A Cranial nerves IX, X, and XI exit the posterior cranial fossa the jugular foramen

25

A. Foramen jugular
B. Innominate canal
C. Foramen magnum
D. Foramen ovale
E. Foramen rotundum
F. Foramen spinosum
G. Foramen stylomastoidum
H. Superior orbital fissure

25. The nerve that projects to
the otic ganglion

25-B The lesser petrosal nerve of CN IX passes through the innominate canal to synapse with postganglionic neurons of the otic ganglion. The innominate canal lies between the foramen ovale and the foramen spinosum.

26

A. Foramen jugular
B. Innominate canal
C. Foramen magnum
D. Foramen ovale
E. Foramen rotundum
F. Foramen spinosum
G. Foramen stylomastoidum
H. Superior orbital fissure

26. Four cranial nerves traverse
this orifice

26-H Cranial nerves III, IV, VI, and V-1 pass through the superior orbital fissure