Lab 10.2: Study Questions

Front 1

Which cranial nerve emerges from the dorsal aspect of the brainstem? What else is unique about this nerve?

Back 1

*Trochlear (CN IV)
*it is also the only cranial nerve that decussates

Front 2

Which nerves emerge from the medulla?

Back 2

*hypoglossal (CN XII)
*spinal accessory (CN XI)
*vagus (CN X)
*glossopharyngeal (CN IX)

Front 3

Which cranial nerves emerge from the pons?

Back 3

*trigeminal (V)

Front 4

Which cranial nerves emerge from the mid-brain?

Back 4

*occulomotor (CN III)
*trochlear (CN IV)

Front 5

Which nerves emerge from the crevice between the pons and medulla?

Back 5

*vestibulocochlear (CN VIII)
*facial nerve (CN VII)
*abducens nerve (CN VI)

Front 6

Which cranial nerve exits from between the olive and pyramid?

Back 6

Hypoglossal (CN XII)

Front 7

Which cranial nerve has a branch that enters the cranium through the foramen magnum and exits through the jugular foramen?

Back 7

Spinal accessory (CN XI)

Front 8

Which cranial nerves course through the superior orbital fissue?

Back 8

*occulomotor (CN III)
*trochear (CN IV)
*ophthalmic division of trigeminal (CN V-1)
*abducens nerve (CN VI)

Front 9

Which cranial nerves are purely motor in function and what is the musculature supplied by each?

Back 9

*CN III - extraocular muscles
*CN IV - superior oblique
*CN VI - lateral rectus
*CN XI - trapezius, SCM
*CN XII - muscles of the tongue

Front 10

Damage to which cranial nerve causes ptosis?

Back 10

Occulomotor (CN III) which innervates the palpebral muscle. Note that ptosis can also be caused by damage to the sympathetic innervation of the superior tarsal plate.

Front 11

Which cranial nerves mediate the corneal reflex? What is a major clinical problem following loss of this reflex?

Back 11

*the sensory aspect is mediated by CN V, the motor aspect is mediated by CN VII
*corneal abrasion

Front 12

Which cranial nerves carry sensation from the skin of the face and scalp?

Back 12

*CN V - skin of face and anterior half of the scalp
*CN VII, X, XI - skin of ear
*C2 - posterior half of the scalp

Front 13

Which cranial nerve carries information from the tip of the tongue about taste? About touch? About thermal events?

Back 13

*CN VII - taste from the anterior 2/3 of the tongue
*CN V - touch, pain, and temperature from the anterior 2/3 of the tongue

Front 14

If the right hypoglossal nerve were damaged, to which side would the tongue deviate upon protrusion?

Back 14

It would deviate towards the side of the lesion - in this case, to the right.

Front 15

Hoarseness, deviation of the uvula, and difficulty swallowing are all signs of damage to which cranial nerve?

Back 15

Vagus (CN X)

Front 16

What test is used to assess the function of CN XI?

Back 16

The sppinal accessory nerve can be tested with the shoulder shrug and lateral rotation of the head.

Front 17

How do deficits produced by damage to CN VII along its intradural course compare with those resulting from damage distal to the stylomastoid foramen?

Back 17

*proximal lesions result in paralysis of facial muscles, loss of taste, and loss of lacrimation
*distal lesions result in paralysis of facial muscles only