Cranial Nerves

Front 1

When to perform a CN exam

Back 1

suspected lesions of the brain, brainstem, and C/S

Front 2

Purpose of CN exam

Back 2

1. Provides location of dysfunction within the brainstem
2. Provides function of mm innervated by the CNs; visual, auditory, sensory, gag reflex integrity, perception of taste, swallowing characteristics, eye movements, and constriction/dilation of pupils

Front 3

Suspect Lesions (name loc)

Back 3

CN I: nasal cavity and ant/inf cerebrum
CN II: visual deficits
CN III and IV: Midbrain lesions
CN V and VI: Pontine lesions
CN VII and VIII: Pons and Medulla
CN IX, X, XI, and XII: Medulla lesions

Front 4

Afferent only CNs

Back 4

I, II, VIII
Olfactory, Optic, and vestibulocochlear

Front 5

Efferent Only CNs

Back 5

III, IV, VI, XI, XII

Front 6

Parasympathetic fibers are carried in which CNs?

Back 6

- CN III smooth mm in the eye ball (edinger wesphal for pupillary response and accomodation)
- CN VII salivary and lacrimal glands
- CN IX: parotid salivary glands
-CN X: heart, lungs, and most of digestive tract

Front 7

Efferent only CNs
-some fibers project directly to ______ _____ ______ ________ (trigeminal , facial, and hypoglossal)
- And others to the _________ formation before reaching the CN nuclei

Back 7

motor cranial nerves nuclei

reticular formation

Front 8

Afferent/Efferent functions of CNs V VII IX and X

Back 8

V: (e) mm of mastication, eardrum tension. (a) sensation from face
VII: (e) facial expression, ear bone tension, lacrimation, salivation. (a): anterior 2/3 tongue for taste,
IX: (e) swallowing, tongue, pharynx, salivation. (a) taste on post 1/3 of tongue
CN X: (e) laryngeal control, thoracic and abdominal viscera. (a) taste and visceral sensory

Front 9

Abnormal Findings:
CN I

Back 9

Anosmia

Front 10

Abnormal findings CN II

Back 10

Blindness, myopia, presbyopia
field deficits (homonymous hemianopsia)

Front 11

Abnormal findings CN II, III

Back 11

absense of pupillary constriction
aniscoria (unequal pupils)
Horner's Syndrome (droopy eye)

Front 12

Abnormal findings: CN III, IV, VI

Back 12

strabismus, impaired eye movements, double vision

Front 13

Abnormal findings CN III

Back 13

strabismus. Cannot look up down and inward

Front 14

AF CN IV

Back 14

Eye cannot look downward when adducted

Front 15

AF CN VI

Back 15

eye cannot look out

Front 16

AF CN V

Back 16

1.Loss of facial sensation, numbness, loss of corneal reflex (usually I/L?)
2. Weakness of jaw deviation to ipsilateral side when opened

Front 17

AF CN VII

Back 17

1. Paralysis, inability to close eyes, drooping corner of mouth, difficulty with articulation
2. Inability to taste and 2/3 tongue
3. Unilateral LMN=bell's palsy
Bilateral LMN= Guillian Barre
Unilateral UMN = stroke

Front 18

AF CN VIII

Back 18

1. Vertigo
2. Dysequilibrium
3. Nystagmus
4. Deafness
5. Impaired Hearing
6. Tinnutus
7. Conductive Loss (use tuning fork)

Front 19

AF CN IX

Back 19

1. Unable to taste post 1/3

Front 20

AF CN IX and X

Back 20

1. Dysphonia (quality and pitch of voice)
2. Dysphagia (difficulty swallowing)
3. Palate Paralysis
4. Absent gag reflex

Front 21

AF XI

Back 21

-UMN: weakness of ipsilateral SCM and contralateral traps
-LMN: atrophy, fasciculations, I/L weakness
Inability to shrug shoulders
Inability to turn head to opposite side

Front 22

AF CN XII

Back 22

1. Dysarthria (also seen with V, VII, X)
2. Tongue deviating to weak side
3. Atrophy or fasciculations of tongue (LMN)
4.UMN: tongue deviates away from side of cortical lesion (C/L weakness).