Nerves

Question 1

CN I

Answer 1

Olfactory - smell

Question 2

CN II

Answer 2

Optic - vision

Question 3

CN III

Answer 3

Oculomotor – eye movements, pupil

Question 4

CN IV

Answer 4

Trochlear – eye movements

Question 5

CN V

Answer 5

Trigeminal – sensations from head/teeth, motor to chewing muscles

Question 6

CN VI

Answer 6

Abducens – eye movements

Question 6

CN VII

Answer 6

Facial – muscles of facial expression, salivation, tears

Question 7

CN VIII

Answer 7

Vestibulocochlear/Acoustic – hearing and balance

Question 8

CN IX

Answer 8

Glossopharyngeal – tongue movement, swallowing, taste

Question 9

CN X

Answer 9

Vagus – numerous functions = parasympathetic function, innervation of larynx/pharynx

Question 10

CN XI

Answer 10

Accessory – head movement

Question 11

CN XII

Answer 11

Hypoglossal – tongue movement

Question 12

Facial nerve

Answer 12

Cranial nerve VII
Superficial on the side of the face
Controls facial muscles
Also innervates tear and salivary glands
Injury = halter or lateral recumbency → causes drooping of the lip, ear and nostril on that side

Question 13

Vagal nerve

Answer 13

Cranial nerve X
Originates from the brainstem
Longest nerve in the body – brainstem → colon
In the neck it runs next to the jugular vein and carotid artery
Motor function to larynx, pharynx, thoracic organs, and digestive tract
Laryngeal paresis in horses
Sensation to GI and respiratory tracts

Question 14

Brachial plexus

Answer 14

Group of intraconnected in the axilla that give rise to nerves of the forelimb
Radial nerve – most cranial, damage causes paw to drag
Median nerve – middle nerve
Ulnar – most caudal, “funny bone” in humans

Question 15

Femoral nerve

Answer 15

Runs on the medial surface of the thigh
Next to the femoral artery and vein
Motor to muscles of the thigh
Sensory to the skin of the hindlimb
Can be damaged during birth if hind limbs under strong traction (foals/calves)

Question 16

Sciatic nerve

Answer 16

On lateral thigh between biceps femoris muscle
Motor to flexors of the stifle and digits
Can be damaged with pelvic or femur fractures, or improper IM injection

Question 17

How to test II

Answer 17

Damage causes varying degree of blindness and pupillary light reflex abnormalities
Tests
Menace (caution of touching or air currents)
Obstacle course or dropping cotton balls
Pupillary light reflex- both pupils should. Less pronounced in the other eye. Called the consensual

Question 18

How to tell if something is wrong with III

Answer 18

Test- pupillary light reflex
Ptosis(drooping of upper eyelid)
A branch innervates the levator palpebrae muscle
Strabismus- abnormal position of eyeball
Dorsal, ventral , medial recti muscle as well as the ventral oblique muscle

Question 19

How to test if something is wrong with V

Answer 19

Dropped jaw
Sensory to head and eye
Tests
Palpebral reflex
Corneal reflex
Response to nasal stimulation

Question 20

How to test if something is wrong with VI

Answer 20

Strabismus
Corneal reflex- with eyelids held open, observe for retraction of eyeball and movement of 3rd eyeball

Question 21

How to test if something is wrong with VII

Answer 21

Motor- muscles of facial expression
Sensory- taste (cranial part of tongue)
Tests
Menace
Palbebral reflex
Corneal reflex
Examine nose for deviation, drooling, accumulation of food and pendulous lower lip
Facial nerve paralysis
Drooping lip, drooling or food accumulation on lips, loss of palbebral reflex, dry eye

Question 22

Signs something is wrong with VIII

Answer 22

Poor hearing
Head tilt, ataxia, tendency to fall, roll or circle
Nystagmus- rapid eye movements in horizontal, vertical or rotary orientation

Question 23

Signs something is wrong with X

Answer 23

Abnormal vocalization
Inspiratory dyspnea
Abnormal heart rate and activity