CNs

Question 1

CN I name, function, test, signs of dysfunction, where originates

Answer 1

• Olfactory
• smell
• not routinely tested
• Anosia, hypponosia
• teloncephalon

Question 2

CN II name, function, test, signs of dysfunction, where originates

Answer 2

• Optic
• Vision, response to light
• menace response, PLR, obstacle course, tracking moving objects
• blindness, dilated, deminished to absent PLRs
• diencephalon

Question 3

CN III name, function, test, signs of dysfunction, where originates

Answer 3

• Oculomotor
• Motor to extraocular muscles, parasympathetic to pupil (pupil constriction)
• Physiologic nystagmus, resting globe position, PLRs
• Ventrolateral stabismus, ptosis, dialated pupils, diminished to absent PLRs
• mesencephalon

Question 4

CN IV name, function, test, signs of dysfunction, where originates

Answer 4

• trochlear
• Motor to dorsal oblique muscle
• resting globe position (easily observed in cats, fundic exam needed to discern in dogs)
• exrtorsion of the globe, dorsomedial stabismus (cat), lateral deviation of retinal vein (dog)
• mesencephalon

Question 5

CN V name, function, test, signs of dysfunction, where originates

Answer 5

• trigeminal
• motor to muscles of mastication (mandibular), sensory to face (ophthalmic, maxillary, mandibular)
• jaw tone, muscle bulk, sensation to face, corneal, and nasal mucosa
• ventral metencephalon

Question 6

CN VI name, function, test, signs of dysfunction, where originates

Answer 6

• Abducens
• Motor to lateral rectus and retractor bulbi muscles
• Physiologic nystagmus, resting globe position
• Medial strabismus
• brainstem

Question 7

CN VII name, function, test, signs of dysfunction, where originates

Answer 7

• Fascial
• Motor to muscles of facial expression, parasympathetic to lacrimal glands, sensory (taste) to rostral tongue
• Menace respose, palpebral reflex, lip retraction, ear movement and position (in animals with erect ears), STT
• Inability to close eyelid, move ear, or retract lip, deviation of nasal philtrum (contralateral), dry eye, alternatively hemifacial tetany where nasal philtrum in deviated towards effected side.
• brainstem

Question 8

CN VIII name, function, test, signs of dysfunction, where originates

Answer 8

• Vestibulocochlear
• Balance, hearing
• Body and head posture, eye movement and position, hearing
• Head tilt, vestibular ataxia, nystagmus, positional strabismus, deafness
• brainstem

Question 9

CN IX name, function, test, signs of dysfunction, where originates

Answer 9

• Glossopharyngeal
• Sensory and motor to pharynx
• Gag reflex, ability to swallow
• Diminished gag reflex, dysphagia
• brainstem

Question 10

CN X name, function, test, signs of dysfunction, where originates

Answer 10

• vagus
• sensory and motor to pharynx, larynx, and viscera
• gag reflex, oculocardiac reflex, observation of inspiratory stridor
• Diminished gag reflex, dysphagia, laryngeal paralysis, megaesophagus
• brainstem

Question 11

CN XI name, function, test, signs of dysfunction, where originates

Answer 11

• Accessory
• External branch - motor to trapezius, internal branch - joins CN X to innervate the larynx
• Evaluation of muscle mass of the dorsal aspect of the shoulder (trapezius), observation of inspiratory stridor
• Atrophy of trapezius m, laryngeal paralysis
• brainstem

Question 12

CN XII name, function, test, signs of dysfunction, where originates

Answer 12

• Hypoglossal
• Motor to tongue muscles
• evaluation of tongue
• atrophy of tongue, inability to retract tongue if bilateral
• brainstem

Question 13

CN - LIST IN ORDER!!!

Answer 13

I - Olfactory
II - Optic
III - Occuomotor
IV - Trochlear
V - Trigeminal
VI - Abducens
VII - Facial
VIII - Vestibulocochlear
IX - Glossopharyngeal
X - Vagus
XI - Accessory
XII - Hypoglossal