cranial nerves VII - XII

Question 1

VII. Facial nerve

Answer 1

Motor
• Skeletal muscle; muscles of facial expression and stapedius
• Visceral motor (parasympathetic): lacrimal gland and submandibular and sublingual salivary glands
Sensory
• Special sense: taste buds of anterior 2/3rd of tongue
One half supplies upper half of face
Other half supplies lower
Upper half – controlled by both sides of brain
Lower – only opposite side
Therefore:
• UPN lesion – paralysis from check down on one side
• LMN lesion – complete paralysis on one side of face

Testing: inspect face (asymmetry) ask to smile ect, test taste e.g. stick with salt on anterior 2/3rds

Question 2

VIII. Vestibulocochlear

Answer 2

Conducts auditory and vestibular related impulses from the organ of corti, semi-circular canals, the utricle and the saccule
Testing: whispering a number into patients ear, using a tuning fork (Rinne & Weber test), balance (stand on one leg)
problems: skull fractures, toxic drug effects, ear infections, vestibular schwannoma

Question 3

IX. Glossopharyngeal

Answer 3

• Emerges from lateral sulcus of medulla and exits the skull via the jugular foramen, accompanied by the vagus and accessory nerves
motor function to pharynx, secretion from parotid gland
sensation to external ear, tastebuds in posterior 3rd of tongue

Question 4

X. Vagus

Answer 4

Emerges from the medulla to exit the skull through the jugular foramen
Function: swallowing, taste, speech, respiratory, cardiovascular, GI regulation: sensations of hunger, fullness and some intestinal discomfort

Question 5

testing of IX and X

Answer 5

observe quality of patients voice – hoarseness, nasal, ask patient to say ‘ah’ – elevation of palate, gag reflex

Question 6

XI. accessory nerve

Answer 6

• Supplies sternocleidomastoid and trapezius muscles
• Cell bodies of the nerve are situated in the ventral horn of the upper 5 segments of the spinal cord
• They send fibres up through the foramen magnum, which then exit the skull with the cranial nerves IX and X through the jugular foramen
• Cranial aspect: motor component of vagus – recurrent laryngeal ect.
Examination: inspect the neck as patient turns the head against resistance (sternocleidomastoid) , ask to shrug shoulders (trapezius)

Question 7

XII. Hypoglossal

Answer 7

Supplies the intrinsic and extrinsic muscles of the tongue
Cell bodies are located in the hypoglossal nucleus, which lies between the dorsal motor nucleus of the vagus and the midline of the medulla
Exits skull via hypoglossal canal
Examination: ask patient to stick tongue out – will push to side of lesion, atrophy and fubrillations = LMN lesion

Question 8

cerebellopontine angle syndrome

Answer 8

progressive hearing loss, tinnitus, dizziness, facial nerve palsy, facial pain, sensory loss, depressed corneal reflex

Question 9

jugular foramen syndrome

Answer 9

loss of taste sensation, paralysis of vocal cords

ipsilateral trapezius and sternocleidomastoid weakness and atrophy