Medulla CNs

Question 1

Which 4 CNs arise from the medulla?

Answer 1

Glossopharyngeal, vagus, spinal accessory, hypoglossal

Question 2

What is the course of the glossopharyngeal nerve? What fibres does it carry?

Answer 2

Arises in medulla, exits through jugular foramen. ALL- SS, M, AN, GS

Question 3

What are the functions of the glossopharyngeal nerve?

Answer 3

• General sensation to soft palate, tonsils and oropharynx
• Tympanic membrane (inner)
• Taste and GS post 1/3 tongue
• Senory from carotid body and sinus
• AN to parotid
• M to stylopharyngeus

Question 4

Which nerves controls the gag reflex?

Answer 4

Glossopharyngeal- sensory limb

Vagus- efferent

Question 5

What is the route of the vagus nerve?

Answer 5

Arises in the medulla exits through jugular foramen, enters carotid sheath and travels down the neck

Question 6

What nerve fibres does the vagus nerve carry?

Answer 6

GS, M, AN, ss

Question 7

What is the function of the vagus nerve?

Answer 7

• Sensory to larygopharynx, larynx and part of ear.
• Muscles of soft palate, pharynx, larynx.
• Parasymp to thorax and abdo viscera

Question 8

What does deviation of the uvula indicate?

Answer 8

Damage to the vagus nerve- deviates away from side of lesion

Question 9

What can damage to the RLN cause clinically? What nerve is it a branch of?

Answer 9

Branch of vagus nerve, causes hoarseness of voice and dysphonia (difficulty speaking)

Question 10

What do the L and R RLN pass under?

Answer 10

R- R subclavian, L- arch of the aorta

Question 11

What is the course of the spinal accessory nerve? What fibres? what does it supply? How to test?

Answer 11

Arises in medulla, through jugular foramen.
M. Fibres from upper 5/6 cervical segments
SCM and trapezius.
Shrug shoulders, turn head against resistance

Question 12

Through what triangle does the spinal accessory nerve run through? When is it susceptible to injury?

Answer 12

Posterior triangle.

Lymph node biopsies, stab wounds

Question 13

What is the course of the hypoglossal nerve? What fibres? What does it supply? Test?

Answer 13

Leaves medulla and passes through hypoglossal canal, runs medial to angle of mandible and crosses internal and external carotids in neck
M.
Supplies muscles of the tongue on that side- inspect tongue movements

Question 14

What would wasting of tongue muscles on one side indicate?

Answer 14

Damage to the hypoglossal nerve on hat side