Accesory Nerve

Question 1

Origin

Answer 1

It is a motor nerve arising by 2 roots:
1. Spinal
2. Cranial

Question 2

Spinal root

Answer 2

From upper 5-6 spinal cord segments

Question 3

Cranial root

Answer 3

From nucleus ambiguous in medulla

Question 4

Course: spinal root

Answer 4

1. Enters skull through foramen magnum
2. Leave through jugular foramen to enter neck
3. Descends inside carotid sheath between ICA and
   IJV
4. Passes backwards deep to digastric posterior belly crossing IJV
5. Pierces sternomastoid at junction of upper and middle 1/3
6. Reach and crosses posterior triangle on Levator scapulae within roof deep fascia
7. Leave it deep to trapezius 5cm above clavicle

Question 5

Course: cranial root

Answer 5

1. Leaves skull through jugular foramen
2. Join vagus nerve to be distributed with pharyngeal and laryngeal branches
   Both roots join each other in jugular foramen and separate below

Question 6

Branches: spinal

Answer 6

2 muscles:
1. Sternomastoid
2. Trapezius

Question 7

Branches: cranial

Answer 7

1. All muscles of larynx
2. All muscles of pharynx
   Except Stylopharyngeus
3. All muscles of soft palate except tensor palati

Question 8

Applied anatomy: injury of spinal root of accessory nerve

Answer 8

Because it is subcutaneous, it can be injured by:
1. Superficial cut wound
2. Lymph node biopsy
Leading to:
1. Weakness and atrophy of sternomastoid and trapezius Causing:
1. Neck and face rotatory movement impairment to opposite side

Question 9

Accessory nerve

Answer 9

11th cranial nerve