Axillary nerve

Question 1

What spinal roots is the axillary nerve derived from?

Answer 1

C5, C6

Question 2

What is the origin of the axillary nerve?

Answer 2

Posterior cord of brachial plexus

Question 3

What is the course of the nerve?

Answer 3

Passes beneath shoulder joint through the quadrangular space

Wraps around surgical neck of humerus

Question 4

What is the sensory supply of the nerve?

Answer 4

Sergeant’s patch on the deltoid

Question 5

What is the motor supply of the nerve?

Answer 5

Shoulder muscles:
Deltoid- Abducts, extends, flexes shoulder
Teres minor- External rotation
Rotator cuff, stabilise shoulder

Question 6

How could this nerve be injured?

Answer 6

Fracture surgical head of humerus
Anterior dislocation of shoulder joint
Crutch palsy

Question 7

What would be the features of nerve injury?

Answer 7

Numbness over sergeant’s patch
Wasting of deltoid
Weak shoulder extension, flexion, abduction, external rotation