Axillary nerve anatomy and palsy

Question 1

Motor function?

Answer 1

• Deltoid : abduction of upper limb

- Teres minor : stabilises glenohumeral joint

Question 2

Sensory function?

Answer 2

Badge area

Question 3

Anatomy?

Answer 3

• Forms in the axilla of the upper arm
• Exits the axilla at the quadrangular space
• Passes medially to the surgical neck of the humerus

Question 4

Aetiology of palsy?

Answer 4

• Fracture to surgical neck of humerus
• Shoulder dislocation
• Saturday night palsy (pressure on posterior cord of brachial plexus)

Question 5

Presentation

Answer 5

• Motor loss of shoulder abduction (deltoid muscle)
• Sensory deficit to badge area
• In long standing cases- atrophied deltoid muscle will be flattened