Axillary & suprascapular nerves
|Origin:||Posterior cord of the brachial plexus|
|Innervation:||Deltoid, teres minor, skin of the lateral upper arm at the area of the deltoid, shoulder|
|Vertebral levels:||C5 nerve root, C6 nerve root|
|Search for Axillary nerve in Gray's.|
The axillary nerve arises from the posterior cord laterally to the radial nerve and posterior to the axillary artery. It lies anterior to subscapularis initially, curving posteriorly around its inferior border beneath the capsule of the shoulder joint. It then accompanies the posterior circumflex humeral artery as it traverses the quadrangular space. Once it has left the quadrangular space the nerve divides into two portions: anterior and posterior.
The anterior branch curves around the humeral neck, accompanying the posterior circumflex humeral artery. It lies deep to deltoid until it reaches that muscle's anterior border, where it provides innervation. A small patch of skin is supplied above the anterior border of deltoid by fibres of the anterior branch.
The posterior branch gives supply to teres minor and the posterior portion of deltoid. It continues on to pierce the deep fascia on the posterior border of deltoid, emerging as the upper lateral cutaneous nerve of the arm.
- Damaged in 5% of shoulder dislocations