Nerve
Axillary nerve
Motor and sensory supply around the deltoid
High-yield
Check both movement and sensation after a shoulder dislocation or proximal humeral fracture. The small skin patch near the lower lateral deltoid is supplied by a cutaneous branch of this nerve.
Overview
This posterior-cord branch curves from the axilla around the upper humerus. It powers deltoid and teres minor, linking its function to arm elevation, outward rotation and shoulder stability.
Learning this group? Read How to learn the brachial plexus.
Reference facts
- Root value
- Usually C5-C6, carried through the posterior cord
- Course
- Leaves the axilla through the quadrangular space beside the posterior circumflex humeral vessels; branches wrap around the surgical neck
- Motor
- Deltoid and teres minor muscles
- Sensory
- Skin near the inferior lateral deltoid through the superior lateral cutaneous nerve of the arm
Clinical correlation
Axillary nerve damage can weaken shoulder abduction and later produce deltoid wasting. Some movement may remain because supraspinatus and other shoulder muscles have separate nerve supplies.
Frequently asked questions
What are the roots of the axillary nerve?
Usually C5-C6, carried through the posterior cord.
What muscles does the axillary nerve supply?
The axillary nerve supplies the deltoid and teres minor muscles.
What is the sensory distribution of the axillary nerve?
The axillary nerve carries sensation from the skin near the inferior lateral deltoid through the superior lateral cutaneous nerve of the arm.
What is the course of the axillary nerve?
Leaves the axilla through the quadrangular space beside the posterior circumflex humeral vessels; branches wrap around the surgical neck.