Quick Facts
Origin: Posterior cord of the brachial plexus.
Course: Laterally through the quadrangular space and into the lateral arm.
Branches: Superior lateral brachial cutaneous nerve and unnamed muscular branches.
Supply: Sensory and motor innervation. Supplies the skin of the lateral arm and motor innervation to the deltoid and teres minor muscles.
Related parts of the anatomy
Origin
The axillary nerve is the smaller of two terminal branches of the posterior cord of the brachial plexus. It carries fibers from the anterior rami of the fifth and sixth cervical nerves (C5 and C6).
Course
The axillary nerve originates posterior to the axillary artery in the axilla. The axillary nerve runs laterally inferior to the glenohumeral joint where it sends a muscular branch inferiorly to the teres minor muscle.
The bulk of the nerve runs out of the axilla by passing laterally through the quadrangular space. It continues laterally, passing posterior to the surgical neck of the humerus where it is accompanied by the posterior circumflex humeral artery and vein.
Posterior and lateral to the humerus, it branches into the superior lateral brachial cutaneous nerve and a muscular branch to the deltoid.
Branches
The axillary nerve has one named branch, the superior lateral brachial cutaneous nerve. Additionally, it has two unnamed muscular branches that serve the deltoid and teres minor muscles.
Supplied Structures
The axillary nerve is a mixed nerve that carries both sensory and motor innervation. The sensory component is carried by the superior lateral cutaneous nerve of the arm and supplies the skin of the lateral arm overlaying the deltoid.
The motor branches innervate the deltoid and teres minor muscles.
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Axillary Nerve
The axillary nerve is the terminal branch of the posterior cord of the brachial plexus, which arises from the C5 and C6 nerve roots.
