Muscular branches of axillary nerve

Muscular branches of axillary nerve are given off to two muscles, namely the deltoid and the teres minor muscles.

The axillary nerve originates from the posterior cord of brachial plexus. It passes behind the axillary artery to traverse through the quadrangular space, winding around the surgical neck of humerus underneath the shoulder joint. During its course, the axillary nerve divides into anterior and posterior divisions. The anterior division provides muscular branches to the anterior and middle heads of deltoid muscle, and helps in abduction of the shoulder joint, along with flexion and internal rotation. While the posterior division innervates the posterior head of deltoid and the teres minor muscles, and helps in extension and external rotation of the shoulder joint.