As the circumflex (axillary) nerve passes through the quadrangular space, it sends twigs to the capsule of the joint; and, on leaving the space, it supplies the Teres Minor. Thereafter, it supplies the Deltoid and the skin covering the Deltoid. This nerve, then, is distributed to the joint, to two muscles that act upon the joint, and to the skin covering the joint.
Surgical Anatomy. Arch Surg. 1996;131(1):108. doi:10.1001/archsurg.1996.01430130110029