Axillary n.

The axillary nerve supplies two muscles: deltoid (a muscle of the shoulder), teres minor (one of the rotator cuff muscles. 

The axillary nerve or the circumflex nerve is a nerve of the human body, that originates from the brachial plexus (upper trunk, posterior division, posterior cord) at the level of the axilla (armpit) and carries nerve fibers from C5 and C6. The axillary nerve travels through the quadrangular space with the posterior circumflex humeral artery and vein.