Teres minor - Musculus teres minor
Origin: Lateral border of the scapula
Insertion: Inferior facet of greater tubercle of the humerus
Artery: Posterior circumflex humeral artery and the circumflex scapular artery
Nerve: Axillary nerve
Action: Laterally rotates and adducts the arm
Antagonist: Subscapularis, pectoralis major, and latissimus dorsi
The Teres minor is a narrow, elongated muscle, which arises from the dorsal surface of the axillary border of the scapula for the upper two-thirds of its extent, and from two aponeurotic laminae, one of which separates it from the Infraspinatus, the other from the Teres major. Its fibers run obliquely upward and lateralward; the upper ones end in a tendon which is inserted into the lowest of the three impressions on the greater tubercle of the humerus; the lowest fibers are inserted directly into the humerus immediately below this impression. The tendon of this muscle passes across, and is united with, the posterior part of the capsule of the shoulder-joint.
Variations.—It is sometimes inseparable from the Infraspinatus.
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).