Action:  Shoulder medial rotation

Nerves:  Axillary, medial and lateral pectoral, subscapular and thoracodorsal

Skeletal muscles:  Deltoid, pectoralis and teres majors, subscapularis, and latissimus dorsi

Cutaneous distribution:  None except for the axillary nerve

Neuromuscular deficit:  Weakness/paralysis when rotating medially at the shoulder joint under resistance. Denervation is accompanied by muscular atrophy, lateral rotation of the shoulder, and cutaneous deficit along the distribution of the axillary (superior lateral brachial cutaneous) nerve.

Differential diagnosis:  Weakness/paralysis plus cutaneous deficit along the superior and lateral arm are diagnostic of axillary nerve impairment, because the medial and lateral pectoral, subscapular and thoracodorsal nerves have no distribution in the skin.