• (n.) An atrophy of the muscles of the shoulder in horses; also, atrophy of any muscle in horses.
Swee'ny noun (Far.) An atrophy of the muscles of the shoulder in horses; also, atrophy of any muscle in horses. [ Written also swinney .] 
Atrophy of the supraspinatus and infraspinatus muscles, located over the scapula (shoulder-blade); usually caused by damage to the nerve supply to these muscles.
atrophy of the shoulder muscles in horses.