Scapula is a flat, triangular bone. Anteriorly it has two extensions called coracoid process and acromial process. At its narrow end is the gynoid cavity. The head of the humerus is inserted into the gynoid cavity. It contains a concave part called the subscapular fossa. Behind it lies a scapular spine. Above the spine is the supraspinous fossa and below the infraspinous fossa.