Anomalies of the scapula.

This is a report of a case of double acromion and double coracoid and a commentary on the comparative anatomy and embryology of the shoulder. Congenital elevation of the scapula, ossification of the transverse scapular ligament, clasp-like superior border of the scapula, coracoclavicular joint, coracoclavicular bridge, coracosternale bone, os acromiale, elongated acromion, convex glenoid, hypoplasia of the inferior border of the glenoid, dentated glenoid, infrascapular bone, and notched inferior angle of the scapula are other anomalies of the scapula reported in the literature.