Modular shoulder prosthesis

A shoulder prosthesis, especially for treatment of degenerative arthritis or trauma, has an articulating head component (34). The shoulder prosthesis includes a humeral stem (32) and a series of humeral heads. The heads are attached to the humeral stem by means of a locking connector. The locking connector allows the humeral head to be oriented in multiple positions of version, varus/valgus angulation, eccentricity and head height, while providing rigid securing of the humeral head to the humeral stem (32) in the selected position relative to the humeral stem. In one form, the locking connector includes an expansion collar (36) that provides radially outward expansion for humeral head position locking. The disclosed shoulder prosthesis provides a means to anatomically position the humeral head relative to the humeral stem and rigidly secure the humeral head in the selected position relative to the humeral stem. This is accomplished by a minimum of components.