Abstract: An endoprosthetic shoulder joint device has a scapular component of generally L-shape, usually with one arm longer than the other, and formed with a spherical concave bearing surface in its inner face to extend at least over the free end portion of the longer arm. If the concave surface extends in the shorter arm, the latter arm is thickened for this purpose. The concave surface can open into the edges of the L-shape, the longer arm is usually of cranked form, and the outer face is relieved for cement securement keying. The associated humeral component can be of conventional ball-headed, stemmed form, but is preferred as a spherical segmental form which is solid with a short stem projecting from its chordal face, or hollowed and grooved in its interior.