Set of four shoulder models, reduced size, illustrating degenerative joint disease (osteoarthritis) of glenohumeral joint: erosion to joint articular cartilage, progression of degenerative disease, osteophyte (bone spur) formation at the articular surfaces, and humeral head flattening. Normal stage includes a full scapula. Advanced stage shows acromioclavicular joint osteoarthritis. All stages show ligaments.