4-Stage Osteoarthritis Knee anatomy model Set of 4 knee models (3/4 scale) illustrating: Degenerative joint disease (osteoarthritis); Erosion to joint articular cartilage; Progression of degenerative joint disease; Osteophytes (bone spurs) at the articular surfaces. Model size: 3" x 1-3/4" x 5-1/2" Card size: 8-1/4" x 6-1/4" 5" x 6" x 1" White Base included with every model. Made of durable high quality materials.