Each model is comprised of two life-size vertebrae. The first pair shows one set with normal anatomy and one with a "bulging" herniated disc. The second set of vertebrae shows one with bone and disc degeneration, and the fourth with advanced osteoporosis with marked bone compression and bone spurs. Model measures: 3-3/4 in. x 3 in. x 3-1/8 in. Base: 5 in. x 6 in. x 1 in. Includes education card.