The Physiological spine model with soft discs and stand has extra soft disc material, which shows natural compression of discs under movement of the spine. While moving the spine one side of a disc gets compression from the vertebrae above and below material gets pressed out of the vertebrae - just like natural human disc material does. The Physiological spine model comes with an extra flexible metal joint rod and a flexible pelvis mounting, spinal cord, nerves, arteries, a sectioned sacrum, femur heads and stand.