Spinous Process

The spinous process of a vertebra is directed backward and downward from the junction of the laminae (in humans), and serves for the attachment of muscles and ligaments. In animals without an erect stance, the process points upward and may slant forward or backward. Spinous processes are exaggerated in some animals, such as the extinct Dimetrodon and Spinosaurus, where they form a sail- or finback.