The human spine is made up of twenty-four small bones, called vertebrae. The vertebrae protect and support the spinal cord. They also bear the majority of the weight put upon your spine. Vertebrae, like all bones, have an outer layer called cortical bone that is hard and strong. The inside of the core is made of a soft, spongy type of bone, called cancellous bone.
The vertebral body is the large, round portion of bone. Each vertebra is attached to a bony ring. When the vertebrae are stacked one on top of the other the rings create a hollow tube for the spinal cord to pass through. Each vertebra is held to the others by groups of ligaments.
The bony ring attached to the vertebral body consists of several parts. The laminae extend from the body to cover the spinal canal, which is the hole in the center of the vertebrae. The spinous process is the bony portion opposite the body of the vertebra. There are two transverse processes (bumps), where the back muscles attach to the vertebrae. The pedicle is a bony projection that connects to both sides of the lamina. This is the ridge that you can see and feel if you observe the vertebrae on anyone’s back.