A column of bones called vertebrae make up your spine. The spinal cord passes through the center o...
Read the full transcript »
A column of bones called vertebrae make up your spine. The spinal cord passes through the center of the column. The bones, or vertebrae, that make up the spinal column are not stacked directly on top of each other. There are spaces between them that are maintained by round, spongy pads of cartilage called intervertebral disks. Each intervertebral disk is made up of two components, the anulus fibrosus and the nucleus pulposus. The anulus fibrosus is the tough, outer portion of the disk. The nucleus pulposus is the inner gel material surrounded by the anulus fibrosus. These disks and the space between the bone that they fill, give the back flexibility. The disks act much like shock absorbers throughout the spinal column to cushion the bones as the body moves.