spine

spine 1 The column of bone known as the vertebral column that surrounds and protects the spinal cord. The spine can be categorized according to the level of the body: cervical spine (neck), thoracic spine (upper and middle back), and lumbar spine (lower back). See also vertebral column. 2 Any short prominence of bone. For example, the spines of the vertebrae protrude at the base of the back of the neck and in the middle of the back. These spines protect the spinal cord from injury from behind.