The human spine consists of 33 vertebra: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral which fuse to form the sacrum and 4 coccygeal which are also fused together to form the coccyx bone or tail bone. These bones surround and support the spinal cord which connects the brain with the body. Between the bones are disks which act as shock absorbers and configure to both the stability and flexibility of the spine. Each spinal disk is called a nucleus pulposus and a herniated nucleus pulposus is a disk that is out of place, otherwise known as a "slipped disk" and abbreviated as HNP. Many people with disabilities have as a component of their physical limitations problems associated with one or more HNPs.