Letter: D

A sheath containing the spinal cord and/or nerve roots.

A radiographic test that measures bone mineral density (BMD) in order to identify osteoporosis, risk for fractures (broken bones), and response to osteoporosis treatment.

A procedure involving surgical excision of the nucleus pulposus which has pushed or broken through the outer rings of the disc. Healthy disc is actually adhered to bone. During surgery, we only remove loose disc material. The remaining portion of the disc is left intact.

The oval-shaped wedges of fibrocartilage found between adjacent vertebrae. The tough, fibrous outer portion is called the annulus fibrosus. It is composed of multiple fibrocartilaginous rings. These rings firmly attach to the vertebrae above and below the disc and help hold the segments together. The inner portion is called the nucleus pulposus and is composed of approximately 80% water. The inner nucleus pulposus actually looks and feels like crab meat. The primary functions of the discs are to act as shock absorbers and to transfer mechanical stresses to allow for smooth movement. The discs also add stability to the spine by virtue of the fact they operate on a pressure gradient system.

A NORMAL wear-and-tear process of the spine which occurs with aging. This affects all of us if you live long enough. Degenerative changes can be noted as early as the teenage years. Genetics as well as environmental factors (i.e., trauma and normal wear & tear) can result in the discs losing water. Tears in the annulus fibrosus may also occur. This, in turn, causes the vertebrae to come closer together producing increased stress on bones, joints, and ligaments. Pain may or may not occur with this condition. Even though the condition may persist or progress, it can sometimes be controlled with proper mechanics and strong muscles.

A procedure involving surgical excision of structures causing pressure on nerves most commonly from bone spurs (osteophytes), ligaments, cysts, and/or disc herniations.