Glossary: Back Pain

Content provided by the Faculty of the Harvard Medical School

Glossary

ankylosing spondylitis: An inflammatory disease of the spine that often leads to pain and stiffness of the spine.

annulus fibrosus: The multilayered, fibrous outer portion of an intervertebral disk.

articular processes: The two upper and two lower bony projections on the back part of each vertebra, which form the facet joints.

bone scan: A diagnostic procedure in which radioactive material is injected into the patient's bloodstream to produce images of the bony skeleton. Used to locate areas of rapid bone formation that might signal, for example, a tumor or an infection.

cauda equina: The bundle of nerve fibers that starts at the top of the small of the back and continues to the bottom of the spinal canal. This bundle of nerves is called cauda equina because it resembles a horse's tail.

chemonucleolysis: A treatment for low back pain that involves injecting the enzyme chymopapain into a herniated disk to dissolve the nucleus pulposus.

computed tomography (CT): A diagnostic technique in which x-rays are taken in many different directions. A computer synthesizes the x-rays to generate cross-sectional and other images of the body.

disk: See intervertebral disk.

diskectomy: The surgical removal of all or part of an intervertebral disk.

diskitis: Inflammation of an intervertebral disk.

electromyography (EMG): A series of diagnostic procedures that involve measuring electrical activity in muscles to help diagnose neuromuscular disorders.

facet joint: The joints between the interlocking vertebrae that form the spine.

free fragment: A displaced portion of an intervertebral disk that has become detached from the central portion of the disk.

herniated disk: Displacement of some portion of the disk out of its normal location.

iliopsoas muscles: Two muscles, each of which is located on and attached to each side of the lumbar vertebrae as well as being attached to the inside of the pelvis and to the thighbone.

intervertebral disk: One of the small, shock-absorbing cushions located between the vertebrae of the spine.

intervertebral foramina: The two narrow spaces between adjacent vertebrae (one on each side), through which nerve roots pass.

intradiscal electrothermal annuloplasty (IDET): A procedure to relieve the pain of certain disk problems, in which a heated catheter — inserted via a needle placed in the affected disk — sears or cauterizes the nerve fibers along the disk wall.

kyphoplasty: A minimally invasive procedure to alleviate pain from spinal compression fractures. An orthopedic balloon is placed in the affected vertebra and is inflated; the resulting cavity is filled with bone cement in order to stabilize the vertebral fracture.

lamina: One of the two thin, platelike parts of each vertebra that join in the midline and form the base of the spinous process of that vertebra.

laminectomy: An operation in which all or a portion of one or both laminae is removed to gain access to the spinal canal or to decompress the spinal cord and nerve roots.

lumbar spine: The five lowermost vertebrae of the spine.

magnetic resonance imaging (MRI): A diagnostic technique in which radio waves generated in a strong magnetic field are used to provide information about the tissues within the body; a computer uses this information to produce images of the tissues in many different planes.

myelography: A diagnostic technique in which x-rays are taken of the spine after a contrast medium has been injected into the space within the sheath that surrounds the spinal cord and the cauda equina. This test enables a radiologist to see distortions in the shape of the space, such as those produced by a herniated disk, tumor, fracture, or spinal stenosis.

nucleus pulposus: The gel-like central portion of each intervertebral disk.

osteophyte: A bony outgrowth, or spur, on the margin of a joint or intervertebral disk.

osteoporosis: A degenerative disease that decreases the density of bone, leaving it vulnerable to fracture.

percutaneous diskectomy: The removal of part of an intervertebral disk by means of a narrow probe inserted through the skin and muscle of the back.

processes: The several bony projections from each vertebra, some of which mesh with similar structures on the vertebrae immediately above and below.

ruptured disk: See herniated disk.

sciatica: Pain along the course of the sciatic nerve (from the buttock, down the back and side of the leg, and into the foot and toes), often because of a herniated disk.

slipped disk: See herniated disk.

spinal fusion: A procedure to join two or more vertebrae with a bone graft in order to eliminate motion and relieve pain.

spinal stenosis: A narrowing of the spinal canal, which can result in compression of nerve roots.

spinous process: The lever-like backward projection from each vertebra, to which muscles and ligaments are attached.

spondylolisthesis: Forward displacement of a vertebra in relation to the vertebra immediately below.

transcutaneous electrical nerve stimulation (TENS): Use of low-voltage electrical current to provide pain-suppressing stimulation.

transverse processes: The ringlike projection on each side of a vertebra to which muscles and ligaments are attached and, in the chest area, to which the ribs are connected.

trigger point: A specific area that, when stimulated, elicits pain.

vertebrae: The 22 bones that form the spine.

vertebroplasty: A minimally invasive procedure to stabilize compressed vertebrae and alleviate pain. A needle is inserted into the compressed portion of a vertebra and surgical cement is injected into it.

Last updated:	January 23, 2007