Low Back Terminology

Listed below are some terms you may have heard in conversations about the low back.

Arthritis of the Spine: Appropriate use of the term “arthritis”, which means inflammation of joints (not discs), is difficult when applied to the spine because there are many causes for pain in the spine only one of which is joint inflammation. Unlike joints elsewhere such as the elbow, hip or finger joints which when painful and tender almost always signify arthritis (since not much else causes pain in those joints), the spinal joints are deep below the skin and thick back muscles. They cannot be felt and have no particular pain characteristics that allow us to say that this person’s back pain is due to joint inflammation (arthritis) while that person’s is due to disc bulging or ligament strain. Until a scan is performed to try to clarify the origin of back pain, it is mostly a guessing game as to the cause of the back pain. Many doctors use the term “arthritis” to cover low back pain without significant leg pain to lessen your concern while the common initial treatments are pursued (and which will tend to work in most people no matter what the cause of the back pain).

CAT Scan (Computer Assisted Tomography): A series of computerized pictures or slices of the body obtained by doing multiple X-rays. This technique uses the subtle differences in density between bone, fat, nerves, muscles, ligaments, spinal fluid and tumors to create an anatomical picture of an area such as the low back and all the structures in and around the spine.

MRI (Magnetic Resonance Imaging) Scan: Computerized pictures of the spine similar to those obtained by a CAT scan but using magnetism rather than X-rays. It is based on the technique of briefly magnetizing your body which imparts energy to the electrons in the atoms of which you are composed and puts them slightly and safely out of their usual orbit around the atomic nucleus. When the magnetism is turned off, those electrons go back to their usual location and emit energy that is detected by the machine which turns it into pictures. If this seems somewhat magical, don’t feel alone. We neurosurgeons don’t understand it well either, but we can sure use the pictures to help us to know what is wrong with you and what we can do to help you.

Cortisone shots: Technique of therapy designed to bathe a structure with concentrated cortisone, a very strong anti-inflammation agent, to reduce presumably inflamed structures that are causing pain because of that inflammation. Low back cortisone shots include trigger point injections into tender muscles or ligaments, epidural injections into the spinal canal to bathe the discs and nerves within spinal canal, joint injections near the spinal joints and nerve block injections near the spinal nerves as they exit the spine to go to the legs. It is the hope that the problem with the target structure is an inflammation which can be reversed by the cortisone.

Disc: Think of the discs in your low back as about the size and shape of a hockey puck (3 inches in diameter and about ¾ inch high) made up of a fairly tough skin inside of which is a pulp (nucleus pulposis—center pulp) that looks and feels like tough crab meat. These discs are found between all the vertebrae (intervertebral) acting like a shimmy or shock absorber and allowing movement between the vertebrae so we can bend.

Disc Degeneration: An aging process that occurs in all discs over time. This happens to us all eventually but can be hastened by a straining back injury. A degenerated disc usually contains less water and looks darker on MRI scans and often loses some of its height and bulges a little. If it has been bulging a little for a long time, the vertebrae on either side of a disc frequently form a little bone spur in reaction to the bulging. We can see the little spurs on regular X-rays and know the disc degeneration must be present. We call those little spurs and the implied disc degeneration “Spondylosis” (we are expected to use fancy terms). Most gradual disc degeneration that occurs over time is not painful but merely an indication of years of use.

Discogram: A diagnostic procedure in which a narrow needle is introduced into a disc under local anesthesia and then a fluid substance is injected into the disc to raise the pressure inside the disc. This is usually done to see if the disc suspected of causing chronic low back pain is indeed the culprit. A positive discogram reproduces your usual back pain type and location whereas a negative one doesn’t hurt or briefly causes an entirely new and unusual pain. Frequently used as a pre-fusion test to identify which structures to fuse.

Herniated disc: Condition when the skin of the disc around its circumference weakens with an injury, a strain or with age and begins to bulge outward. All discs bulge a little with age and usually don’t cause pain but when they bulge (herniate) suddenly with an injury or strain or if they bulge a lot with age, they can cause back pain. If they bulge or herniate enough to reach the nerves to the legs which lie very close to them, a sciatica or pinched nerve (pain running down the leg to the calf or below) can occur.

Ruptured disc: Condition when the central pulp (nucleus pulposis) of a disc breaks through the skin of the disc and usually compresses (pinches) a nearby nerve causing sciatica. Usually not dangerous but can be pretty painful, can cause damage to bladder and bowel nerves and is commonly hard to beat short of surgery.

Lumbago: An old term for low back pain when due to strains of the sacro-iliac ligaments which connect the pelvic bones in the lowest part of the back. Also called sacro-ilitis meaning an inflammation of those ligaments.

Spinal joint: Each vertebra is connected to the next one by a disc, some ligaments and two joints called facet or apophyseal joints. When these joints get inflamed with age or injury (arthritis=inflamed joints) they cause back pain, sometimes leg pain, and frequently respond to anti-inflammatory (arthritis) medications such as aspirin, ibuprofen, naprosyn or numerous other ones. When these joints significantly thicken with age, they can be the predominant cause of spinal stenosis.

Spinal stenosis: Usually caused by the gradual aging of the ligaments, joints and discs of the spine which narrows the central canal of the spine in which run the nerves to the legs so that leg pain, tingling or numbness occurs, usually when standing or walking, and which is commonly relieved by sitting down.

Sprain: A synonym for strain.

Scoliosis: Curvature of the spine which is almost always congenital (you were born with it) and commonly causes back pain when severe and almost never when mild.

Spondylolisthesis: Condition when the vertebrae are not lined up neatly right above one another. Most common at the junction of the last lumbar vertebra and the sacrum (tail bone) and usually not symptomatic.

Spondylolysis: Condition in which parts of a vertebra failed to form correctly in the womb. Usually doesn’t cause pain but can lead to spondylolithesis as it weakens the connections between vertebrae.

Spondylosis: Fancy name for disc bulging or mild herniation that has been present for a long time so that the spine vertebrae form reactive bone spurs which are easily seen on regular X-rays. Everyone gets this as we get older and it usually is not particularly symptomatic.

Spondylitis: 1850 term for inflammation of the vertebrae which almost never happens nowadays.

Slippage of the spine: Common synonym for Spondylolisthesis.

Slipped disc: Bad term usually implying a disc herniation.