The spinal column runs down the center of the back and is composed of several nerve cords surrounded by bony vertebrae. Each vertebra is separated by a disc which acts as a shock absorber. Numerous ligaments and muscles surround the spinal column. Because many of the forces affecting the body are exerted in this region, nearly any of these tissues or structures can become stretched or stressed and contribute to pain.
Back pain can arise from nerves in the back or from other tissues in the region. Spinal stenosis, a narrowing of the space in the spine’s central canal, is a common condition in older adults and may be associated with back and leg pain. Disc herniation, which is an injury to the intervertebral disc, is a more common condition for younger and middle-aged adults. Muscle weakness, strain or the inflammation of the small facet joints that connect each vertebra could also be culprits for back pain.
In patients with osteoporosis, a condition most commonly seen in older women, a compression fracture may also be a source of pain. Compression fractures are caused by a collapse of the vertebrae. Even minor trauma may cause compression fractures in the elderly. On rare occasions, benign or malignant tumors in the spine can cause back pain. Also rare is a condition called osteomyelitis, an infection in the bones of the back.
Pain radiating from the back to the legs is an indication of a pinched or irritated nerve. This can result from either disc herniation or osteoarthritis, which is an overgrowth of bone due to worn disc cartilage.
Back pain is a common malady in pregnant women, also. Approximately 50 percent of all pregnant women will experience back pain, particularly in the third trimester of pregnancy. Furthermore, this pain may persist for up to six months after the baby is born. Such pain is understandable given structural and hormonal changes in a pregnant woman’s body.
As her abdominal muscles stretch to accommodate the fetus, they are less able to support the spine. A pregnant woman also experiences a 10-fold increase in production of the hormone relaxin, which allows her joints to relax and accommodate the expanding uterus.
The same relaxation that benefits the fetus may also weaken supports in the lumbar spine. In the last months of pregnancy, the extra weight of the baby affects the mother’s posture, which may contribute to back pain. Pregnant women particularly notice back pain when rising from a seated position.
While there are many other conditions that can cause back pain, it is important to emphasize that back pain is not life threatening in the majority of cases.