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.