Degenerative disc disease involves wear and tear changes in the disk. Medically referred to as spondylosis, it appears on X-rays or MRI scans as a narrowing of the normal space between adjacent vertebrae. Virtually everyone has signs of lumbar disc degeneration after age 40. Some patients experience no symptoms, others may experience backaches. In some cases, severe pain and loss of muscle function may occur if nerves are compressed between discs. The condition is referred to as cervical disc disease when the neck portion of the spine is affected, as thoracic disc disease when the mid-back is affected and as lumbago when the lumbar spine is affected.


A herniated disc — also known as HNP (herniated nucleus pulposus), ruptured disc or slipped disc — involves the rupture of the fibrocartilage surrounding an intervertebral disc. This releases the nucleus pulposus that cushions the vertebrae above and below. The resulting pressure on spinal nerve roots may cause considerable pain and nerve damage. A herniated disc may occur suddenly with an event such as a fall or accident, or gradually with repetitive straining of the lumbar spine. Often, people who experience a herniated disc already have spinal stenosis. Common symptoms of a herniated disc include radiating leg or arm pain, abnormal sensations of tingling or numbness and muscle weakness.


Spinal stenosis involves a narrowing in the vertebral canal or vertebral openings of the spine, which in turn causes compression of either the spinal cord or the nerve roots that exit the spinal cord. When the narrowing is in the cervical region, symptoms of pain, numbness or weakness are usually experienced in the arm and hands. In the lumbar region, symptoms are most commonly felt in the legs and feet. Spinal stenosis can be inherited or acquired. The condition affects men and women equally, most frequently in individuals over the age of 50. The most common cause is degenerative arthritis. People engaged in labor-intensive careers are also more prone to developing this condition.


Sprains and strains are both minor injuries occurring at joints where ligaments connect bone to bone and tendons connect bone to muscles. A sprain is an injury to ligaments, the thick, tough, fibrous tissue that connects bones. Ligaments can be sprained by being stretched too far from their normal position under conditions such as excessive exercise, heavy lifting, repetitive motion or minor impacts. A strain is an injury to muscles or tendons. When muscles contract they pull on tendons, which in turn are connected to bone. A strain may result if the muscle is stretched too far, or if it is stretched while contracting. Strains most often occur when a joint is pulled, twisted or jerked suddenly. These soft-tissue injuries exhibit symptoms of redness, swelling, surface bruising, reduced mobility and a dull, throbbing ache or sharp, cramping pain.


Sciatica — radiating pain along the large sciatic nerve that runs from the lower back down the back of each leg — is a relatively common form of low-back and leg pain. Causes include pressure on the sciatic nerve from a herniated disk, lumbar spinal stenosis or degenerative disk disease. There is often no particular event or injury that causes the condition, which may develop solely as a result of general wear and tear on the structures of the lower spine. Sciatica occurs most frequently in people between 30 and 50 years of age. It can cause burning, tingling or shooting pain in the buttocks and/or down the leg, as well as weakness, numbness or difficulty moving the leg or foot.