Neck and back pain, especially pain in the lower back, is one of the most common health problems in adults. Fortunately, most back and neck pain is temporary, resulting from short-term stress on the muscles or ligaments that support the spine rather than from a serious injury or medical condition such as nerve damage or kidney disease.
The back is an intricate structure of bones, ligaments, muscles, nerves, and tendons. The backbone, or spine, is made up of 33 bony segments called vertebrae:
- 7 cervical (neck) vertebrae
- 12 thoracic (middle back) vertebrae
- 5 lumbar (lower back) vertebrae
- 5 sacral (lowest area of the back) vertebrae
- 4 coccygeal (coccyx, or tailbone) vertebra (made up of several fused segments)
The vertebrae are arranged in a long vertical column and held together by ligaments, which are attached to muscles by tendons. Between each vertebra lies a gel-like cushion called an intervertebral disc, consisting of semifluid matter (nucleus pulposus) that is surrounded by a capsule of elastic fibers (annulus fibrosus).
The spinal cord is an extension of the brain that runs through a long, hollow canal in the column of vertebrae. The meninges, cerebrospinal fluid, fat, and a network of veins and arteries surround, nourish, and protect the spinal cord.
Thirty-one pairs of nerve roots emerge from the spinal cord through spaces in each vertebra. The spinal cord and peripheral nerves perform essential sensory and motor activities of the body. The peripheral nervous system conveys sensory information from the body to the brain and conveys motor signals from the brain to the body.
Incidence and Prevalence of Back Pain
In the United States, back pain is reported to occur at least once in 85% of adults below the age of 50. Nearly all of them will have at least one recurrence. It is the second most common illness-related reason given for a missed workday and the most common cause of disability. Work-related back injury is the number one occupational hazard.