Back pain is pain felt in the back. Back pain is divided into neck pain (cervical), middle back pain (thoracic), lower back pain (lumbar) or coccydynia (tailbone or sacral pain) based on the segment affected. The lumbar area is the most common area affected. An episode of back pain may be acute, sub-acute, or chronic depending on the duration. The pain may be characterized as a dull ache, shooting or piercing pain, or a burning sensation. Discomfort can radiate into the arms and hands as well as the legs or feet, and may include numbness, or weakness in the legs and arms.
The majority of back pain is nonspecific with no identifiable causes. Common underlying mechanisms include degenerative or traumatic changes to the discs and facets joints, which can then cause secondary pain in the muscles, and nerves, and referred pain to the bones, joints and extremities. Diseases and inflammation of the gallbladder, pancreas, aorta, and kidneys may also cause referred pain in the back. Tumors of the vertebrae, neural tissues and adjacent structures can also manifest as back pain.
Back pain is common, with about nine out of ten adults experiencing it at some point in their life, and five out of ten working adults having it every year. Some estimate up to 95% of people will experience back pain at some point in their lifetime. It is the most common cause of chronic pain, and is a major contributor of missed work and disability. For most individuals, back pain is self-limiting. In most cases of herniated disks and stenosis, rest, injections or surgery have similar general pain resolution outcomes on average after one year. In the United States, acute low back pain is the fifth most common reason for physician visits and causes 40% of missed days off work. Additionally, it is the single leading cause of disability worldwide.