Most acute low back pain is mechanical in nature, meaning that there is a disruption in the way the components of the back (the spine, muscle, intervertebral discs, and nerves) fit together and move. Some examples of mechanical causes of low back pain include:
Congenital
- Skeletal irregularities such as scoliosis (a curvature of the spine), lordosis (an abnormally exaggerated arch in the lower back), kyphosis (excessive outward arch of the spine), and other congenital anomalies of the spine.
- Spina bifida which involves the incomplete development of the spinal cord and/or its protective covering and can cause problems involving malformation of vertebrae and abnormal sensations and even paralysis.
Injuries
- Sprains (overstretched or torn ligaments), strains (tears in tendons or muscle), and spasms (sudden contraction of a muscle or group of muscles)
- Traumatic Injury such as from playing sports, car accidents, or a fall that can injure tendons, ligaments, or muscle causing the pain, as well as compress the spine and cause discs to rupture or herniate.
Degenerative problems
- Intervertebral disc degeneration which occurs when the usually rubbery discs wear down as a normal process of aging and lose their cushioning ability.
- Spondylosis the general degeneration of the spine associated with normal wear and tear that occurs in the joints, discs, and bones of the spine as people get older.
- Arthritis or other inflammatory disease in the spine, including osteoarthritis and rheumatoid arthritis as well as spondylitis, an inflammation of the vertebrae.
Nerve and spinal cord problems
- Spinal nerve compression, inflammation and/or injury
- Sciatica (also called radiculopathy), caused by something pressing on the sciatic nerve that travels through the buttocks and extends down the back of the leg. People with sciatica may feel shock-like or burning low back pain combined with pain through the buttocks and down one leg.
- Spinal stenosis, the narrowing of the spinal column that puts pressure on the spinal cord and nerves
- Spondylolisthesis, which happens when a vertebra of the lower spine slips out of place, pinching the nerves exiting the spinal column.
- Herniated or ruptured discs can occur when the intervertebral discs become compressed and bulge outward
- Infections involving the vertebrae, a condition called osteomyelitis; the intervertebral discs, called discitis; or the sacroiliac joints connecting the lower spine to the pelvis, called sacroiliitis
- Cauda equina syndrome occurs when a ruptured disc pushes into the spinal canal and presses on the bundle of lumbar and sacral nerve roots. Permanent neurological damage may result if this syndrome is left untreated.
- Osteoporosis (a progressive decrease in bone density and strength that can lead to painful fractures of the vertebrae)
Non-spine sources
- Kidney stones can cause sharp pain in the lower back, usually on one side.
- Endometriosis (the buildup of uterine tissue in places outside the uterus)
- Fibromyalgia (a chronic pain syndrome involving widespread muscle pain and fatigue)
- Tumors that press on or destroy the bony spine or spinal cord and nerves or outside the spine elsewhere in the back.
- Pregnancy (back symptoms almost always completely go away after giving birth)