Lower back pain is any type of pain or discomfort in the lower, rear portion of the trunk to the hips. This area is also called the lumbar area or the lumbar spine.
Lower back pain is the most common work-related disability or absenteeism. It may last briefly or it may last for more than three months. The majority of acute back pain is mechanical in nature, meaning that there is a disruption in the components of the back. This may be due to:
- The large nerve roots in the low back that go to the legs may be irritated
- The smaller nerves that supply the low back may be irritated
- The large paired lower back muscles (erector spinae) may be strained
- The bones, ligaments or joints may be damaged
- An intervertebral disc may be degenerating
What causes low back pain?
Causes of low back pain include:
- Sprains or strains. Sprains are caused by overstretching or tearing ligaments, and strains are tears in tendon or muscle. Both can occur from twisting or lifting something improperly, lifting something too heavy, or overstretching.
- Intervertebral disc degeneration. It occurs when the usually rubbery discs lose integrity as a normal process of aging.
- Herniated or ruptured disc. Occur when the intervertebral discs become compressed and bulge outward (herniation) or rupture, causing low back pain.
- Radiculopathy. Caused by compression, inflammation and/or injury to a spinal nerve root. Pressure on the nerve root results in pain, numbness, or a tingling sensation that travels or radiates to other areas of the body that are served by that nerve.
- Sciatica. Caused by compression of the sciatic nerve, the large nerve that travels through the buttocks and extends down the back of the leg. This compression causes shock-like or burning low back pain combined with pain through the buttocks and down one leg, occasionally reaching the foot.
- Spondylolisthesis. A condition in which a vertebra of the lower spine slips out of place, pinching the nerves exiting the spinal column.
- Traumatic injury. Traumatic injury may also cause the spine to become overly compressed, which in turn can cause an intervertebral disc to rupture or herniate, exerting pressure on any of the nerves rooted to the spinal cord. This is caused by playing sports, car accidents, or a fall can injure tendons, ligaments or muscle resulting in low back pain.
- Spinal stenosis. A narrowing of the spinal column that puts pressure on the spinal cord and nerves that can cause pain or numbness with walking and over time leads to leg weakness and sensory loss.
- Skeletal irregularities. Include scoliosis, a curvature of the spine that does not usually cause pain until middle age; lordosis, an abnormally accentuated arch in the lower back; and other congenital anomalies of the spine.
Often doctors don’t really know what causes low back pain.
There are several factors that may increase the chance of having lower back pain. It includes:
- Age. As people grow older, loss of bone strength from osteoporosis can lead to fractures, and at the same time, muscle elasticity and tone decrease. The intervertebral discs begin to lose fluid and flexibility with age, which decreases their ability to cushion the vertebrae.
- Fitness level. Back pain is more common among people who are not physically fit
- Pregnancy. Results from pelvic changes and alterations in weight loading. Back symptoms almost always resolve postpartum.
- Weight gain. This caused increase pressure in the back.
- Genetics. Conditions such as ankylosing spondylitis, a form of arthritis that involves fusion of the spinal joints leading to some immobility of the spine, have a genetic component.
- Occupational risk factors. Having a job that requires heavy lifting, pushing, or pulling, particularly when it involves twisting or vibrating the spine, can lead to injury and back pain.