Sciatica refers to pain, weakness, numbness, or tingling in the leg. Often, the pain extends from the lower back all the way through the back of the thigh and down through the leg. Depending on where the sciatic nerve is affected, the pain may also extend to the foot or toes. For some people, the pain from sciatica can be severe and debilitating. For others, the sciatica pain might be infrequent and irritating, but has the potential to get worse. Immediate medical attention is required if there is symptoms of progressive lower extremity weakness, numbness in the upper thighs, and/or loss of bladder or bowel control.
When sciatica is caused by compression of a dorsal radix, it is considered a lumbar radiculopathy. When there is a tear in the anulus fibrosus, the nucleus pulposus may extrude through the tear and press against spinal nerves within the spinal cord, cauda equina, or exiting nerve roots, causing inflammation, numbness, or excruciating pain. Inflammation in the spinal canal can also spread to adjacent facet joints and cause lower back pain in the posterior thigh.
Diagnosed by physical examination, and the history of the symptoms. The most applied diagnostic test is the straight leg raise to produce Lasègue's sign, which is considered positive if pain in the distribution of the sciatic nerve is reproduced with between 30 and 70 degrees passive flexion of the straight leg. lumbar disc herniation can be diagnosed by computerised tomography or magnetic resonance imaging.