Sciatica is a common type of pain affecting the sciatic nerve, a large nerve extending from the lower back down the back of each leg. Pain typically occurs in the distribution of a dermatome and goes below the knee to the foot. It may be associated with neurological dysfunction, such as weakness. Causes are Spinal disc herniation, Piriformis syndrome, Lumbar spinal stenosis, Degenerative disc disease, Spondylolisthesis and Pregnancy.
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.
Sciatica is generally caused by the compression of lumbar nerves or by compression of the sciatic nerve. 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. Pseudosciatic pain can also be caused by compression of peripheral sections of the nerve, usually from soft tissue tension in the piriformis or related muscles.