If any of these conditions occur, the nerve roots passing between the discs and facets may be stretched or pinched, causing low back pain, often the pain known as sciatica. The nerve most likely to cause trouble is the sciatic nerve. Each of the two branches of the sciatic nerve is about as wide as a thumb and threads through the pelvis and deep into the buttocks, then down the hip and along the back of the thigh to the foot. Sciatica usually occurs on one side when a sciatic nerve has been stretched or pinched, usually by a herniated disc, although spinal stenosis or other vertebral abnormalities can also cause this pain. The sensation of sciatica can vary widely, from a mild tingling to pain severe enough to cause immobility.
Some people experience sharp pain in one part of the leg or hip and numbness in other parts.
The pain increases after prolonged standing or sitting and is aggravated by sneezing, coughing, or laughing. If spinal stenosis is causing sciatica, patients may also experience it after bending backwards or walking more than 50 to 100 yards.