The sciatic nerve is the largest nerve in the body and runs from the lower portion of the spine, through the buttocks and down into the thigh and lower leg. It is responsible for feeling and movement in the major muscles of the hamstring, lower leg, and foot. Sciatica, a disorder caused by irritation of the sciatic nerve, can cause pain, numbness, or tingling in these areas.
The sciatic nerve is the largest single nerve in the body. It begins in the lower part of the back and runs through the hip/buttock region, giving off two branches; the articular branch, which provides nerve function to the hip-joint, and the muscular branch, which extends into the muscles of the thigh. Eventually, the muscular branch also splits into the tibial nerve and the common peroneal nerve, which extend into the lower leg and foot.
Like all nerves, the function of the sciatic nerve is to transmit nerve impulses between the central nervous system (CNS) and the tissues that it innervates. The two branches of the sciatic nerve cover nearly the entire lower part of the body including the skin, and the muscles of the back of the thigh, lower leg, and foot. The nerve signals are responsible for relaying sensations of pain and feeling, as well as transmitting impulses that give rise to muscle movement. The sciatic nerve is responsible for feeling and movement in many leg muscles, including the biceps femoris, semimembranosus, and semitendinosus, better known as the “hamstring” muscles.
Sciatica is a disorder in which irritation of the sciatic nerve causes pain. Sciatica typically results from a herniated lumbar disc that presses on the nerve. However, a number of other causes, including tumors, infections, and injury can all give rise to the disorder. Damage to the sciatic nerve can be a complication of hip surgery or replacement, occasionally resulting in sciatic palsy or paralysis.
Sciatica can be identified by a burning sensation, tingling, or numbness in the regions where the sciatic nerve runs, namely, the lower back, buttocks, and back of the thigh. The pain is often made worse by walking or bending over, and severe cases can make walking unbearably painful. Sciatica can often be diagnosed simply through a physical examination. However, more complicated procedures, such as x-rays, CAT scans, or MRIs may be required to pinpoint the cause of the irritation to the nerve.
While the traditional treatment for sciatica has been a simple prescription of bed-rest, recent research suggests that it may not be any more effective at relieving the symptoms of sciatica than simply waiting for the discomfort to disappear on its own. In some cases, medications may be used to relax muscles or reduce inflammation in the area, and surgery may be able to remove the source of the pressure on the sciatic nerve, such as a herniated disc.