Sciatica can have many causes

Like other common medical terms, sciatica is not the name of a disease. Rather, it is a set of symptoms (a syndrome) that includes pain, numbness, weakness or tingling in the lower back, buttocks and parts of the legs, knees or feet. Usually, this happens on one side of the body only. We give this syndrome the name “sciatica” because of its relation to the sciatic nerve.

What causes sciatica?
The sciatic nerve is the longest and widest nerve in your body. It starts in your lower back, runs through your buttocks, divides into two branches in your thighs and runs down each leg to your feet. Very simply, when the fibers of this nerve are compressed or irritated, it hurts big time.
What’s happening in your body? There are many ways that the sciatic nerve can get in trouble, and depending on the location, we give it a different name. For example: There is a muscle called the piriformis that goes from your sacroiliac joint (bottom of the spine) to your hip bone. And alas, the sciatic nerve runs right under the piriformis. That means that if the piriformis spasms or is just too tight, then you have instant sciatica. This is called piriformis syndrome. Sciatica can result from a herniated (ruptured) disc, a bone spur on the spine or stenosis (abnormal narrowing) of the spinal canal. The weight of the fetus during pregnancy, and rarely, vigorous coughing or even sneezing, and even more rarely, one vertebra sliding over another can result in sciatica. Arthritis, osteoporosis, a tumor, blood clot or abscess can be sources of pressure on the nerve, as well.


Herniated disc Between each pair of vertebrae in your spine is a cushioning pad that we call a “disc.” The disc consists of a tough fibrous outer ring that contains a soft, central portion. In this most common cause of sciatica (some say 90 percent), that fibrous ring gets torn, allowing the jellylike inside of the disc to bulge out. This may not only put pressure on nerve fibers, but also release an inflammatory chemical called tumor necrosis factor-alpha that causes pain even without compression; TNF may also be present if there is stenosis. And isn’t it really annoying when your doctor says something like, ‘You know, Mr. Keller, age is a factor!’ Alas, however, aging, as well as wear and tear, leads to some unfortunate changes in the spinal discs. Specifically, that soft, cushioning interior becomes a bit stiff, and so more of the load it bears is transferred to the outer ring. This additional pressure can lead to cracks in the ring, sometimes big enough to allow the inner material to bulge through.

Prevention
But the best therapy for sciatica is preventing it in the first place, and there are some very simple precautions you can take: Keep your weight under control, get regular physical activity and don’t sit for extended periods of time. Also — especially to men — don’t carry your wallet or anything else in your hip pockets, and wear an elastic belt instead of the unforgiving leather that most men use. Daily stretching exercises (15 minutes maximum) will keep your piriformis and other gluteal muscles flexible. To help head off disc herniations, avoid especially heavy lifting and exaggerated twisting of the torso.

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