Sciatica - Getting to the Root of the Problem
The sciatic nerve is the longest and largest nerve in your body. Many have referred to the sciatic nerve as the "6 foot neuron". The spinal cord has a spinal nerve root for each spinal level. The spinal cord ends about the level of the last rib in the lower mid back(T12 spinal level). From the end of the spinal cord, nerves descend through the spine (spinal canal) and then at each spinal level spinal nerves exit the spinal column through holes on each side, called foramen. The nerve exiting the foramen are called nerve roots. Four to five nerve roots from the lower back and sacrum flow down from the lower back through the pelvis and in the hip, deep in the hip the four or five spinal nerves become one large bundle of nerves called the sciatic nerve.
From the hip region the sciatic nerve goes down the back of thigh and then branches out to supply the lower leg, ankle, foot, and toes. The sciatic nerve is for sensation of the lower extremity, muscle movement, and helps control vascular supply in the lower extremity.
Another important anatomical landmark is the piriformis muscle. The piriformis muscle extends from the large bone you feel on the lateral part of your hip (greater trochanter) to the triangular bone in your pelvis (sacrum). The sciatic nerve is most often found directly under the piriformis muscle. Some anatomical variations at times finds the sciatic nerve going through the piriformis muscle. Piriformis Syndrome occurs when spasms of the piriformis muscle irritate the sciatic nerve.
For a vast majority cases of sciatica the root of the problems is compression of the lumbar and sacral nerve roots. Learn more about what causes sciatica by clicking on this link, "Causes of Sciatica."