The sciatic nerve is the largest nerve and longer in your body. Five groups of nerve roots combine to form pairs, and is about the diameter of a finger. The sciatic nerve starts in the lower back, called the lumbar spine. Nerve roots are in the L4 and L5 vertebrae (the “L” means low back, and the numbers indicate the level of the vertebra, which is on your back). The sciatic nerve also travels through your pelvic region (sacrum).
In most people, the sciatic nerve runs under the piriformis muscle, which moves from side to side of the thigh. From there, the sciatic nerve descends through the buttocks and the back of the thighs. Behind the knee, smaller nerves branch from the sciatic nerve and travel to their feet.
His sciatic nerve is part of a complex structure: the nervous system of your body. This system is responsible for transmitting pain sensations to other parts of your body. So when something presses on a nerve, you’re going to feel and not feel well. With sciatica, something in his lower back, a herniated disc, for example, compresses the sciatic nerve, which then transmits the pain down the legs.


