What is the Sciatic Nerve?

Sciatica (sciatic nerve pain) is caused by pressure, disease or irritation of the sciatic nerve. The sciatic nerves are the largest nerves in the body. We have a left sciatic nerve and a right sciatic nerve, each running from the lower part of the spine down the leg to the foot. Each sciatic nerve supplies sensation and stimulates muscle movement of the buttocks and most of the leg and foot on the same side of the body. The sciatic nerve is formed by the merging of nerve roots of the lower spine, specifically the sacral spine and the lower parts of the lumbar spine. Nerve roots are large nerves that directly exit or enter the spine through the spinal foramen (holes on the sides of the spine.) 

Nerve roots are the main nerves that bring sensation into the spinal cord, ultimately to reach the brain and 'tell' us sensory information detected by the body, such as where a sensation is located (arm, hand, leg, foot etc.) and what type of sensation it is (hot, cold, sharp, dull etc.) Thus, the sciatic nerve relays sensory information about much of the lower part of the body to the spine and ultimately to the brain. At the same time, the sciatic nerve also stimulates muscles to move. Put simply, the symptoms of sciatica are related to either the muscle function that relies on the sciatic nerve, the sensory function that relies on the sciatic nerve or irritation of the nerve itself, which triggers pain. 

The symptoms of sciatica may be mild or severe, depending on a number of factors, such as the specific cause and extent of pressure on the nerve, whether other nerves are also involved besides the sciatic nerve, and how long the problem has lasted.

Next: Symotoms Of Sciatica