For some people, sciatica pain can be severe and debilitating. For others, the sciatica symptoms might be infrequent and irritating, but have the potential to get worse. Usually, sciatica only affects one side of the lower body, and the pain often radiates from the lower back all the way through the back of the thigh and down through the leg. Depending on where the sciatic nerve is affected, the pain and other sciatica symptoms may also radiate to the foot or toes.
One or more of the following sciatica symptoms are typically experienced:
Pain in the rear or leg that is worse when sitting
Burning or tingling down the leg
Weakness, numbness or difficulty moving the leg or foot
A constant pain on one side of the rear
A shooting pain that makes it difficult to stand up
With sciatica, low back pain may be present along with the leg pain, but usually the low back pain is less severe than the leg pain
Sciatica symptoms occur when the large sciatic nerve is irritated. The sciatic nerve is the largest single nerve in the body and is composed of individual nerve roots that start by branching out from the spine in the lower back and combine to form the “sciatic nerve”.
The sciatic nerve starts in the lower back at lumbar segment 3 (L3).
The sciatic nerve roots run through the bony canal in the spine, and at each level in the lower back a pair of nerve roots exits from the spine and then comes together to form the large sciatic nerve that runs all the way down the back of each leg.
Portions of the sciatic nerve then branch out in each leg to innervate certain parts of the leg (e.g. the calf, the foot, the toes).
The nerve roots that originate in the lower back are named for the upper vertebral body that they run between (for example, the nerve that exits at L4-L5 in the spine is named L4). The nerve passing to the next level runs over a weak spot in the disc space, which is the reason discs tend to herniate (extrude) right under the sciatic nerve root and can cause sciatica.
The sciatica symptoms (e.g., low back pain, leg pain, numbness, tingling, weakness) are different depending on where the pressure on the nerve occurs. For example, a lumbar segment 5 (L5) nerve impingement can cause weakness in extension of the big toe and potentially in the ankle (foot drop) .
