The term sciatica usually describes the symptoms of hip leg pain—and possibly tingling, numbness, or weakness—that start in the lower back region and travel down through the buttock and down the large sciatic nerve that travels down the back of each leg.
Common causes of Sciatica
Piriformis syndrome is a condition in which the piriformis muscle which is located in the lower hip region, goes into spasm and causes pain in the hip. The piriformis muscle can also irritate and put pressure on the nearby sciatic nerve and cause pain, numbness and tingling along the back of the leg and into the foot (similar to sciatic pain).
Sacroiliac joint dysfunction
Dysfunction in the sacroiliac joint, or SI joint, is known to be the cause of some low back and/or leg pain. The leg pain can be particularly defined at dull numbness to a sharp shooting pain
Too much movement (hypermobility or instability): When the SI joint becomes unstable the body signals pain.This pain is usually felt in the lower back and/or hip rgion. In some cases this pain may radiate into groin area.
Too little movement (hypomobility or fixation): When the SI joint becomes locked down the lumbar spine looses range of motion which in turns causes pain commonly felt on the side of felt on one side of the low back or buttocks, and can radiate down the leg.