The sciatic nerve starts at the back of the pelvis and extends down to the feet, running through the buttocks and the back of the leg. It is the longest nerve in the body and for some individuals is a major source of pain. Sciatica is a condition when the sciatic nerve gets compressed, irritated or pinched manifesting with pain and other symptoms. It may be caused by things such as a bone spur, bulging disc, or herniated disc.
Piriformis Syndrome is a medical condition causing muscle spasms and pain in the leg and buttocks. This syndrome occurs when the piriformis muscle becomes inflamed or spasms, putting pressure on the sciatic nerve and causing pain and discomfort. The piriformis muscle runs from the lower spine to the buttocks and assists in the hip rotation process when the leg and foot are turned outward.
Coccyx pain or discomfort, or coccydynia, occurs at the base of the spine in the tailbone. This condition is associated with pain and tenderness at the tip of the tailbone between the buttocks, and is more intense when sitting down. The coccyx can be damaged in a variety of ways causing mild to intense pain that gets worse when raising up from a chair, leaning back while sitting, using the bathroom, or during sex, and may cause a shooting pain down the legs.