Most patients describe symptoms of acute tenderness in the buttock and sciatica-like pain down the back of the thigh, calf and foot. Typical piriformis syndrome symptoms may include:
- A dull ache in the buttock
- Pain down the back of the thigh, calf and foot (sciatica)
- Pain when walking up stairs or inclines
- Increased pain after prolonged sitting
- Reduced range of motion of the hip joint
These symptoms often become worse after prolonged sitting, walking or running, and may feel better after lying down on the back.
Causes and Risk Factors
The exact causes of piriformis syndrome are unknown. Suspected causes include:
- Muscle spasm in the piriformis muscle, either because of irritation in the muscle itself or irritation of a nearby structure such as the sacroiliac joint or hip
- Tightening of the muscle, in response to injury or spasm
- Swelling of the piriformis muscle, due to injury or spasm
- Bleeding in the area of the piriformis muscle
Any of the above problems, or a combination of them, can affect the muscle, causing buttock pain, and may affect the adjacent sciatic nerve (causing pain, tingling or numbness in the back of the thigh, calf or foot).