Piriformis syndrome is a condition in which the piriformis muscle, located in the buttock region, spasms and causes buttock pain. The piriformis muscle also can irritate the nearby sciatic nerve and cause pain, numbness and tingling along the back of the leg and into the foot (similar to sciatic pain).
The piriformis muscle:
- Starts at the lower spine and connects to the upper surface of each femur (thighbone)
- Functions to assist in rotating the hip and turning the leg and foot outward
- Runs diagonally, with the sciatic nerve running vertically directly beneath it (although in some people the nerve can run through the muscle)
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).
Diagnosis of piriformis syndrome is based on a review of the patient's medical history, a physical examination and possibly diagnostic tests (such as X-rays, MRI or nerve conduction tests).
Piriformis syndrome is often diagnosed through a process of ruling out other possible conditions that may be causing the patient’s symptoms, such as a lumbar disc herniation or sacroiliac joint dysfunction.
Almost every treatment for piriformis syndrome will include a focus on carefully and progressively stretching the muscle.
Other treatment modalities include:
- Physical therapy: Range-of-motion exercises and deep massage
- Ice packs and ice massage
- Heat therapy
- Medications: anti-inflammatory medications (such as ibuprofen or naproxen) to reduce the swelling that is usually contributing to the patient's pain
- Injections: corticosteroid plus a local anesthetic; Botox
- TENS unit