What is Piriformis Syndrome?
Piriformis syndrome is a condition in which the piriformis muscle, located
in the buttock region, spasms and causes buttock pain. The piriformis
muscle can also 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).
Causes of Piriformis Syndrome
The exact causes of piriformis syndrome are unknown. Suspected causes include:
- Muscle spasm in the piriformis muscle, either because of irritation in
the piriformis 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 one or combination of the above problems can affect the piriformis
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).
Symptoms and Diagnosis of Piriformis Syndrome
There is no simple diagnostic test for piriformis syndrome causing irritation
of the sciatic nerve. The condition is primarily diagnosed on the basis
of the patient’s symptoms and on a physical exam, and after excluding
other possible causes of the patient’s pain.
Symptoms of Piriformis Syndrome
Most commonly, patients describe 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
Symptoms of piriformis syndrome often become worse after prolonged sitting,
walking or running, and may feel better after lying down on the back.