Overview
Piriformis syndrome is a cause of low back pain (LBP) characterized by pain and instability. It occurs when the piriformis muscle which externally rotates and moves the thigh out to the side, impinges (puts pressure on) the sciatic nerve.
Causes
Having tight adductor (inside of thigh) muscles
Acute trauma
Overuse of the glutes and other muscles in the hip
Poor body mechanics and posture
Gait problems
Symptoms
Tenderness in the area of the muscle
Pain in the buttocks
Pain which radiates down the back of the leg, usually into the hamstrings and sometimes even the calf muscles
Reduced range of motion of the hip joint, especially into internal hip rotation
Diagnosis
Physical examination and medical history consultation
MRI
Treatment
Rest
Anti-inflammatory drugs
Heat therapy
Physical therapy
Massage
Ultrasound therapy
Corticosteriod injection
Surgery
http://www.sportsinjuryclinic.net/sport-injuries/hip-groin-pain/piriformis-syndrome