a factor in piriformis syndrome. Some researchers discount the importance of this relationship in the etiology of the syndrome. MRI findings have shown that both hypertrophy (unusual largeness) and atrophy (unusual smallness) of the piriformis muscle correlate with the supposed condition. Piriformis syndrome may also be associated with direct trauma to the piriformis muscle, such as in a fall or from a knife wound. Diagnosis Piriformis syndrome occurs when the sciatic nerve is compressed or pinched by the piriformis muscle of the hip. It usually only affects one hip at a given time, though both hips may produce piriformis syndrome at some point in the patient's lifetime, and having had it once greatly increases the chance that it will recur in one hip or the other at some future point unless action is taken to prevent it. Indications include sciatica (radiating pain in the buttock, posterior thigh, and lower leg) and the physical exam finding of tenderness in the area of the sciatic notch. If the piriformis muscle can be located beneath the other gluteal muscles, it will feel noticeably cord-like and will be painful to compress or massage. The pain is exacerbated with any activity that causes flexion of the hip including lifting, prolonged sitting, or walking. The diagnosis is largely clinical and is one of exclusion. During a physical examination, attempts may be made to stretch the irritated piriformis and provoke sciatic nerve compression, such as the Freiberg test, the Pace test, the FABER test (flexion, abduction, external rotation), and the FAIR test (flexion, adduction, internal rotation). Sciatica secondary to conditions to be ruled out include herniated nucleus pulposus (HNP), facet arthropathy, spinal stenosis, and lumbar muscle strain. Pathology in the sacroiliac joint region, Sacroiliac joint dysfunction and Sacroiliitis are other conditions that present with pain in the low back and hip regions, which may radiate down along the back of the thigh, rarely going down below knee. Wallet neuritis is an extra-spinal tunnel neuropathy of sciatic nerve, occurring mostly in men. Sitting down on a thick Wallet in the back pocket produces uneven pressure in the hip region that impinges on the Piriformis muscle and / or sciatic nerve. Wallet induced chronic sciatic nerve constriction produces gluteal and ipsilateral lower extremity pain, tingling, and burning sensation. Diagnostic modalities such as ultrasound Imaging, MRI, CT scan, and EMG are mostly useful in excluding other conditions. Increased thickness [iTh]