In a survey conducted on the general population, 12.2–27% included a lifetime occurrence of PS, while 2.2–19.5% showed an annual occurrence. However further studies show that the proportion of the sciatica, in terms of PS, is about 0.1% in orthopaedic practice. This is more common in women with a ratio of 3 to 1 and most likely due to the wider quadriceps femoris muscle angle in the os coxae. Between the years of 1991–1994, PS was found to be 75% prevalent in New York, Connecticut, New Jersey, Pennsylvania; 20% in other American urban centers; and 5% in North and South America, Europe, Asia, Africa and Australia. The common ages of occurrence happen between thirty and forty, and are scarcely found in patients younger than twenty; this has been known to affect all lifestyles.Piriformis syndrome is often left undiagnosed and mistaken with other pains due to similar symptoms with back pain, quadriceps pain, lower leg pain, and buttock pain. These symptoms include tenderness, tingling and numbness initiating in low back and buttock area and then radiating down to the thigh and to the leg. A precise test for piriformis syndrome has not yet been developed and thus hard to diagnose this pain. The pain is often initiated by sitting and walking for a longer period. In 2012, 17.2% of low back pain patients developed piriformis syndrome. Piriformis syndrome does not occur in children, and is mostly seen in women of age between thirty and forty.
It usually only affects one hip at a given time, though both hips may produce piriformis syndrome at some point in the patients 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.