Piriformis syndrome (PS) data is often confused with other conditions due to differences in definitions, survey methods and whether or not occupational groups or general population are surveyed. This causes a lack of group harmony about the diagnosis and treatment of PS, affecting its epidemiology. In a study, 0.33% of 1293 patients with low back pain cited an incident for PS. A separate study showed 6% of 750 patients with the same incidence. About 6% - 8% of low back pain occurrences were attributed to PS, though other reports concluded about 5% - 36%. 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.