 Piriformis syndrome

Piriformis syndrome is a clinical syndrome in which pain, sometimes with numbness or radiating leg symptoms, is attributed to irritation or compression of the sciatic nerve near the piriformis muscle. The nerve and muscle lie close together in the deep buttock region, making a mechanical interaction anatomically plausible.^[ref]

Anatomical plausibility is not proof of the explanation in a particular case. A 2018 study reviewed magnetic resonance imaging and clinical records to compare people with usual and variant relationships between the sciatic nerve and piriformis muscle. It found no significant difference in the recorded frequency of piriformis syndrome, buttock pain or sciatic symptoms between the anatomical groups.^[ref] The study illustrates why an unusual scan finding must be distinguished from demonstrated symptomatic nerve compression.