The piriformis syndrome is characterized by pain in the buttock radiating to the leg and to the coccydeal region. It is an isthmus syndrome of the N. ischiadicus and/or N. cutaneous femoris posterior. The most frequent causes are blunt traumas of the buttocks and spasms of the N. piriformis. More often than not the piriformis syndrome is the cause of a "postlaminectomy syndrome" or of a coccygodynia. The diagnosis can be established by a clinical examination with sufficient reliability.