[Osseous avulsion of the ischio-crural muscle group with concomitant sciatica].

Avulsion fractures of the ischial tuberosity are rare. They are often caused by a typical "splits"-like accident. In general the patients feel sudden severe pain in the buttock with localized tenderness in the region of the ischial tuberosity, rarely in combination with sciatic nerve irritation. According to the functional anatomy, flexion of the knee and extension of the hip may be impaired. Roentgenograms often reveal no abnormality and show no evidence of fracture. Therefore, inadequate therapy because of missed diagnosis can result in avoidable persistent pain. We report on a 42-year-old man with an avulsion fracture of the ischial tuberosity. The epidemiology, symptoms, including irritation of the sciatic nerve, differential diagnoses, diagnostic procedures and therapy are presented in detail.