Aseptic osteonecrosis of the humeral trochlea (Hegemann's disease).

A differential diagnosis of diseases affecting the elbow joint in children should also give due consideration to osteonecroses. They are very rare in the context of the humeral trochlea, the case with which we are concerned being one of a total of 15. In the light of this syndrome's relative rarity, we will report on the case of a 7-year-old boy. This is also the first time that a MR image of Hegemann's disease has been shown.