1. Stress fractures of the femoral neck in twenty-five patients are described.
2. Two distinct radiological types, compression fractures and transverse fractures, are described. A clinical distinction cannot be made in the early stages.
3. The importance of the early differential diagnosis between the two types is emphasised because the transverse stress fracture of the femoral neck will become displaced.
4. The morbidity after a displaced transverse fracture of the femoral neck can be severe.