In order to check the correct position of the fibula in the Incisura fibularis tibiae by means of X-ray, four radiological parameters could be distinguished in patients with surgically or conventionally treated fractures of lateral malleolus. In spite of easy access, inserting the fibula into the incisure can be difficult in the case of bony or ligamentous injuries of the distal tibiofibular syndesmosis. With the help of these easily measurable X-ray parameters, an incongruence in the distal tibiofibular syndesmosis, which have to be corrected in any case, can easily be detected. The clinical relevance of these results could be verified in 105 patients.