During the last 7 years, 57 patients were treated surgically for head injuries caused by skiing accidents. In 49 (84%) cases depressed skull fractures were observed with or without brain damage-bleeding. Clinically the-mechanisms of the fractures were analysed and depressed skull fractures were studied experimentally. A depressed fracture is caused by direct smal;​ local impact energy,of which in the present study a tolerance threshold of about 1 to 2 kN was observed for a depressed fracture in the temporal region. From these studies it can be shown very clearly that only the wearing of helmets offer in fact an effective possibility for the prevention of head accidents in the ski sport.