Every now and then there appears in the literature a name associated with a definite type of fracture because of the latter's frequent occurrence in a certain type of injury. Among these are the "crank" fracture of the lower end of the forearm due to the "back kick" of the crank, the "bumper" fracture of the upper end of the tibia and the "dashboard" fracture of the acetabulum. In two years' observation of the fractures occurring among the parachute jumpers or "paratroopers" in training at Fort Benning, Ga., it has been noted that a substantial number of the jumpers sustain fracture of the posterior articular margin or "posterior lip" of the tibia (fig. 1). Fracture of this type occurring alone constitutes about 12 per cent of the total number of fractures (272). At least another 4 per cent consist of fracture of the posterior lip of the tibia associated with