"Motor cyclist" fracture among the following
Hinge fracture of base of skull
Ring fracture of base of skull
Depressed fracture of skull
Comminuted fracture of skull
Hinge' fracture (Motorcyclist fracture) occurs when the linear fracture passes across the middle cranial fossa, separating the skull base into 2 halves, and may be caused by a heavy blow to the side of the head (e.g. in motorcycle accidents). Ref - Krishnan Vij 5th edition pg 300
Mechanical injuries