This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Orthopaedics
Pathognomic sign of traumatic fracture is 
Select and explain. 
A. Tenderness, B. Swelling, C. Crepitus, D. Bruising
C: Crepitus
Answer: C: Crepitus 
Explanation: C. i.e. (Crepitus) (545 - Apley 8th)* Crepitus or abnormal movement is pathognomic to traumatic fracture.* Posterior - interosseous nerve invovemet in Monteggia fracture dislocation* Peroneal nerve involvement in knee dislocationMotor cyclists fractures - The motorcyclists sustains a ring fracture and the pillion rider an atlanto - occipital avulsion with dural tear Anteroflexion without impact on the occiput seems to be a rare casual mechanism of the 'ring' fracture.