Keyhole defect production in tubular bone

Fracture characteristics, reported primarily for the cranium, are valuable indicators of bullet direction. A bullet striking the vault tangentially pr oduces an irregular opening, termed a "keyhole defect," with the circular p ortion of the defect being the initial point of impact. Identifying this fe ature in tubular bone (long bone) can also demonstrate bullet direction and the position of the bone at the time of the shooting. This case study invo lving a tangential shot (i.e., a keyhole fracture) to the humerus demonstra tes some of the same fracture mechanics seen in the cranium.