These two photos are of the same stab wound to a skull.  The top view is the wound to the exterior portion of the skull, while the bottom photo is the view of the wound from the inside of the skull.  What is of importance to note here is that on the interior view of the wound the bone is bent as well as cut.  This slight curling, as opposed to a clean break, is one way that forensic anthropologists can tell that the wound was made around the time of death (perimortem) and not after (postmortem).


Photo courtesy of Pickering and Bachman, p. 125