An exit wound is always larger than the entry wound. That much is given. I admit I have a problem reconciling this to my theory. And, it's supposed to take only one contradiction to disprove a theory. On that basis my theory would be proven wrong. However, the seeming contradiction between the appearance of an exit wound from a bullet from behind, and the head appearing to move backward from a shot from the front would seem to indicate there is more at work here.
If JFK was shot from the front, why would there be an exit in the front of his head. However, I don't buy the force of his brains being blown out causing the head to move backwards (and to the left). And, if the head shot was from the back, why did his head not move at least somewhat to the front before moving back and left?
My theory of a gunman behind the corner of the grassy knoll only explains so much. I know there has to be more.
Here is where your theory falls apart. The inital movement of President Kennedys head from the momentum of the slug entering the skull was forward as it should have been when struck from behind.
Had he been struck from the grassy knoll, the inital movement would have been to the rear and left with massive damage to the left hemisphere. Thats how physics works, you really can't argue that.
It's all in the Zapruder film for anybody to see that wants to see. Now I suppose one could argue that the Zapruder film was edited by some conspiracists but if you accept the Zapruder film at face value, then Oswald murdered our President plain and simple.
I also heard a theory (from a doctor) on TV who stated that Kennedy's muscles throughout his body were stimulated for a fraction of a second by the nerve impulses being fired when his brain was destroyed, and that accounted for his movements. I think that's bull, though.
And, if the head shot was from the back, why did his head not move at least somewhat to the front before moving back and left?
A 1988 NOVA show on PBS compared frames 313 and 314 back and forth rapidly. There is an almost imperceptible movement of Kennedy's head slightly forward (i.e., about an inch) before it snaps backward. I'm not sure where you can get a copy of the Zapruder film (maybe it can be downloaded from some site), but if you get your hands on it and are able to compare 313 and 314 back and forth quickly, you might be able to see his head moving very slightly forward -- but I admit it's quite hard to see.
Nothwithstanding the conspiracy theories that say the Zapruder film was doctored, that's one of the reasons I'm convinced the third (fatal) shot hit Kennedy from the rear.