Note: Detached skull fragments were drawn at a larger scale than the head. |
I'm wondering if the bullet entered at the back of the skull and created a few linear fractures radiating from the impact point, that ran into the lower rear of the skull.
Some of the surface of the skull at the point of impact was pushed forward such that it jutted forward of the intact skull above (see lateral X-ray):
The bullet fragmented into multiple pieces at the entry point and may not have had enough energy to fracture the intact skull opposite the entry. Possibly it was the bullet pressure wave that caused the fragmentation of skull above the right ear, or the gaping wound.
It is hard to say exactly what happened but I expect that the copper jacket ruptured on impact and much of the lead in the front part of the bullet melted and became a lead spray. The copper jacket and a bit of still solid lead at the base is probably what passed through the skull.
As an aside, it would have been nice if the ballistics experts actually weighed the copper jacket part and lead part of the bullet fragments separately to determine how much copper was recovered from the fragments. We could then determine with a bit better detail what likely happened. It would also help determine whether the fragments were from only 1 or 2 bullets. If the amount of copper recovered exceeded the amount of copper of a single bullet we would know that more than one bullet struck in the car.
Nalli writes:
"It is noted that the massive “defect” was not the “exit wound”
of the bullet (as is commonly misunderstood), but rather
corresponded roughly to the area where the maximum
explosive energy was deposited by the bullet during its passage "
"Here the large wound inflicted on the President's head was not a
bullet exit wound, but rather the region of maximum temporary
cavitation associated with KE transfer. This KE deposit
propagated radially outward in the form of an expanding pressure
wave resulting in a rupture and explosion of the skull."
"However, all this said, note well that because such explosions are
not necessarily the bullet outshoots, the momentum directly carried
forward by a given bullet during passage may not be the primary
player in a recoil effect."
The HSCA drawing seems to imply the right-side gaping wound was caused by the path of a bullet, or more precisely, one of its fragments, that impacted the inside of the skull to fracture it.
The size of the exit wound and the ruptured skull was definitely caused by the explosive exit wound. However, there had to have been a significant piece of the missile to compress the brain matter that exploded out of the front part of the skull. Whether the skull ruptured because of the pressure alone before the bullet struck the skull from the inside or whether it occurred with the exit of that fragment through the skull is probably not possible to determine.
