Dr. McClelland famously described the cerebellum falling out of the head wound. This is used as evidence of rearward exit as the cerebellum is at the back of the head. Right? Not exactly.
At the back of the head is the visual cortex, located in the occipital lobes which buttress the rear of the skull. Beneath these sits the cerebellum (generally thought to coordinate brain and motor activity), somewhat inward to the point where it is somewhat covered by the cerebrum.
Cerebellum is outlined.
Notice the thing to be left of the cerebellum on the MRI. Those structures and nuclei are crucial to brain and body function, including automatic breathing and heartbeat. JFK was given a tracheostomy at Parkland for what they noted was disturbed, but still present breathing. A bullet getting to the cerebellum without hitting these nuclei is slim, as even a totally lateral shot?s?one striking the cerebellum?disruptive force would knock them out of commission. Indeed, the whole reason (we think) one looses consciousness after a hard enough hit to the head is disruption of neural networks?and a good enough punch will do that.
McClelland said he saw both cerebral and cerebellur tissue exuding from the defect. Of course, it?s difficult to distinguish two types of brain tissue when they?ve been chewed up by a bullet, so this must?ve been an inference and, from what we?ll see, not a very good one, but not very bad either.
For starters, McClelland and all the doctors described a wound encompassing the occipital, parietal, and temporal bones of the skull. The most famous description is ?occipito-parietal.? Big problem. The parietal bones are on top of the skull, as the doctors famously indicated:
The autopsy report itself reads: ?There is a large irregular defect of the scalp and skull on the right involving chiefly the parietal bone but extending somewhat into the temporal and occipital regions.?
Refer back to the MRI. There?s no way the cerebellum came out of that, and indeed, cerrebellur damage was most likely only inferred, as Dr. Paul Peters staged he believed there to be cerebellum damage as it appeared to him that the occipital lobes were resting on the foramen magnum, the bone floor of the skull where he cerebellum ususally sits. (See pp. 317-324 of Lifton?s
Best Evidence)
So he couldn?t see it damaged, but guessed it was. This is strange, considering the other doctors said the cerebellum could be observed through the injury.
Moreover, Boswell told the ARRB that not only was the cerebellum not damaged, it was still encased in dural tissue, while the cerebral cortex presented with torn dura. He further stated that the tentorium?dural partition of the cerebrum and cerebellum?was scathed.
But Humes stated that the cerebellum was slightly disrupted but without any actual lesions, and opined this was due a pressure wave generated by the bullet. So does this confirm the confusions of the Parkland staff? Maybe it being disrupted amongst all the cortical damage might have influenced their perceptions?
Photos of the brain apparently showed the HSCA a lot of interesting detail. They noticed the cerebellum disruption observed by Humes, stating that it was ?virtually intact.? So not totally normal, but not damaged. They also noted major discolouration of the right sylvian fissure (the ?gap? between the frontal and temporal lobes), with the temporal lobe being somewhat depressed. Notably, they observed massive fragmentation and disruption to the inferior cerebrum, mainly on the right side but also the left temporal area. (7 HSCA 129)
One last piece of the puzzle came from the pictures, maybe the most important fact about the head wound:
the right cerebellum was visble in superior pictures of the brain?it could be seen through the damaged cortex! (Ibid.)
Superior view of brain, note cerebellum not visible.
So in conclusion, what the Parkland doctors likely saw was massive disruption of mainly the posterior parietal, but also temporal and superior occipital lobes which left a portal to observe a slightly off looking cerebellum, covered with shredded cortical tissue. They inferred damage to it based on these and other visual features.
This model explains how the doctors could?ve seen the cerebellum through the mainly parietal defect and the other evidence mentioned without invoking any particular theory as to the origin of the shot. It also ends the only basis for the speculation regarding forgery of medical or Z-film evidence.