...a drawing where he assumes lobes equate to regions of the head (though they do not equate directly to bones) and a drawing of a red arrow?
The illustration of a brain with no collocated cranium, no discussion or further reference to anatomical features, is misleading. Landmarks on the head are not given with respect to the brain, but to the bones of the cranium. The lobes of the brain are named for the cranium bone beneath which they most closely lie. But this does not mean that the
occipital lobe of the brain defines the occiput of the head.
Further, the herniation of the cerebellum need not occur through the occipital bone, but would just as easily occur through a fracture in the temporal bone. The cerebellum actually lies farther superior than most people think, locating itself generally right behind the ear. Substantial injury to the occipital bone would most likely result in a missing cerebellum.
Here is a more helpful illustration that roughly collocates the regions of the skull with the lobes of the brain.
http://www.sciencephoto.com/media/306517/enlarge
Note the cerebellum, the more finely crenellated region. Posterior to it, barely visible, is the lambdoid suture, which demarcates the temporal bone from the cranial occipital bone. Therefore a cranial would that extended "to the occiput" (but didn't include it) [Giesecke] would clearly expose the cerebellum and subject it to possible herniation.
The superior boundary of the temporal bone corresponds roughly with the top of the corpus colossum, the uncrenellated body at the center of the brain's bulk. The parietal bone continues to the top (vertex) of the cranium. The witness testimony I see in this thread identifies the
My second thought: the extent of the wound described does not have to relate to the direction of travel as the arrow suggests.
Indeed I rather ignore the red arrow. It has been added perhaps as a suggestion of bullet path, but Robert gives no discussion.
The witness that Robert belabors for the word "occiput" is clearly describing the geometric extent of the wound he remembers: vertically from the vertex (i.e., the sagittal crest) to the ear (cf. the auditory foramen in my illustration), longitudinally from browline to occupit. None of the other three limits suggest significant encroachment, hence there is no reason to suppose that the physician here "really" means to say up to
and including the occipital bone.
Others [Akins] describe "occipitalparietal," which is not strictly a region, but rather describes features that share the occipital bone and parietal bone in common, or describes the lateral extent of the lambdoid suture. This is still confined to the side of the head and still allows for herniation of the cerebellum. Robert does not properly interpret the medical terminology in terms of actual locations on the head.
One outlier [Jenkins] describes injury to the "temporal and occipital" in his initial report, but doesn't specify the injured regions in his lengthier testimony in 1964. We crave additional information because temporo-occipital identification is rare and comprises only a small portion of the cranium. It is odd for those two regions to be combined in the description of the site of an injury. But then Dr. Jenkins is an anesthesiologist, not a surgeon or orthopedist, hence he can be forgiven for misidentifying the site of the injury. We can expect him to be an expert in the anatomy of tracheal and bronchial tissues (i.e., for intubation), but not necessarily proficient in the fine positioning of cranial anatomy under duress. His sworn testimony describes significant "heat of battle" confusion, including uncertainty over the number, site, and appearance of injuries to the patient.