The skull shape affects the pitch, layout and flow of the circulatory system of the brain, which includes blood and cerebrospinal fluid (CSF). It also affects the position of the brain within the cranial vault.
The skull shape and it’s affect on the brain was where I began my investigation. It started following a discussion about the bend in the base of the cranium and the state of the special joints of the cranium (open or closed), called the sutures. But it was the open state of the sutures of the artificially deformed crania from the former indigenous people of Peru and Bolivia that started me looking into hydrocephalus and the role of venous drainage problems in neurodegenerative diseases.
In particular, it was the sutures of the membranous bones, the bones that form the cover over the cranial vault. Normally the sutures of the membranous bones close with advancing age. In cases such as the one below the sutures were wide open when they should have been closed. The only thing that came to mind that would cause the sutures to stay open in that way was hydrocephalus, so I began to explore further. Much further than I would have guessed at the time.
As it turned out the shape of the head may explain why there is a much lower incidence of multiple sclerosis (MS) among Asians. On the other hand, it may explain why Asians have a higher incidence of a variant of MS called Devic’s disease or neuromyelitis optica. See racial skull design for additional information on racial differences.
What I found more peculiar than the shape was that some of the artificially deformed crania from the same Peruvian and Bolivian people also had trepinations. Trepinations are man-made holes into the cranial vault. They are considered to be the oldest form of surgery. It may have started as a treatment for head trauma. But these particular skulls weren’t associated with trauma. If you look at the picture below you can see the trepination on the front toward the top of the skull
At first I thought they inadvertently caused hydrocephalus by deforming the skull shape of their children and were trying to fix the problems they created. Then I began to wonder if they were trying to correct hydrocephalus by banding the child’s head in the first place. Perhaps they passed on genetic problems in the design of the drainage system of the brain. In either case, whether they inadvertently caused the problem or were trying to correct a problem they didn’t cause, the patient lived well into adulthood with hydrocephalic type conditions. This is far longer than modern medicine could keep them alive.
Looking into hydrocephalus further led me to a condition called normal pressure hydrocephalus (NPH), which is sometimes associated with Alzheimer’s disease. Disturbances in CSF flow and normal pressure hydrocephalus may play a significant role in neurodegenerative diseases of the brain.
That was the beginning of a long journey into the unique design of the human skull, spine and circulatory system of the brain. In the section on skull base I discuss one of its most unique characteristics – the bend in the base of the skull.
The bent basicranium is an asset to upright posture, brain blood flow, an extra-large brain and exceptional intelligence. On the other hand, the bend in the basicranium is also behind many serious health problems. In particular it plays a role in migraine headaches, seizure disorders, and neurodegenerative diseases such as Alzheimer’s, Parkinson’s and mutliple sclerosis. Those with neurodegenerative diseases may also find posterior fossa and Chiari and venous inversion flows and skull shape.