Neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis are some of the most costly and critically important health care issues of the day. Yet, despite decades and billions of dollars in research their causes remain a mystery. All three, however, as well as other serious neurological conditions, may have similar root causes related to design changes in the skull, spine and circulatory system of the brain due to upright posture.
Upright posture caused significant changes in the anatomy of the skull, spine and circulatory system of the brain. For the most part those changes were beneficial but they also caused some negative consequences that sometimes show up as we age.
In addition to Alzheimer’s disease, Parkinson’s disease and mutliple sclerosis other neurological conditions that share suspiciously similar roots include: migraine headaches, seizure disorders, transient ischemic attacks (mini strokes), normal pressure hydrocephalus (NPH) Chiari malformatons, tethered cord syndromes, amyotrophic lateral sclerosis (ALS), and primary lateral sclerosis (PLS) to name a few.
The problem with upright posture is that it stacks the skull on top of the nearly vertical segements of the spine. This decreases the tension loads that typically pull on the spine for support in four legged species. At the same time it increases the compression loads stacked up on the spine. The cervical spine or neck for example gets compressed by the weight of the head above. Likewise the lower segments, especially the low back, get compressed by the weight of the entire spine above it. The increased compressive forces cause us to lose a little height over the course of a day. Over the course of a lifetime it can do far more irreparable damage.
Upright posture also puts the foramen magnum of the skull directly over the spinal canal which houses the spinal cord. The foramen magnum is the large hole in the base of the skull through which the brainstem passes and becomes the spinal cord. This arrangement predisposes the brainstem to sinking into the foramen magnum resulting in a Chiari malformation. Among other things, Chiari malformations have been associated with mutliple sclerosis. In fact, Chiari malformations are probably far more common than we realize and play a role in other conditions as well.
The vertical arrangement of the spine also pulls on the brainstem from below. The pull comes from the attachment point at the tailend of cord, called the filum terminale, to the tailbone of the spine, called the coccyx. A short spinal cord can cause excessive tension in the lower cord, called tethered cord syndrome. Abnormal curvatures of the spine also cause tension on the cord, as do abnormal head and neck tilts. Consequently, short cords, scoliosis and head tilts can lead to Chiari malformations. Lastly, the design of the skull, particularly the length and slope of its base, likewise predispose humans to Chiari malformations.