Humans are born from a water (reduced gravity) environment into full gravity at about 9 months of development. The introduction of gravity is done with a twist helping us to understand why we are not completely symmetrical. Throughout a lifetime interaction with gravity facilitates growth and adaptation or decline and degeneration. The varying amount that people interact with gravity within their body during physical movements alters body (and brain) mechanics.
Pressure Change and Physical Structure
Astronauts who live at zero gravity are thought to have a risk of the blood brain barrier leaking meaning long space travel is not possible without a form of gravity. Those people who have never walked would not have had chance to pressurise their spine. Without walking people develop ‘Cod Fish’ vertebrae. The (approx’) 10kg of gravity has an effect upon brain and body structure through pressure regulation. From basic science we know that pressure can change the rate of reactions and when applied in the body a change in physiology.
The human body is made up of chambers, the brain and spine (thecal sac), the abdomen, the lungs (pleura) and heart (pericardium) to name a few. Anatomically we are really a series of chambers.
Muscles as Pressure Regulators
Giving birth is a great example of pressure regulation (See blog post of how intercostal muscle activity is predictive of birthing experience). Illustrating that muscles can be seen as pressure regulating tissue and not just movement devices. Muscles need joints to generate linear and angular forces e.g. a change in direction. Muscles and joints work together to insure all nooks and crannies can be affected by force. Sometimes odd postures are needed such as in Yoga. This is why a variety of movement as a life habit provides for my healthiest body if I do not have access to a Chiropractor or other bodyworker.
In consideration of anatomical connections we can see that the brain/spine cavity is linked to the abdominal cavity through venous blood supply and changes in abdominal pressure are (as found in Pigs to be 75%) passed onto the pleura of the lungs. Demonstrating a link between abdominal pressure and lung pressure. Pleural pressure and abdominal pressure influence pericardial pressure. The pressure of the heart chamber is wired (via nerve) to the pressure of the eye ball, a known indicator of intracranial pressure. Intracranial pressure is also known as intrathecal (spine/brain) pressure.
Pressure dys-regulation in the spine and brain will affect the other chambers of the body, posture, efficiency of movement, muscular tone and joint mobility. Musculature may hold tight, spasm up or go loose to assist in regulation of body cavity pressure, independent or in conjunction with physical tasks. Just think as a muscle holds tight it also increases pressure locally.
The brain and spine float in fluid (CSF) altering direct effects of pressure during postural and physical activity tasks (imagine a force applied to water and how the force will be dispersed by the fluid). The Sacro-occipital Technique system in Chiropractic has categorised muscle and joint dysfunctional patterns based upon the premise of pressure dysregulation.