A healthy gut is arguably one of the most desirable outcomes for a Functional Medicine doctor. As a whole, a well functioning digestive system is imperative if global health is the goal. If Functional Medicine works from the inside out, Posturology, to improve the digestive system, works from the outside in. Here’s how!
The digestive system spans over two cavities: the thoracic and the abdominal cavities. As such, mechanically, it is in relationship with the thorax as well as the shoulder and pelvic girdles.
The viscera can potentially be compromised in its function where it can be compressed. A right tilt of the shoulder, for example, can create compression of the liver or yet a ptosis, thus affecting its efficiency at performing its varied tasks.
As well, a key muscle separating the two cavities, the diaphragm, has a mobilizing effect of the entire abdominal viscera, contributing to the necessary movement for optimal transit. When the shoulder and pelvic girdles are imbalanced, the diaphragm is under tension and, thus, cannot contract powerfully to mobilize the viscera. If peristalis is the organ’s intrinsic movement, mobilization of these same organs via the diaphragm contributes to the overall effort and, I believe, needs to be addressed in the case of postural imbalances where the patient presents with GI related symptoms.
The source of innervation of the digestive system is as interesting as it is varied. Of notice, parasympathetic innervation for the heart and the digestive tract originates from cranial nerve X.
Cranial nerve X exits the cranium at the jugular foramen (junction between the occipital and temporal bone). Many muscles surround this suture and, if stiff, can compress cranial nerve X, thus reducing its ability to perform both its sensory and motor functions.
In the case of a static head tilt, there can be compression of the occipital/temporal suture. Considering that a static head tilt is actually quite common, I believe we should address it structurally in order to maximize innervation of the gut… if we are to heal it.
Sympathetic innervation of the digestive system comes from the splanchinc nerves. The splanchnic nerves are mixed nerves. The greater and lesser splanchnic nerves innervate the celiac ganglia as well as the superior mesenteric ganglia and the aorticorenal ganglia, which, as a whole, connect to the viscera of the thoracic and abdominal cavities.
Their origin is T5-T12. Essentially, all of the lower thoracic segments and their alignment can play a role in the functioning of these ever so important nerves.
A postural imbalance at the level of the neck and shoulders often compromises this key region, and this can affect the innervation of the organs of digestion.
In summary, both parasympathetic and sympathetic innervation of the gut can be altered by postural imbalances.
In recent years, key neuro anatomical links have been made between the afferents of the neck muscles and the autonomic nervous system.
Brain Struct Funct. 2014 Mar 5.
Neck muscle afferents influence oromotor and cardiorespiratory brainstem neural circuits.
This study by Edwards and associates describes the many fascinating links between the sensory information the neck muscles and specific targets found in the brainstem that influence the gut.
Neck muscle afferents projects to the intermedius nucleus of medulla. Once in the medulla, there are two projections that affect the digestive system.
One of these projections is the nucleus of the solitary tract (NST). It is a cluster of nerves in the medulla. Through the center of the NST runs the solitary tract, a white bundle of nerve fibers, including fibers from cranial nerve X.
As well, projections from the NST are the reticular formation, hypothalamus and thalamus.
Based on this specific neuro anatomy, an abnormal sensory feedback from the neck muscles can potentially affect the autonomic nervous system as a whole, and even more specifically the digestive and endocrine systems.
Another link between the afferents of the neck musculature and cranial nerve X is the nucleus ambiguus, also found in the medulla.
So there you have it, a postural imbalance can affect digestion via 3 mechanisms: mechanics, innervation and neuro anatomy. To heal the gut, we need to heal the whole body, from the inside out… and from the outside in!