This article was originally published in Positive Health issue 50 – March 2000

Last month, I portrayed the diaphragm as the king of muscles, a muscle with multifarious duties to perform. Interfering with it will play havoc with many systems. Like any powerful ruler with ‘a finger in every pie’, it demands our close attention if it is to function efficiently. As an incentive for you to do this, let me describe some of the consequences of an unhappy diaphragm.

Classically, the diaphragm has been considered mainly from the point of view of breathing. F Mézières, original as ever, was more interested in its little known postural involvement.

The diaphragm, the psoas, and the iliacus form a muscular chain. When they become too tight (which is the habitual fate of any muscular chain) these three fellows conspire to over-arch the lumbar spine, causing an hyper-lordosis.

Lordosis is the source of all deformations and distortions. It is a wandering concavity which likes to play hide-and-seek. It is the bête noire of the Mézièriste whose job is to chase and erase this great ‘distorter’.

By promoting a lordotic bend, a tight diaphragm can cause a pseudo-sciatica, or a femoral neuritis (pain felt from the groin down the front part of the thigh). Or, because of its inherent asymmetry, it can twist the spine and instigate a scoliotic deformation.

It is Man’s universal habit to hold his breath at the drop of a hat. Concentration, pain, fear and stress… are all factors that encourage the diaphragm to freeze. As this contraction happens during inspiration, the diaphragm characteristically adopts an inspiratory, low position.

When you take a deep breath, the diaphragm, by pulling on the part of the spine where it’s attached, creates a fixed point in the back.

The back muscles use this fixed point as an opportunity to contract and further arch the spine. So, a tight diaphragm can be the starting point of a vicious circle where many muscles contract in unison, all protecting and reinforcing the dreaded lordosis. It is a circle so vicious that intervertebral discs can, with time, become squashed, and nerves impinged by the compressive force of the shortened musculature.

Each movement of the diaphragm affects the shape of the rib-cage. In normal breathing, as I explained last time, the diaphragm expands the three diameters of the rib-cage. But when the diaphragm is allowed, by weak abdominal muscles and a slouched posture, to venture into lower and lower excursions, it might do the opposite of what it is supposed to do, and pull inward the inside wall of the thorax. As a result, the diaphragm then causes the sternum to cave in, resulting in various grooves or flares.

Even organs lose their normal shape and position when the diaphragm sags. The heart, sitting as it is on the top of the diaphragm, is constrained to follow its constant movements. With a low diaphragm, the heart is dragged down. Squeezed in its bag (pericardium) by a tight diaphragm, the heart will show signs of functional disturbances such as arrhythmia and tachycardia. The symptoms sometimes mimic those of angina pectoris. The heart is structurally okay, but it’s ‘choking’, and its owner suffers and feels anxious.

This brings us to the circulatory system. The diaphragm has been called the ‘second heart’ for good reason. According to Sir Arthur Keith, the movement of the diaphragm is the most vital factor in the filling of the right side of the mammalian heart. Like the abdominal and leg muscles, it acts as a muscular pump which is designed to assist the return of blood, from the lower part of the body to the heart, against the force of gravity.

There are ‘holes’ in the diaphragm (see previous column) for the passage of tubes from the venous, arterial and lymphatic systems. A chronically tensed diaphragm interferes with the circulation of all of these. Congestion and stagnation ensue, resulting in varicose veins, menstrual problems and haemorrhoids.

The digestive system is not spared either. The torso could be compared to a churn, with the diaphragm as the dasher churning and squeezing the abdominal organs. In this case, it helps the making, not of butter, but of chyme, and assists peristalsis. A blocked diaphragm has limited excursions which reduce peristalsis – sluggish digestion and constipation are to be expected.

Burping, a normal occurrence after a meal, so valued in babies but so discouraged in adults, may be difficult with a blocked diaphragm.

Without a burping outlet, air accumulates under the left dome of the diaphragm and pushes on the bottom of a complaining heart.

Another pathology linked with diaphragmatic function is hiatus hernia. The oesophagus (gullet) is one of the tubes that goes through the diaphragm. Firmly anchored to part of the spine and to the surrounding organs, it has restricted movement. A stooped posture will eventually shorten the gullet. A brusque attempt to straighten up or to take a deep breath, associated with a pulling back of the head, might distend its attachments with the diaphragm. In time, the gullet and its diaphragmatic opening become enlarged. The stage is set for a sliding hiatus hernia, so called because a part of the stomach slides through the opening of the diaphragm. This usually happens during a forceful lowering of the diaphragm.

Although this list of pathologies is not exhaustive, you can perhaps begin to see the true importance of this undervalued muscle. Next time I’ll discuss how best to keep it happy.