THE RESPIRATORY DIAPHRAGM

pressure the researchers conceptualise that the transversus abdo- minis forms the walls of a pressurised cylinder, with the muscles of the pelvic floor and diaphragm forming its base and lid respec- tively.

It is believed that the co-activation of the transversus

abdominis and the muscles of the pelvic floor and diaphragm is likely to maintain the IAP at a critical level, thus allowing the contractions of the transversus abdominis to affect spinal support either via IAP or the connections into the thoracolumbar fascia.

Control of continuous muscle recruitment for joint stability, as with the transversus abdominis, relies not only on pre-pro- grammed motor patterns from the cortex but also on the state of the feedback system from kinaesthetic input.

sensitivity of any of these organs or structures.

MECHANICAL INFLUENCES The diaphragm and its fascial covering interface with the pleura (the covering of the lungs) and pericardium (covering of the heart) superiorly, and inferiorly with the parietal peritoneum (stomach lining), the liver, kidneys and supra-renal glands, gas- tric fundus and spleen as well as the transversalis fascia.

The If it is assumed

that the recruitment of the transversus abdominis, the respirato- ry diaphragm, and the pelvic floor play a dynamic and interde- pendent role in creating stability of the spine, then anything that may alter afferent input (signals from sense receptors transmitted to the brain or spinal cord) to any one of these structures may influence the efferent output of the central nervous system (CNS) to the muscles and thereby their synchronised recruitment pat- tern. So what factors may play a part in changing this pattern of recruitment with particular reference to the diaphragm, the vis- cera and their supportive network of connective tissue?

NEUROANATOMICAL INFLUENCES The phrenic nerve not only innervates the diaphragm but is also a pathway for visceral afferents from the liver, gallbladder, pari- etal viscera, stomach, ligament of Treitz, (2,3) and pericardium and pancreas (3). Changes in respiration, to the point of chron- ic partial contraction of the diaphragm (4), have been noted by several investigators during mechanical stimulation of the biliary structures noted above (5,6).

In

other words, the recruitment and subsequent con- traction of

the diaphragm muscle can be

affected by nerve input from structures such as the liver, stomach and pan- creas. This prompts the question of what consequences there might be for the

respiratory diaphragm, if any, if there was an increase in the

diaphragm is effectively a transverse link in the kinetic chain between the thoracic and abdominal contents. Hence any ten- sion, whether it is compressive or tensile within or between any of the structures, either in the thorax or abdomen could lead to tension within the diaphragm. This tension may be transmitted via the connective tissue into the internal fabric of the diaphragm muscle itself. This may change the tension within the actin/myosin bridging complex and thereby influence the propri- oceptive sensitivity of the muscle and possible mechanical advan- tage and recruitment patterns.

PERSONAL VIEW POINT OF A SHIFTING PARADIGM So in specific terms, I hope it is a little more apparent as to why it is important to assess and treat the diaphragm, having placed the diaphragm within a broader scientific paradigm. But is this where the journey ends?

My personal journey started when I had deep-seated chronic tho- racic spine pain. I