Dynamics of breathing 11
the thoracic cavity. Once the transverse septum is in this location, the muscular tissue of
the diaphragm grows toward it from the interior surface of the abdominal wall. Thus, the
association of the central tendon with the heart is the original manifestation of the dia-
phragm, and further justifies labeling it as its origin.
Because of its firm anchorage to the heart, the tough, fibrous tissue of the central tendon
has limited ability to move vertically within the thoracic cavity (between 1/2 to 1 inch).
Therefore, the upper muscular attachments of the diaphragm closest to the central tendon
have little movement potential. However, the muscular domes that rise up on either side of
the central tendon do have the ability to strongly push downward on the abdominal viscera,
and this (not the downward movement of the central tendon itself) mostly accounts for the
bulging of the upper abdomen commonly referred to as a belly breath.
Conclusions For all the reasons just mentioned, we have concluded that traditional texts
reverse the structural labeling of origin and insertion of the diaphragm by describing distal
structures (lower attachments) as origin and proximal structures (upper attachments) as
insertion. This structural confusion leads to a functional confusion because of the assump-
tion that muscular insertions are mobile and muscular origins are stable. We will explore
this shortly.
organic relations
Studying the diaphragm’s origin and insertion allows us to understand what structures it
is attached to. But unlike other muscles, the diaphragm has a lot of structures attached to
it. This is what is meant by the term organic relations.
As the prime mover of the thoracic and abdominal cavities, the diaphragm is a place of
anchorage for the connective tissue that surrounds the thoracic and abdominal organs. The
names of these important structures are easily remembered as the three Ps:
- Pleura, which surrounds the lungs
- Pericardium, which surrounds the heart
- Peritoneum, which surrounds the abdominal organs
It should be clear that the shape-changing activity of these cavities has a profound effect
on the movements of the organs they contain. The diaphragm is a fundamental source
of these movements, but the viscera are also a source of resistance and stabilization for
the diaphragm. This reciprocal relationship illuminates why the coordinated movements of
breath and body promoted by yoga practice can lead to such dramatic improvements in
the overall health and functioning of all the body’s systems.
action of the Diaphragm
It is important to remember that the mus-
cular fibers of the diaphragm are oriented
primarily along the vertical (up–down) axis
of the body (see figure 1.11).
E5267/Kaminoff/fig1.12/417561/alw/pulled-r1Figure 1.11 The muscular fibers of the
diaphragm all run vertically from their
lower attachments to the central tendon.