Body and Breath - Yoga Shop Talk

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Yoga shoptalk, August, 2002

Question: Are 3-dimensional plastic models of the chest and diaphragm available from medical supply houses? For years I have wanted to see how the diaphragm is actually shaped and situated in the torso, and neither drawings or photographs are very satisfactory. When in south India, I was shown around the medical college of Deshikenra Swamiji in Mysore, and the physician head of the anatomy lab pulled out a cadaver for me to look at. It was awesome to see the actual diaphragm. My thought is that a full size plastic cut-away model would be extremely useful in teaching diaphragmatic breathing. Over and over I see blank stares in the faces of people who really don't "get it," something with which I can also relate. There must be many yoga teachers who would value such a learning tool.

Answer: This is an important question and a continuing challenge for most students of yoga. To first point you toward an answer to your question, if you search Google's www.refdesk.com using three words: anatomy models plastic, you will find many sources of anatomical models, both pricey and cheap. If some interested party is willing to do the research and make suggestions as to a source for an inexpensive and helpful model, I'll post your recommendations in the archives to the this column.

An editorial comment, however: I should warn that anatomists are generally disdainful of using anatomical models for instruction, and anyone who has taught or learned from cadavers in anatomical dissection laboratories will readily agree that no model can substitute for the real thing. The high point of anatomy and hatha yoga classes that I taught at the University of Minnesota Extension Division in the 1980s was a final three-hour session in which students were able to study cadavers in various stages of dissection and thus place everything covered earlier in the course in perspective. Although a few students were initially apprehensive of studying a real cadaver, the session was popular with everyone in the end because it was so valuable. Structures such as superficial muscles of the extremities that are obvious on the surface of the body are easy to grasp from pictures, but it is a lot more difficult to conceptualize deeper structures, even from an expensive color atlas, and to understand them there is no substitute for a cadaver. For example, picturing exactly where the rotator cuff tendons insert in the shoulder joint is greatly aided by studying a real dissection. And although all structures that are hidden beneath the surface of the body present problems, the respiratory diaphragm is a special challenge, as, I might add, is the pelvic diaphragm.

Without the benefit of a cadaver or plastic model, we have to use the tools that are available, and the shape and function of the respiratory diaphragm can be understood, even by those with a limited biomedical background, by using a combination of approaches. First study three-dimensional cutaways that are pictorially illustrated in two-dimensional drawings (figures 2.8 and 2.9 in Anatomy of Hatha Yoga) and sectional views that also portray function (figures 2.29a-e). Then study the photographs of living models that superimpose outlines of inhalation on halftones of exhalation (figures 2.10-11, 2.16-17, 2.19-20, 2.22-26, and 3.33-34). The photographs, of course, are also likely to illustrate the function of more muscles of respiration than the diaphragm alone. To figure everything out, you have to read the text carefully, study the pictures, and think through the reasoning. Then you have to experiment with the postures that are illustrated, feel the movements, and then go back and do more reading and studying. The practical test for your own understanding is whether you can explain the structure and operation of the diaphragm in your own words to yoga students who do not have a biomedical background. If they are not comprehending your explanations you need to go back to your personal inquiries.

I can't resist mentioning that even though the respiratory diaphragm is difficult to illustrate convincingly, the pelvic diaphragm is even more so. The most beautiful color drawing of the pelvic diaphragm is a sham and disappointment in comparison with a real dissection, which is in turn no less than astonishing. In spite of the most skillful artistic efforts, drawings of this region appear flat and two-dimensional, and nothing can prepare the student for the startling semi-conical/cylindrical shape of the pelvic diaphragm with the anus at its apex, dissected genitals in front, and coccyx and sacrum behind. And yet a clear understanding of the disposition and anatomy of the pelvic diaphragm and of the structures in the overlying urogenital and anal triangles is extremely important to anyone who wishes to understand aswini mudra and mula bandha. Without the anatomical concepts in combination with postural experimentation, aswini mudra and mula bandha remain vague and mysterious, and their discussion and description is more often than not an example of the blind leading the blind.