Untying the Knot: Your Heart is actually a Spiral

The heart is, “an arrangement so unusual and perplexing,
that it has long been considered as forming a kind of Gordian knot in Anatomy.
Of the complexity of the arrangement I need not speak further than to say that
Vesalius, Albinus, Haller and De Blainville,
all confessed their inability to unravel it”.
James Bell Pettigrew, 1834-1908

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If anyone suggests to you that science, particularly biological science and medicine, is not beautiful and not much more than “a dissection”, as someone once said to me, I could offer you a place to begin… a place of great beauty to point to.

It is one of the fascinating details of evolutionary embryology that I loved learning as a student: the vertebrate heart evolved from a single simple tube into the complex structure we know as our heart. Here is the heart of a human embryo before two weeks:

Tubular heart. Lithograph from the 20th U.S. edition of Gray's Anatomy of the Human Body, originally published in 1918. License is in the public domain because its copyright has expired.
Tubular heart of human embryo before 14 days.
Lithograph from the 20th U.S. edition of Gray's Anatomy of the Human Body, originally published in 1918. License is in the public domain because its copyright has expired.
Human embryonic heart. 14 day old.


Here is great old animation depicting the human heart formation:


Circulation functions with a “two-chambered” heart in fish, as you can see in this illustration:

This is a file from the Wikimedia Commons and is licensed freely.
“Two-chambered” heart of fish.


It is a three-chambered in amphibians and reptiles. And it is four-chambered in mammals and birds.

Four Chambered Adult Human Heart. Illustrated by Laura Maaske.
Four Chambered Adult Human Heart. Illustrated by Laura Maaske.

For further comparison, visit these pages which offer comparative imagery: Fish, amphibian, and mammalian hearts, and Fish, amphibian, reptile, and mammal & bird hearts.

During my undergraduate coursework in zoology, this evolution had stuck me as beautiful, that organisms tend towards complexity in their evolution. Later, as a student in biomedical communications at the University of Toronto, I found heart dissections reveal beautifully complicated anatomy compared to what I’d seen in the fish just a few years before.

In fact, while embryologists understood this folding pattern by observing cardiac development, it wasn’t until 2006 that the anatomist Torrent Guasp, using a special technique, dissected the human heart for the first time in history. In this skillful dissection he uncovered the original embryonic tube structure. Here is a video explaining Torrent Guasp’s dissection:

“When I looked at the heart for the first time I saw a circumferential basal loop. And then I saw a descending limb and an ascending limb. And they curl around each other at a helix and a vortex, except for the ventricle. And the angles at which they go is about 60 degrees. 60 degrees down and 60 degrees going up, and they cross each other in that way. For years people had wondered why this happened. I realized this is really a spiral. And I began to think about spirals. And I began to understand that spirals are almost the master plan of nature in terms of structure and in terms of rhythm.… if you pick the middle of the spiral up you form a helix. And of course the heart is a helix.”
-Dr. Gerald Buckberg, M.D.


So, for one of my own favorite illustration projects, I began my work by researching this folding pattern, and drawing its reach into the heart. As you can see, the folding works a little bit like a knot, and it is also a two-ended spiral.

The folding structure of the heart


I made a sample out of clay and practiced the folding pattern.

Mar102013_iph_0728 Mar102013_0701


And here are my illustrations to reveal the tubular unfolding pattern of the human heart:

Revealing embryology
Unfolding the Heart 1
Revealing embryology
Unfolding the Heart 2
Revealing embryology
Unfolding the Heart 3
Revealing embryology
Unfolding the Heart 4
Revealing embryology
Unfolding the Heart 5

As you can see in these illustrations, the adult human heart in its evolved form is a flattened tube, and behaves like a rope as the muscles wrap and squeeze blood. But it is a very complex knot, the dissection of which was not even achieved until the past few years, with Torrent Guasp. How remarkable that a structure so complex can be reduced, backwards, so that its simpler origin is apparent.

Gor·di·an knot
noun: Gordian knot; plural noun: Gordian knots
1. an extremely difficult or involved problem.
mid 16th cent.:
from the legend that Gordius,
king of Gordium,
tied an intricate knot and prophesied that
whoever untied it would become the ruler of Asia.
It was cut through with a sword by Alexander the Great.

Laura Maaske, B.Sc., M.Sc.BMC, Medical Illustrator & Designer

October 29, 2013

Medimagery Medical Illustration & Design

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21 thoughts on “Untying the Knot: Your Heart is actually a Spiral

  1. helical heart is a discovery that breaks with the foundations of anatomy and physiology, the most controversial is the fact that not a relaxation diastole is actually a contraction by the ascending segment of the apical loop in myocardial band

      1. batista procedure had a high mortality, knowing the BMH is developing a procedure to resize the heart to their original shape, This procedure is called “pacopexy” in other terms is “septal anterior ventricular exclusion operation. and in effect is to ischemic cardiomyopathy. all these concepts we introduce in our book and publication

  2. A very interesting and informative piece of work. Well presented. One of the most informative presentations that I have seen on the net. well done keep me informed of further developments Thanks

    1. Thank you Nihal. I will post any new updates I learn about on this great topic. I hope that anyone who is interested will post here, and that you may find new connections with others who have been doing research.

  3. A Unique and Marvelous Masterpiece of knowledge, biomechanics, dance, music, spirals in motion, nature in human motion, medical information, joy, happines, a way of restoration for ignorance, sadness, depression, nonsense behavior; normal helical sructure in chronic cardiac failure !! All and more embeded in:
    Cardiac Dance, The Spirals of Life
    The University of Cincinnati College Conservatory of Music

  4. Well, well, well !! When I was involved with the development of tissue heart valves in the 70’s I observed, as I guess many others did, that blood flow spiralled out of the left ventricle, through the aortic valve into the ascending aorta. Perhaps I now have the explanation.

      1. Thank you Juan. I hadn’t visually connected the embryonic folding of the heart to the general body musculature, because, for me, even having taken two embryology courses, the unfolding of the embryo is such a complicated process to envision. But i certainly have had clients over the years who requested me to illustrate the spiral arrangement of the body musculature.

        As I looked up the publication you referred to, I noticed that it is the famous anatomist, Raymond Dart, who wrote it. That’s a wonderful reference! Thank you again!

        Dart, Raymond A. 1950. Dec;13(12):265-8. “Voluntary musculature in the human body; the double-spiral arrangement”. British Journal of Physical Medicine.

  5. Have you heard of Gil Hedley? Here he shows his kinesthetic way to appreciate the movement of the heart. He was the first to introduce me to the concept that the Heart is not a Pump.

      1. He`s amazing. He runs a program called Integral Anatomy. Practices disections and holds normally 6 day courses of disection with the aim, not to show the different regions but to show the integrated harmony and wholeness of the body. Worth attending. An amazing experience. His facebook gil hedley – integral anatomy is full of his blogposts and he is a beautiful poet blending life, body, spirit into amazing words.

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