Thoracic diaphragm – introduction

The journey of a thousand miles begins with one step” – Lao Tzu

Since my adventure in studying anatomy started with “breath” I determined to begin this project with the thoracic diaphragm, the main muscle of respiration.

At some point in life I figured there was something missing. Not in a “romantic” manner, however in an “anatomical” manner. A connection with my body. Knowledge about functions of my body were missing. I realized that my attitude towards it, was all about “habits” and not about knowledge or better: experience and proprioception.

Aim of these posts is to rationalize informations and studies to maybe lead them to be beneficial for someone else too.

I got this realisation when I “discovered my breath”. In that precise moment, I noticed that my respiratory process was almost a mystery to me, even though it automatically took place since the day I was born, essentially without me notice it!

That became the moment I learnt that it turned into very important have a better knowledge and a deeply experience about this wonderful “machine” I’m driving: my human body. When I use the word “body” I suggest “mind” as well. So I have become inquisitive about disciplines which purpose is to increase our awareness.

That’s why I decided to put in practice my repository project beginning with the most important muscle related to breathing, because it was my kick-start and because… it all begin with an inhale!


The thoracic diaphragm is also briefly called “diaphragm“, even though is not the unique “diaphragm” in human anatomy, however more probably due to the fact it’s far the primary one.

The term descend from the ancient Greek word: διάφραγμα – diáphragma, which means “partition“, therefor in anatomy is used also for other tissues or structures in our body which as well has the function to “separate”.


The thoracic diaphragm separates the thoracic cavity from the abdominal cavity. The thoracic cavity includes fundamental organs like heart and lungs. The abdominal cavity includes: stomach, liver, gallbladder, spleen, pancreas, small intestine, kidneys, large intestine and adrenal glands. The thoracic cavity has the diaphragm as its “floor” while the abdominal cavity has it as its “roof“.


The diaphragm is a slightly asymmetric double dome-like” structure of muscle and tendons. It is split into two lobes: left and right. It sets up its shape both from the organs that surrounds it and from its intersections. Its right lobe is lightly higher than the left one. It reaches as high as the upper border of the fifth rib since the right lobe of the liver, which is larger, rests beneath the right half of the diaphragm. The left lobe is lower and it may reach up to the lower border of the fifth rib, because of the heart which lies on it.
During inhalation and exhalation and depending from which posture of the body we assume, the diaphragm  can assume a different position.


Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.