A little bit about the diaphragm

Have you ever had a client with chronic shoulder pain, stubborn low back issues, or even digestive discomfort that just won’t resolve no matter what you do?

What if I told you that one overlooked muscle could be the missing link in your treatments?

The diaphragm isn’t just a breathing muscle—it’s the epicenter of the entire body’s function. It’s connected to the vagus nerve, the autonomic nervous system, and even fluid pressure regulation between the thoracic, abdominal, and pelvic cavities. In all reality, it is connected to everything in your body, because of how it grew during embryonic development.

But here’s the problem: Most bodyworkers barely touch it. It’s a huge blind spot in our education, and that’s a travesty.

A chronically contracted diaphragm can cause shoulder pain, low back pain, hip and knee issues, hiatal hernias, and even brain fog by restricting circulation to the head. It can pull on the psoas, compress the stomach and liver, and disrupt the nervous system’s balance. That’s why I believe every bodyworker should know how to assess and treat it.

Take a moment and open up your favorite anatomy book. (My favorite is Netter’s Atlas, any edition, either version.) Find a few pictures of the diaphragm and make a list of all of the structures that connect to it. Now you get the idea of why it is so important to treat the diaphragm if you want to have good health in the body.

The diaphragm not only draws in air from the outside when it contracts. It acts as a fluid pressure modulator. You learned in school that when the diaphragm contracts, it causes lower pressure in the thoracic cavity than in the outside air, which draws air into the lungs. But did you also learn that when it contracts, the pressure in the abdominopelvic cavity is also increased?

Think about what this means for our bodies. In health, the pressure is increasing and decreasing above and below the diaphragm, alternately. What does this do for venous return of blood to the heart? What does it do for lymph movement towards the heart? It acts as another way to pump the fluid superiorly toward the heart. Remember, the heart is not a strong enough pump to get the fluid all returned to itself on its own.

What does this mean for someone whose diaphragm stays partially contracted and never fully releases for a full exhale? It means many things.

Let’s look at the abdominopelvic cavity. With a chronically contracted diaphragm, the pressure will be chronically increased below the diaphragm. Venous return and lymphatic flow will be decreased dramatically. (We can talk about the mechanics of why this happens later.) Take a moment and think about what this means for the ankles, knees, reproductive organs, and digestion.

With more fluid than necessary in those places, that will look like inflammation, right? Swelling of the ankles, too much fluid around the knees, will cause pain in those joints, leading to less movement, which will eventually affect the movement of the sacroiliac (SI) joints, because if the ankle isn’t moving well, you will not take a full stride, and the SI joints will eventually lose the ability to have free motion.

What about the reproductive and digestive organs? With too much fluid around them, they will also have less of their inherent motions, causing them to learn to stick together. The body is very good at supporting lack of motion, by adding connective tissue to lend support if something doesn’t move. These turn into adhesions. Lack of venous return also causes a problem with the uterus specifically. It provides a feeding ground for fibroid tumors.

There is so much more to say about what a contracted diaphragm does to the body, but I will leave some for another day.