Muscle of the Month: Diaphragm
Updated: Feb 24
The diaphragm is the strongest breathing muscle we have. Let's learn more about this very important muscle that works hard for us everyday.
But first, the deets:
ACTIONS: Depresses costal cartilages, primary muscle of breathing (inspiration)
Sternal part: Posterior aspect of xiphoid process
Costal part: Internal surfaces of lower costal cartilages and ribs 7-12
Lumbar part: Medial and lateral arcuate ligaments (lumbocostal arches), bodies of vertebrae L1-L3 (+intervertebral discs), anterior longitudinal ligament
INSERTION: Central tendon of diaphragm
NERVES: Phrenic nerves (C3-C5) (sensory innervation of peripheries via 6th-11th intercostal nerves)
IN SHORT: This thin, dome-shaped muscle separates the organs of the chest from those of the abdomen. It attaches to the inside of the lowest ribs all the way around your body.
The word "diaphragm" is derived from the Ancient Greek word "phren" and has two separate meanings. One is the feeling center for thought, and the other meaning is the brain or mind. Aristotle believed that the phren was located in the heart rather than the cranium. Words like "schizophrenic" or "frenzy" (formerly spelled "phrenzy") are derived from this meaning.
The term diaphragm in anatomy can refer to other flat structures such as the urogenital diaphragm or pelvic diaphragm, but "the diaphragm" generally refers to the thoracic (middle section of spine) diaphragm. In humans, the diaphragm is slightly asymmetric—its right half is higher up to the left half, since the large liver rests beneath the right half of the diaphragm.
The diaphragm is a 2-4mm thin, dome-shaped flat muscle and tendinous structure that separates the chest from the belly. It is located below the lungs and the heart and above the liver. It allows passing for the two important blood vessels (the vena cava and the aorta) and the oesophagus. Its base is formed at the back by asymmetrical vertebral fibers that attach to the 3rd lumbar vertebra. It has a fibrous central tendon out of which muscular fibers rise to attach to the entire circumference of the rib cage, sternum, and deep surface of the lower 8 ribs.
As we breathe in, the diaphragm contracts and flattens out, allowing more space for the lungs above to expand and fill with air. Then the diaphragm expands and the lungs push out the air through the nose or mouth.
Another way to think about the diaphragm: It flattens and draws down as it contracts. As it contracts and lowers, displacing the soft contents of the abdomen, lung volume increases, reducing air pressure in the lungs and drawing in air from the outside. As the diaphragm relaxes, it moves up as the lung's natural elasticity pushes the air out, completing a cycle of breath.
What else is affected by the diaphragm? SO MUCH!
The vagus nerve passes through the diaphragm as well, linking breath to the parasympathetic function (the rest and digest response instead of fight or flight). The heart rests on the left side of the diaphragm, and the stomach, spleen, liver, kidneys, pancreas, and upper portion of the large intestines are all also in close connection to the movement of the diaphragm.
Not only does the diaphragm relate closely to our organs, but it also works with surrounding muscles to stabilize your posture. The iliopsoas and quadratus lumborum, which are both primary muscles for mobility and stability for the pelvic girdle, attach fascially to the diaphragm. This fascial connection suggests that there is no real separation between these muscles and the diaphragm, which is why I often tell my clients "it's all connected." If one muscle is tight or short, it may pull on surrounding muscles, tightening and shortening those muscles, and so on and so on.
When the diaphragm's movement is not working efficiently, you have to use the other surrounding muscles to help make room for air. One type of compensation involves the crura and the scalenes working together to make up for the lack of diaphragm's function. This can result in chronic contraction of spinal extensor muscles.
If you've ever experienced hiccups, these are simply minor, rhythmic spasms in your diaphragm. Some people can develop pain patterns in their diaphragm, too. Some symptoms of diaphragm pain include:
* pain in your side when coughing or sneezing
* pain that wraps around your middle back
* sharp pains when drawing a deep breath or exhaling
* discomfort and shortness of breath after eating
* a pain in the side when exercising
* inability to take a full breath
* low blood oxygen levels
* tension after having a cold or cough, or having respiratory problems such as asthma
So how can we give love and attention to this very important muscle?
* diaphragmatic breathing exercises
* eating smaller portions
* improve posture
* lowering stress
* quitting smoking
* avoid foods that cause heartburn or acid reflux
Very simple diaphragmatic breathing exercise:
Sit comfortably, or lay down on your back. Place one hand on abdomen and inhale slow and low into the belly. Begin by focusing on your breathing. Observe where you feel your inhalation move your rib cage. Next, try to change the focus of your breathing and expand your rib cage evenly in all directions. Allow your breath to "fill all parts of the balloon," the top, bottom, front, back, both sides. You could do one cycle of breath, or try 5-10 breath cycles in one sitting to experience a very relaxing feeling. It is very meditative and calming.
When practicing deep belly breathing, we aren't actually breathing into our abdomen. Instead, we are pulling the diaphragm muscle down deep, causing the organs of the abdominal cavity to push forward and expand the belly. It's not air down there, it's our stomach and small intestines and more.
Lotus pose (padmasana) is a simple position to practice diaphragmatic breathing, too. If the hips and knees aren't quite ready for this pose, you can bolster under your knees with pillows or blocks.
Practicing diaphragmatic breathing can happen any time, any place, not just while meditating or doing fancy yoga poses. While driving the car, stuck in traffic, or pushing your shopping cart in the grocery store, we can bring awareness to our breath and diaphragm any time we feel we need to. I invite you to give your diaphragm a little more attention and love, and see how your mind, body and spirit appreciate your efforts :)
Please read my other blog post where I go into depth on the breathing process, and how our diaphragm works for us, and so much more.
Thank you for reading. Please reach out with any questions, comments or concerns.