How Does the Diaphragm Work? Diaphragm Structure and Function

The diaphragm is a muscle that forms an umbrella dome shape at the base of your ribcage and helps you breathe.

Every breath begins with an umbrella shaped muscle that flexes underneath your ribcage. This dome-shaped muscle that stretches across your torso is called the diaphragm (die-uh-fram) and when your diaphragm is relaxed, it resembles an oblong umbrella top that is squeezed underneath your ribs and creates the base of your chest cavity.

How Does the Diaphragm Work?

To solidify the concept of diaphragm function, place your hand below your ribcage and pay attention to the movement underneath your hand as you take deep, belly breaths. With every inhalation, your diaphragm flattens, (pulling down on the metaphorical umbrella handle), which expands your ribcage and reduces pressure in your chest to pull air into your lungs. Now when you exhale, imagine the umbrella top pushing upward and forming the dome shape underneath your ribs. Can you feel that each exhale is guided by the diaphragm pushing back up into your chest?

Diaphragm injuries are most often caused by traumatic physical events such as traffic accidents. Considering that the umbrella muscle is essential for breathing, injuries to the diaphragm results in life-threatening scenarios that require serious medical care. Doctors can use a variety of tests, such as chest X-rays, computerized tomography (CT) scans and surgical procedures, to determine whether a diaphragm is in need of surgical repair.

However, there is also a much more prevalent, non-vital issue that affects the diaphragm and intercostal muscles: hiccups. Those sneaky bastards come out of nowhere. The surprising moment when air is sucked into your lungs and a little “hic” sound is released from your throat can feel as though your respiratory system was hijacked. A hiccup is caused when the diaphragm and intercostal muscles contract without your control. It’s as if a little chest cavity goblin does exist and tugs down on the umbrella muscle handle. 

The common hiccup is often caused by a rapid expansion of the stomach that can occur with overeating, eating too fast, eating spicy food, drinking carbonated drinks and even changes in temperature. Everyone has their favorite cure. People hold their breath, eat sugar and use surprise scare tactics with varied success. Unfortunately, a scientifically proven non-invasive hiccup treatment remains a mystery.

Diaphragm Anatomy Summary

Diaphragm: The diaphragm is the umbrella muscle that forms a dome shape at the base of your ribcage. When the diaphragm contracts, it flattens and creates more space and less pressure in the chest cavity. This reduced pressure causes air to flow into the lungs. When the diaphragm relaxes, air flows out of the lungs as the umbrella muscle re-forms the dome.

Intercostal Muscles: Muscles that fill the gaps between your ribs provide structure and flexibility to your upper body and when you breathe, they allow your ribcage to expand and contract. 

References:

• Harrison's Principles of Internal Medicine, 18th Edition. Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J. eds.
• Anatomy, Physiology, and Disease: An Interactive Journey for Health Professions , 2nd Edition. Bruce J. Colbert, University of Pittsburgh, Johnstown.