We are independent & ad-supported. We may earn a commission for purchases made through our links.

Advertiser Disclosure

Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.

How We Make Money

We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently from our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is the Thoracic Diaphragm?

By John Markley
Updated May 17, 2024
Our promise to you
WiseGEEK is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WiseGEEK, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

The thoracic diaphragm is a structure found in the bodies of all mammals, including human beings. It is a sheet of muscle in the lower part of the chest with a dome-like shape that spreads across the lower rib cage and divides the thoracic and abdominal cavities of the body. It is very important to respiration in humans and many other animals and is also involved in other functions, such as excretion and vomiting.

When the thoracic diaphragm contracts as an organism inhales, this causes the thoracic cavity to expand. This takes pressure off of the lungs and allows them to expand, creating an empty space that in turn produces suction, drawing air from outside of the body through the esophagus and into the lungs. Once the thoracic diaphragm relaxes, this causes the thoracic cavity and lungs to return to their original size. If there is gas in the lungs, the sudden reduction in available space pushes some of the gas out through the esophagus, causing exhalation.

The importance of the thoracic diaphragm to normal human breathing can be seen by what happens when its normal functioning is disrupted. The reason people often struggle to breathe, or “have the wind knocked out of them,” after being knocked or thrown to the ground or being struck in the torso is that the impact causes a muscle spasm in the thoracic diaphragm that temporarily paralyzes it, forcing the person to struggle to breathe without its assistance until it recovers. This is why being punched in the upper abdomen just below the rib cage, a region commonly called the solar plexus that lies in front of the tendons that connect the thoracic diaphragm to the spinal column, can be so incapacitating. Hiccups are caused by sudden involuntary contractions of the diaphragm, which produces a “hic” sound when the vocal cords close due to the sudden surge of air into the expanded lungs.

The thoracic diaphragm also assists with other bodily functions, most of which involve expelling things from the body. Contraction of the diaphragm puts pressure on the abdominal cavity. This helps to push waste out of the body by putting pressure on the gastrointestinal tract while defecating and on the bladder while urinating. Vomiting is caused by the combined, extended contractions of the thoracic diaphragm and abdominal muscles, which puts pressure on the stomach that forces its contents upwards into the esophagus.

WiseGEEK is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Discussion Comments

WiseGEEK, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGEEK, in your inbox

Our latest articles, guides, and more, delivered daily.