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 Transversus Thoracis?

By V. Cassiopia
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 transversus thoracis is a thin, flat layer of muscles and tendons connecting the lower back of the sternum, or central breastbone, to the 2nd through 6th ribs inside the rib cage — each side is mirrored on the opposite side of the body. This muscle is part of the intercostal muscles, all of which are located between the ribs and attach to them. The primary function of these muscles is to assist with breathing activities by moving the ribs when the lungs contract and expand. The contraction and expansion movements form an essential part of the breathing process by promoting air movement within the lungs.

The transversus thoracis begins as part of the fibers of the transversus abdominis muscle that end above the diaphragm in the rib cage area. These fibers start out in the horizontal direction, following the way the fibers are arranged in the transversus abdominis, then begin to slope upward and outward as they attach to various ribs, becoming nearly vertical by the time they attach to the 2nd rib. These rib attachment areas can vary significantly among different individuals, and they can also be formed quite differently in one person on opposite sides of the chest.

The transversus thoracis is also called the transverse thoracic muscle. This flat muscle extends along the front chest wall between the rib cage and parietal pleura, the membrane covering the inside chest wall and upper part of the diaphragm. It is a skeletal muscle, in that it has the characteristics of these types of muscles: a banded appearance due to the admixture of light and dark rows of expansion and contraction cells as well as an attachment to the sternal bone. However, as with other skeletal muscles involved in the respiratory function, it has the capability of working without conscious direction.

The chest and abdomen contain other torso muscles, such as the abdominals, which also support breathing functions, but the intercostal muscles are the primary chest muscles involved in respiration. They have three layers: the external intercostals, the internal intercostals, and the innermost intercostals — with the transversus thoracis belonging to the innermost intercostal layer. These muscles help to maintain space separations between the ribs, along with establishing rhythmic rib cage movements during breathing. To do this, the external intercostals contract to lift and expand the ribs for inhaling, while the transversus thoracis and other intercostals contract to lower the ribs for exhaling. The transversus thoracis can also force the lungs to sharply exhale by strongly contracting.

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.