Transversus Thoracis

General information

The transversus thoracis muscle is a thin muscle situated on the interior aspect of the anterior thoracic wall and its function includes pulling the rib cartilages caudally, in turn supporting expiration.

Literal meaning

The crosswise muscle of the chest.

Interesting information

This muscle’s insertional tendons contribute to its serrated appearance while the amount and insertion points appear to vary. This makes the transversus thoracis a highly variable muscle in the human body. Some of the variations include the merging of the transversus thoracis and transversus abdominus, which runs close to parallel to the transversus thoracis.

In respiration, this muscle is not a primary contributor as it is only slightly active in supine and also because in a lot of people this muscle is not well developed but they have no issues with breathing. Therefore, it is mainly considered to be an expiratory accessory muscle.

Origin

The dorsal surface of the xiphoid process and the body of the sternum.

Insertion

Five insertion tendons run craniolaterally to the cartilage of the 2nd to 6th ribs.

Function

Pulls the rib cartilages caudally, thus supporting expiration.

Nerve supply

Intercostal nerves arising from the thoracic nerves (Th2-Th6).

Blood supply

The sternal branches and anterior intercostal branches of the internal thoracic artery via the subclavian artery.

Relevant research

Recently, this muscle has been used in surgery as a site for analgesia. The transversus thoracis muscle plane block can be used for anterior chest wall operations such as breast and cardiac surgeries.

Fujii, S., Bairagi, R., Roche, M., & Zhou, J. R. (2019). Transversus Thoracis Muscle Plane Block. BioMed research international, 2019, 1716365.

Transversus thoracis exercises

None