The transversus thoracis is a muscle of the thoracic wall. It is located on the internal surface of the thoracic wall and is continuous with the transversus abdominis inferiorly.
- Attachments: Arises from the posterior surface of the inferior sternum and costal cartilage of the lower ribs. The fibres ascend and attach onto the internal surface of costal cartilages 2-6.
- Actions: Weak depressor of the ribs during expiration.
- Innervation: Intercostal nerves (T2-T6).
- Blood supply: Internal thoracic artery.
By TeachMeSeries Ltd (2025)
Fig 1
View of the internal aspect of the thoracic wall. The internal intercostal and transverse thoracis muscles are visible.