From where does the transversus thoracis muscle originate?

The transversus thoracis muscle indeed originates from the internal surface of the xiphoid process, as well as from the lower part of the sternum and the adjacent costal cartilages of ribs 2 to 6. The xiphoid process is the small, cartilaginous extension at the lower end of the sternum, and it provides an attachment point for the muscle fibers of the transversus thoracis.

This muscle plays a role in the stabilization of the ribs during respiration, particularly in forced expiration. Its positioning within the thoracic cavity allows it to function effectively in depressing the ribs. Understanding the origin of the transversus thoracis can help students appreciate how its anatomical location contributes to its function in respiratory mechanics and why it may not originate from the other structures listed, such as costal cartilage or the thoracic spine.