Trunk (thorax, abdomen, back)

Transversus Thoracis

Musculus transversus thoracis

Origin

Posterior surface of the body of the sternum and the xiphoid process

Insertion

Inner surface of the costal cartilages of ribs 3 through 6

Function

Pulls the costal cartilages downward; assists forced expiration

Innervation

Intercostal nerves (T2-T6)

Movement & chain

Functionally works together with the other deep expiratory muscles (internal intercostals, subcostales) during forced expiration, for example while coughing.

Palpation

Lies on the inner aspect of the lower sternum and costal cartilages; not accessible to surface examination.

Clinical

Depresses costal cartilages in forced expiration; overlies and protects the internal thoracic artery during sternotomy and cardiac surgery.

Segmental innervation

T2-T6 (intercostal segments).

In clinical practice

Ergonomic patient repositioning (log-roll technique in spinal trauma) and pressure offloading; maintain neutral spinal alignment in bedridden patients.

Region in the model

Trunk (thorax, abdomen, back)