The transversus thoracis is a thin band of muscle and tendon arising from the lower posterior surface of the sternum, posterior edge of the xiphisternum and the costal cartilage of the lowest 3 - 4 ribs at their sternal end. It diverges supero-laterally to attach by slips to the underside of the 2nd to 6th costal cartilages 1. The transversus thoracis muscle is morphologically identical to the transversus abdominis muscle 2.
The transverse thoracis muscle is an accessory muscle for respiration. It pulls the ribs crainally which supports expiration.
- 1. Gray Henry, T. Pickering Pick and Robert Howden. Anatomy, descriptive and surgical. 39th ed. New York: Bounty Books, 1977
- 2. Sinnatamby, C. and Last, R. Last's anatomy. 12th ed. Edinburgh: Churchill Livingstone/Elsevier, 2011
- 3. West J. Respiratory physiology - the essentials. 9th ed. Philadelphia: Wolters Klower/Lippincott Williams and Wilkins, 2011