In human anatomy, the internal thoracic artery (ITA), previously known as the internal mammary artery (a name still common among surgeons), is an artery that supplies the anterior chest wall and the breasts. It is a paired artery, with one running on each side of the body.
Twelve anterior intercostal branches, two to each of the top six intercostal spaces. In a given space, the upper branch travelling laterally along the botton of the rib until it anastomoses with its corresponding posterior intercostal artery. The lower branch of the space anastomoses with a collateral branch of the posterior intercostal artery.
After passing the sixth intercostal space, the internal thoracic artery splits into the following two terminal branches:
Musculophrenic artery - roughly follows the costal margin
Superior epigastric artery - continues the course of the internal thoracic artery, travelling downward into the abdominal wall
^ Kitamura S, Kawachi K, Kawata T, Kobayashi S, Mizuguchi K, Kameda Y, Nishioka H, Hamada Y, Yoshida Y. [Ten-year survival and cardiac event-free rates in Japanese patients with the left anterior descending artery revascularized with internal thoracic artery or saphenous vein graft: a comparative study] Nippon Geka Gakkai Zasshi. 1996 Mar;97(3):202-9. PMID 8649330.
^ Arima M, Kanoh T, Suzuki T, Kuremoto K, Tanimoto K, Oigawa T, Matsuda S. Serial Angiographic Follow-up Beyond 10 Years After Coronary Artery Bypass Grafting. Circ J. 2005 Aug;69(8):896-902. PMID 16041156. Free Full Text.
^ Cohen G, Tamariz MG, Sever JY, Liaghati N, Guru V, Christakis GT, Bhatnagar G, Cutrara C, Abouzahr L, Goldman BS, Fremes SE. The radial artery versus the saphenous vein graft in contemporary CABG: a case-matched study. Ann Thorac Surg. 2001 Jan;71(1):180-5; discussion 185-6. PMID 11216742.
Figures of ITA grafts
Figure of heart with two saphenous vein grafts (SVGs) and a LITA graft - texheartsurgeons.com
Drawing of the heart with a SVG to the right coronary artery (RCA) and a LITA graft to the LAD - darcystudios.com
Drawing of the heart with a SVG to the RCA and a LITA graft to the LAD - mayoclinic.org