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.
Course
The internal thoracic artery arises from the
subclavian artery near its origin.
It travels downward on the inside of the ribcage, approximately a centimeter from the sides of the
sternum, and thus medial to the
nipple.
It runs posterior to the
internal intercostal muscles, but anterior to the
transverse thoracic muscles.
It continues downward until it divides into the
musculophrenic artery and the
superior epigastric artery around the sixth
intercostal space.
Branches
★
Mediastinal branches
★
Thymic branches
★
Pericardiophrenic artery - travels with the
phrenic nerve
★
Sternal branches
★ Perforating branches
★ 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
Revascularization with the ITA
The internal thoracic artery is the
cardiac surgeon's blood vessel of choice for
coronary artery bypass grafting. The left ITA has a superior long-term patency to
saphenous vein grafts
[1][2] and other arterial grafts
[3] (e.g.
radial artery,
gastroepiploic artery) when grafted to the
left anterior descending coronary artery, generally the most important vessel, clinically, to revascularize.
Additional images
References
1. 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.
2. 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.
3. 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.
External links
★ - Internal thoracic artery
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