Internal thoracic artery

Internal thoracic artery
Right internal thoracic artery and its branches (labeled under its old name the Internal mammary artery, at upper right.)
Details
Latin	Arteria thoracica interna, arteria mammaria interna
Source	Subclavian artery
Branches	Pericardiocophrenic Anterior intercostal branches Musculophrenic Superior epigastric Perforating branches
Vein	Internal thoracic vein
Identifiers
MeSH	A07.231.114.891.525
Dorlands /Elsevier	a_61/12156309
TA
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terminology [[[d:|edit on Wikidata]]]

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 along each side of the sternum, to continue after its bifurcation as the superior epigastric and musculophrenic arteries.

Structure

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 is accompanied by the internal thoracic vein.

It runs deep to the internal intercostal muscles, but superficial 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
• Pericardiacophrenic 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 bottom 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

Clinical significance

Use in bypass grafts

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 and other arterial grafts (e.g. radial artery, gastroepiploic artery) when grafted to the left anterior descending coronary artery, generally the most important vessel, clinically, to revascularize.

Plastic surgeons may use either the left or right internal thoracic arteries for autologous free flap reconstruction of the breast after mastectomy. Usually a micro-vascular anastomosis is performed at the second intercostal space to the artery on which the free flap is based.

Additional images

• Grant 1962 407.png

  Anterior Thoracic Wall, from behind

• Grant 1962 405.png

  Diagram of an Intercostal Space

External links

• -502923206 at GPnotebook - 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