In human anatomy, the internal thoracic artery (ITA), previously commonly known as the internal mammary artery (a name still common among surgeons), is an

artery An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

that supplies the anterior chest wall and the

breasts The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and sec ...

. It is a paired artery, with one running along each side of the

sternum The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sha ...

, to continue after its bifurcation as the superior epigastric and

musculophrenic The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery (supreme intercostal artery or superior intercostal artery) is an artery in the human ...

arteries.

Structure

The internal thoracic artery arises from the anterior surface of the subclavian artery near its origin. It has a

width Length is a measure of distance. In the International System of Quantities, length is a quantity with dimension distance. In most systems of measurement a base unit for length is chosen, from which all other units are derived. In the Intern ...

of between 1-2 mm. It travels downward on the inside of the

rib cage The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a sem ...

, approximately 1 cm from the sides of the

, and thus medial to the

nipple The nipple is a raised region of tissue on the surface of the breast from which, in females, milk leaves the breast through the lactiferous ducts to feed an infant. The milk can flow through the nipple passively or it can be ejected by smooth m ...

. It is accompanied by the internal thoracic vein. It runs deep to the abdominal external oblique muscle, but superficial to the

vagus nerve The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and righ ...

. In adults, internal thoracic artery lies closest to the

at the first intercoastal space. The gap between the artery and lateral border of the sternum increases when going downwards, up to 1.1cm to 1.3cm at sixth intercoastal space. In children, the gap range from 0.5cm to 1.0cm.

Branches

* Mediastinal branches * Thymic branches * Pericardiacophrenic artery - travels with the phrenic nerve *

Sternal The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Sh ...

branches * Perforating branches * Twelve anterior intercostal branches, two to each of the top six

intercostal space The intercostal space (ICS) is the anatomic space between two ribs (Lat. costa). Since there are 12 ribs on each side, there are 11 intercostal spaces, each numbered for the rib superior to it. Structures in intercostal space * several kind ...

s. In a given space, the upper branch travels laterally along the bottom of the rib until it

anastomoses An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be norm ...

with its corresponding

posterior intercostal artery The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery (supreme intercostal artery or superior intercostal artery) is an artery in the human ...

. 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 The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery (supreme intercostal artery or superior intercostal artery) is an artery in the human ...

- roughly follows the costal margin and it again gives branch for 7,8,9 ribs * Superior epigastric artery - continues the course of the internal thoracic artery, travelling downward into the abdominal wall and to the content of recuts sheath

Function

The internal thoracic artery supplies the chest wall and the breasts.

Clinical significance

Use in bypass grafts

The internal thoracic artery is the cardiac surgeon's

blood vessel The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide away ...

of choice for

coronary artery bypass graft Coronary artery bypass surgery, also known as coronary artery bypass graft (CABG, pronounced "cabbage") is a surgical procedure to treat coronary artery disease (CAD), the buildup of plaques in the arteries of the heart. It can relieve chest pai ...

ing. The left ITA has a superior long-term patency to saphenous vein grafts and other arterial grafts (e.g.

radial artery In human anatomy, the radial artery is the main artery of the lateral aspect of the forearm. Structure The radial artery arises from the bifurcation of the brachial artery in the antecubital fossa. It runs distally on the anterior part of th ...

, 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 Mastectomy is the medical term for the surgical removal of one or both breasts, partially or completely. A mastectomy is usually carried out to treat breast cancer. In some cases, women believed to be at high risk of breast cancer have the operat ...

. Usually, a microvascular anastomosis is performed at the second intercostal space to the artery on which the free flap is based.

Additional images

File:Grant 1962 407.png, Anterior Thoracic Wall, from behind File:Grant 1962 405.png, Diagram of an Intercostal Space

References

External links

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 {{Authority control Arteries of the thorax