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
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 ...
,
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
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 ...
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