Internal Thoracic Artery

Origin

The internal thoracic artery arises from the first part of the subclavian artery. It arises from the inferior border of the subclavian, opposite to the origin of the thyrocervical trunk.

Course

The internal thoracic artery descends into the thorax, posterior to the first six costal cartilages on either side. It sits about 1cm lateral to the sternum. The artery ends at the sixth intercostal space when it divides.

Branches

As the internal thoracic artery descends in the thorax, it gives several branches, including:

- anterior intercostal branches;

- pericardiacophrenic artery;

- thymic branches;

- perforating branches;

- sternal branches;

- musculophrenic artery;

- superior epigastric artery.

Supplied Structures

The anterior intercostal branches of the internal thoracic artery supply the corresponding intercostal spaces and overlying skin. Additionally, the internal thoracic artery provides sternal branches to supply the periosteum of the posterior sternum and its red marrow. Perforating branches accompany the anterior cutaneous branches of the intercostal nerves (anterior rami of thoracic nerves) to supply the overlying skin, while thymic branches send blood to the thymus in the superior mediastinum. The internal thoracic artery terminates as it bifurcates into the musculophrenic and superior epigastric arteries. These arteries supply structures of the lower thoracic and abdominal wall.

List of Clinical Correlates

- Coronary artery bypass grafting

- Brest reconstruction