Aims: 

The internal thoracic artery (ITA) is one of the major vessels supplying the external and internal surface of the anterior thoracic wall together with the organs of the mediastinum. This vessel is frequently used as a graft by cardiovascular surgeons in coronary bypass surgery, however, with a left preference. Furthermore, the perforator branches of the ITA supply the medial aspect of the mammary region, thus offering an arterial source for free myocutaneous flaps in breast reconstruction following mastectomy. Here a vascular anastomosis is performed between the second intercostal perforator branch and the vessel of the free flap (e.g. inferior epigastric). Moreover, endothelial nitric oxyde (NO) production is thought to be superior within the major stem and the branches of the ITA when compared to other arteries or the great saphenous vein, also frequently used for bypass surgery.

Methods: 

Five male and four female hemithoracal specimens were fixed and dissected to follow the course of the ITA. The morphological findings were then compared with CT images. As a further step, the vascular distribution of endothelial nitric oxyde synthase has been compared on 50 micrometer sections between the left and the right internal thoracic vessels using a monoclonal anti eNOS antibody.

Results: 

The course and the branching pattern of the ITA has solely been followed in the parasternal region, between the 1st and 7th intercostal spaces. Here we found a regular pattern, consistent with previous descriptions, of the anterior intercostal branches, however, some of those had a common trunk with the perforator branches. The largest perforators were apparent only in the first three intercostal spaces. eNOS immunocytochemistry has revealed a similar distribution of enzyme within in the endothelium and the subendothelial layers of the vascular wall of both the right and left internal thoracic arteries. Therefore the preference for selecting the left artery over the right ITA may only be explained by its position.