A rare origin of the internal thoracic artery on the left thyro-cervical trunk

Introduction: The internal thoracic artery is known for its anatomical variations and their clinical implications. It has important anatomical characteristics that make it an excellent arterial graft for myocardial vascularization. However, data from the literature report variations regarding the origin, course, and termination of the internal thoracic artery. Through this dissection work we wanted to report a rare origin of the left internal thoracic artery directly from the thyrocervical trunk, instead of its usual subclavian origin. Material and methods: The dissected patient was a 64-year-old subject with no history of cervical region surgery or previous deformity. The cadaver showed no asymmetry about the shoulders or the lateral cervical regions, it had been preserved in a non-formaldehyde solution. Initially, on the subject in supine position, the lateral triangle of the neck was approached and a cleidectomy was performed. The subclavian artery and its collaterals were dissected, identified, and marked. The collateral branches of the subclavian artery were injected with a solution made from a mixture of gelatin, methylene blue and iron powder. Dissection of the subclavian artery and its collateral branches was then continued until their course was fully exposed. Results: On the course of the left subclavian artery and after the left vertebral artery, we found a thyrocervical trunk giving rise to 4 classic terminal branches, among which an oblique left internal thoracic artery due to its more lateral birth than d 'habit. Discussion and Conclusion: The left internal thoracic artery is the first choice in coronary bypass surgery because of the permeability of the graft. However, an abnormal origin of the internal thoracic artery on the thyrocervical trunk and a modification of its proximal course, can firstly increase the risk of vascular lesions during different invasive procedures of the lateral triangle of the neck. secondly, they can have circulatory consequences in the vertebrobasilar arterial system. It is important for the practitioner to resort to a morphological study of this region to expose and prevent this anatomical variation.