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The superior intercostal artery (SIA), also known as the highest intercostal artery or the supreme intercostal artery, is a division of the costocervical trunk which itself originates from the subclavian artery. The superior intercostal artery passes inferiorly and posteriorly between the necks of the first and second ribs and the pleura. As it traverses the neck of the first rib, it diverges into two posterior intercostal arteries. These arteries function to supply blood to the first and second intercostal spaces.[1] Though the SIA traditionally originates from the costocervical trunk, it may also arise from the thyrocervical trunk or its branches, including the dorsal scapular artery or inferior thyroid artery, among others. Knowledge of the structure, function, and variant pathways of the SIA becomes essential when operating in the neck and superior chest, particularly the 1 and 2 intercostal spaces. Aneurysm of the SIA is a rare vascular abnormality associated with coarctation of the aorta and neurofibromatosis type 1. In cases of aortic coarctation, the SIA may give rise to collateral arteries that help to supply arterial flow to the descending aorta.