The internal thoracic artery is the largest artery of the thoracic wall. The internal thoracic artery is often mobilized for coronary artery bypass grafting. During routine dissection (MBBS Batch 2009-2010) of a middle aged male cadaver at Dr. Pinnamaneni Siddhartha Institute of Medical Sciences & Research Foundation, Gannavaram, (INDIA); an aberrant right lateral branch from right internal thoracic artery was found. It arose from right internal thoracic artery behind right first rib. It ran downward for first four intercostal spaces about 1 cm away from the mid-axillary line. It terminated into two intercostal arteries on either side in the 4th intercostal space. The rare and unexpected occurrence of variation of the internal thoracic artery such as the one reported here may complicate the entire procedure of coronary artery by-pass grafting. Thus this rare variant of the internal thoracic artery is of great concern during any surgical procedure that involves this artery.
