Retroesophageal Right Subclavian Artery

During routine dissection of head and neck region in a 65-year-old female cadaver variation in the origin of right subclavian artery was found. The right subclavian artery originated as a direct branch of arch of aorta distal to the origin of left subclavian artery and it was found passing behind esophagus (retroesophageal) and ascending upwards to the right side while the left subclavian artery originated normally from arch of aorta distal to the origin of left common carotid artery. Anomalous variations in the origin and course of arteries have serious implications in angiographic and surgical procedures; hence it is of great importance to be aware of such possibilities of variations. 1. Introduction Subclavian artery is the artery of the upper limb, but it also supplies a considerable part of the thoracic wall, neck, and brain through its branches. On the left side it arises from arch of aorta and ascends on the pleura to enter the neck behind the left sternoclavicular joint. On the right side, it arises from the brachiocephalic artery behind the sternoclavicular joint. On each side it arches laterally across the anterior surface of cervical pleura onto the first rib, posterior to scalenus anterior. It becomes axillary artery at the outer border of first rib. The artery is divided into three parts by scalenus anterior muscle, and the second part of artery lies posterior to scalenus anterior [1]. Right subclavian artery may arise above or below sternoclavicular level. It may be a separate branch from aortic or the first or the last branch of the arch. Sometimes when the right subclavian artery is the last aortic branch, it passes between trachea and oesophagus and can cause dysphagia, a condition known as dysphagia lusoria. It may perforate scalenus anterior and very rarely may pass anterior to it. Sometimes the subclavian vein accompanies the artery behind scalenus anterior. The left subclavian artery is occasionally combined at its origin with the left common carotid artery [2]. 2. Case Report During routine dissection of head and neck region in a 65-year-old female cadaver variation in the origin of right subclavian artery was found. The right subclavian artery originated as a direct branch of arch of aorta. It was seen arising as a last branch of arch of aorta distal to the origin of left subclavian artery and was found passing behind esophagus and ascending upwards to the right side while the left subclavian artery originated normally from arch of aorta distal to the origin of left common carotid artery (Figure 1). Figure 1: Origin of right