An Anomalous Right Subclavian Artery with a Retrotracheal Course: A Case Report

Abstract

During routine dissection for teaching undergraduate medical students, we came across an arch of aorta with four branches in a male cadaver. From proximal to distal the branches were right common carotid, left common carotid, left subclavian and the anomalous right subclavian artery.The aberrant right subclavian artery took origin from the dorsal aspect of the arch of aorta as its last branch distal to the usual left subclavian artery, instead of its origin from brachiocephalic trunk. From its origin, the anomalous artery turned right and coursed between trachea and oesophagus inclining upwards and to the right to reach behind the right sternoclavicular joint and continued to supply the upper limb. Because of this variation there was no brachiocephalic trunk. Right subclavian artery appeared to be slightly larger and longer than the left subclavian artery. The trachea and oesophagus were positioned normally. No abnormalities were noted in the heart and other thoracic or abdominal viscera. The recurrent laryngeal nerves on both sides were found to have a normal course. The observations are depicted in [ An aberrant right subclavian artery arising as the last vessel of the arch of aorta is an uncommon anatomic anomaly with prevalence reported between 0.2% and 2.0%. In 80% of the cases the aberrant right subclavian artery takes a retro-oesophageal course to the right upper limb. During routine dissection of cadavers for teaching undergraduate medical students an anomalous Retrotracheal right subclavian artery which is a very rare vascular anomaly was encountered in a 35-year-old male cadaver. The artery arose as the last branch of the arch of aorta and coursed to the right between the trachea and oesophagus. The presence of this vascular anomaly could be an unusual cause of dysphagia and breathing difficulty. The clinical significance and embryological aspects of this vascular variant is discussed in this paper.anomalies, the clinician should be aware of their existence which could help in adequately managing the variations in emergency approaches to the arch of aorta and great vessels when imaging studies are not available [1]. The aberrant right subclavian artery (ARSA) arises from the arch of aorta or proximal descending aorta, and in 80% of the cases takes a retro-oesophageal course to the right upper limb [2].Autopsy based studies have revealed that the right subclavian artery can have an anomalous origin as the fourth branch of arch of aorta in 1-2% of the normal population [3]. Though 15% of the ARSA are reported taking a retrotracheal course [2], our literature search revealed only a single case [4] of retrotracheal right subclavian artery, but co-existing with a common trunk from the arch of aorta, which bifurcated into right vertebral artery and left thyroidea ima. In this context, we report a very rare case of RtRTSA (right Retrotracheal subclavian artery) arising distal to the left subclavian artery encountered during routine dissection for undergraduate medical teaching.Pharyngeal arches form during th...

Anatomical Variations of the Aortic Arch: A Computerized Tomography-Based Study

“…ARSA is formed by the distal portion of the right dorsal aorta and right seventh intersegmental artery. With the shortening of the aorta between left common carotid and left subclavian arteries, the origin of ARSA settles inferior to that of the left subclavian artery [ 4 ]. As its stem derives from the right dorsal aorta, ARSA has to cross the midline in order to reach the right arm.…”

Retrotracheal Aberrant Right Subclavian Artery: Congenital Anomaly or Postsurgical Complication?

“…13 Two additional cadaveric case reports were also identified. 14,15 We believe that there is no clear consensus on the epidemiology of this rare variant.…”

Prevalence and Anatomy of Aberrant Right Subclavian Artery Evaluated by Computed Tomographic Angiography at a Single Institution in Korea

“…Because the persisting right aortic arch forms the root of the ARSA, the artery often has a broad base, which is referred to as a Kommerell diverticulum [ 19 ]. The stem of the anomalous subclavian artery is derived from part of the right dorsal aorta; this explains the retroesophageal course that this artery takes as it passes to the right upper limb [ 30 , 32 ].…”