During right thyroid lobectomy, the surgeon finds a nerve entering the larynx directly from the carotid sheath region without ascending in the tracheo-oesophageal groove. Which anatomical variant explains this finding?

• A Aberrant right subclavian artery arising from the descending aorta ✓
• B Aberrant left subclavian artery with a right-sided aortic arch
• C Persistent right sixth aortic arch
• D Double aortic arch

Explanation

B non-recurrent right laryngeal nerve occurs in about 0.5 to 1 percent of patients and results from an aberrant right subclavian artery (arteria lusoria) arising distally from the descending aorta. Because the vessel does not hook under the subclavian artery in the usual way, the nerve takes a direct transverse course from the vagus to the larynx. The left side is essentially never affected unless there is situs inversus, which rules out options B and D.

Reference: Sabiston Textbook of Surgery, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.