During right thyroid lobectomy, the surgeon identifies a nerve entering the larynx directly from the vagus at the level of the cricothyroid joint, without any course in the tracheo-oesophageal groove. This anomaly is classically associated with which vascular abnormality?

• A Double aortic arch
• B Left-sided superior vena cava
• C Aberrant right subclavian artery arising from the descending aorta ✓
• D Coarctation of the aorta

Explanation

C non-recurrent laryngeal nerve occurs in roughly 0.5 to 1 percent of right-sided operations and results when the right subclavian artery arises abnormally from the descending thoracic aorta (arteria lusoria), passing behind the oesophagus. Because the subclavian never takes its usual embryonic position, the nerve has no need to loop under it and travels straight from the vagus into the larynx. It is almost never seen on the left except with situs inversus. Recognising it prevents traction injury.

Reference: Schwartz's Principles of Surgery, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.