Before a planned right thyroidectomy, flexible laryngoscopy shows a mobile right vocal cord. At operation the surgeon cannot find a recurrent laryngeal nerve in the usual tracheo-oesophageal groove, and the cord later proves paralysed. Which vascular anomaly best explains this finding?

• A Coarctation of the aorta
• B Persistent left superior vena cava
• C Aberrant right subclavian artery (arteria lusoria) ✓
• D Right-sided aortic arch with mirror-image branching

Explanation

C non-recurrent right laryngeal nerve occurs in about 0.5 to 1 percent of individuals and results when the right fourth aortic arch regresses abnormally, producing an aberrant right subclavian artery that arises distal to the left subclavian and passes behind the oesophagus. Without the subclavian artery to hook around, the vagus branch passes directly from the carotid sheath into the larynx. It is strongly associated with retro-oesophageal subclavian artery and risks inadvertent division.

Reference: Sabiston Textbook of Surgery, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.