During right-sided thyroid surgery, the surgeon finds a recurrent laryngeal nerve that does not loop around any vessel and instead enters the larynx directly from the carotid sheath region. Which anatomical variant explains this finding?

• A Persistent right aortic arch with ligamentum arteriosum on the right
• B Aberrant right subclavian artery arising from the descending aorta (arteria lusoria) ✓
• C Double aortic arch encircling the trachea and oesophagus
• D Anomalous origin of the right common carotid artery from the brachiocephalic trunk

Explanation

B non-recurrent right laryngeal nerve occurs in about 0.5 to 1 percent of people and results from an aberrant right subclavian artery arising distally from the descending aorta and passing behind the oesophagus. Without the vessel to loop around during embryonic development, the nerve descends directly from the vagus to the larynx. It is a recognised hazard of right thyroid surgery because the nerve may be mistaken for a vessel or branch and divided. Left-sided non-recurrence is rare and linked to situs inversus.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.