During thyroidectomy, the inferior thyroid artery must be carefully managed to avoid injuring the recurrent laryngeal nerve (RLN). The right RLN loops around which structure before ascending in the tracheoesophageal groove?

• A Aortic arch
• B Right subclavian artery ✓
• C Right common carotid artery
• D Ligamentum arteriosum

Explanation

The right recurrent laryngeal nerve loops around the right subclavian artery and then ascends in the tracheoesophageal groove to enter the larynx. The left RLN takes a longer course, looping around the arch of the aorta (just lateral to the ligamentum arteriosum) before ascending. This asymmetry means the left RLN is more vulnerable in mediastinal pathology (aortic aneurysm, mediastinal lymph nodes) while the right RLN is occasionally non-recurrent (0.5–1%), looping directly from the vagus to the larynx when associated with an aberrant right subclavian artery.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.