The left recurrent laryngeal nerve loops under which structure in the thorax, making it vulnerable to compression by aortic aneurysm, lung malignancy, or lymphadenopathy (Ortner's syndrome)?

• A Subclavian artery
• B Pulmonary artery
• C Arch of the aorta ✓
• D Left main bronchus

Explanation

The left recurrent laryngeal nerve loops under the arch of the aorta (ligamentum arteriosum level) and ascends in the tracheo-oesophageal groove to supply all intrinsic laryngeal muscles except the cricothyroid. Aortic aneurysm, large hilar lymph nodes (sarcoidosis, lung cancer), or mediastinal masses at the aortic arch can compress this nerve causing hoarseness (Ortner's cardiovocal syndrome). The right RLN loops under the right subclavian artery in the neck.

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

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Written and medically reviewed by the StethoPrep medical team.