The left recurrent laryngeal nerve courses under which structure?

• A. Under the right subclavian artery
• B. Under the aortic arch
• C. Through the thyroid cartilage
• D. Into the cricothyroid area

Answer: (B)

The left recurrent laryngeal nerve takes a distinctive route through the chest: it descends into the mediastinum and loops under the arch of the aorta (near the ligamentum arteriosum) before turning upward in the tracheoesophageal groove to reach the larynx. This looping under the aortic arch is what sets the left side apart and is why this structure is the correct answer. After ascending, the nerve supplies most intrinsic muscles of the larynx and carries sensation below the vocal folds.

The other options don’t fit because the right recurrent laryngeal nerve loops under the right subclavian artery, not the aortic arch; the nerve does not pass through the thyroid cartilage; and it does not travel into the cricothyroid area (that region is innervated by the external branch of the superior laryngeal nerve).