A 62-year-old male smoker presents with hoarseness. Laryngoscopy shows a paralysed left vocal cord in the paramedian position. Chest imaging reveals a mass in the left lung apex. The left recurrent laryngeal nerve is involved more often than the right in thoracic disease because:
- A It runs a longer course, looping under the aortic arch in the thorax ✓
- B It lies within the carotid sheath throughout its course
- C It passes anterior to the subclavian artery on the left
- D It supplies the cricothyroid muscle bilaterally
Correct answer: A. It runs a longer course, looping under the aortic arch in the thorax
Explanation
The left recurrent laryngeal nerve loops under the aortic arch behind the ligamentum arteriosum before ascending in the tracheo-oesophageal groove, giving it a long intrathoracic course exposed to apical lung tumours, mediastinal nodes, and aortic aneurysms. The right nerve loops under the right subclavian artery and has a much shorter thoracic course, so right-sided palsy usually points to neck pathology. The nerve never enters the carotid sheath.
Reference: Gray's Anatomy for Students, 4th ed.
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Written and medically reviewed by the StethoPrep medical team.