Recurrent laryngeal nerve (left, anatomy)

The left recurrent laryngeal nerve originates from the left vagus nerve as it passes over the arch of the aorta inferior to the left superior intercostal vein. It passes medially and posteriorly deep to the ligamentum arteriosum before curving inferior to the arch of the aorta. It then passes superiorly over the left main bronchus to ascend in the groove between the left side of the trachea and the anterior of the oesophagus.

Ascending in the tracheo-oesophageal groove, consecutively the recurrent laryngeal nerve is related to:

• medially:
  • small branches it gives off to supply mucosa of the upper oesphagus
  • inferior thyroid artery
  • inferior thyroid veins
• laterally:
  • paratracheal lymph nodes
  • parathyroid glands
  • lateral lobe of thyroid gland On route, it also gives off cardiac and tracheal branches.

At the level of the thyroid gland, it passes beneath the inferior border of the muscle cricopharyngeus to run deep to it and superiorly towards the pharynx and larynx. Within the latter areas, the recurrent laryngeal nerve supplies the:

• intrinsic laryngeal muscles except cricothyroid - special visceral motor fibres:
  • posterior cricoarytenoids
  • lateral cricoarytenoids
  • transverse arytenoids
  • oblique arytenoids
  • thyroarytenoids
  • vocalis
• mucosa of the larynx and pharynx below the vocal cords inferiorly to the top of the oesophagus and trachea