What is the anatomy of the recurrent laryngeal nerve relative to thyroidectomy?

Updated: May 08, 2018
  • Author: Neerav Goyal, MD, MPH; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The recurrent laryngeal nerve branches off the vagus nerve and is present by the sixth gestational week, associated with the sixth branchial arch. Because the aortic arches are cranial to the larynx at this stage, the nerve does not loop at this point. As the larynx moves cephalad, the recurrent nerve also ascends. Although the distal portion of the sixth aortic arch degenerates on the right, it persists in the left as the ductus arteriosus. For this reason, the left recurrent laryngeal nerve stays below the ductus arteriosus and ascends to the larynx.

On the right, the nerve ascends with the larynx until it reaches the fourth aortic arch (the subclavian artery). In approximately 1% of the population, the right subclavian arises from posterior to the esophagus, allowing the right recurrent laryngeal nerve to ascend further and enter the larynx directly without forming a loop. Additionally, the loops of the recurrent laryngeal nerves can be reversed in patients with a right-sided aortic arch. [8]

Recurrent laryngeal nerve anatomy. Recurrent laryngeal nerve anatomy.

The left recurrent laryngeal nerve begins a course that is parallel and close to the tracheoesophageal groove at a more inferior position than the right nerve. The right nerve, on the other hand, angles toward the tracheoesophageal groove before running parallel to it. The middle portion of the recurrent nerve is often in close proximity to Berry's ligament, with some papers describing its course as penetrating through the ligament. [12] Both nerves follow the inferior thyroid artery, and, as it approaches the thyroid gland, they can be found either anterior to the artery, between branches of the artery, or posterior to the artery.

Berry's ligament. Berry's ligament.
Inferior thyroid/recurrent laryngeal nerve relatio Inferior thyroid/recurrent laryngeal nerve relationship.

Occasionally, the nerves branches prior to entering the thyroid gland into motor and sensory components. Additionally, a branch of the nerve ascends and anastomoses with the superior laryngeal nerve to form the Galen anastomosis. [9, 13]

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