Under which artery does the right recurrent laryngeal nerve loop?

Right Recurrent Laryngeal Nerve Loops Under the Subclavian Artery

The right recurrent laryngeal nerve loops posteriorly around the right subclavian artery before ascending in the tracheoesophageal groove to reach the larynx. 1

Anatomical Course of the Right Recurrent Laryngeal Nerve

Origin and Looping Point

• The right recurrent laryngeal nerve branches from the vagus nerve at the level of the subclavian artery (typically at T1-T2 or inferior), then loops upward and medially posterior to the subclavian artery. 1
• After branching from the vagus, the nerve turns dorsally around the subclavian artery before beginning its cranial ascent. 2
• The nerve becomes invested in the tracheoesophageal fascia greater than 0.5 cm inferior to C7-T1 after looping around the subclavian artery. 3

Ascending Path

• Following its loop around the subclavian artery, the right recurrent laryngeal nerve ascends in the tracheoesophageal groove, traveling slightly anterior to this groove. 1, 3
• The nerve courses between the trachea and thyroid gland as it approaches the larynx. 3
• In 82% of cases, the right recurrent laryngeal nerve enters the larynx at or inferior to the C6-C7 level. 3
• The only consistent anatomical landmark is that the nerve always passes posterior to the cricothyroid joint before entering the larynx. 2

Contrast with Left Recurrent Laryngeal Nerve

• The left recurrent laryngeal nerve follows a different path, arising to the left of the aortic arch and looping beneath the ligamentum arteriosum in the aortopulmonary window before ascending. 1
• The left nerve loops around the aortic arch rather than the subclavian artery, giving it a longer and deeper course. 4
• Both nerves ultimately ascend in their respective tracheoesophageal grooves to innervate all intrinsic laryngeal muscles except the cricothyroid. 1

Clinical Significance

Surgical Implications

• The relationship between the right recurrent laryngeal nerve and the inferior thyroid artery is highly variable, with the nerve most commonly passing between the arterial branches on the right side. 4, 2
• The short segment (<2 cm) adjacent to Berry's ligament represents the highest risk zone for nerve injury during thyroid surgery. 4
• Complete visualization and dissection of the nerve from the thoracic inlet to the larynx is the gold standard technique for nerve preservation during thyroidectomy. 4

Anatomical Variants

• Non-recurrent laryngeal nerve is a rare variant (0.3-1.6% incidence) occurring almost exclusively on the right side, where the nerve takes a direct course to the larynx without looping around the subclavian artery. 4, 5
• This variant is associated with an aberrant (retro-esophageal) right subclavian artery and places the nerve at higher risk for iatrogenic injury. 4, 5