Anatomical Basis of Recurrent Laryngeal Nerve Injury

Embryological Development and Course of the Recurrent Laryngeal Nerve

The recurrent laryngeal nerve (RLN), a branch of the vagus nerve (cranial nerve X), plays a crucial role in innervating intrinsic muscles of the larynx, except for the cricothyroid muscle. Its unique trajectory predisposes it to injury during surgical procedures in the neck and thorax.

Embryological Development

During embryonic development, the RLN follows the descent of the heart and great vessels. Initially, the vagus nerve gives rise to the RLN high in the neck. However, as the arteries elongate with the growing embryo, the RLN is pulled downward, leading to its final anatomical position looping around the subclavian artery (right side) and aortic arch (left side).

Anatomical Course

Right RLN: Loops around the subclavian artery and ascends between the trachea and esophagus.
Left RLN: Loops around the aortic arch and ascends similarly to the right RLN.

Common Causes of Injury

Thyroid and parathyroid surgery
Esophageal and lung surgery
Neck trauma
Prolonged intubation

Clinical Implications

Damage to the RLN can result in voice changes, hoarseness, and airway compromise. Bilateral injury may lead to respiratory distress, necessitating urgent intervention.