Left recurrent laryngeal n.

The left recurrent laryngeal nerve (RLN) is a branch of the left vagus nerve (cranial nerve X) that supplies most of the intrinsic muscles of the larynx. The left recurrent laryngeal nerve branches from the left vagus nerve at the level of the arch of aorta, turns superiorly, and travels along the side of the trachea to the larynx. (In contrast, the right recurrent laryngeal nerve branches off the right vagus nerve at the level of the right subclavian artery, under which it loops before travelling superiorly in the neck).

The recurrent laryngeal nerves are notable in that they follow a recurrent course, moving in the opposite direction to the nerve from which they branch. The recurrent laryngeal nerves carry sensation from the larynx below the vocal cords, and supply motor innervation to the intrinsic muscles of the larynx with the exception of the cricothyroid muscle. The recurrent laryngeal nerves also have branches to the deep cardiac plexus, the trachea, the esophagus and the inferior pharyngeal constrictor muscles.