The recurrent laryngeal nerves branch off the vagus, the left at the aortic arch, and the right at the right subclavian artery.

[8]: 86–88  Sensory cell bodies are located in the inferior jugular ganglion,[9] and the fibers terminate in the solitary nucleus.

[8]: 86–88  Parasympathetic fibers to segments of the trachea and esophagus in the neck originate in the dorsal nucleus of the vagus nerve.

Each arch develops its own artery, nerve that controls a distinct muscle group, and skeletal tissue.

There is suspected variability in the configuration of these branches to the cardiac plexus, trachea, esophagus and inferior pharyngeal constrictor muscle.

This is the sole muscle responsible for opening the vocal cords, and paralysis may cause difficulty breathing (dyspnea) during physical activity.

[20][4] Nerve damage can be assessed by laryngoscopy, during which a stroboscopic light confirms the absence of movement in the affected side of the vocal cords.

Studies have shown that 2–18% of lung cancer patients develop hoarseness because of recurrent laryngeal nerve compression, usually left-sided.

The nerve may be severed intentionally during lung cancer surgery in order to fully remove a tumor.

The length of the nerve is a factor since it is more common in larger horses, and the left side is affected almost exclusively.

The common presentation is a sound, ranging from a musical whistle to a harsh roar or heaving gasping noise (stertorous), accompanied by worsening performance.

[30]: 771 In sauropod dinosaurs, the vertebrates with the longest necks, the total length of the vagus nerve and recurrent laryngeal nerve would have been up to 28 metres (92 ft) long in Supersaurus, but these would not be the longest neurons that ever existed: the neurons reaching the tip of the tail would have exceeded 30 metres (98 ft).

[31] The extreme detour of the recurrent laryngeal nerves, about 4.6 metres (15 ft) in the case of giraffes,[32]: 74–75  is cited as evidence of evolution, as opposed to intelligent design.

Over the course of evolution, as the neck extended and the heart became lower in the body, the laryngeal nerve remained in its original course.

[16]: 7–8 [33] In 1838, five years before he would introduce the concept of homology to biology, anatomist Richard Owen reported upon the dissection of three giraffes, including a description of the full course of the left recurrent laryngeal nerve.

[34][35] Anatomists Andreas Vesalius and Thomas Willis described the nerve in what is now regarded as an anatomically standard description, and doctor Frank Lahey documented a way for its interoperative identification during thyroid operations.