The larynx, also known as the voice box, is a complex structure responsible for a number of processes but most notably involved in speech. It is part of the respiratory system. The larynx is located in the neck, anterior to the oesophagus. It is continuous inferiorly with the trachea.
The larynx is innervated by two nerves that branch from the vagus nerve: the superior laryngeal nerve and the recurrent laryngeal nerve.
The superior laryngeal nerve splits into internal and external branches. The internal branch provides sensory innervation to the upper half of the larynx, above the vocal cords. The external branch provides motor innervation to the cricothyroid muscle which aids in vocalisation.
The recurrent laryngeal nerve provides sensory innervation to the lower half of the larynx, below the vocal cords. It also provides motor innervation to all the intrinsic muscles of the larynx except for the cricothyroid muscle. It is important to note that the left and right recurrent laryngeal nerves are not symmetrical. The left recurrent laryngeal nerve travels under the aortic arch while the right recurrent laryngeal nerve travels under the right subclavian artery.
You can visualise the pathway of the nerves of the larynx by using the Origin Path tool in Complete Anatomy. To do so follow these steps:
⒈ Select one of the nerves, for example, the left recurrent laryngeal nerve. Do this by simply clicking on the nerve or using the search function to locate the nerve.
⒉ Click on Origin Path on the left side of the screen.
⒊ You now have the option to either isolate or highlight the origin path. Let’s select Highlight Origin Path for the example.
⒋ You can now see the vagus nerve as the origin of the left recurrent laryngeal nerve.
⒌ Repeat with the other nerves that innervate the larynx.