Recurrent laryngeal nerve

The recurrent laryngeal nerve ( declining laryngeal nerve, vocal nerve) is a branch of the tenth cranial nerve, the vagus nerve.

Description

It separates at the level of the upper thoracic aperture ( thoracic inlet ) from the vagus, left describes a noose around the aortic arch and right around the subclavian artery and pulling on the trachea back to the larynx, where it gives off some branches for the supply of food and trachea. The rest of the throat near section is now referred to as the inferior laryngeal nerve ( in animals caudal laryngeal nerve ). He supplies all laryngeal muscles except the cricothyroid muscle muscle, which is innervated by the upper laryngeal nerve.

The striking profile of the recurrent laryngeal nerve arises from complex ontogenetic processes and is directly by the so-called descent ( descent ) of the heart due to the embryo. Interpreted phylogenetically applies the recurrent laryngeal nerve as originally sixth Kiemenbogennerv. His strange color gradient is historically interpreted with reference to the topology of valuated as homologous structures and should have resulted from the transformation of the so-called branchial arches.

Damage to the nervous

Unilateral damage to the recurrent laryngeal nerve - for example, by mechanical damage during neck surgery ( thyroidectomy ), inflammation in his surroundings or of the nerves themselves - lead to paralysis or paresis of the vocal cords ( recurrent laryngeal nerve palsy ) and thus to a hoarse voice. Bilateral lesions also lead to severe shortness of breath because of the not far enough open glottis breathing is obstructed.

In animals ( esp. in the horse ) are paralysis of the left recurrent laryngeal nerve is relatively common and a warranty defect. They lead to a unilateral laryngeal paralysis, which is also called laryngeal whistling.

Variety

Rarely is an aberrant course of the nerve without noose around the aortic arch, in which the nerve takes a largely straight course. With this variety in the context of thyroid surgery and especially in surgical removal of the parathyroid glands is an increased risk of injury. It is usually associated with the variety of a lusoria artery, which can be detected in a three-dimensional thin-layer computed tomography for prevention of nerve injury before a Nebenschildrüsenoperation.

Evidence for evolution

The extremely long detour to the nerve goes through the body (in the case of the giraffe, the length of almost 5 meters ) is listed by evolutionary biologists as evidence for evolution or as counter-evidence for intelligent design. In a constructed living things would have been foolish to choose such a long history. The nerve has this length is achieved in that the neck was longer in the course of evolution and the heart has wandered deeper into the body.

Swell

• Cranial nerve
• Vagus