Anatomy of recurrent laryngeal nerve(RLN)DENT113

PBL 3.4“ Complicated thyroidectomy “

Supervision : Prof.Hanaa GazaerlyBy Ebtisam Ali

RECURRENT LARYNGEAL NERVE• The recurrent laryngeal nerve is a myelinated nerve . It is

a branch of the vagus nerve (cranial nerve X).

• It's supply the sixth pharyngeal arche .

• The Branches provide both sensory and motor fibers.

There are two recurrent laryngeal

nerves right and leftin the human body

both arising from the vagus nerve but they

follow slightly different courses on

the left and right side.

The right recurrent laryngeal nerve• Originates from the descending right vagus nerve as

it passes intermediate to the right subclavian vein anteriorly and the right subclavian artery posteriorly.

• It curves posteriorly around the inferior margin of the right subclavian artery.

• Then, it passes medially and ascends over the posterolateral surface of the trachea into the groove between esophagus and trachea.

The left recurrent laryngeal nerve• Originates from the left vagus nerve as it passes

over the arch of the aorta inferior to the left superior intercostal vein.

• It passes medially and posteriorly deep to the ligamentum arteriosum before curving inferior to the arch of the aorta.

• It then passes superiorly over the left main bronchus to ascend in the groove between the left side of the trachea and the anterior of the esophagus.

Initially these nerves, branches of the vagus, supply the sixth pharyngeal arches. When the heart descends, they hook around the sixth aortic arches and ascend again to

the larynx, which accounts for their recurrent course.

• On the right, when the distal part of the sixth aortic arch and the fifth aortic arch disappear, the recurrent laryngeal nerve moves up and hooks around the right subclavian artery.

• On the left the nerve does not move up, since the distal part of the sixth aortic arch persists as the ductus arteriosus, which later forms the ligamentum arteriosum.

• The left RLN is longerthan the right Because it crosses under the arch of the aorta at the ligamentum arteriosum

• Considering the extra length and the distance the left recurrent laryngeal nerve has to travel, it is the common nerve affected by diseases / disorders / trauma etc .

Functions of RLN

• It has motor control of all the intrinsic muscles of the

larynx, the thyroarytenoid, the posterior and lateral

cricoarytenoid, and arytenoid muscles depends

upon the recurrent laryngeal nerve

• It transmits sensory information from the mucous

membranes of the larynx from the lower surface of the

vocal fold, downwards.

References

• Sunderland S, Swaney WE. The intraneural topography of the recurrent laryngeal nerve in man. Anat Rec. Nov 1952;114(3):411-26

• Moore, Keith L (1992), Clinically Oriented Anatomy (3rd ed.)

• F. Charles Brunicardi; F. Brunicardi; Dana Andersen; E. Pollock Raphael, Timothy Billiar, David Dunn, John Hunter, Jeffrey Matthews, Raphael E. Pollock (September 11, 2009). Schwartz's Principles of Surgery (9th ed.). McGraw Hill Professional. pp. 1346–1347. ISBN 978-0-07-154769-7.

• Grey's Anatomy , Henry Gray ,40th Ed.

• Textbook of laryngology Edited by : Albert L. Merati,MD,Steven A . Bielamowicz,MD ,FACS ( 2006 )