Anatomy of recurrent laryngeal nerveAnatomy of recurrent laryngeal nerveAnatomy of recurrent laryngeal

Anatomy of recurrent laryngeal nerve

1. Anatomy of recurrent laryngeal   nerve   (RLN ) DENT113   PBL 3.4 “ Complicated thyroidectomy “ Supervision :  Prof.Hanaa Gazaerly By Ebtisam Ali  

2. 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 .  

3. There are two recurrent laryngeal nerves  right  and  left  in the human body both arising from the vagus nerve but they follow slightly different courses on the left and right side.

4. 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.

5. 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.

6. 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.

7. 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 .

8. The left RLN is longer than 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  .

9. 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.

10. 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 )