As for good reasons owen did not draw evolutionary conclusions, there are several. What is the anatomy of the recurrent laryngeal nerve relative to. Background the nonrecurrent laryngeal nerve nrln is a rare embryologicallyderived variant of the recurrent laryngeal nerve rln. Finally, it ascends within the visceral compartment of the neck, behind the thyroid gland, between the esophagus and trachea. The importance of the recurrent laryngeal nerve in surgery on the anterior region of the neck has motivated many published papers on critical points of its pathway, relationship with the inferior thyroid artery, penetration in the larynx, division outside the larynx, and branches communicating with the internal branch of the superior laryngeal nerve.
This means that the descending portion of the featured nerve belongs to the vagus, and the. Anatomical variations of the recurrent laryngeal nerve rln, such as an extralaryngeal terminal bifurcation etb, threaten the safety of thyroid surgery. Sep 09, 2012 right recurrent laryngeal nerve dissection in thyroidectomy. What you need to know about the recurrent laryngeal nerve. The superior laryngeal nerve consists of two branches.
The left recurrent laryngeal nerve design in mammals is not poor design. The recurrent laryngeal nerve rln is a branch of the vagus nerve cranial nerve x that supplies all the intrinsic muscles of the larynx, with the exception of the cricothyroid muscles. Recurrent laryngeal nerve radiology reference article. The presence of an nrln significantly increases the risk of iatrogenic injury and operative complications. The necks of 143 68 male and 76 female human adult embalmed cadavers were examined. Anatomy for tracheostomy litfl medical blog ccc airway. The right and left nerves are not symmetrical, with the left nerve looping under the aortic arch. Otolaryngol clin n am 37 2004 2544 recurrent laryngeal nerve paralysis. The recurrent laryngeal nerve carries somatic efferent axons to the larynx while the phrenic nerve carries somatic efferent fibers to the diaphragm. The identification and dissection of the recurrent laryngeal nerve is essential to guarantee its anatomical and functional integrity. Anatomy of the thoracic recurrent laryngeal nerves from a. Its peculiar route results from evolutionary lengthening of the neck. Doctors can also carry out a laryngeal electromyography, which measures. We hope this picture recurrent laryngeal nerve anatomy can help you study and research.
As described in the anatomy section, slight variations in the anatomy and location of the recurrent laryngeal nerves rlns can exist. The recurrent laryngeal nerve branches off the vagus nerve and is present by the sixth gestational week, associated with the sixth branchial. The right recurrent laryngeal nerve travels up the paratracheal region from lateral to medial as it. The vocal cord assumes a median or paramedian position. It is mostly caused by thyroid and cervical surgery, trauma, endotracheal intubation, central. Additionally, the nerves are one of few nerves that follow a recurrent course, moving in the. The recurrent laryngeal nerves and the thoracic surgeon. The recurrent laryngeal nerve and the inferior thyroid. Dec, 2014 anatomy of recurrent laryngeal nerveanatomy of recurrent laryngeal nerveanatomy of recurrent laryngeal 1.
Both recurrent laryngeal nerves enter the larynx through the inferior. What is the anatomy of the recurrent laryngeal nerve. Ta the terminal branch of the recurrent laryngeal nerve as the latter passes deep to the inferior pharyngeal constrictor. The reason for this fear is the dreaded complication of damaging the nerve and causing loss of voice, among other serious complications. The recurrent laryngeal nerve receives sensory innervation from the trachea, esophagus and pyriform sinus before it enters the larynx deep to the inferior constrictor muscle and posterior to the cricothyroid articulation. There are two recurrent laryngeal nerves, right and left. Anatomy of recurrent laryngeal nerve rln dent1 pbl 3. The recurrent laryngeal nerve may be traumatized during surgery on the thyroid and parathyroid glands. The anatomy of the recurrent laryngeal nerve is complex and different on both sides of the body. Methods we have undertaken an intraoperative study aimed to determine the course, distribution, and rlns anatomical relationships with adjacent structures. Routine exposure of recurrent laryngeal nerve in thyroid surgery can. A variant nerve that mimics the left recurrent laryngeal. Ionm of the recurrent laryngeal nerve springerlink.
This requires indirect laryngoscopy preoperatively, and, as soon as. Elizabeth davis, in equine internal medicine fourth edition, 2018. Background the most frequent postthyroidectomy complication is recurrent laryngeal nerve rln damage with subsequent vocal cord palsy. Recurrent laryngeal nerve injury in the chest is due to cardiac surgery, lung cancer, pulmonary tuberculosis, oesophageal cancer, mitral stenosis, and thoracic aortic aneurysm.
If you would like a large, unwatermarked image for your web page or blog, please purchase the appropriate license. The recurrent laryngeal nerve may exist as two bundles on one side. Recurrent laryngeal nerve injury causes and surgery in. Previous anatomic studies of the recurrent laryngeal nerves rlns have described the variability in the course of the rln. Indeed, our understanding of the superior and recurrent laryngeal nerves has hardly changed since gray 7. Revisited anatomy of the recurrent laryngeal nerves. The laryngeal nerve is a nerve branching down from the vagus nerve towards the larynx. Partial recurrent laryngeal nerve paralysis is a diagnosis inconsistent with the spectrum of vocal fold immobility disorders that have been proposed to date. It arises from the middle of the inferior ganglion of vagus nerve and in its course receives a branch from the superior cervical ganglion of the sympathetic nervous system the cricothyroid muscles are innervated by the superior laryngeal nerve.
To avoid the risk of nerve damage during thyroid surgery, a good knowledge of the variations of the inferior laryngeal nerve is essential. Overall incidence of transient rlnp is reported to be 0. Continuous monitoring of the recurrent laryngeal nerve inomed duration. Eighty adult cadavers 160 sides fixed with formalin were dissected, analyzed and measured.
Neck ultrasonography for detection of nonrecurrent laryngeal. Randolph the accident of hemorrhage is a minor evil. Monitoring can assist in nerve localization and in reducing the incidence of neural trauma. Recurrent laryngeal nerve injury causes and surgery. However, the two rlns are different from other nerves in that their courses are not symmetrical. Partial recurrent laryngeal nerve paralysis or paresis. Recurrent laryngeal nerve sensation of the subglottis motor fibres to intrinsic muscles of the larynx this nerve branches from the vagus in the mediastinum, then turns back up into the neck on the right, it travels inferior to the subclavian artery, and on the left, the aorta. The anatomical relationship between the recurrent laryngeal nerve rln and the inferior thyroid artery ita was studied in 76 embalmed corpses, 8 females. Both recurrent laryngeal nerves enter the larynx through the. It is difficult to identify this anomaly preoperatively unless an associated vascular anomaly is suspected.
Find out information about laryngeal nerve, recurrent. The recurrent laryngeal nerve branches off the vagus nerve and is present by the sixth gestational week, associated with the sixth branchial arch. Intraoperative neurophysiological monitoring of the vagus and recurrent laryngeal nerves is increasingly used during thyroidectomy, parathyroidectomy, skull base surgery, and cervical discectomy with fusion. I have asked joseph scharpf, md, to chair this important new task force, which will focus on the extra cranial seventh nerve parotid surgery, vagus recurrent laryngeal nerve preservation during the thyroid surgery as well as spinal accessory and hypoglossal nerve preservation during head and neck surgery. Stewart, et al reported that of a total of 3496 recurrent laryngeal nerves 1776 on the right side and 1720 on the left side only 6 were found to be nonrecurrent, all occuring on the right side. As the recurrent nerve hooks around the subclavian artery or aorta, it gives off several cardiac filaments to the deep part of the cardiac plexus. Anatomical variations of the recurrent laryngeal nerve in. A case study in human anatomy dickran altounian1, cathy tran2, christina tran1, allison spencer1, alexandra shendrik3, brian p. Chapter 33 surgical anatomy and monitoring of the recurrent laryngeal nerve gregory w. We are pleased to provide you with the picture named recurrent laryngeal nerve anatomy. Nonrecurrent laryngeal nerve nrln is a rare anatomical variant 0. Bifurcation of the nerve was mostly observed on the left side. After the recurrent laryngeal nerve leaves the vagus nerve, it goes down into the chest and then loops back up, to supply nerves to the larynx the voice box. Morphology and functional anatomy of the recurrent.
The recurrent laryngeal nerve rln and the superior laryngeal nerve sln are branches of the vagus nerve cn x. Bones and cartilages coronal section cricothyroid muscle function and development inlet and epiglottis muscles rules of. Impairment of swallowing is an accompanying symptom to dysphonia in roughly 60% of patients. The laryngeal nerves supply impulses from the brain to control their movement. Recurrent laryngeal nerve definition of recurrent laryngeal. Recurrent laryngeal nerve an overview sciencedirect topics.
If you can imagine a block of wood attached to the wall a. A nonrecurrent laryngeal nerve has not been reported to occur on the left side. Neck ultrasonography for detection of nonrecurrent laryngeal nerve background. The anatomy of the nerve appears more constant along its distal segment near the cricothyroid joint, which is our surgical approach to the initial identification of the nerve. Although there are others more terrible and frightening. Among the 548 cases undergoing recurrent laryngeal nerve dissection, 128 developed anatomical variations of the recurrent laryngeal nerve incidence rate of. Besides the morphology of the nerve branches, intraoperative evaluation of their functional anatomy may be useful to preserve motor activity. Relationship between the recurrent laryngeal nerve and the inferior. Recurrent laryngeal nerve rln injury is considered to be the most severe complication in thyroid surgery. Malignant neoplasms of the lung and pulmonary tuberculosis were the most frequent causes of the paralysis. Recurrent laryngeal nerve injury produces an abductor laryngeal paralysis.
Surgical anatomy of the recurrent laryngeal nerve revisited. The various causes of recurrent laryngeal nerve paralysis that i have observed during the past 24 years are reported. Jul 26, 2019 we are pleased to provide you with the picture named recurrent laryngeal nerve anatomy. Instant anatomy is a specialised web site for you to learn all about human anatomy of the body with diagrams, podcasts and revision questions.
Accurate diagnosis can be made only by visualizing the vocal cords while the patient is awake. The recurrent laryngeal nerve branches from the vagus in the. Instant anatomy head and neck nerves cranial x vagus. Apr 17, 2019 unilateral vocal fold paralysis uvfp occurs from a dysfunction of the recurrent laryngeal or vagus nerve innervating the larynx. The main trunk, bifurcation point, and terminal branches of. Recurrent laryngeal nerve the recurrent laryngeal nerve is a myelinated nerve. Surgical anatomy and monitoring of the recurrent laryngeal. Anatomical perspective lalruatkimi k balasubramanian thiagarajan stanley medical ollege abstract. The sln external branch innervates the cricothyroid muscle, which tenses and adducts the vocal cords.
During surgery, a few anatomic landmarks can assist in. This article highlights the normal anatomy, anatomical variants and ways to identify the nerve as the. The recurrent laryngeal nerve rln, also known as the inferior laryngeal nerve, is a branch of the vagus nerve cn x which has a characteristic loop around the right subclavian artery on the right and the aortic arch on the left before returning up to achieve the tracheoesophageal groove and then the larynx. It courses medially in the neck and divides into the internal and external laryngeal branch lateral to the greater cornu of the hyoid bone and travels inferiorly to pierce the thyrohyoid membrane and travels under the pyriform fossa. You have two, one on each side, as you do with other nerves. The recurrent laryngeal nerve rln innervates all the important laryngeal muscles except the cricothyroid. Risk factors for rln damage include thyroid cancer surgery, revision surgery, lymph node dissection, retrosternal extension, and abnormal anatomy. Bilateral recurrent laryngeal nerve paralysis can be a fatal emergency. The doctor can also examine the larynx to assess the injury.
Aug 06, 2015 the recurrent laryngeal nerve is a branch of cranial nerve x, otherwise known as the vagus nerve. The recurrent laryngeal nerve rln is a branch of the vagus nerve cranial nerve x that. Nov 29, 2011 the aim of this study was to provide some important information about the morphology and topography of the recurrent laryngeal nerve rln and inferior thyroid artery ita, which significantly helps localize and protect the rln in neck surgery, especially in thyroid surgery. Treatment of recurrent laryngeal nerve injury jama surgery. The left recurrent laryngeal nerve curves medially around the aortic arch during development and is approximately 1 m long. Management of unilateral recurrent laryngeal nerve injury. Partial paralysis for most authors is identical to paresis, meaning that all muscles innervated by the iln are equally or almost affected. You may not embed one of our images on your web page without a link back to our site. Careful dissection of the rln during surgery reduces the risk of damage. Inferior laryngeal nerve definition of inferior laryngeal.
Only its identification and its careful exposure allow prevention of iatrogenic injuries. The connection between the vagus nerve and the pharyngeal arches that give rise to the larynx is established early in development. This article highlights the normal anatomy, anatomical. The superior laryngeal nerve is a branch of the vagus nerve. How is the recurrent laryngeal nerve identified in a. All other intrinsic laryngeal muscles are innervated by the recurrent laryngeal nerve. As the heart migrates from the region of the pharynx to the. Sercarz, md functional laryngeal reinnervation depends upon theprecise reinnervation ofthe laryngeal abductor and adductor muscle groups. Berke, md losangeles, california ming ye, md joel a. The recurrent laryngeal nerve rln, also known as the inferior laryngeal nerve, is a branch of the vagus nerve cn x which has a characteristic loop around the right subclavian artery on the right and the aortic arch on the left before returning up to achieve.
It is suggested that the use of the horizontal band to locate the recurrent laryngeal nerve would be of particular value when the inferior thyroid artery is absent, when the nerve is non. The vagus nerve, recurrent laryngeal nerve, and external branch of the superior laryngeal nerve have unique latencies allowing for intraoperative documentation of intact neural function during thyroid surgery. The recurrent laryngeal nerve can be a real challenge to the surgeon operating in its area. One or both cords can be affected, and depending on the severity of nerve damage, paralysis can be a temporary condition or cause lifelong speech difficulties. Aug 17, 2016 recurrent laryngeal nerve paralysis 1. The non recurrent laryngeal nerve nrln is a rare variant of the recurrent laryngeal nerve rln that takes an aberrant course, not descending into the thorax as is usual. Rln palsy should be an historical event for the thoracic surgeon. The recurrent laryngeal nerve rln, also known as the inferior laryngeal nerve, is a branch of the vagus nerve cn x which has a characteristic loop around the right subclavian artery on the right and the aortic arch on the left before returnin.
The recurrent laryngeal then passes below and behind the aorta, at the level of the ligamentum arteriosum. Anatomy of laryngeal nerves otolaryngology houston. Our aim was to provide a comprehensive metaanalysis of the overall prevalence of the nrln, its origin, and its association with an aberrant subclavian artery. If you would like a large, unwatermarked image for your web page or. May 28, 2016 sritharan n, chase m, kamani d, randolph m, randolph gw. Practitioners interested in maximizing the information obtained from laryngeal imaging must be familiar with laryngeal anatomy. The recurrent laryngeal nerve rln branches off the vagus nerve and supplies function to some muscles of the larynx voice box. An applied anatomical study on the recurrent laryngeal nerve. It then branches into the superior and recurrent laryngeal nerves rln, of which the latter is remarkably interesting from the point of view of evolutionary biology.
The major consequence of laryngeal nerve damage is weakness or paralysis of the vocal cords. Injury to the nerve can produce changes in voice quality. The recurrent and superior laryngeal nerves springerlink. Intralaryngeal anatomy of the recurrent laryngeal nerve. The aim of this work was to evaluate, to prove their reliability, the different surgical landmarks previously proposed as a mean to locate the recurrent laryngeal nerve rln. A common claim by evolutionists is that the mammalian left recurrent laryngeal nerve was poorly designed because it travels downward past the larynx, then around the aorta and, last, back up to the larynx. Kendall the interpretation of laryngeal imaging in the evaluation of patients with voice problems requires a strong foundation in the anatomy and physiology of the larynx. Introduction many thoracic surgeons are terrified to come anywhere near the recurrent laryngeal nerve rln, especially on the left side.
It causes a characteristic breathy voice often accompanied by swallowing disabilty, a weak cough, and the sensation of shortness of breath. The doctor will examine both vocal folds to determine if one or both nerves are damaged. Because of the inefficiencies of the routing the nerve takes, its often hailed as one of. Causes of recurrent laryngeal nerve paralysis jama. Doctors can usually diagnose recurrent laryngeal nerve damage by examining the patient and asking about the symptoms. If the superior laryngeal nerve is also paralysed the cord will assume an intermediate or paramedian slightly off the median line position because of the loss of adductive force. Surgical anatomy and monitoring of the recurrent laryngeal nerve. In 4 patients with recurrent laryngeal nerve paralysis, the left recurrent nerve was most commonly involved. Anatomy of recurrent laryngeal nerveanatomy of recurrent. Definition of recurrent laryngeal nerve medicinenet. Home aba keyword categories anatomy laryngeal innervation. The left recurrent laryngeal nerve arises from the vagus trunk, as it passes in front of the aortic arch. Laryngeal nerve, recurrent article about laryngeal nerve. The nonrln nrln is a rare anatomical anomaly of the rln, with an incidence of 0.