The cricothyroid muscles are innervated by the superior laryngeal nerve. The anatomy of the recurrent laryngeal nerve is variable. All other intrinsic laryngeal muscles are innervated by the recurrent laryngeal nerve the superior laryngeal nerve consists of two branches. Whether the injury is accidental or due to deliberate resection for oncologic soundness, the surgeon must be prepared to offer the best available treatment to patients, either at the time of injury or early in the recovery process. Inferior laryngeal nerve definition of inferior laryngeal. The left recurrent laryngeal nerve design in mammals is not poor design.
Clinically relevant anatomy of recurrent laryngeal nerve. Surgical anatomy and monitoring of the recurrent laryngeal nerve. Optimal management of acute recurrent laryngeal nerve injury. Intralaryngeal anatomy of the recurrent laryngeal nerve. 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.
Practitioners interested in maximizing the information obtained from laryngeal imaging must be familiar with laryngeal anatomy. 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. Eleven adult cadavers 5 male6 female were dissected bilaterally to expose the path of the recurrent laryngeal nerve. Recurrent laryngeal nerve rln injury is considered to be the most severe complication in thyroid surgery. Anatomy of the thoracic recurrent laryngeal nerves from a. The left recurrent laryngeal nerve arises from the vagus trunk, as it passes in front of the aortic arch. The connection between the vagus nerve and the pharyngeal arches that give rise to the larynx is established early in development. Anatomical variations of the rln, such as extra laryngeal branches, distorted rln, intertwining between branches of the rln and inferior thyroid artery, and non recurrent laryngeal nerve, can be a potential cause of nerve injury due to visual misidentification. Recurrent laryngeal nerve request pdf researchgate. What is the anatomy of the recurrent laryngeal nerve. The right recurrent laryngeal nerve leaves the vagus nerve at the level of the second rib turning around the costocervical trunk before ascending toward the larynx.
We think this is the most useful anatomy picture that you need. Surgical management of the recurrent laryngeal nerve in. The recurrent laryngeal nerve rln branches off the vagus nerve and supplies function to some muscles of the larynx voice box. Anatomical variations of recurrent laryngeal nerve during. There were 12 cases of recurrent laryngeal nerve injury following recurrent laryngeal nerve dissection injury rate of 2. A novel variation of the recurrent laryngeal nerve bmc. 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. Non recurrent nerve is a very rare variation of the inferior laryngeal nerve. 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 summary. Full text is available as a scanned copy of the original print version. A case study in human anatomy dickran altounian1, cathy tran2, christina tran1, allison spencer1, alexandra shendrik3, brian p.
A novel variation of the recurrent laryngeal nerve gaosong wu1,2 and kun wang2 abstract background. The recurrent laryngeal nerve rln and the superior laryngeal nerve sln are branches of the vagus nerve cn x. The laryngeal nerve is a nerve branching down from the vagus nerve towards the larynx. Contrary to routine dissection of the rln, most surgeons tend to avoid rather than routinely expose and identify the external branch of the superior laryngeal nerve ebsln during thyroidectomy or parathyroidectomy. A variant nerve that mimics the left recurrent laryngeal nerve peerj.
Because of the inefficiencies of the routing the nerve takes, its often hailed as one of. As the heart migrates from the region of the pharynx to the. Reputable anatomy books describe the rln in cadavers, and this doesnt pay a great service to the surgical practice on living humans 11,12. The recurrent laryngeal nerve can be a real challenge to the surgeon operating in its area. It is a branch of one of the cranial nerves, those nerves that lead directly from the brain rather than from the spinal cord. Natal, south africa introduction a series of neck dissections was don one 90 fresh, frozen, nonembalmed human cadavers 48 hours following death to sho,w the anatomy of th righe t and left recurrent laryngeal nerves. Anatomy of recurrent laryngeal nerveanatomy of recurrent. Extralaryngeal branching of the recurrent laryngeal nerve. The recurrent laryngeal nerves rln are branches of the vagus nerve that go on to innervate most of the intrinsic muscles of the larynx. 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.
Aug 06, 2015 the vagus nerve exists within the body as a pair, one on the right side and the other on the left. The left recurrent laryngeal nerve curves medially around the aortic arch during development and is approximately 1 m long. This requires indirect laryngoscopy preoperatively, and, as soon as. 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. Recurrent laryngeal nerve definition of recurrent laryngeal.
The recurrent laryngeal then passes below and behind the aorta, at the level of the ligamentum arteriosum. Anatomy of recurrent laryngeal nerve rln dent1 pbl 3. The recurrent and superior laryngeal nerves springerlink. The branches provide both sensory and motor fibers.
Recurrent laryngeal nerve radiology reference article. Elizabeth davis, in equine internal medicine fourth edition, 2018. She had no history of surgery or radiation to the head or neck. External branch of the superior laryngeal nerve monitoring. The most common complications of anterior neck surgery are dysphagia and rln palsy.
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. Berke, md losangeles, california ming ye, md joel a. Dec, 2014 recurrent laryngeal nerve the recurrent laryngeal nerve is a myelinated nerve. The rln is consistently present superior to the inferior thyroid artery before it ascends behind the inferior constrictor to the nerve s entry point into the larynx. Overall incidence of transient rlnp is reported to be 0. The book is visually oriented with color illustrations and photomicrographs embracing all aspects of recurrent laryngeal nerve anatomy including branching patterns, relationship of the nerve and the inferior thyroid artery and the nonrecurrent recurrent laryngeal nerve.
A branch of the vagus nerve curving upward, on the right side around the root of the subclavian artery, on the left side around the arch of the aorta, then passing superiorly, posterior to the common carotid artery between the trachea and the esophagus to the larynx. Chapter 33 surgical anatomy and monitoring of the recurrent laryngeal nerve gregory w. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Anatomical variations of the recurrent laryngeal nerve in. 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. May 05, 2016 the recurrent laryngeal nerve rln is a branch of the vagus nerve, which carries motor, sensory and parasympathetic fibers to the larynx. Historically, the rln has been considered to branch after it enters the larynx, but numerous studies have demonstrated that it often branches before. Previous anatomic studies of the recurrent laryngeal nerves rlns have described the variability in the course of the rln.
May 17, 20 recurrent laryngeal nerve rln injury is commonly encountered by thyroid surgeons and may carry with it great morbidity. There are two recurrent laryngeal nerves right and left in the human body both arising from the vagus. The rln is consistently present superior to the inferior thyroid artery before it ascends behind the inferior constrictor to the nerves entry point into the larynx. The recurrent laryngeal nerve carries somatic efferent axons to the larynx while the phrenic nerve carries somatic efferent fibers to the diaphragm. The recurrent and superior laryngeal nerves gregory w. You have two, one on each side, as you do with other nerves. Because of the anatomical variations of the nerve, preservation of the nerve is the optimal strategy during surgery. 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. A variant nerve that mimics the left recurrent laryngeal. The book is visually oriented with color illustrations and photomicrographs embracing all aspects of recurrent laryngeal nerve anatomy including branching patterns, relationship of the nerve and the inferior thyroid artery and the non recurrent recurrent laryngeal nerve. Routine exposure of recurrent laryngeal nerve in thyroid surgery can. The recurrent laryngeal nerve branches off the vagus nerve and is present by the sixth gestational week, associated with the sixth branchial arch. Finally, it ascends within the visceral compartment of the neck, behind the thyroid gland, between the esophagus and trachea. Dawkins complains about the recurrent laryngeal nerve.
Careful dissection of the rln during surgery reduces the risk of damage. Ta the terminal branch of the recurrent laryngeal nerve as the latter passes deep to the inferior pharyngeal constrictor. This article highlights the normal anatomy, anatomical variants and ways to identify the nerve as the. The recurrent laryngeal nerve may be traumatized during surgery on the thyroid and parathyroid glands. Get a printable copy pdf file of the complete article 4. The nonrecurrent laryngeal nerve a rare phenomenon. The morbidity of these complications has led to the investigation of the impact of sidedness in anterior cervical spine surgery. Jul 26, 2019 we hope this picture recurrent laryngeal nerve anatomy can help you study and research. Treatment of recurrent laryngeal nerve injury jama surgery. The recurrent laryngeal nerve rln innervates all the important laryngeal muscles except the cricothyroid. The vocal cord assumes a median or paramedian position. Sercarz, md functional laryngeal reinnervation depends upon theprecise reinnervation ofthe laryngeal abductor and adductor muscle groups. Surgical anatomy of the recurrent laryngeal nerve revisited. This means that there is also a right and left recurrent laryngeal nerve.
The recurrent and superior laryngeal nerves download. The recurrent laryngeal nerve rln is a branch of the vagus nerve, which carries motor, sensory and parasympathetic fibers to the larynx. Injury to the recurrent laryngeal nerve rln andor external branch of the superior. 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. Several anatomic variations of the nerve increase the likelihood of iatrogenic damage. Anatomical course of the thyroarytenoid branch of the recurrent. Recurrent laryngeal nerve an overview sciencedirect topics. Objectiveshypothesis to determine the position and anatomic variability of the thyroarytenoid ta branch of the recurrent laryngeal nerve. A 50yearold woman was presented to our department with a nodule in the right thyroid lobe, and she reported no voice changes.
Injury to the recurrent laryngeal nerve is one of the most severe complications of thyroid surgery. The book is visually oriented with color illustrations and photomicrographs embracing all aspects of recurrent laryngeal nerve anatomy including branching. Setubal, portugal a r t i c l e i n f o article history. Recurrent laryngeal nerve the recurrent laryngeal nerve is a myelinated nerve. Accurate diagnosis can be made only by visualizing the vocal cords while the patient is awake. The nonrln nrln is a rare anatomical anomaly of the rln, with an incidence of 0. The recurrent and superior laryngeal nerves pdf download.
The wide variability of this extralaryngeal branching elb has significant implications for the risk of. The sln external branch innervates the cricothyroid muscle, which tenses and adducts the vocal cords. One of the cranial nerves, the vagus the name means wandering and is apt, has various branches, two of which go to the heart, and two on each side to the. Recurrent laryngeal nerve injury produces an abductor laryngeal paralysis.
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