Aug 06, 2015 the vagus nerve exists within the body as a pair, one on the right side and the other on the left. Bula g, mucha r, paliga m, koziolek h, niedzielski z, gawrychowski j. Nonrecurrent laryngeal nerve in thyroid surgery a n hisham ms, a sarojah ms, a alvin ms, nteast and endoetine surgical unit, departmentofsurgety,kualalumpurhospital, kualalumpur, malaysia introduction the nonrecuncntlaryngeal nerve nrin is a rare clinical entity. We assessed the contribution of the laryngeal nerves to motor innervation of the cpm. The right recurrent laryngeal nerve usually passes around and behind the subclavian artery and then ascends to enter the larynx. Paralysis of the larynx voice box caused by damage to the recurrent laryngeal nerve or its parent nerve, the vagus nerve, which originates in the brainstem and runs down to the colon. 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. Background the nonrecurrent laryngeal nerve nrln is a rare embryologicallyderived variant of the recurrent laryngeal nerve rln. Recurrent laryngeal nerve definition of recurrent laryngeal. Anatomy of the human internal superior laryngeal nerve sanders. The left recurrent laryngeal nerve design in mammals is not poor design. The recurrent laryngeal nerve is an often cited example of unintelligent design in biology. All other intrinsic laryngeal muscles are innervated by the recurrent laryngeal nerve the superior laryngeal nerve consists of two branches. Historically, the rln has been considered to branch after it enters the larynx, but numerous studies have demonstrated that it often branches before.
Injury to the recurrent laryngeal nerve is a serious complication in thyroid and parathyroid surgery. Topography of the recurrent laryngeal nerve in relation to the thyroid. The presumed course of the recurrent laryngeal nerve in acta. 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 does not refute intelligent.
The recurrent laryngeal nerve is a branch of the vagus nerve that supplies all the intrinsic muscles of the larynx, with the exception of the cricothyroid muscles. Quantitative analysis of myelinic fibers in human laryngeal nerves. Photographs of the artery and nriln were taken after the. Extralaryngeal branching of the recurrent laryngeal nerve. The nonrecurrent 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. The branches provide both sensory and motor fibers. We performed an intraoperative electromyographic study of 27 patients. Jan 20, 2015 the nerve used to line up with a blood vessel, both servicing the gills of our fishy ancestors. When the vessel moved backwards during evoution, the rln was constrained to remain behind it, still retaining its connection to the larynx, which. The paths of the left and right recurrent laryngeal nerves vary slightly with the left recurrent laryngeal nerve dividing from the main vagus nerve at the level of the aortic arch.
At the pterygopalatine ganglion receives parasympathetic fibers that supply pharyngeal mucosal glands which. 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. Treatment of recurrent laryngeal nerve injury jama. A novel variation of the recurrent laryngeal nerve bmc. As the heart migrates from the region of the pharynx to the. A new type of nonrecurrent inferior laryngeal nerve in a. The laryngeal nerve is a nerve branching down from the vagus nerve towards the larynx.
Medical considerations for the intelligent design of the recurrent laryngeal nerve. Wedel1, 3 1 college of osteopathic medicine of the pacific, western university of health sciences, pomona, ca usa. 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. The setting for this work is the human anatomy laboratory of the. The aim of the study was to assess the frequency of nonrecurrent laryngeal nerves nonrln. The descent of the recurrent nerves below the aortic arch and subclavian artery is the result of patterns of coalescence and movements of components of the aortic arch during embryogenesis. This means that there is also a right and left recurrent laryngeal nerve. This article highlights the normal anatomy, anatomical variants and ways to identify the nerve as the. There are two recurrent laryngeal nerves right and left in the human body both arising from the vagus. 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. Injury to the nerve can produce changes in voice quality, but is generally. How did the recurrent laryngeal nerve evolve from fish to. Dawkins complains about the recurrent laryngeal nerve.
The recurrent laryngeal nerve may be traumatized during surgery on the thyroid and parathyroid glands. Anatomy of the human internal superior laryngeal nerve. The rln is composed by afferent and efferent myelin fibers and is responsible for subglottic sensitivity and for the innervation of the intrinsic laryngeal muscles,25. Anatomy of recurrent laryngeal nerveanatomy of recurrent. Non recurrent nerve is a very rare variation of the inferior laryngeal nerve. 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. Because of the inefficiencies of the routing the nerve takes, its often hailed as one of. Sercarz, md functional laryngeal reinnervation depends upon theprecise reinnervation ofthe laryngeal abductor and adductor muscle groups. The recurrent laryngeal nerves rln are branches of the vagus nerve that go on to innervate most of the intrinsic muscles of the larynx. Damage to the recurrent laryngeal nerve can result from diseases inside the chest, such as a tumor, an aneurysm of the arch of the aorta, or an aneurysm of the left atrium of the heart. Inferior laryngeal nerve definition of inferior laryngeal.
The presence of an nrln significantly increases the risk of iatrogenic injury and operative complications. Clinically relevant anatomy of recurrent laryngeal nerve. The nerves found in the thoracic cavity are either sympathetic or parasympathetic autonomic nerves, with two exceptions. Nonrecurrent nerve is a very rare variation of the inferior laryngeal nerve. It is a component of the respiratory tract, and has several important functions, including phonation, the cough reflex, and protection of the lower respiratory tract. 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. The pharyngeal nerve is a branch of the maxillary division of the trigeminal nerve and contributes to the pterygopalatine ganglion gross anatomy. We think this is the most useful anatomy picture that you need. The superior laryngeal nerve descends, by the side of the pharynx, behind the internal carotid artery, and divides into two branches the external laryngeal nerve and the internal laryngeal nerve the external laryngeal nerve is the smaller, external branch.
The morbidity of these complications has led to the investigation of the impact of sidedness in anterior cervical spine surgery. 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. 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. Elizabeth davis, in equine internal medicine fourth edition, 2018. We are pleased to provide you with the picture named recurrent laryngeal nerve anatomy. The phrenic nerve, for example, arises from high cervical nerves c35 and descends within the. The major component of the upper esophageal sphincter is the cricopharyngeal muscle cpm. The vocal cord assumes a median or paramedian position.
An unusual anomaly is the socalled nonrecurrent laryngeal nerve. The aim was to study the anatomic relationship between recurrent laryngeal nerve rln and cervical fascia combined with the requirements in anterior cervical spine surgery acss summary of background data. The recurrent laryngeal then passes below and behind the aorta, at the level of the ligamentum arteriosum. The left recurrent laryngeal nerve curves medially around the aortic arch during development and is approximately 1 m long.
Recurrent laryngeal nerve rln injury is considered to be the most severe complication in thyroid surgery. Anatomical variations of recurrent laryngeal nerve during. Recurrent laryngeal nerve palsy and hypoparathyroidism are the most common, important complications in thyroid and parathyroid surgery. The right and left nerves are not symmetrical, with the left nerve looping under the aortic arch, and the right nerve looping under the right. There are two recurrent laryngeal nerves, right and left. Berke, md losangeles, california ming ye, md joel a. Anatomy of the human internal superior laryngeal nerve ira sanders and liancai mu grabscheid voice center, department of otolaryngology, the mount sinai medical center, new york, new york 10029 abstract the mucosa of the larynx contains one of the most dense concentrations of sensory receptors in the human body. The pharyngeal nerve divides off the maxillary division just after emerging from the foramen rotundum to enter the pterygopalatine fossa. Anatomical variations of the rln, such as extralaryngeal branches, distorted rln, intertwining between branches of the rln and inferior thyroid artery, and nonrecurrent laryngeal nerve, can be a potential cause of nerve injury due to visual misidentification. Original research article study on recurrent laryngeal. Injury to the recurrent laryngeal nerve is one of the most frequent and important causes of morbidity in thyroidectomies 1,2. A total of 6110 patients were operated in our hospital between 1 january 2005 and 31 december 20 for various goiters 5429. Anatomy of recurrent laryngeal nerve rln dent1 pbl 3. The recurrent laryngeal nerve provides motor innervation to the intrinsic muscles of the larynx, which provide the majority of movement of the vocal cords see fig.
In most series the incidence is reportedto beless than 1%. 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. Because of the inefficiencies of the routing the nerve takes, its often hailed as one of the most striking cases against intelligent design. She had no history of surgery or radiation to the head or neck. Recurrent laryngeal nerve injury produces an abductor laryngeal paralysis. Topography of the recurrent laryngeal nerve in relation to the thyroid artery. Compared to the recurrent laryngeal nerve, the superior laryngeal nerve and its. Anatomic relationship between right recurrent laryngeal. Innervation of the human cricopharyngeal muscle by the. Eleven adult cadavers 5 male6 female were dissected bilaterally to expose the path of the recurrent laryngeal nerve.
The recurrent laryngeal nerve rln, vagus nerve, external branch of the superior laryngeal nerve ebsln, and pharyngeal plexus pp were. Surgical anatomy and monitoring of the recurrent laryngeal nerve. A variant nerve that mimics the left recurrent laryngeal. Intro to human anatomy by professor fink introductory lecture to human anatomy by professor fink. Dec, 2014 recurrent laryngeal nerve the recurrent laryngeal nerve is a myelinated nerve. Injury to the recurrent laryngeal nerve is one of the most severe complications of thyroid surgery. But the argument that the anatomy of the recurrent laryngeal nerve is evidence for bad design fails on many levels. Therefore it is important for the thyroid surgeon to be mindful of such anatomical variations during surgery. 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. The recurrent laryngeal nerve carries somatic efferent axons to the larynx while the phrenic nerve carries somatic efferent fibers to the diaphragm.
The recurrent laryngeal nerve rln and the superior laryngeal nerve sln are branches of the vagus nerve cn x. The larynx voice box is an organ located in the anterior neck. Nonrecurrent laryngeal nerve nrln is a rare anomaly which is reported in 0. Abstract the mucosa of the larynx contains one of the most dense concentrations of sensory receptors in the human body. An anatomic study of anterior cervical dissection of 42 embalmed cadavers. Overall incidence of transient rlnp is reported to be 0. Finally, it ascends within the visceral compartment of the neck, behind the thyroid gland, between the esophagus and trachea. In the previous three posts see part 1, part 2, and part 3, weve seen that the arguments of intelligent design id critics based that the recurrent laryngeal nerve rln is an imperfect design fail for a variety of reasons. The structure of the larynx is primarily cartilaginous, and is held together by a series of ligaments and membranes. Recurrent laryngeal nerve an overview sciencedirect topics. The rln is composed by afferent and efferent myelin fibers and is responsible for subglottic sensitivity and for the innervation of the intrinsic laryngeal muscles, 25. Dec 27, 2018 the larynx will be paralyzed on the side where this nerve has been damaged, unless the problem originated with damage to the vagus nerve itself.
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. The sln external branch innervates the cricothyroid muscle, which tenses and adducts the vocal cords. Because of the anatomical variations of the nerve, preservation of the nerve is the optimal strategy during surgery. The left recurrent laryngeal nerve arises from the vagus trunk, as it passes in front of the aortic arch. Damage to this nerve during the surgical procedure may lead to severe iatrogenic morbidity. The most common complications of anterior neck surgery are dysphagia and rln palsy.
In this condition, which has a frequency of between. Chapter 33 surgical anatomy and monitoring of the recurrent laryngeal nerve gregory w. Jul 26, 2019 we hope this picture recurrent laryngeal nerve anatomy can help you study and research. Surgical anatomy and monitoring of the recurrent laryngeal. Laryngeal nerve palsy limits a patients quality of life by either temporary or even permanent disorders of the voice and dyspnea. Anatomic relation between the external branch of the superior. The cricothyroid muscles are innervated by the superior laryngeal nerve. It descends on the larynx, beneath the sternothyroid muscle, to supply the cricothyroid muscle. 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. The recurrent laryngeal nerve carries somatic efferent axons to the larynx while the phrenic nerve carries somatic efferent fibers to the diaphragm the connection between the vagus nerve and the pharyngeal arches that give rise to the larynx is established early in. Dysfunctions of the recurrent laryngeal nerve rln manifested as nerve.
Ta the terminal branch of the recurrent laryngeal nerve as the latter passes deep to the inferior pharyngeal constrictor. We describe a variant nerve in a human cadaver patient that parallels the. 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. Temporary laryngeal nerve palsy usually disappears within 6 months. Damage to this nerve during the surgical procedure may lead to severe iatrogenic morbidity and should therefore be prevented from being damaged. The connection between the vagus nerve and the pharyngeal arches that give rise to the larynx is established early in development. The recurrent laryngeal nerve supplies the larynx voice box. Several anatomic variations of the nerve increase the likelihood of iatrogenic damage. Recurrent laryngeal nerve the recurrent laryngeal nerve is a myelinated nerve. The recurrent laryngeal nerve can be a real challenge to the surgeon operating in its area. Larynx, laryngeal nerve, superior laryngeal nerve, recurrent laryngeal nerve injury, thyroidectomy, vagus nerve. The vagus nerve exists within the body as a pair, one on the right side and the other on the left. The nonrecurrent laryngeal nerve is an anomaly of the rln because its origin is cervical and it runs a direct course from the vagus nerve to the larynx without looping around any of the above named structures.
Exprofessor of human anatomy at the morphological science department. The anatomy of the recurrent laryngeal nerve is variable. This requires indirect laryngoscopy preoperatively, and, as soon as possible, postoperatively. Anatomy of the thoracic recurrent laryngeal nerves from a. A case study in human anatomy dickran altounian1, cathy tran2, christina tran1, allison spencer1, alexandra shendrik3, brian p.
External branch of the superior laryngeal nerve monitoring. Accurate diagnosis can be made only by visualizing the vocal cords while the patient is awake. A 50yearold woman was presented to our department with a nodule in the right thyroid lobe, and she reported no voice changes. 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. It is a branch of one of the cranial nerves, those nerves that lead directly from the brain rather than from the spinal cord. During the dissection of a 93yearold female cadaver by students in a medical gross anatomy course, an aberrant right subclavian artery with an associated nriln was found. Randolph the accident of hemorrhage is a minor evil. Non recurrent laryngeal nerve nrln is a rare anomaly which is reported in 0.
Recurrent laryngeal nerve radiology reference article. The larynx will be paralyzed on the side where this nerve has been damaged, unless the problem originated with damage. The recurrent laryngeal nerve does not refute intelligent design. In cases in which the subclavian artery arises dorsally either between the esophagus and trachea arteria lusoria or retroesophageal, the right recurrent laryngeal nerve branches passes directly downward and medially from the vagus nerve to the larynx. Evolution dictates a function for the design of the laryngeal nerve in his book why evolution is true, evolutionary biologist jerry coyne claims that imperfect design is the mark of evolution. Practitioners interested in maximizing the information obtained from laryngeal imaging must be familiar with laryngeal anatomy. Laryngeal nerve injury clinically oriented anatomy moore page 25. The nonrecurrent laryngeal nerve a rare phenomenon. Get free clinically oriented anatomy moore latest edition.
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