A Rare Case Of Bilateral Variant Ansa Cervicalis And Review Of Literature

Ansa cervicalis is a nerve loop that is embedded in the anterior wall of carotid sheath of the neck. It is formed bydescendent hypoglossi and descendens cervicalis. It supplies the infrahyoid muscles. During routine dissection,a rare variant in the morphology of Ansa cervicalis was observed in adult male cadaver. The variant ansacervicalis exhibited two loops, and was present bilaterally. The formation, course and relations of the nerve loopis complex. During literature search, we came across studies which propose different classifications. Hence wehave added a note on the different classifications.Ansa cervicalis is important since it can be used in nerve-nerve anastomosis, nerve-muscle pedicle implantationin relation to reconstructive surgeries of larynx. Hence, the knowledge of variations in the formation, anddistribution is relevant. It can affect the outcome during reinnervation surgeries following recurrent laryngealparalysis and surgeries around this area of neck.

Ansa cervicalis: a comprehensive review of its anatomy, variations, pathology, and surgical applications / 대한해부학회지

The ansa cervicalis is a neural loop in the neck formed by connecting the superior root from the cervical spinal nerves (C1–2) and the inferior root descending from C2–C3. It has various anatomical variations and can be an important acknowledgment in specific operations of the neck region. This is a review the anatomy, variations, pathology and clinical applications of the ansa cervicalis.

The efficacy of ansa cervicalis anterior root for unilateral recurrent laryngeal nerve injury / 中华耳鼻咽喉头颈外科杂志

Objective@#To discuss the long-term efficacy of laryngeal reinnervation using the anterior root of the ansa cervicalis in the treatment of unilateral vocal fold paralysis (UVFP) caused by thyroid surgery.@*Method@#From January 2010 to January 2016, a total of 39 UVFP patients who underwent ansa cervicalis anterior root-to-recurrent laryngeal nerve (RLN) anastomosis and who had suffered nerve disfunction for 6 to 24 months were enrolled as UVFP group.Another 39 age and gender matched normal subjects served as control group. Videostroboscopy, vocal function assessment (acoustic analysis, perceptual evaluation and maximum phonation time), and laryngeal electromyography were performed preoperatively and postoperatively for assessing surgery efficacy. Paired sample t test was used for statistical analysis.@*Result@#Videostroboscopic reports indicated that the glottic closure, vocal fold edge, vocal fold position, phase symmetry and regularity were significantly improved in the UVFP group (P<0.01, respectively, postoperative vs. preoperative)and showed no statistical differences compared to the control group (P>0.05, respectively). Both the postoperative GRBAS assessment and acoustic parameters were also significantly improved in the UVFP group, Pre-operative acoustic parameters/Post-operative acoustic parameters were 1.68±0.82/0.39±0.27, 10.08±2.56/4.58±2.96, 0.203±0.216/0.018±0.038, 5.96±1.92/17.42±4.11(P<0.01, respectively) and Pre-operative acoustic parameters/Post-operative acoustic parameters were 0.39±0.27/0.32±0.19, 4.58±2.96/3.32±1.27, 0.018±0.038/0.014±0.027, 17.42±4.11/18.76±5.29, which showed no statistical differences compared to the control group (P>0.05, respectively).@*Conclusion@#Delayed laryngeal reinnervation with the anterior root of ansa cervicalis, it can restore the physiological laryngeal phonatory function to the normal or a nearly normal voice quality, which is a feasible and effective approach for the treatment of thyroid surgery-related UVFP.

Schwannoma of Ansa Cervicalis in the Submandibular Space / 대한이비인후과학회지

Although schwannomas can arise from all types of nerves except the optic and olfactory nerves, those that arise from the ansa cervicalis is extremely rare, with only four cases having been reported worldwide. Because of their rarity, ansa cervicalis schwannomas are rarely considered in patients presenting with schwannomas of the neck region. In the present case, we did not consider ansa cervicalis as the nerve of origin preoperatively, but during the surgery, found a mass originating from the ansa cervicalis by identifying a contracture of the strap muscles. We thus address the need to consider ansa cervicalis as a possible original site in the evaluation and management of schwannomas of the neck region. In addition, surgeons should focus on the intraoperative findings to determine the nerve of origin and to anticipate postoperative complications, as well as performing appropriate preoperative imaging studies.

Anatomical variations in the Ansa cervicalis and innervation of infrahyoid muscles.

Background: – Infrahyoid muscles are supplied by the ansa cervicalis. The present study aimed to study the variations in the ansa cervicalis and the innervation of infrahyoid muscles. Methods: The study was conducted on 40 cadaveric hemi-necks. Results: Out of the 40 hemi-necks, high level of ansa cervicalis was observed in 2 hemi-necks, intermediate level of ansa was observed in 35 hemi-necks and low level of ansa was observed in 3 hemi-necks. Additionally, dual ansa with absence of inferior root was seen in 4 hemi-necks, dual ansa with absence of inferior root and inter-communication between C2 and C3 was seen in 2 hemi-necks, common trunk supplying all infrahyoid muscles including superior belly of omohyoid was seen in 2 hemi-necks, nerve to inferior belly of omohyoid from inferior root was seen on 1 side. In one specimen unilaterally, superior belly of omohyoid was innervated by a branch from hypoglossal nerve, two superior roots arising from hypoglossal nerve and the inferior root formed only by C3 was seen in the same specimen. Discussion: The knowledge of the possible variations of ansa in relation to the great vessels of the neck prevents the inadvertent injury to those vessels. Any injury can result to phonation disability in professional voice users. In case of infrahyoid muscles palsy, patients have no serious voice problems in their normal speech but the pitch of their voice and also prosody in their singing are lost dramatically. Conclusion: These variations are of clinical importance for the reconstructive surgeries which involve the infrahyoid muscles.

The Ansa Cervicalis in Fetuses / El Asa Cervical en Fetos

The formation of ansa cervicalis (AC) is somewhat complex with both its course and location along the common carotid artery and internal jugular vein (IJV) varying. The aim of the study was to document the anatomy, formation and variations of AC. Forty fetuses (gestational age: 15 to 28 weeks) were obtained from the Department of Clinical Anatomy, Westville Campus, UKZN. A detailed micro-dissection of the posterior triangle of the neck and AC were completed using standard micro-dissecting instruments. Results of the formation of AC, its relationship to IJV and variations were recorded. The superior root was identified as a long willowy nerve that branched from the hypoglossal nerve, descended on the carotid sheath, anterior to the common carotid artery and IJV in 70 % and posterior to IJV in 30 % of the specimens. The inferior root of AC originated from the ventral rami of C2-C3 in 26%; ventral ramus of C3 in 58% and ventral ramus of C2 in 16%. Variations: a) Formation: (i) Dual formation of AC: The Hypoglossal nerve formed separate loops with the ventral rami of C2 and C3 (3%); (ii) "W" shaped appearance of AC above the superior belly of omohyoid (1%); (iii) A "vago-cervical complex" 3%; b) Origin and course: The superior root of AC received a contribution from the hypoglossal nerve, a short distance later it formed a loop around the IJV to ascend to the ventral ramus of C2 as the inferior root. The precise understanding of the anatomy of AC together with variations may assist anesthetists and surgeons to accurately identify the vascular and neural relations during surgical procedures.

La formación del asa cervical (AC) compleja, tanto en su curso como en ubicación, pueden variar a lo largo de la arteria carótida común y de la vena yugular interna (VYI). El objetivo del estudio fue determinar la anatomía, formación y variaciones del AC en fetos humanos. Cuarenta fetos (edad gestacional: 15 a 28 semanas) fueron obtenidos desde el Departamento de Anatomía Clínica, Westville Campus, UKZN. En cada muestra se realizó una detallada microdisección del triángulo posterior del cuello y del AC utilizando instrumental de microdisección estándar. Fueron registrados los resultados de la formación del AC, su relación con VYI y sus variaciones. La raíz superior fue identificada como un nervio largo y delgado que se ramificaba desde el nervio hipogloso, descendía por la vaina carotídea, anterior a la a. carótida común y la VYI en el 70% de los casos, y posterior a la VYI el 30%. La raíz inferior del AC se originaba desde los ramos ventrales de C2-C3 en el 26% de los casos; desde el ramo ventral de C3 en el 58% y desde el ramo ventral de C2 en 16% de los casos. Se observaron variaciones de formación: (i) dual del AC: el nervio hipogloso formó asas separadas con los ramos ventrales de C2 y C3 (3%), (ii) forma aparente de "W" sobre el vientre superior del m. omohioideo (1%) y (iii) un "complejo vago-cervical" (3%), y variaciones de origen y curso: la raíz superior del AC recibió una contribución del nervio hipogloso, y a corta distancia formó un bucle alrededor de la VYI para ascender al ramo ventral de C2 como una raíz inferior. El conocimiento preciso de la anatomía del AC junto con variaciones pueden ayudar a identificar con precisión las relaciones vasculares y neuronales durante los procedimientos quirúrgicos a anestesistas y cirujanos.

Variant inferior root of ansa cervicalis / Variación de la raíz inferior del asa cervical

Ansa cervicalis is a loop of nerves found in the anterior wall of the carotid sheath in the carotid triangle of neck innervating infrahyoid muscles. Its superior root has fibres from the first cervical nerve that leaves the hypoglossal nerve and joins the inferior root formed by the branches from the second and third cervical nerves. The two roots join to form ansa cervicalis. The ansa cervicalis nerve formation is relatively complex, as its course and location along the great vessels of the neck vary. In the present case on the left side of an adult male cadaver the inferior root was absent and the contributions from C2 and C3 were joining independently with the superior root of ansa to form ansa cervicalis. However no such variation was found in the ansa cervicalis formation on the right side.

El asa cervical es un loop de nervios que se encuentra en la pared anterior de la vaina carotídea, en el triángulo carotídeo del cuello, que inerva los músculos infrahioideos. Su raíz superior tiene fibras del primer nervio cervical que sale del nervio hipogloso y se une a la raíz inferior formada por las ramas de los nervios cervicales segundo y tercero. Las dos raíces se unen para formar el asa cervical. La formación del asa cervical del nervio es relativamente compleja, ya que su curso y ubicación varía a lo largo de los grandes vasos del cuello. En el lado izquierdo del cuello de un cadáver adulto de sexo masculino, la raíz inferior del asa cervical estaba ausente y las contribuciones de los ramos de C2 y C3 se unieron, de forma independiente, con la raíz superior del asa y así formar el loop.

Anatomical variations of the ansa cervicalis in Thais.

The aim of this study was to examine the variation of ansa cervicalis in Thais in terms of its origin, formation and relation to the great vessels of the neck. Anatomical dissections were examined bilaterally in 108 cervical plexuses of Thai cadavers ranging in age from 34 to 87 years. There were 57 male and 51 female cervical plexuses. The ansa cervicalis which consists the first to third cervical ventral rami (C1-C3), is formed by the junction of the superior and inferior roots. Its anatomical course and morphology are complicated by the variable lengths, origins, and relations with the great vessels of the neck. Twenty types of ansa cervicalis were classified into 5 different groups according to the length of ansa loop as compared with the level of cricoid cartilage and the relation of the inferior root of the ansa to the internal jugular vein. Depending on the origins of the inferior and superior roots, each group consisted of various types. Group I and II had long ansa loops with the inferior root lying lateral to the internal jugular vein in group I, and nedial to the vein in group II. Similarly, group III and IV had short loops of the ansa with the inferior root lying lateral to the internal jugular vein in group III, and medial to the vein in group IV. However, group V was not related to the criteria. It was suggested that the majority of ansa cervicalis were found to be group IV and group I. The variation of ansa cervicalis patterns occurred in both sides. This was not statistically different with regard to either gender of side. The results of this study provide additional information and new insights into the variation of the ansa cervicalis which may have useful applications in laryngeal reinnervation surgery and anrsthesia.

Ansa cervicalis and herve to superior belly of omohyoid.

Eighty Cardavers were studied. The mean kength of nerve to superior belly of omohyoid was 4.37 cm., with the range varying from 1.39 to 8.26 cm. There was no trouble swinging part of superior belly of Omohyoid together with its nerve, to posterior surface of posterior cricoarytenoid. The pattern of a nsa cervicalis varied in many difference types not as simple as described in standard textbooks.