The recurrent laryngeal cardiac nerve in fetuses / El nervio laríngeo recurrente cardiaco en fetos

The recurrent laryngeal nerve has been reported to supply cardiac branches to the cardiac plexus. A review of anatomical literature on the existing term used to describe these branches revealed that varying interpretations and descriptions exist among various authors. Therefore, this study aimed to investigate the origin and incidence of branches from the recurrent laryngeal nerves to the cardiac plexus and their connections with sympathetic cardiac nerves. The sample comprised 40 cadaveric fetuses (n=80) (gestational ages: 16-30 weeks). The recurrent laryngeal cardiac nerve was described as the cardiac branch that originated directly from the recurrent laryngeal nerve and reached the superficial or deep parts of the cardiac plexus. This study found the recurrent laryngeal cardiac nerve in 76% of the cases contributing direct and indirect branches in 75% and 25% of the cases, respectively. This study recorded only two (2%) of these branches contributing to the superficial cardiac plexus while the rest (74%) of these branches contributed to the deep cardiac plexuses. The remaining 24% had no contributions from the recurrent laryngeal nerve to either the superficial or deep part of the cardiac plexus. The most common point of origin for the recurrent laryngeal cardiac nerve was at the lower distal part in 59% of the specimens. In the remaining 41% of branches, this nerve originated from the point of curvature, upper proximal part and both the point of curvature and lower distal part in 26%, 10% and 5% of the specimens.

El nervio laríngeo recurrente suministra las ramas cardiacas para el plexo cardíaco. Una revisión de la literatura anatómica nos muestra que existen diferentes interpretaciones y descripciones de estas ramas por parte de los distintos autores consultados. En consecuencia este estudio tuvo como objetivo investigar el origen, además de la incidencia de las ramas de los nervios laríngeos recurrentes al plexo cardíaco y sus conexiones con los nervios cardiacos simpáticos. La muestra incluyó 40 fetos (n=80) (edades gestacionales: 16-30 semanas). El nervio laríngeo recurrente cardiaco fue descrito como la rama cardíaca que se originó directamente del nervio laríngeo recurrente, que llega a las partes superficiales o profundas del plexo cardíaco. En este estudio observamos que el nervio laríngeo recurrente cardiaco en el 76% de los casos contribuye a las ramas directas e indirectas, en el 75% y el 25% de los casos, respectivamente. Se observó en este estudio que solamente dos (2%) de estas ramas contribuían en la formación del plexo cardíaco superficial, mientras que el resto (74%) de estas ramas contribuía a los plexos cardíacos profundos. El 24% restante no tenía contribuciones del nervio laríngeo recurrente ya sea para la parte superficial o profunda del plexo cardíaco. El punto de origen más común del nervio laríngeo recurrente cardiaco se observó en la parte distal inferior en un 59% de las muestras. En el 41% restante de las ramas este nervio se originó desde el punto de curvatura, la parte proximal superior y tanto en el punto de curvatura inferior como la parte distal en 26%, 10% y 5% de los especímenes.

The Sympathetic and Parasympathetic Contributions to the Cardiac Plexus: a Fetal Study / Contribuciones Simpáticas y Parasimpáticas al Plexo Cardíaco: Estudio Fetal

The cardiac plexus is formed by sympathetic nerves originating from the superior, middle, inferior cervical or cervicothoracic ganglia as well as from the first to the fifth thoracic ganglia. Furthermore, the vagus nerve and its counterpart, the recurrent laryngeal nerve supply the cardiac plexus with parasympathetic cardiac nerves. This investigation aimed to review and record the medial contributions of the cervical ganglia, first to fifth thoracic ganglia and medial contributions of the vagus and recurrent laryngeal nerves to the cardiac plexus. The study involved bilateral micro-dissection of forty cadaveric fetal specimens (n=80). The origins of sympathetic contributions to the cardiac plexus were described as either ganglionic, inter-ganglionic or from both the ganglion and the inter-ganglionic sympathetic chain. The number of cervical sympathetic ganglia varied from two to five in this study; the superior cervical ganglion was constant while the middle cervical, vertebral, inferior cervical or cervicothoracic ganglia were variable. The prevalence of cardiac nerves were as follows: superior cervical cardiac nerve (95%); middle cervical cardiac nerve (73%); vertebral cardiac nerve (41%); inferior cervical cardiac nerve (21%) and cervicothoracic cardiac nerve (24%). This investigation records the thoracic caudal limit of the thoracic sympathetic contributions to the cardiac plexus as the T5 ganglion. The findings of this study highlight the importance of understanding the medial sympathetic contributions and their variations to the cardiac plexus as this may assist surgeons during minimal access surgical procedures, sympathectomies, pericardiectomies and in the management of diseases like Raynaud's Phenomenon and angina pectoris.

El plexo cardíaco está formado por los nervios simpáticos procedentes de los ganglios cervicales superior, medio e inferior o cervicotorácico, así como los ganglios torácicos desde el primero al quinto. Por otra parte, el nervio vago y su contraparte, el nervio laríngeo recurrente suministra al plexo cardíaco nervios cardíacos parasimpático. Esta investigación tuvo como objetivo revisar y registrar las contribuciones mediales de los ganglios cervicales, ganglios torácicos del primero al quinto ganglios y contribuciones mediales de los nervios laríngeos recurrentes y vagos en el plexo cardíaco. Se realizó la micro-disección bilateral de cuarenta especímenes cadavéricos fetales (n = 80). Los orígenes de las contribuciones simpáticas hacia el plexo cardíaco se describen de forma independiente como ganglionar o inter-ganglionar, o desde ambos ganglios y la cadena simpática interganglionar. El número de ganglios simpáticos cervicales varió de dos a cinco; el ganglio cervical superior fue constante, mientras que los ganglios medio-cervical, vertebral, cervical inferior o cervicotorácico fueron variables. La prevalencia de los nervios cardíacos fueron: nervio cardíaco cervical superior (95%); nervio cardíaco cervical medio (73%); nervio cardiaco vertebral (41%); nervio cardíaco cervical inferior (21%) y nervio cardíaco cervicotorácico (24% ). La investigación registró el límite torácico caudal de las contribuciones torácicas simpáticos al plexo cardíaco como el ganglio T5. Los resultados de este estudio muestran la importancia de comprender las contribuciones simpáticas mediales y sus variaciones en el plexo cardíaco, ya que podrían ayudar a los cirujanos durante los procedimientos quirúrgicos mínimanente invasivos, simpatectomías, pericardiectomías y en el manejo de enfermedades como el fenómeno de Raynaud y la angina de pecho.

IMMUNOHISTOCHEMICAL RESEARCH ON CGRP AND SP IN THECANINE MAIN SUPERFICIAL CARDIAC PLEXUS / 解剖学报

Objective To investigate the chemical properties of superficial cardiac neurons. Methods By means of immunohistochemical ABC technique,the study was performed concerning the distribution of calcitonin gene-related peptide(CGRP) and substance P(SP) in the canine main cardiac superficial plexus. Results CGRP-immunoreactive(IR) neurons were found in every plexus,but SP-IR neurons could be observed only in dorsal atria plexus(DAP),inter atria plexus(IAP) and aorta-pulmonary plexus(A-PP).The shape and size of CGRP-IR and SP-IR neurons were similar.The comparative study on atria and ventricles indicated that CGRP-IR and SP-IR neurons in atria were more than those in ventricles.Numerous CGRP-IR,SP-IR nerve fibers could be observed in each fat pats and intermyocardiocytes.These nerve fibers were usually situated near blood vessels,or were attached to vessel wall.Somewhat CGRP-IR and SP-IR nerve fibers were connected with myocardiocytes in some regions.Conclusion The results indicated that actually existed two peptides in canine cardiac superficial plexus.These implied that the regulations of the two kinds of peptidergic neurons to atria and ventricle were different.The two kinds of neurons mentioned above were likely to perform different or similar functions in canine heart.CGRP and SP could possibly modulate the activities of myocardiocytes and vessels of heart directly.