A case of the right aortic arch with the left subclavian artery as its last branch]

A case of the right aortic arch with the left subclavian artery as its last branch was found in an 80-year-old Japanese female cadaver during the 1990 dissection for students. The main findings were as follows. The ascending aorta arose from the left ventricle and ran right and upward to the level of the intervertebral disc between the 2nd and 3rd thoracic vertebrae. It then curved right and backward to form the aortic arch. The aortic arch joined the thoracic aorta that descended along the right side of the vertebral column and crossed obliquely the vertebral column at the level of the 8th thoracic vertebra. Finally it entered the abdomen through the aortic hiatus behind the esophagus. Four branches were given off from the aortic arch in the following order from left to right: the left common carotid, the right common carotid, and the right subclavian and the left subclavian arteries. The left subclavian artery, which had an aortic diverticulum at the origin of the aortic arch, ran left and upward behind the esophagus. The ligamentum arteriosum connected the left pulmonary artery with the aortic diverticulum of the left subclavian artery. The left common carotid artery, which normally had no branches before entering the cranium, gave off an accessory esophageal branch about 20 mm distally from its origin. The right and left vertebral arteries entered the transverse foramen of the 6th cervical vertebra. The left recurrent laryngeal nerve hooked around from the left dorsal to the right ventral part of the ligamentum arteriosum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Topological changes of the human autonomic cardiac nervous system in individuals with a retroesophageal right subclavian artery: two case reports and a brief review

The topological changes of the human autonomic cardiac nervous system in two cadavers with a retroesophageal right subclavian artery (Rersa) were compared with the normal autonomic cardiac nervous system. The following new results were obtained in addition to the conventional deficient finding of the right recurrent laryngeal nerve. (1) Right superior cardiac nerves arising from the superior cervical ganglion were consistently observed in both cadavers, in addition to the right thoracic cardiac nerves along the Rersa. (2) A segmental accompanying tendency of the right cardiac nerves was recognized: the cardiac nerves arising from the sympathetic trunk cranial to the middle cervical ganglia ran along with the right common carotid artery, whereas the cardiac nerves arising from the sympathetic trunk caudal to the vertebral ganglion ran along the Rersa. (3) The right thoracic cardiac nerves, which have never been observed to accompany the normal right subclavian artery, ran along the proximal part of the Rersa. According to previous reports of individuals with the Rersa, a thick right thoracic cardiac nerve is commonly observed instead of a right superior cardiac nerve. However, all the cardiac nerves were recognized in both the individuals described in the present report. Therefore, we strongly disagree with the previous idea that the origin of the right cardiac nerves from the sympathetic trunk and ganglia is shifted caudally in individuals with the Rersa. The topological changes of the autonomic cardiac nervous system in two cases of Rersa also reflected spatial changes of great arteries.     

A comparative morphologic study of the cardiac innervation in domestic animals I. The canine

Cardiac nerves arising from the cervical and thoracic sympathetic chain, the vagi, and the recurrent laryngeal nerves of the dog were described. The findings are correlated with the nomenclature of the NA ('66) and proposals of the NAV ('67), and additional suggestions are made when appropriate. Although individual cardiac nerves were followed to specific areas of the heart, additional supplies to these areas were noted from the cardiac plexus. Sympathetic cardiac innervation arose primarily from the vertebral ganglion. Cranial vagal cardiac nerves on the left and caudal vagal cardiac nerves on the right contributed the majority of the parasympathetic cardiac innervation. Right cardiac nerves ramified primarily along the right coronary artery, left descending branch of the left coronary artery, circumflex branch of the left coronary artery on the left surface of the heart, and onto the right atrium. Left heart nerves, in addition to their direct contributions to all but the last area, proceeded along the circumflex branch of the left coronary artery on the caudal and right surfaces of the heart. Right nerves contributed more in the area of the S.A node, while left nerves formed a network in the area of the coronary sinus and A.V. node. Both sympathetic and parasympathetic nerves were followed to each area. It was noted that pulmonary innervation via the cardiac plexus would be disturbed by the technique of cardiac denervation referred to as regional neural ablations.     

Functional anatomy of the major cardiac nerves in cats

In recognition of the extensive use of the cat as an experimental model of cardiac innervation, the effects of electrical stimulation of stellate ganglia, thoracic vagosympathetic complexes, and individual feline cardiopulmonary nerves on heart rate, blood pressure, and contractility in all four cardiac chambers were analysed and correlated with the anatomy of the thoracic autonomic nervous system. The right and left stellate ganglia in cats are relatively large and globular. Distinct dorsal and ventral ansae subclavia arise from these ganglia, connecting with the relatively small, spindle-shaped middle cervical ganglia situated in the apices of the thoracic cage bilaterally. A cranial pole nerve arises from each of the middle cervical ganglia and courses cranially to unite with the ipsilateral superior cervical ganglia. On each side, the major cardiopulmonary nerves arise from the middle cervical ganglion, the relatively large vagosympathetic trunk, and the stellate ganglion. On the right side these nerves consist of a very small right stellate cardiac nerve, a recurrent cardiac nerve, a group of craniovagal nerves and a group of caudovagal cardiopulmonary nerves. On the left side are the left stellate cardiac, ventrolateral, ventromedial, and innominate cardiopulmonary nerves. All of these nerves contain efferent parasympathetic and/or sympathetic fibers which modify cardiac chronotropism and/or inotropism. Some contain afferent fibers. These results indicate that specific cardiopulmonary nerves exist in cats, which when stimulated, modify the cardiovascular system in specific fashions.     

A comparative morphologic study of the cardiac innervation in domestic animals II. The feline

Detailed morphological studies of the cardiac innervation of the cat were reported. Sympathetic cardiac nerves arose from the thoracic, cervicothoracic, vertebral, and intermediate ganglia. Parasympathetic cardiac nerves arose from the vagi, both cranial and caudal to the origin of the recurrent laryngeal nerves, and from the right recurrent laryngeal nerve. Left cardiac nerves passed primarily to the caudal and right surfaces of the left chambers while right ones ramified on the right chambers and left portion of the left chambers. Left cardiac nerves are more prominent around the coronary sinus and atrioventricular node, while right ones contribute more to the area of the sinoatrial node. Both sympathetic and parasympathetic nerves were followed to each chamber. Interconnections through the cardiac plexus facilitated overlapping of nerve distributions.     

Morphological pattern of intrinsic nerve plexus distributed on the rabbit heart and interatrial septum

Although the rabbit is routinely used as the animal model of choice to investigate cardiac electrophysiology, the neuroanatomy of the rabbit heart is not well documented. The aim of this study was to examine the topography of the intrinsic nerve plexus located on the rabbit heart surface and interatrial septum stained histochemically for acetylcholinesterase using pressure‐distended whole hearts and whole‐mount preparations from 33 Californian rabbits. Mediastinal cardiac nerves entered the venous part of the heart along the root of the right cranial vein (superior caval vein) and at the bifurcation of the pulmonary trunk. The accessing nerves of the venous part of the heart passed into the nerve plexus of heart hilum at the heart base. Nerves approaching the heart extended epicardially and innervated the atria, interatrial septum and ventricles by five nerve subplexuses, i.e. left and middle dorsal, dorsal right atrial, ventral right and left atrial subplexuses. Numerous nerves accessed the arterial part of the arterial part of the heart hilum between the aorta and pulmonary trunk, and distributed onto ventricles by the left and right coronary subplexuses. Clusters of intrinsic cardiac neurons were concentrated at the heart base at the roots of pulmonary veins with some positioned on the infundibulum. The mean number of intrinsic neurons in the rabbit heart is not significantly affected by aging: 2200 ± 262 (range 1517–2788; aged) vs. 2118 ± 108 (range 1513–2822; juvenile). In conclusion, despite anatomic differences in the distribution of intrinsic cardiac neurons and the presence of well‐developed nerve plexus within the heart hilum, the topography of all seven subplexuses of the intrinsic nerve plexus in rabbit heart corresponds rather well to other mammalian species, including humans.     

The coronary vessels in the heart of a marsupial,Trichosurus vulpecula

The coronary arteries and veins are described in the phalanger (Trichosurus vulpecula), an Australian marsupial, after study of 16 hearts. Several hearts were prepared by injection of the vessels with either latex or vinyl plastic. The distributing branches of both coronary arteries are within the myocardium and are not visible on the surface of the heart. The right coronary artery arises in typical fashion and supplies the non-septal wall of the right ventricle almost entirely, the dorsal half of the interventricular septum, the dorsal part of the non-septal wall of the left ventricle and part of the right artium and its ventral auricle. The left coronary artery also arises typically and supplies the greater part of the non-septal wall of the left ventricle, the ventral part of the interventricular septum, part of the infundibulum, the left atrium and part of the right atrium. At its origin it is larger than the right coronary artery. The ventral and dorsal septal arteries have an unusual course lying in the subendocardial tissue of the right ventricle. It is believed that arteries in this position have not been described previously. The great cardiac vein opens directly into the right atrium. A typical coronary sinus is present but formed only from veins draining the dorsal aspect of the heart. It is concluded that the coronary circulation in T. vulpecula closely resembles that of the avian heart and is unlike both the monotreme and placental mammalian patterns.     

Contribution of the cervical sympathetic ganglia to the innervation of the pharyngeal arch arteries and the heart in the chick embryo

In the chick heart, sympathetic innervation is derived from the sympathetic neural crest (trunk neural crest arising from somite level 10–20). Since the trunk neural crest gives rise to sympathetic ganglia of their corresponding level, it suggests that the sympathetic neural crest develops into cervical ganglia 4–14. We therefore tested the hypothesis that, in addition to the first thoracic ganglia, the cervical ganglia might contribute to cardiac innervation as well. Putative sympathetic nerve connections between the cervical ganglia and the heart were demonstrated using the differentiation markers tyrosine hydroxylase and HNK‐1. In addition, heterospecific transplantation (quail to chick) of the cardiac and trunk neural crest was used to study the relation between the sympathetic neural crest and the cervical ganglia. Quail cells were visualized using the quail nuclear antibody QCPN. The results by immunohistochemical study show that the superior and the middle cervical ganglia and possibly the carotid paraganglia contribute to the carotid nerve. This nerve subsequently joins the nodose ganglion of the vagal nerve via which it contributes to nerve fibers in cardiac vagal branches entering the arterial and venous pole of the heart. In addition, the carotid nerve contributes to nerve fibers connected to putative baro‐ and chemoreceptors in and near the wall of pharyngeal arch arteries suggesting a role of the superior and middle cervical ganglia and the paraganglia of the carotid plexus in sensory afferent innervation. The lower cervical ganglia 13 and 14 contribute predominantly to nerve branches entering the venous pole via the anterior cardinal veins. We did not observe a thoracic contribution. Heterospecific transplantation shows that the cervical ganglia 4–14 as well as the carotid paraganglia are derived from the sympathetic neural crest. The cardiac neural crest does not contribute to the neurons of the cervical ganglia. We conclude that the cervical ganglia contribute to cardiac innervation which explains the contribution of the sympathetic neural crest to the innervation of the chick heart. Anat Rec 255:407–419, 1999. © 1999 Wiley‐Liss, Inc.     

Contribution of the cervical sympathetic ganglia to the innervation of the pharyngeal arch arteries and the heart in the chick embryo.

In the chick heart, sympathetic innervation is derived from the sympathetic neural crest (trunk neural crest arising from somite level 10-20). Since the trunk neural crest gives rise to sympathetic ganglia of their corresponding level, it suggests that the sympathetic neural crest develops into cervical ganglia 4-14. We therefore tested the hypothesis that, in addition to the first thoracic ganglia, the cervical ganglia might contribute to cardiac innervation as well. Putative sympathetic nerve connections between the cervical ganglia and the heart were demonstrated using the differentiation markers tyrosine hydroxylase and HNK-1. In addition, heterospecific transplantation (quail to chick) of the cardiac and trunk neural crest was used to study the relation between the sympathetic neural crest and the cervical ganglia. Quail cells were visualized using the quail nuclear antibody QCPN. The results by immunohistochemical study show that the superior and the middle cervical ganglia and possibly the carotid paraganglia contribute to the carotid nerve. This nerve subsequently joins the nodose ganglion of the vagal nerve via which it contributes to nerve fibers in cardiac vagal branches entering the arterial and venous pole of the heart. In addition, the carotid nerve contributes to nerve fibers connected to putative baro- and chemoreceptors in and near the wall of pharyngeal arch arteries suggesting a role of the superior and middle cervical ganglia and the paraganglia of the carotid plexus in sensory afferent innervation. The lower cervical ganglia 13 and 14 contribute predominantly to nerve branches entering the venous pole via the anterior cardinal veins. We did not observe a thoracic contribution. Heterospecific transplantation shows that the cervical ganglia 4-14 as well as the carotid paraganglia are derived from the sympathetic neural crest. The cardiac neural crest does not contribute to the neurons of the cervical ganglia. We conclude that the cervical ganglia contribute to cardiac innervation which explains the contribution of the sympathetic neural crest to the innervation of the chick heart.     

Anatomical study of a left single coronary artery with special reference to the various distribution patterns of bilateral coronary arteries

A left single coronary artery of heart was observed during anatomy practice at Kumamoto University School of Medicine in a 73-year-old female cadaver who died from a thalamic hemorrhage. The left single coronary artery, having a single orifice in the left aortic sinus, bifurcated into the anterior interventricular (IVa) and circumflex (CIR) arteries. No orifice of the right coronary artery was found on the aortic wall. Giving off a branch which traversed the upper part of the infundibulum to supply the anterior upper region of the right ventricle, the IVa descended in the anterior interventricular sulcus to supply the apex of the heart. The CIR curved leftwards in the atrioventricular sulcus to reach the posterior surface, after which it continued to emerge again into the anterior surface. The atrial arteries showed no anomalous distribution pattern and histological observation revealed no pathological abnormality other than a slightly thickened tunica intima. Furthermore, we observed the distribution patterns of bilateral coronary arteries in 377 hearts dissected during anatomical practice over 13 years at Kanazawa University (1980–1986) and Kumamoto University (1993–1998). Although the reason why only the right coronary artery was absent is left unexplained, it was concluded that the left single coronary artery in this study, having the developed left conal and circumflex branches, was an extreme case of the left dominant series of coronary arteries. The formation of single coronary arteries can be explained embryologically by the change of flow in the capillary plexus established on the ventricle wall.     

Neuroanatomy of the Pig Cardiac Ventricles. A Stereomicroscopic,Confocal and Electron Microscope Study

Although the pig is a model for heart disease, the neuroanatomy of cardiac ventricles (CV) in this species remains undetailed. We aimed to define the innervation pattern of pig CV, combining histochemistry for acetylcholinesterase, immunofluorescent labeling and electron microscopy. Forty nine examined pig hearts show that the major nerves supplying the ventral side of CV descend from the venous part of the heart hilum. Fewer in number and smaller in size, epicardial nerves supply the dorsal half of the CV. Epicardial nerves on the left ventricle are thicker than those on the right. Ventricular ganglia of various sizes distribute at the basal level of both CV. Averagely, we found 3,848 ventricular neuronal somata per heart. The majority of somata were cholinergic, although ganglionic cells of different neurochemical phenotypes (positive for nNOS, ChAT/nNOS, or ChAT/TH) were also observed. Large and most numerous nerves proceeded within the epicardium. Most of endocardium and myocardium contained a network of nerve bundles and nerve fibers (NFs). But, a large number of thin nerves extended along the bundle of His and its branches. The majority of NFs were adrenergic, while cholinergic NFs were scarce yet more abundant than nitrergic ones. Sensory NFs positive for CGRP were the second most abundant phenotype after adrenergic NFs in all layers of the ventricular wall. Electron microscopy elucidated that ultrastructure of nerves varied between different areas of CV. The described structural organization of CV provides an anatomical basis for further functional and pathophysiological studies in the pig heart. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1756–1780, 2017. © 2017 Wiley Periodicals, Inc.     

Reflex Relaxation of the Stomach Elicited from Receptors Located in the Heart. An Analysis of the Receptors and Afferents Involved.

In cats anesthetized with chloralose electrical afferent stimulation of the right cardiac nerve promptly elicited marked hypotension, bradycardia and relaxation of the stomach. Stimulation threshold and conduction velocity measurements indicated that the stimulated afferents were unmyelinated fibres. The circulatory and gastric responses were abolished by cervical vagal blockade on the stimulation side. Administration of nicotine intrapericardially or veratrum alkaloids i.v. produced similar circulatory and gastric responses as the electrical nerve stimulation. The effects of veratrum were markedly reduced upon application of a local anesthetic in the pericardial cavity. Reflex gastric relaxation was also elicited in response to occlusion of the ascending aorta or mechanical stimulation of the left ventricle. With occlusion of the pulmonary artery only slight gastric responses were obtained during the occlusion. Pronounced gastric responses were recorded upon occlusion of a coronary artery, the effect being abolished by section of the vagi in the neck. – It is concluded that marked reflex relaxation of the stomach can be elicited from heart receptors, probably located in the left ventricle and with unmyelinated afferents in the vagi. It is suggested that the described reflex gastric response may form part of a vomiting pattern.     

Tachypnea after stimulation of afferent cardiac sympathetic nerve fibers.

The role of afferent cardiac sympathetic nerve fibers in the regulation of respiration has been examined. Application of potassium chloride or lactic acid solutions to the left ventricular surface of anesthetized vagotomized dogs resulted in a decrease in the manimum firing rate and shortening in period duration of firing of phrenic nerves. Also, application of the agents caused a decrease in amplitude and an increase in rate of respiratory thoracic movements. The same changes in phrenic nerve activity and respiratory movements were produced by coronary artery occlusion and centrifugal electrical stimulation of the left inferior cardiac nerves. The results indicate tachypnea that can be produced by excitation of afferent cardiac sympathetic nerve fibers.     

Investigation of coronary arteries in the porcupine (Hystrix cristata) by latex injection and angiography

Coronary arteries were investigated in the porcupine by means of angiography performed on each of 5 adult porcupines (3 male, 2 female) which was followed by injection of a colored latex mixture from the aortic arch for the demonstration of these arteries. The results showed that the aorta branched out at the level of the cardiac outlet to form the left and right coronary arteries and right ramus coni arteriosi. Coronary arteries coursed and ramified in the myocardium. The left coronary artery divided to form the paraconal interventricular artery and left circumflex artery when it reached the coronary sulcus. The interventricular septum was vascularized by the septal branch of the paraconal interventricular artery and by the small septal branches. The left and right coronary arteries gave off all the branches reported in the literature for other species. When the ramus coni arteriosi originates from the right coronary artery, it is designated a third coronary artery. In conclusion, it was found that the coronary arteries of the porcupine had an "intramyocardial course" as in other rodents. The coronary supply of the heart represented a "left coronary type" which was similar to those of carnivores and ruminants. The results of this study may contribute to the data in this area of science.     

A case of the scalenus anterior muscle passing behind the left subclavian artery

The scalenus anterior muscle was found to pass behind the left subclavian artery and the first thoracic nerve in a 95-year-old Japanese woman. The scalenus anterior muscle originates from the fifth and sixth cervical vertebrae and inserts on the first rib more dorsal than typical. It is innervated by the fifth and seventh cervical nerves. The muscle belly is thin. The scalenus minimus was not found. The left vertebral artery originates from the aortic arch and enters the transverse foramen of the fifth cervical vertebra. The primary vertebral artery arises from the costocervical artery. The internal thoracic artery originates from the subclavian artery more distally than typical. The axillary artery crosses the brachial plexus between the eighth cervical and first thoracic nerves. Because the first thoracic nerve joins the brachial plexus more distally than usual, the plexus has no typical inferior trunk. Comparative anatomy shows that the muscles, nerves and arteries of the lateral cervical region of the present case maintains primitive characteristics. From the functional viewpoint, the mechanical efficiency of the scalenus anterior muscle is probably lower than usual due to the lower point of origin and the dorsal shift of the insertion.