Septomarginal Trabecula Research Articles

Myoendocardial formations of the chambers of the heart of the water deer (Hydropotes Inermis) in statistics

This article is a continuation of a series of studies devoted to a fairly new animal species for the Russian Federation – the water deer (Hydropotes inermis argyropus). This representative of the animal world was recorded not so long ago in the expanses of the Far Eastern taiga, but is already listed in the Red Book of Russia. The water deer spreads its habitat from China and Korea, which are traditional for it, and is still not numerous for our country, but it is already becoming an object of illegal extraction for poachers. The Diagnostic Center of the Primorsky State Agricultural Academy receives cadaverous material from a water deer for examination, as part of the investigation and legal proceedings, which also allows to study its morphology. In the process of forensic veterinary examination, standard methods for studying morphometric features of the organism are applied to the material. The organs are measured, photographed with a description of all the noted features. In the process of writing the article, we studied three hearts from animals of both sexes, aged 2-3 years. It was found that the morphometric parameters of the heart within the group varied slightly. The heart is well developed, the index corresponds to a spherical shape. The architectonics of myoendocardial formations is quite stable in its structure in animals of the studied group, they are recognizable when working with each new heart of a water deer. The heart of a water deer is rounded, with a pointed tip, has pronounced auricles of the atria, while the right one is slightly larger than the left one. The ratio of the thickness of the walls of the left and right ventricles is 2:1, respectively. Similar indicators of the walls of the atria vary slightly. The heart of a water deer is distinguished by a well-defined trabecular system, the scallop muscles of the atria and the fleshy trabeculae of the ventricles have a pronounced comblike structure. The absence of a caudal septomarginal trabecula in the right ventricle was noted, however, its role is performed by a network of tendon-shaped trabeculae located between the interventricular septum and the caudal wall, forming several tiers.

Morphology features of the endocardial structures of the right ventricle of the Siberian roe deer heart

Hemodynamics of blood through the heart is carried out in one direction, where the diastole of the heart is replaced by a systole, and promotes the movement of blood through the circulatory circles. An important role in this is played not only by the heart valves, which restrain the movement of blood into the atria (sash) and ventricles (aortic valve and pulmonary artery), but also by myoendocardial formations and respiratory motility organs. In the available literature, the specific features of the heart in different animal species have been determined, however, no descriptions of the anatomy of endocardial formations of the right ventricle of the heart have been found in males of the Siberian roe deer.To assess the morphometric structures, hearts from 18-month-old Siberian roe deer males (n=3) obtained on the territory of the hunting grounds of the Irkutsk region were used. The heart has an ellipsoid shape, where the right ventricle is located above the level of the rounded tip of the left ventricle. Its internal structure is characterized by pronounced trabeculation, where two folding trabeculae are defined from the side of the free wall, which prevent the overgrowth of the fibrous ring. Among the relief of the right ventricle of the heart of the Siberian roe deer, four papillary muscles are distinguished – large, small, subterranean and additional, with certain morphological forms and indicators.Muscles give up to 24-27 tendon strings to the valve flaps. The septomarginal trabecula connects the base of the large papillary muscle and the interventricular septum, and three to four tendon cords between the septum and the ventricular wall.The greatest value of the height of the tricuspid valve flap was noted at the wall, and the width of the fastening and thickness at the partition flaps. The presence of two or three intermediate flaps was noted, which differ in smaller sizes (height - 9.5 ± 0.71; width – 10.2 ± 0.21 and thickness – 0.19 ± 0.01 mm).

Coronary type of blood supply to the calf's heart

The high variability of branching of the heart vessels in animals is a proven and irrefutable fact in veterinary morphology. In individuals of the same species and breed, quite high discrepancies can sometimes occur in the topography of the coronary arteries of the heart. When studying the coronary bed of the heart of animals, we recorded a case of the presence of a right-handed type of blood supply in a two-month-old Blackand- White calf in the absence of a left coronary artery. In this regard, we set ourselves the goal of studying the features of the vascularization of the right half of the heart in a two-month-old Black-and-White calf with a right-sided type of blood supply.To achieve this goal, the heart of the corpse of a two-month-old Black-and-White calf, obtained from a private farm in the Leningrad Region, was studied. The study was conducted at the Department of Animal Anatomy, St. Petersburg State University of Veterinary Medicine. To study the vascularization of the heart of the studied animal, classical and modern anatomical techniques were carried out, such as fine anatomical preparation, photography, and the manufacture of corrosion preparations using latex.According to the results of the study, it was found that in the absence of the left coronary artery in the studied two-month-old calf of the Black-and-White breed, the right coronary artery completely and completely compensates for its absence. The presence of the right interventricular artery was established, which has such branches as the artery of the right septomarginal trabecula and atrioventricular branches that supply blood to the tricuspid valve area and the right septomarginal trabeculae of the heart. It was determined that the vessels that vascularize the structures of the right atrium and right ventricle in their topography in the studied individual are inferior in the number of S-shaped bends and sharp corners in comparison with the arteries of the left half of the heart, which can reduce the risk of developing coronary pathologies in the right half of the heart. It was established that the subsinus artery differs from the generally accepted classical topography and plunges into the thickness of the myocardium of the right ventricle and interventricular septum, and practically does not pass as part of the subsinus sulcus.

Some features of the morphology of the heart (nasua nasua)

Nasua nasua is a representative of the forests of South America, and is also kept as a zoo animal. The animals have a pronounced mobile and long nose, a fluffy long tail, as a means of signaling; strong claws on the pectoral limbs, which serve not only to move through trees, but also to get food. Currently, there are isolated works on the morphology of the abdominal aorta of this type, but no features of the morphology of the heart have been found, which was the purpose of our study. The material was preserved in a 10% formalin solution of the heart, taken in different years from sexually mature noses received from the Irkutsk Zoo Gallery and the Siberian Zoo of Irkutsk. Classical methods of morphological research were used in the work: fine dissection, morphometry of the heart and its structures, description, sketches and photographing. According to the results of the studies, it was found that the average value of the absolute mass of the heart was 18.2 ± 0.33 g, has an ellipsoid shape, and the ratio of the thickness of the ventricles is at the level of 1:2.8. The internal structure of the right atrium is built of five scallop muscles of the 1st order and nine of the 2nd order, and four scallop muscles of the 1st order and eight of the second order participate in the relief of the left atrium. The shape of the auricle at the right atrium of the heart is 1.5 times greater than the value of the left atrium. In the left ventricle of the heart there are three papillary muscles (cranial and two caudal) with 21-24 tendon strings, and in the right ventricle there are six papillary muscles that carry up to 31 tendon strings on their surface. The septomarginal trabecula connects the parietal pedicle of the accessory and the base of the large papillary muscle.

The Heart of the Killer Whale: Description of a Plastinated Specimen and Review of the Available Literature.

Simple SummaryThe killer whale (Orcinus orca, Linnaeus, 1958) is an odontocete and is the largest member of the family Delphinidae. Free-ranging animals are capable of considerable physical efforts, either as acute bursts or sustained speeds during foraging, diving or protracted long-distance migrations. In this article, the morphology of a plastinated heart of a killer whale and functional adaptations of the gross anatomy in the context of a variety of physiologic demands is evaluated. The four chambers, their content, respective openings and communicating passages are defined based on a specimen used for plastination and thus available for extended and detailed anatomic studies.The killer whale (Orcinus orca, Linnaeus, 1958) is the largest extant delphinid. Despite its worldwide distribution in the wild and in dolphinariums, its anatomy remains relatively poorly described. In the present study, we describe the detailed morphology of a plastinated killer whale heart. The gross description of the arteries and veins reaching the organ and its coronary vessels are reported. Additional endoscopy and CT (computed tomography) scanning were performed to provide extensive measurements of its parts. In many aspects, the killer whale heart conformed to other delphinid heart descriptions, including position, relative size and shape and specific features such as extensive papillary muscles, trabecular endocardium and trabecula septomarginalis. These characteristics are representative of the delphinid family, suggesting that its functions and capacities are similar to that of other, smaller, dolphins and help understand the conditions in which these predators exert their remarkable physical performance necessary for their survival.

The morphometric study of the moderator band in Thais.

A moderator band, also known as the septomarginal trabecula, is a group of muscle bundles located in the ventricle of almost all human hearts. The morphology of the moderator band has various forms and several studies have focused mostly on its structure. Thus, in the present study, we sought to study the morphology and morphometry of the moderator band and tried to rearrange the criteria based on the previous studies to classify the moderator band in Thais. The study investigated 67 formalin-fixed human hearts of both sexes obtained from Thai donors aged 24-101years with mean age at death 69.92years. The moderator band was evident in 66 of the 67 specimens (98.51%). The moderator band had the mean or median of overall length, thickness, distance to the base of the tricuspid valve, distance to the base of the pulmonary valve, distance to the apex of the right ventricle, the angle at the septal connection, and angle of the papillary, which were 18.9 ± 6.4mm, 3.17 (2.04-4.55) mm, 33.0 ± 7.97mm, 38.8 ± 9.62mm, 56.4 ± 8.09mm, 50 (30-105)°, 73.9 ± 30.1°, respectively. The mean distance originating point from the supraventricular crest to the anterior papillary muscle was 0.396 ± 0.07 of the distance from the base of the tricuspid valve to the apex of the right ventricle. Our present classification found that crest-like and thick moderator band with complex secondary branching at high origin (type IVc), and low origin (type IVd) were the most common subtypes. This study provided both anatomical and clinical information that should be useful in cardiac surgery, radiology, and cardiac electrophysiological interventions.

Morphological Study of the Heart of the Indonesian Short-Nosed Fruit Bat (Cynopterus titthaecheilus)

Abstract. Rahma A, Hanadhita D, Prawira AY, Kasmono S, Maheshwari H, Satyaningtijas AS, Agungpriyono S. 2020. Morphological study of the heart of the Indonesian short-nosed fruit bat (Cynopterus titthaecheilus Temminck, 1825). Biodiversitas 21: 5094-5101. The energy demand of an animal becomes an important factor that affects the adaptation of cardiac or heart anatomy. As the largest Cynopterus bat in Indonesia, Cynopterus titthaecheilus (Temminck, 1825) is one of the flying mammals that need a lot of energy to accommodate its flying activity. This study aims to acknowledge the anatomical adaptation of the heart in C.titthaecheilus, which includes the weight ratio of the heart, heart structure, and primary blood vessel branches. This study conducted of 10 juvenile C. titthaecheilus (56.15±13.43 g), 13 females (74.38±10.34 g), and 18 males (73.27±13.54 g). Bats ware killed by ketamine overdoses, then the thoracic cavity was opened and the heart was removed from the thoracic cavity for observation. The results of this study revealed that the ratio of heart mass to body mass of adult female C. titthaecheilus was 0.014, male adult C. titthaecheilus was 0.015 and juvenile C. titthaecheilus was 0.015. The heart-shaped was an oval, located in the thoracic cavity, tilted to the left. On the other hand, the heart structure of C. titthaecheilus consisted of a thicker left ventricle compared to the right ventricle, but the musculi pectinati, musculus papillaris, and trabecula septomarginalis were well developed on the right side of the heart compared to the left side. Subsequently, the branches of the primary blood vessels in the heart consisted of an aortae ascendens, three arteria pulmonalis dextra and one arteria pulmonalis sinistra, a vena pulmonalis, the vena cava anterior dextra et sinistra, and a single vena cava posterior. In addition, the conus arteriosus, which is an enlarged space of the pulmonary artery, was observed in a large size. Based on this study, it was concluded that the heart structure of C. titthaecheilus was very important in supporting their ability to fly.

Multiple ventricular bands and the associated trabecula septomarginalis dextra in the right ventricle of the domestic dog (Canis familiaris).

Ventricular bands are strand-like intraventricular structures extending between adjacent papillary muscles; a papillary muscle and the ventricular wall or the interventricular septum and ventricular wall. Examination of the domestic dog right ventricle documented six ventricular band types. Eighty-five of the 89 examined hearts had at least one right ventricular band. In the current study, the right ventricle of the 85 dog hearts was re-examined for more than one ventricular band type. Seven patterns of multiple different bands were identified in the 24 dog hearts. The patterns (i.e., combinations) of different ventricular bands were grouped into three categories. Category 1 had five different patterns of bands. Each pattern had two different band types. Category 2 had one combination of three different bands. Category 3 had one combination of four different bands. The presence of right ventricular bands around the trabecula septomarginalis dextra was also documented. All 24 dog hearts with multiple ventricular bands had a trabecula septomarginalis dextra. The main goal of this study was documentation of multiple right ventricular band patterns. A secondary goal was documentation of the combined presence of these bands and a trabecula septomarginalis dextra. In the dog, the ventricular bands and trabecula are both thin, strand-like intraventricular structures with variable branching patterns before blending into the ventricular wall. The gross similarity of these structures and lack of information on their combined presence could precipitate their misidentification.

Histological and anatomical variations of septomarginal trabecula in bovine hearts.

The use of hearts from different animals as models in the experimental pharmacology and surgical clinic has led, in recent years, to an increase on interest of research with this organ. The heart's conducting system, from the septomarginal trabecula, presents several variations, which generates numerous controversies in the literature. So, the objective of the present study is to analyse the morphology of the septomarginal trabecula of bovine hearts, identifying possible macro- and microscopic variations. Thirty-four bovine hearts were analysed. Each trabecula was analysed macroscopically to obtain an anatomical description and measurements of its length and thickness. For histological and morphometric analysis, the samples were fixed in Bouin's solution and then subjected to histological processing. In all the analysed bovine hearts, the septomarginal trabecula presented itself as a smooth, tubular meaty structure of muscular consistency, with variable length and diameter. The anatomical variations observed included a trabecula with forked marginal fixation, and single septal fixation, in addition to a trabecula with extremely reduced or excessively thick caliber. The septomarginal trabecula consists of cardiac muscle fibres, connective tissue, vascular tissue and conduction myofibrils or Purkinje fibres. In the samples of smaller thicknesses, there was a predominance of connective tissue and scarce cardiac muscle tissue, whereas in the thicker samples the predominance was of cardiac striated muscle tissue. Therefore, there are significant macro- and microscopic differences between the bovine septomarginal trabecula concerning their diameter and constituent tissue, and that can lead to possible changes in cardiac physiology.

Individual variability of vascularization of the anterior papillary muscle within the right ventricle of human heart.

BackgroundTo date there is scarce published evidence reporting the dual blood supply reaching anterior papillary muscle (APM), which descends from both major coronary arteries. Such a vascular configuration can prevent the dysfunction of right ventricular entire valvular system in case of the occlusion of proximal part of either right coronary artery (RCA) or left coronary artery (LCA). The aim of our study was to determine the vascular pattern of APM blood supply which originates from two main coronary arteries, in the context of the APM and septomarginal trabecula (SMT) topography.MethodsThe study was carried out using tissue obtained from 36 human hearts. The material was divided into four morphological types of SMT/APM arrangement. Vascularization and blood supply pattern of papillary muscle was investigated following the analysis of multiple tissue cross sections. The origin of APM arterial supply was traced back to both main coronary arteries. Cross-sectional area of the arteries was estimated at the base of APM and compared within mixed male-female population, aged 18–76.ResultsWe noted that as much as 78% of entire APM material had a blood supply vasculature originating from both LCA and RCA branches. In contrast, 22% of cases APM was supplied by a single coronary artery, while in each case it proved to be LCA. We have never found APM arterial supply provided exclusively by RCA. In case of double AMP blood supply an average of total cross-section area of the arteries branching from LCA, was noted to be in excess of two and a half times bigger in type III and more than two times bigger in type IV, as compared with the arteries originating from RCA.ConclusionsOur research confirm the possibility of double blood supply which vascularizes APM, but the finding does not necessarily apply in all cases. However, APM seems to be predominantly vascularized by arteries deriving from LCA, regardless of their morphological type.

The artery of Mouchet: blood supply of the septomarginal trabecula in 50 human hearts.

The septomarginal trabecula is a muscular structure which transmits the right branch of the atrioventricular bundle. It is usually supplied by a branch from the second anterior septal artery. Anastomoses between the right and left coronary arteries may happen on the septomarginal trabecula. They are of great significance in order to prevent ischemia during a myocardial infarction. Surgeries such as Konno's and Ross' procedures implies in knowledge of these vessels anatomy. The coronary arteries of 50 human hearts were injected with latex and subsequentely dissected with the purpose of identifying the arterial branch that supplied the septomarginal trabecula. The trabecular branch arose from the second anterior septal artery in 38% of cases, and the branch arose from the first anterior septal artery in 26%. One of the hearts had its septomarginal trabecula supplied by the conus arteriosus arteryliterature. Anastomoses between the right and left coronary arteries were found inside the septomarginal trabecula. The right branch of the atrioventricular bundle is subject to a great number of clinical conditions and is often manipulated during surgery, thus, the study of the septal branches of the coronary arteries and the trabecular branch is essential.

Variations in vascular anatomy and unilateral adrenal agenesis in a female cadaver with situs inversus totalis.

Situs inversus totalis is mirror transposition of thoracic and abdominal organs. Very few reports have been published on anatomic dissections of cadavers with this condition. This work describes a case of situs inversus totalis identified during the anatomical dissection of a 91-year-old woman. Thoracic and abdominal viscera were inverted, but otherwise normal. The aorta originated from the right ventricle, which exhibited characteristics of the systemic ventricle. The pulmonary artery originated from the left ventricle, which had a tricuspid valve, three papillary muscles, thick trabeculae, a supraventricular crest, and septomarginal trabecula. The atrial situs was concordant with ventricular morphology. Lungs and paranasal sinuses were not suggestive of Kartagener's syndrome. Only the right adrenal gland was present, and variations in vascular anatomy were observed. The latter included: the celiac trunk branching into a phrenic artery, the splenic artery and a right gastric artery; the common hepatic artery originating from the superior mesenteric artery; and, on the left side, two inferior thyroid arteries, both originating from thyrocervical trunk. The occurrence of a double inferior thyroid artery and agenesis of adrenal gland was never communicated in situs inversus. Embryonic origin of celiac trunk and superior mesenteric artery variations could be explained by the separation at higher levels of the longitudinal anastomoses formed between the four roots of omphalomesenteric artery. It can be hypothesized that this phenomenon could occur more frequently in situs inversus than in situs solitus. However, the number of cases investigated in such detail is too small to draw firm conclusions.

The structure of the vascular system of the septomarginal trabecula in the heart of an adult.

In cardiology, the paths of the arteries penetrating the septomarginal trabecula (SMT) are especially important. They provide blood supply to the apparatus of the right atrioventricular orifice and often form anastomoses with the system of the right coronary artery. Despite this, only a few publications discuss the morphological aspect of the septomarginal trabecula, and available histological analyses seldom deal with its blood supply. The aim of this study was to analyze the vessel structure of the septomarginal trabecula in terms of the variability of the area of the cross-section of the lumen and the muscular layer of the artery. The study was carried out on the material of 50 human hearts from adults of both sexes. The material was divided into 4 morphological types. Histological examinations were conducted by means of classic staining methods. At the initial cross-section of the septomarginal trabecula, the area of the cross-section increased to half of the length of the trabecula, and then it started to decrease. This is connected with the thickening of the inner muscular layer of the artery, which proportionally takes up more area of the cross-section of the whole artery of the SMT. The total area of the cross-section of all vessels in both types examined was also the largest in the middle part of the SMT. Furthermore, the results of this study confirm the presence of a connection between both systems of coronary arteries. As the septomarginal trabecula passes through the lumen of the right ventricle, its arteries become exposed to the influence of the factors which may evoke a biological response from the walls of this vessel, causing the thickening of the muscular layer and, as a result, of the section of the whole artery, in particular its middle part.

Gross anatomy of the heart of the alpaca (Vicugna pacos, Linnaeus 1758).

The available information about anatomical characteristics of the cardiovascular system of the alpaca (Vicugna pacos, Linnaeus 1758) is scarce. The general objective of this work was to describe its heart anatomy. We dissected six adult animals and five neonates. The heart of the alpaca was located in the middle mediastinum, with a craniocaudal extension from the third to the sixth rib. No ligament that connected the fibrous pericardium to the sternum or to the diaphragm was detected. In the right atrium, there was a developed crista terminalis and small pectinate muscles. In the right ventricle, the septomarginal trabecula was very large. From the proximities of the interventricular septum arose small septomarginal trabeculae that ended in carnous trabeculae of the septal wall. The left atrium included little developedpectinate muscles. On the left ventricle, both papillary muscles were bilobed. Two left septomarginal trabeculas were detected in this ventricle. The left subclavian artery was originated from the aortic arch separately from the brachiocephalic trunk, and bicarotid trunk was present. The other branches of the subclavian artery were similar to the domestic ruminants. The arterial supply of the heart was of the right type. In conclusion, the heart anatomy of alpaca and the irrigation of thoracic cavity were more similar to those of old world camels and different from domestic ruminants.

Anatomical investigation of the papillary muscles of the septomarginal trabecula in fetal ontogenesis

The aim was to study papillary muscles of the right ventricular septomarginal trabecula. Materials and methods: 98 formalinfixed normal hearts from human fetuses aged 17 to 28 weeks were studied by means stereomicroscope. Results. Muscles in such position were found to be in 55.1%. The free-standing papillary muscles predominated over the muscles of fixe type. The muscles had monolithic base, one belly and mostly one apex. Tendinous chords of these muscles entered only the septal cusp of the right atrioventricular valve. A potential clinical importance of the papillary muscles was mentioned. Conclusion. The papillary muscles situated at the septomarginal trabecula are proposed to regard as particular subgroup of septal papillary muscles.

ANATOMICAL CHARACTERISTICS OF SEPTOMARGINAL TRABECULA OF THE RIGHT VENTRICLE OF THE HUMAN FETAL HEART

Anatomical structure of right ventricular septomarginal trabecula (SMT) was studied at micro-macroscopical level in 99 preparations of human fetal heart formed without malformations and minor abnormalities, obtained at 17-28 weeks of development. SMT was found to be a constant cardiac structure consisting of the body and two branches: anterior and posterior. Body of SMT is a myocardial vallum, unseparable from the interventricular septum, the long axis of which is always located along the conventional line connecting septal insertion of supraventricular crest and right ventricular apex. Posterior margin of SMT body was distinct in 75% of cases and smoothened in 21.9%. Base of the SMT was solid in 46.3% and split into secondary trabeculae in 52.6% of cases. Narrow and wide forms of SMT body were considered as its extreme anatomical variants. It is suggested to distinguish two anatomical types of SMT: a complete type, in which SMT was represented by a complex consisting of body in the form of muscular vallum and both branches, and an incomplete one, in which one of the branches was absent. Human fetal heart SMT is characterized by a variability, which is manifested by certain combinations of anatomic variants of SMT base form, its posterior margin, and the presence, shape and mutual location of its branches.

Morphological Variations in the Canine (Canis familiaris) Right Ventricle Trabecula Septomarginalis Dextra and a Proposed Classification Scheme.

The trabecula septomarginalis dextra is a structure routinely mentioned in veterinary anatomy. While there are several studies on the morphology of this structure in select animal species, there are some characteristics that are not adequately described. The purpose of this study was to describe and classify this trabecula in the domestic dog using the number of branches that insert onto the ventricular free wall. In the 39 examined hearts, 17.95% were single stranded (type I) and 2.56% were y-shaped (IA). Then, 28.21% were web-like with 3 to 4 points of insertion (IB) and 51.28% were web-like with 5 or more points of insertion (IC). While the purpose of this study was to describe the morphology of this trabecula, it also showed there is variability in this structure within the same species. This undocumented variability could present a problem to researchers who use dogs as an animal model when testing catheters for invasive cardiac monitoring or cardiac stem cell therapy. Also a web-like trabecula could create problems during pacemaker lead placement for the treatment of symptomatic bradycardia because of the potential for catheter entanglement in these branches.

Right ventricle/interventricular septum electrophysiological anatomy (determination of optimal right ventricular lead placement)

Notwithstanding a theoretically justified lead placement into the interventricular septum (IVS), the data from the clinical trials demonstrate somewhat controversial results. One of these controversies is the absence of consolidated criteria for positioning the electrode to deliver pacing from the interventricular septum (IVS) area. The study describes anatomic features of RV and IVS with respect to the cardiac conduction system, normal ventricular excitation and electrode implantation techniques for continuous pacing. A comparative study of 73 specimens of cadaver hearts was carried out by using electro-anatomic 3D mapping of the heart, X-ray examination, computer-aided tomography, morphological and morphometric investigation. It was found out that the medium part of IVS in the septomarginal trabecula zone could be considered the best for continuous pacing. The criteria for the RV lead to be implanted in this zone were determined.

Stereometry Study of Septomarginal Trabecula in Equines

There were studied in 30 heart horses, with age between two and six years, 18 males and 12 females without history of cardiac problems, the septomarginal trabecula which were classified in number, dimension, constitution and tissue organization in order to provide data to morphophysiological studies and to surgical clinic. Were removed fragments from the middle third of the trabecular structures and subsequently fixed in Bouin solution for 24 hours. The fragments of trabecula were subjected to conventional histological technique, cut to a thickness of 5 μm and stained with modified Mallory’s trichrome. The septomarginales trabecules, varied macroscopically in six types of insertion, being in simple form (13.33%), with double form (26.67%), triple form (16.67%), quadruple form (10%), branched form (16.67%) and irregular form (16.67%). Microscopically the septomarginales trabecules showed constituted of striated muscle tissue (69.37%), connective tissue (25.27%), cardiac conduction myofibers (5.33%) and discrete number of vessels. Considering the results, it was concluded that in the equine septomarginal trabecula have different proportions between the constituent tissues and forms of insertion, establishing a standard of proper arrangement for the species.

The trabecula septomarginalis (Leonardo's cord) in abnormal ventriculo-arterial connections: anatomic and morphogenetic implications.

BackgroundThe abnormal ventriculo-arterial connections in atrio-ventricular concordance and situs solitus with two well developed ventricles include the range from tetralogy of Fallot throughout the different forms of double outlet right ventricle to transposition of great arteries.The infundibular septum and the trabecula septomarginalis are the fundamental anatomical landmarks for the segmental analysis.In these abnormalities there is a pathological progressive counter-clockwise rotation of the infundibular septum which divorces from the antero-superior limb of the trabecula septomarginalis and achieves his identity. Is there any anatomical evidence of a simultaneous abnormal counter-clockwise rotation of the trabecula septomarginalis?MethodsMalposition of great arteries is a generic term since all relationships have to be expected.We present specimens with anatomical evidence of a progressive counter-clockwise rotation from 0° to about 180°of the plane passing throughout the trabecula septomarginalis’s limbs.ResultsWe can observe sequentially:1. Malformations in which the posterior limb of the trabecula septomarginalis is committed to the ventriculo infundibular fold: (tetralogy of Fallot, double outlet right ventricle with sub-aortic ventricular septal defect, truncus arteriosus and doubly committed ventricular septal defect);2. Malformations in which the posterior limb of the trabecula septomarginalis is committed to the infundibular septum (double outlet right ventricle with sub-pulmonary ventricular septal defect, transposition of great arteries).Conclusions1. The sequential-segmental analysis identify all the morphologies.2. The trabecula septomarginalis plane presents a progressive counter-clockwise twist on the long axis.3. Since the trabeculated portions of the ventricles are the oldest developmental components, our observations support the hypothesis that the abnormal ventriculo-arterial connections could be in relation with a pathological myocardial process during early cardio-genesis.We are promoting new studies to investigate our anatomical observations.