Background: The arch of aorta in man has three main branches that supply the region of head and neck and upper limbs. The aorta beginning at the base of left ventricle, curves to the right and ascends upto the level of upper border of second right sternocostal joint. In animals the aorta is the main systemic arterial trunk and ascends to curve sharply backwards forming the arch to reach the eighth or ninth thoracic vertebra. The branches arising from the arch of aorta in man supply the head and neck. This study was undertaken to compare the arrangement of branches arising from the aorta considering the differences in posture and locomotion between the animals and man. Materials and Methods: The specimens of the human heart were obtained from the regular dissection done on the cadavers for teaching purpose in the department of Anatomy, P.E.S Institute of medical sciences and research. The heart specimens of the domestic animals were obtained from the local butcher who had legal permission to sacrifice the animals for sale. The heart was removed carefully along with the arch and its branches. 10% formalin was used to transport and preserve the specimens in glass jars. Results: Only one large vessel was seen arising from the convexity of the arch called the Common brachiocephalic trunk (CBCT) in domestic animals.The brachiocephalic trunk arises from the aortic arch and branches cranially. It provides the blood supply for the thoracic limbs, the neck, the head, and the ventral portion of the thorax. The brachiocephalic trunk gave both subclavian arteries and continued as the bicarotid trunk. The bicarotid trunk bifurcates in to left and right common carotid arteries. The left subclavian artery was found to lie at a lower level than the right in the animals in this study. Conclusion: The arrangement of branches of aorta in man and animals is certainly different and this could be due to postural adaptations and haemodynamics specific to the species. This area has potential for research in trying to understand the evolution of cerebro-vascular flow and dominance.
The objective of this study was to observe the patterns of different arteries that supply the kidneys. The kidney has a segmental distribution of arteries. The kidneys are divided into five vascular segments. The arteries that arise from the aorta above or below the main renal artery and reach the hilum are called accessory renal arteries. They are persistent embryonic lateral splanchnic arteries. Accessory renal arteries may arise from the celiac or superior mesenteric arteries, near the bifurcation or from the common iliac arteries. The present study has attempted to find out accessory, and aberrant arteries to kidneys with review of literature. Materials and Methods: The study was done on 52 kidneys randomly selected from cadavers that were used for the purpose of teaching in the department of Anatomy at P.E.S Medical College. The kidneys were removed from the cadavers en-block with the arteries and veins intact. The renal artery was observed for its pattern of branching. Observations and Discussion: The pre-hilar branching pattern was absent only in six kidneys out of the 52 kidneys selected. The branches given before entering the hilum were either in the form of a fork pattern or a ladder pattern in the remaining 46 kidneys. The fork pattern wherein the branches arose from a single point was found in 42 kidneys. The ladder patterns were seen in two posterior segment arteries and two anterior segment arteries. The anterior division often showed the fork patterns which were either duplicate or triplicate outside the hilum more proximally, with further division into duplicate or triplicate terminal branches closer to the hilum but significantly outside.
The segmental arteries of the kidneys arise from the anterior and posterior divisions of the main renal artery. These segmental arteries branch into lobar and then into interlobar arteries. At the junction of the cortex and medulla they dichotomize into arcuate arteries. Interlobular arteries branch off at right angles from the arcuate arteries. The present study was attempted to find out the course taken by the polar arteries, whether they have a specific area of blood supply and whether they contribute to any anastomoses in the cortex with other arteries or whether they end in the cortex separately. Results: 12 kidneys out of the 52 kidneys had arteries which entered the upper pole of the kidneys. The arteries that entered the upper poles took origin from the main renal artery proximal to the origin of anterior segmental artery and went to the poles directly from outside the hilum. The course of the artery was traced through radiological procedure and found that they entered the substance of the kidney and no traces of anastomoses could be made out. The terminal capillaries could not be traced in this particular method of study. Therefore it was not possible to find out if the polar arteries gave rise to interlobular arteries after they entered the poles of the kidneys. Conclusion: The study did not find any anastomoses with the other arteries in the segment. The polar arteries ended in the substance of the kidney. Though it was not possible to trace if they divided into interlobular arteries in this study it has potential for research in the future to detect any disturbance in the kidney functions of those who have polar arteries. If the polar arteries were to end in the cortex would they contribute to a capsular network that results in increase in the formation of stellate veins which drain into interlobular veins and therefore increase the venous drainage of the kidneys? Will such an arrangement affect the counter current exchange mechanism?
Gastrointestinal: Absent coeliac axisA 66-year old man with obstructive jaundice was found to have an unresectable pancreatic tumour on contrast-enhanced CT scan. Sagittal ( Figure 1) and 3-D (Figure 2) reconstructions of the CT scan images revealed complete agenesis of the coeliac axis, with the splenic and hepatic arteries arising directly from the superior mesenteric artery.The arterial supply of the gastrointestinal tract develops in week 4 of embryological life. The future blood vessels of the GI tract are formed from the vitelline system, which is composed of two bilateral arterial plexuses which coalesce to form arteries from the dorsal aorta to GI tract. Above the diaphragm the vitelline channels amalgamate to form about 5 pairs of arteries which supply the thoracic oesophagus. Below the diaphragm the vitelline system condenses to form the three major abdominal arteries of the foregut, midgut and hindgut. The coeliac artery is the most superior of these arteries; it leaves the aorta at the seventh cervical level in the embryo but later descends to the twelfth thoracic level during development. In addition to supplying the abdominal foregut proper, the coeliac artery also supplies its endodermal derivatives; the hepatic diverticulum (future liver), the cystic diverticulum (future gallbladder), and the dorsal and ventral pancreatic bud (future pancreas). It also supplies the mesodermally derived spleen. The anatomical variation in the celiac trunk is assumed to be caused by different patterns of vitelline reduction. However, some animal studies have suggested that the major abdominal arteries arise from medial umbilical roots of the dorsal aorta.Anomalies of the coeliac axis have been described in up to 28% of subjects. The commonest variation appears to be a common hepatosplenic trunk with a separate left gastric artery. Complete absence of the coeliac axis, with the splenic and hepatic arteries originating from the superior mesenteric artery is rare.Identification of these anomalies is particularly important in the event of angiographic or surgical intervention and organ harvest for transplantation, and can be achieved using reconstructions derived from multi-detector CT images.
Background: In large elastic arteries the media has elastin fibres and collagen fibres to maintain pressure during the cardiac cycles of systole and diastole. The contracting heart stretches the elastin in their walls and after the ventricle finishes contraction and the valve is closed the walls of the elastic arteries contract passively to maintain pressure for the short interval between filling and contraction. In contrast to the function of elastic arteries that maintain pressure the muscular arteries or distributing arteries have the function of supplying blood to different parts of the body under varied conditions. Since the domestic animals have a different set of branches from the aorta as was observed by the authors in a previous study comparing them with human aorta this study was undertaken to study the differences in the histological differences in the aorta of man and domestic animals. Materials and Methods: The heart specimens of the domestic animals were obtained from the local butcher who had legal permission to sacrifice the animals for sale. The heart was removed carefully along with the arch and its branches and processed for the histological observations with use of standard histological slide preparation. Results: It was found that the section of the aorta taken at the origin had elastic fibres in the mediassthe brachiocephalic trunk had muscle fibres arranged in bundles between the elastic fibres and the part of aorta going posteriorly to form the descending aorta also had muscle bundles in the Conclusion: The arrangement of muscle fibres in the anterior aorta which supplies the head,neck upper limbs could be significant. The function of aorta to maintain pressure during the cardiac cycle of systole and diastole is taken care of by the elastic fibres. The distributive function of supplying blood according to the needs of the parts of the head is probably served by the muscle bundles present. This could be due to the continuous adaptation of the animals to the environment for feeding and locomotion towards and against gravity.
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