ABSTRACT
Introduction: The sinuatrial (SA) node is known as natural pacemaker of the heart. SA node is supplied by the sinuatrial (SA) nodal artery is an atrial branch. Ischemia of SA nodal artery due to injury or during surgical intervention leads arrhythmia. Origin of sinuatrial (SA) nodal artery is variable; most commonly arise from right coronary artery. It may arise from the circumflex branch of the Left circumflex artery (LCA). In some cases it may originate from the trunk of left coronary artery, aorta or left bronchial artery. SA node may be supplied by single SA nodal artery or may have dual and triple arterial supply. Methods: This study was conducted on 25 cadavers from the dissection laboratory with an age range of 50 – 70 years. The cadavers were embalmed through carotid arterial perfusion of formaldehyde solution, spirit, water and glycerine and preserved in a weak formalin solution before dissection. Dissection method was employed for this study. Result and Observation: Single SA nodal artery found in 22/25 hearts (88%) and dual supply found in 3/25 hearts (12%). The SA nodal artery originated from proximal segment of right coronary artery (RCA) in 16/25 hearts (64%), from proximal segment of circumflex branch (LCX) of left coronary artery (LCA) in 6/25 hearts (24%). The Mean+SD of diameter of SAN artery from right coronary artery was 1.7+0.42mm. The Mean+SD of diameter of SAN artery from circumflex branch of left coronary artery was 1.29+0.30mm. The termination types were 1) precaval found in 44% (11/25), 2) retrocaval in 52% (13/25) and 3) pericaval found in 4%(1/25) of all SA nodal arteries.Conclusion: To be aware of the origin and course of SAN artery may provide a safe approach to interventional cardiologist and cardiac surgeon during cardiac interventions. Cardiac surgeons especially should be careful because compensation.
ABSTRACT
Introduction: A study of placental vasculature pattern was undertaken by using corrosion cast technique. The placenta is a highly vascularised organ. In this study we aimed to elucidate the structure of the cotyledonary vasculature of the human placenta after delivery, which serves as a core for the shape of the whole foetal villosity. Material & Method: Appropriate cast material was injected through placental vessels to form a corrosion cast model of placental blood vessels which was followed by meticulous dissection. Results: The cast models demonstrated very well the Hyrtl anastomosis between the umbilical arteries in the vicinity of the umbilical cord insertion into the placenta but no extra-placental anastomosis found between umbilical artery and umbilical vein. The chorionic vasculature exhibits a combination of the dichotomous and monopodial patterns. The chorionic vessels branch through 6 to 8 generations from the cord insertion towards the margins of the chorionic plate. The vein bifurcated twice immediately after insertion into the placenta. Conclusion: 3-dimensional structure of placenta can be demonstrated by micro vascular casts which reflect the shape of the whole or part of the organ, and include specific details such as the capillary architectural structure. Macroscopic visualisation can technically be advanced in 3 ways: treatment of maternal and fetal circulatory systems in common or each of the 2 systems separately.