Source:http://linkedlifedata.com/resource/umls/id/C0037189
MSH: The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).,FMA: Subdivision of conducting system of heart at the junction of the right atrium and the superior vena cava, around the sinoatrial nodal branch of right coronary artery and is continuous with the internodal tract.,NCI: A cluster of specialized cells located in the upper area of the right atrium. These cells generate the electrical impulses that result in the normal sinus rhythm.