. Quain's elements of anatomy . /, arcli of the aorta ;1, coronary sinus ; 2, great coronary vein turn-ing round the heart in the auriculo-ventriculargroove ; 3, posterior cardiac veins ; 4, middlecardiac vein; 5, one of the anterior cardiac veinspassing directly into the right auricle ; 6, thevestige of the left superior vena cava proceed-ing over the left auricle downwards to join thecoronary sinus. The coronary vein (fig. 423, 1) is con-sideral^ly dilated before it enters theauricle, and this dilated portion, which isembedded in the posterior wall of the leftauricle, is termed the coronary
. Quain's elements of anatomy . /, arcli of the aorta ;1, coronary sinus ; 2, great coronary vein turn-ing round the heart in the auriculo-ventriculargroove ; 3, posterior cardiac veins ; 4, middlecardiac vein; 5, one of the anterior cardiac veinspassing directly into the right auricle ; 6, thevestige of the left superior vena cava proceed-ing over the left auricle downwards to join thecoronary sinus. The coronary vein (fig. 423, 1) is con-sideral^ly dilated before it enters theauricle, and this dilated portion, which isembedded in the posterior wall of the leftauricle, is termed the coronary the junction of the coronary vein withthe dilated portion there is a valve con-sisting of one or two segments. Othersmall veins likewise enter the coronary sinus, each of them protected by avalve. One of these small veins, the oblique vein of Marshall (fig. 423,T)), takes a straight course from the vestigial fold before mentioned, over theback of the left auricle, to open into the coronary siuus. This vein has no valve. THE EIGHT VENTKICLE. 485 over its orifice : it, together witli the coronary sinus, is to be looked upon asthe remnant of the original left superior vena cava of the embryo (vide antea,p. ttSO). The right or anterior ventricle (fig. 420, 1) occupies the chief partof the anterior surface of the heart, the right border, and a smallerportion of the posterior surface. It extends nearly, but not quite,to the apex. The upper and left angle is prolonged in a conicalform to the commencement of the pulmonary artery : this part ofthe ventricle is named conus arteriosus, or wfunclihidum. The muscularwall of this ventricle is thickest at the base, and becomes thinnertowards the apex. When the cavity is laid open (fig. 422) the septumof the heart is seen to bulge into it, so that in cross section this ventricleis crescentic in form (fig. 424, G). At the base of the ventricle are twoorifices, protected by valves ; the auriculo-ventricular, of an ovalform, and situated
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Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
