Outlines of human physiology . uplicature of the inner membrane, thickened by inter-vening fibrous substance. Its floating margin is irre-gular, and presents three points in the right, two in theleft ventricle ; whence the former is termed the tricus-pid, the latter the mitral valve. The floating edge ofthe valve is attached by short tendinous threads, calledchordae tendinese, to the fleshy columns of the ven-tricle. Each fleshy column receives all the tendinouschords from the opposite edges of two adjoining pointsof the valve. The valve at its broadest parts is abouteight or nine lines in dep
Outlines of human physiology . uplicature of the inner membrane, thickened by inter-vening fibrous substance. Its floating margin is irre-gular, and presents three points in the right, two in theleft ventricle ; whence the former is termed the tricus-pid, the latter the mitral valve. The floating edge ofthe valve is attached by short tendinous threads, calledchordae tendinese, to the fleshy columns of the ven-tricle. Each fleshy column receives all the tendinouschords from the opposite edges of two adjoining pointsof the valve. The valve at its broadest parts is abouteight or nine lines in depth, intermediately about margin of the valve is strengthened by numerouslittle granular bodies, called corpora sesamoidea. Of Ihe Mitral and Tricuspid Valves. 67 The action of the mitral and tricuspid valves may beeasily understood, when the parts forming either valveare displayed in their entire state, either by openingthe ventricles from the aorta and pulmonary artery, orby removing the apex of the heart. t-^^a^. Fig. 1 represents the passive state of the mitralvalve, while the blood is flowing from the auricle intothe ventricle. Fig. 2 represents the state of the valvewhen acting: its edges are in that case drawn togetherso as to meet by the action of the fleshy columns. Ifthe heart be opened in either of the methods describedabove, it is only necessary to imitate the natural ac-tion of the fleshy columns by pulling upon them in aproper direction, and the valve will be seen to close in 68 Of the Semilunar Valves. the manner represented. Fig. 3 is a diagram, givinganother view of the mitral valve when closed. Thetricuspid valve acts upon exactly the same principle. The valves at the root of the aorta and of the pul-monary artery are of a different description; they con-sist of three semilunar folds of the inner membrane, at-tached by their convex margin, each along a third ofthe circumference of the artery. They are so disposed,that when blood issues from the ven
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