VALVES OF THE HEART. 



265 



which form the fixed attachment of each of the curtains of the 

 valves. The free edges and ventricular surfaces of the curtains 

 are blended with the tendinous cords coming from the papillary 

 muscles, and thus give points of tendinous attachment to some of 

 the bundles of muscle fibres in the wall of the ventricle. At the 



Portion of the Wall of Ventricle (d d') and Aorta (ab c), showing attachments of one 

 flap of mitral and the aortic valves; (A and g) papillary muscles; (f, e' and/) attachment 

 of the tendinous chords. (Allen Thomson.) 



right auriculo-ventricular opening there are three chief curtains ; 

 hence it is called the "tricuspid" valve (Fig. 117, RAV). The 

 opening from the left auricle to the left ventricle, which is about 

 one-third smaller, is guarded by two large valvular flaps, and 

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