VALVES OF THE HEART. 



259 



protected by valves with a sail-like action. These are made up 

 of delicate curtains formed of thin sheets of connective tissue 

 arising from the margins of the auriculo-ventricular openings, 

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



Portion of the Wall of Ventricle (d d'} and Aorta (a b c), showing attach- 

 ments of one flap of mitral and the aortic valves; (h and g) papillary mus- 

 cles ; (e, e', and /) attachment of the tendinous chords. (Allen Thomson.) 



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 

 right auriculo- ventricular opening there are three chief curtains ; 





