978 



A MANUAL OF ANATOMY 



wall of the ventricle. Their free extremities are connected with a 

 number of filiform processes, called chordce tendinece, which pass 

 to the margins and ventricular surfaces of the segments of the 

 auriculo-ventricular valve. When the ventricle contracts, the 

 musculi papillares also contract, and, by tightening the chordae 

 tendineae, they prevent the segments of the auriculo-ventricular 

 valve from being driven back into the auricle. The segments are 

 therefore maintained in contact during the ventricular systole, 

 and no regurgitation of blood from the ventricle into the auricle 

 is allowed, in health. The musculi papillares are arranged in two 

 groups, anterior and posterior, and their bases are attached to the 



Superior Vena Cava 



Aoita 



Annulus Ovalis 



Fossa Ovalis ^ 



Pulmonary Artery (opened) 



Pulmonary Valves 



Interventricular 

 Septum 



Left Ventricle 



Eustachian Valve - 



Orifice of Coronary - 

 Sinus 



Thebesian Valve ■'\\ 



Inferior Vena Cava 



Tricuspid Valve' 



Chordae Tendineje 



Musoulus Papillaris 



Fig. 400. — The Interior of the Right Auricle and Right Ventricle. 



wall of the ventricle in the region of the apex of the cavity. The 

 anterior musculus papillaris is of large size, and the posterior is^ 

 usually broken up into two or more secondary papillary muscles. 



In most hearts a fleshy column, called the moderator hand, is| 

 met with in the right ventricle, which extends from the inter- 

 ventricular septum to the base of the anterior papillary muscle. 

 It is regarded as controlling distension of the right ventricle, which' 

 it effects by the influence it exerts upon the anterior wall. 



The openings connected with the right, ventricle are two in 

 number, namely, the auriculo-ventricular and jnilmonary. They 

 are situated at the base of the cavity, and are guarded by most 

 important valves. The auriculo-ventricular orifice is situated on the 



