182 



Heart. 



. papilUr. 



Chordae 

 tendin. 



524. The Left Heart, laid open. 



The left a u r i c 1 e, Auricula sinistra, has opening into it the four 

 pulmonary veins, two into the right and two into the left side. The 

 direction of the Appendix auriculae is forwards and towards the right 

 side, overlapping the root of the pulmonary artery. 



The right ventricle, Ventricuhis dexter, is separated from the 

 left by the Septum vcntriculorum. The auriculo-ventricular opening is guarded 

 by the t r i c u s p i d v a 1 v e, Valvida tricuspidalis, which consists of three seg- 

 ments or flaps, an anterior, a posterior and an internal, of which the anterior 

 is the largest. These segments are connected by their bases to the auriculo- 

 ventricular orifice, and by their sides with one another, their free margins 

 and ventricular surfaces giving attachment to a number of Chordae tendineae. 

 The arterial opening is at the left side of the base of the ventricle, and 

 leads into the pulmonary artery; the conical prolongation from which 

 it is given off is called Conus arteriosus (see Fig. 52 1). The three semi- 

 lunar valves at the orifice of the pulmonary artery are divided into an 

 anterior, a right and a left ; their Moduli Arantii are often very small. 



