244 



THE VASCULAR SYSTEMS 



from which springs the pulmonary artery. Its cavity has a 

 capacity of three ounces. On opening the ventricle the following 

 parts are presented for examination: 



1. The auricula ventricular orifice, oval in form and placed 

 near the right side of the heart. Around its circumference is a 

 fibrous ring, and it is guarded by the tricuspid valve. 



FIG. 38 



ANNULUS 

 OVALIS 



TUBERCLE. 

 OF LOWER ~M 



FOSSA 

 OVALIS 

 A N N U LU S... 

 OVALIS 



EUSTACHIAN 

 VALVE 



VALVE OF 

 THEBESIUS 



RIGHT CORO- 

 NARY ARTERY 



OPENING or 

 CORONARY SINUS 



iTRICUSPID 

 VALVE 



Right auricle and part of right ventricle, the front wall having been removed. 



(Testut.) 



2. The opening of the pulmonary artery, circular in form, at 

 the summit of the conus arteriosus, near the septum ; is guarded 

 by the pulmonary valve (semilunar). 



ii. The /nV//.v/W m/rr consists of three triangular Haps formed 

 of fibrous tissue covered by endocardium. They are continuous 



