THE RIGHT VENTRICLE 243 



2. The orifice of the inferior vena cava, at the lowest part, near 

 the septum, looking upward and inward. 



3. Between the two caval openings a projection, the tuber- 

 culum Loweri. 



4. The opening of the coronary sinus, between the inferior 

 cava and the auriculoventricular opening, and protected by 

 the fold of endocardium forming the coronary valve. 



5. Numerous small openings (foramina Thcbesii) of the venae 

 cordis minimee. 



6. The auriculoventricular opening. 



7. The Eustachian valve, between the front of the inferior 

 vena cava and the auriculoventricular orifice. It is semilunar 

 in form, the free concave margin sending one cornu to join the 

 front of the annulus ovalis and the other to the auricular wall. 



8. The fossa ovalis, at the back of the septum, in the situation 

 of the fetal foramen ovale, its prominent margin being known 

 as the annulus ovalis. 



9. The musculi pectinati, small elevated columns which trans- 

 verse the appendix and the adjacent part of the sinus. 



The auriculoventricular bundle of His is situated in the median 

 septum between the auricles and ventricles. It commences 

 near the opening of the coronary sinus, where the fibers con- 

 verge, forming a node (node of Tawara), and continues as a 

 compact bundle which passes forward in the lower part of the 

 pars membranacea septi to the upper part of the muscle portion 

 of the ventricular septum, and divides into right and left 

 fasciculi. Each limb passes to the papillary muscles surrounded 

 by a layer of connective tissue, embedded within the muscle 

 of the septum, but in the lower parts of the ventricles each 

 fasciculus divides into several strands, which pass to the papil- 

 lary muscles and entire internal surface of the ventricular 

 surfaces and forms there histological connections with the cells 

 of the heart muscle fibers (Gray). 



THE RIGHT VENTRICLE 



The right ventricle is pyramidal, and extends nearly to the 

 apex of the heart. It is bounded internally by the convex sur- 

 face of the septum ventriculorum, and prolonged above and 

 internally into a pouch, the infundibulum, or conus arteriosus, 



