9 8 



THORAX 



Ventriculus Dexter. The cavity of the right ventricle has 

 a triangular outline. The atrio-ventricular orifice opens into 

 the lower and posterior angle, the pulmonary artery springs 

 from the upper and posterior angle, and between the two orifices 

 is a strong and rounded muscular ridge, the supra-ventricular 

 crest. The supra-ventricular crest projects into the cavity of 

 the ventricle, converting it into a U-shaped tube which 

 commences posterior to and below the supra-ventricular crest, 



Innominate artery 

 Left subclavian artery 

 Left common carotid artery 



Superior vena cava 



Aortic arch 

 Serous pericardium 



Ascending aorta 

 Pulmonary artery 



Right auricle (O.T. appendix) 



Left anterior pulmonary 

 sinus (Valsalva) 

 Pulmonary valve 



Conus arteriosus 



Anterior segment of 

 tricuspid valve 



Medial segment 



Anterior papillary 

 muscle 

 - Moderator band 



Inferior vena cava 



Inferior segment of tricuspid valve 



FIG. 49. The Interior of the Right Ventricle. 



runs forwards and to the left, towards the apex, and turns 

 upwards and backwards, along the anterior part of the inter- 

 ventricular septum and anterior to the supra-ventricular crest, 

 to the orifice of the pulmonary artery. 



On transverse section the cavity of the right ventricle is 

 semilunar in outline, in consequence of the thick interven- 

 tricular septum, which forms the left and posterior wall, 

 bulging into the cavity (Fig. 50). Its walls are much thicker 

 than the walls of the right atrium, but much thinner than the 



