THORACIC CAVITY 



81 



formed entirely by the ventricles, and mainly by the left 

 ventricle, which forms the left two -thirds, the separation 

 between the ventricles being indicated by the inferior longi- 

 tudinal sulcus. As the apex of the heart is held upwards 

 and to the right, the dissector should note that a recess of 

 the pericardia! cavity ascends behind the base or posterior 

 surface of the heart. That recess is the oblique sinus of the 



Innominate artery -i 



Aortic arch 

 Pulmonary artery .. 



Pulmonary valve - 

 Conus arteriosus 



Pericardia! cavity - 

 Ascending aorta 



Aortic valv 

 Aortic sinus 



Left common carotid 



Superior vena cava 



Vena azygos 



-\ Right 



> pulmonary 

 J artery 



Transverse sinus 

 of pericardium 

 Oblique sinus 

 of pericardium 

 Upper right 

 pulmonary vein 

 Left atrium 



Lower right 

 pulmonary vein 



Base of anterior cusp 

 of mitral valve 

 Oblique sinus of pericardium 

 Coronary sinus 



FIG. 37. Sagittal section of Heart. 



pericardium. Its orifice is below, where it is bounded to 

 the right and below by the upper end of the inferior vena 

 cava, and to the left and above by the inferior left pulmonary 

 vein (Fig. 32). The posterior boundary of the sinus is the 

 pericardium ; and the pericardium separates the cavity of the 

 sinus from the oesophagus, which, in this region, especially 

 at its lower part, is lying between the pericardium and 

 the descending part of the thoracic portion of the aorta. 

 Both the oesophagus and the aorta can be palpated through 



VOL. II 6 



