88 



THORAX 



Dissection. Divide the phrenic nerves immediately above the diaphragm ; 

 then, with the handle and the edge of the scalpel, detach the lower part 

 of the pericardium from the diaphragm. The attachment of the peri- 

 cardium to the muscular part of the diaphragm is not close, and can 

 easily be broken down. The attachment to the central tendon is much 

 more firm and, as the median plane is approached, the aid of the edge of 

 the knife will probably be necessary before a separation can be effected. 



FIG. 44. The relations of the Heart and of its Orifices to the Anterior 

 Thoracic Wall. (Young and Robinson. ) 



to VII. Costal cartilages. 



A. Aorta. 

 Ao. Aortic orifice. 



C. Clavicle. 

 LA. Left atrium. 

 LV. Left ventricle. 



M. Mitral orifice. 



P. Pulmonary orifice. 

 RA. Right atrium. 

 RV. Right ventricle. 

 SVc. Superior vena cava. 



T. Tricuspid orifice. 



Divide the right innominate vein and the right phrenic nerve, immediately 

 above the upper end of the superior vena cava, and as the division is made 

 take care not to injure the right vagus posterior to the vein. Then divide 

 the vena azygos just posterior to its entrance into the superior vena cava. 

 Cut the inferior thyreoid veins, the innominate artery, and the left common 

 carotid artery, immediately above the upper border of the left innominate 

 vein, and then divide the left innominate vein, in the interval between the 

 left common carotid and the left subclavian arteries. Cut the left phrenic 



