320 ANAT03nCAL TEGSNOhOGT. 



Push the lungs on both sides toward the dorsal part of the cav- 

 ity and with the "bone scissors, or nippers and bone scissors, remove 

 the sternal ends of all the exposed ribs for 2-3 cm., so as to facili- 

 tate access to tlie viscera. 



§ 836. Removal. — Lift the heart slightly by the pericardium and 

 sever its pleural attachments to the diaphragm as far dorsad as the 

 postcava (Fig. 101). Put two ligatures upon the postcana, the cau- 

 dal one about 2 cm. from the diaphragm if the abdominal vessels 

 are to be injected. In passing the ligatures about the vessel with 

 the fine forceps, avoid injuring the azygous lohe of the left lung. 

 This ligature should not be tied very hard. 



Double ligature (Fig. 41) the prcecava near its bifurcation, and 

 divide this and the postcava between the two ligatures. 



If the lungs are to be studied or experimented upon, place the 

 cloth or chamois over the cut edges of the thoracic parietes so as to 

 protect the lungs from laceration by the sharp ends of the ribs. 



Grasp the apex of the heart and draw it ventro-cephalad. This 

 will expose the caudal and azygous lobes of the lungs (see Fig. 89), 

 the thoracic aorta and cesopJiagus. Insert the fingers dorsad of the 

 lungs, lift them and sever their attachments as far cephalad as the 

 central end of the azygous vein (Fig. 101). Double ligature this 

 vein just centrad of the point of junction of the cephalic branch. 

 Employ the tracer in isolating the vein so as not to injure other 

 parts. Then divide between the ligatures. 



Cut the aorta opposite the head of the 8th rib, and note that, 

 usually, some blood remains therein. Grasp its central part and 

 draw it ventro-cephalad, cutting the intercostal arteries and other 

 connections as far as the origin of the A. subclavia (Fig. 101, 102). 

 Then grasp the heart and lungs together, draw them ventrad and 

 divide the trachea and the vessels cephalad of the heart at the de- 

 sired points, and the organs may be removed from the thorax. 



§ 837. Separation of the Heart from the Lungs. — On the dorsal 

 aspect, at the bifurcation of the trachea, is a mass of connective tis- 

 sue and fat enveloping a dark glandular body. Eemove these with 

 the tracer and fingers so as to open a way ventro-cephalad to the 

 ventral side of the bifurcation. With the tracer, expose the bron- 

 chus on each side, and note that, on its ventral side, the lung is con- 

 nected with the heart by a group of vessels, the AA. et VV. pul- 

 monales. Ligate very firmly the roots of the lungs and divide them 



