FROZEN SECTIONS OF THE THORAX. 



341 



Fig. 100.— Frozen Transection of the Thorax, Cephalic Aspect ; x 1.5. 



mediastlnale to become continuous with the parietal pleura. The ental lamina is reflected 

 to form the proper serous covering of the heart. At the dorsal points of junction of the 

 two laminae are the phrenic nerves. 



The sternal arteries and 'veins appear dorso-laterad of the mesostemeber. The vems 

 lie mesad of the arteries (§ 921). 



§ 911. Nerves, etc.— The sympathic trunks (JST. sympatMcus) appear just ventrad of 

 the heads of the ribs in Fig. 99, and in corresponding places in Fig. 100. 



