wssrcmoN of the do<; 



61 



The branches of that pari of the aorta now under consideration are ae 



follows: (I) N'iru' or t » -i i intercostal arteries arising from its dorsal aspect ; 

 (2) two or three small bronchial arteries arising either from the aorta itself or 

 from th<- first intercostal artery, and supplying the bronchial lymph-glands 

 and the oesophagus ; (.'{) two or three small oesophageal arteries leaving the 

 ventral aspect of t he vessel. 



Ductus thorai u us. By means of the thoracic duct the lymph from the 

 whole body, with the exception of that from the right side of the thorax, the 



Truncus atophagt ns d 



n. tplanchnicus 



n. spJanehnicus minot 



ganglion 



\ mesenterirum 



Ganglion eaeOaeum 



-Ventrieulus 





n. TtOlTrnu 



trachea I 

 i 



Ganglion ccrvicale caudal* \ 



n. plirenicus 



Truncus asophageus ventral is 



Diaphraqma 

 Mi;. 24. — Diagram of part of the sympathetic nervous system. 



right thoracic limb, and the right side of the head ami neck, gains the venous 

 system. The thoracic duct begins in the abdomen between the lumbar 

 parts of the diaphragm, as a dilation known as the cistema chyli. It enters the 

 thorax on the right side of the aorta, between this vessel and the vena azygos. 



Variable as is its thoracic course it may be said generally that, inclining 

 slightly towards the left, the duct passes for some distance through the chest 

 dorsal to the oesophagus. Afterwards it crosses the oesophagus on the left, and 

 finally opens into the left innominate vein. 



The duct is nearly always double for a greater or shorter part of its course, 

 frequent intercommunications existing hetween the two vessels. 



Pars thoracalis systems sympathici. — A large, elongated ganglion, 

 the first thoracic ganglion (ganglion thoracale primum), lies between^the longus 



