THORAX AND ABDOMEN OF THE HORSE 



43 



colli muscle. It is not, as a rule, related to the oesophagus, because this 

 tube is here placed to the left of the median plane of the body. 



The right costo-cervical and deep cervical arteries behave in the 

 same manner as do those on the left side of the thorax. 



A. intercostalis. 



Eighth rib. 

 Thoracic duct. ! 



r 



Aorta. 



Last intercostal nerve. 



— (■ 



Sympathetic nerve-cord. 

 V. azygos. 



■ A. bronchooesophageus. 



M. longus colli. 

 , Oesophagus. 

 Trachea. 



A. transversa 

 colli. 



Diaphragm. 

 ,ine of reflection of pleura 



A. thor- 

 acica 

 interna. 



Truncus . 

 costocervicalis. 

 Vena cava cranialis. 



A. oesophagea. 



Truncus oesophageus ventralis. / 

 Truncus oesophageus dorsalis. 



N. vagus. 



I I 



I N. phrenicus. 

 Pericardium. 



A. pulmonalis. 

 Vena cava caudalis. 



Fig. 21. — Dissection of the thoracic contents from the right side, after 

 removal of the lung. 



Truncus bicaroticus. — The bicarotid trunk, presumably because 



of its production by the fusion of two vessels, is very variable in length. 



It passes to the entrance to the chest ventral to the trachea, and divides 



into the right and left common carotid ^ arteries. Ventral to the trunk 



1 KapwTis (carotis) [Gr.], from /cdpos (cares), deep sleep. It is stated that the 

 ancients believed that sleep was induced by increased flow of blood through the 

 arteries passing to the head. 



