466 TOPOGRAPHICAL ANATOMY. 



tkoracicus as high as the' third and fourth dorsal vertebrae, curves 

 around branch, dexter and art. pulmon. forwards to the posterior 

 wall of ven. cava sup., in which it terminates. 



720. VI. Ductus thoracicus passes through hiat. aortic., lying 

 between aorta thoracic, and ven. azygos before the bodies of the 

 vertebrae ; goes to the left, in the region of the fifth and sixth dor- 

 sal vertebrse behind the oesophagus and the termination of arc. 

 aorta, and opens in the angle between ven. jugular, interna, and 

 subclavia sinistra. 



721. VII. Trachea, behind the manubr. sterni, ven. anonyma, 

 and carotis sinistra, it divides before the third dorsal vertebra, close 

 behind areas aorta, into the two bronchi. Bronch. dexter [the 

 largest] lies behind v. cava super., passes away under the curve of 

 v. azygos ; bronch. sinister [the longest and most oblique] under 

 the arch of the aorta to the lungs. Both lie behind the art. and 

 above the v. pulmonales. 



722. VIII. (Esophagus passes behind the trachea and rather 

 to the left of it, into the cav. mediastin. post. ; lying, at the com- 

 mencement, more in the central line, and to the right of the aorta; 

 lastly to the left and before aorta and duct, thoracic., and enters, 

 upon a plane with the ninth dorsal vertebra, the abdominal cavity 

 through for. ozsophageum. 



723. IX. Nerves. 



1. Nero, vagus, passes down and close to carotis, rather external 

 to it, before art. subclavia and behind ven. anonyma obliquely into 

 cav. mediast. anticum. 



a. N. recurrent dexter, passes off from it, and around the 

 art. subclavia dext. backwards to the larynx : sinister like- 

 wise around the arcus aorta,. Both ascend behind the carotis 

 in the groove between trachea and oesophagus. 



b. Nn. pulmonales. 



The vagus then turns into the cav. mediast. post., passes ob- 

 liquely inwards behind the bronchi to the oesophagus (the left on 

 its anterior, the right upon its posterior surface), and are lost 

 through for. oesophageum of the abdominal cavity. 



2. Pars thoracica nerv. sympathies, lies on the outside of cav. 

 mediast. post, behind the pleura costalis, close to the vertebral bo- 

 dies, before the proc. transv. and heads of the ribs. Ganglia 

 thoracici (eleven to twelve) between, upon, or before the heads of 

 the ribs. 



a. Splanchnicus major, arises from six to ten ganglia 



