THE THORACIC DUCT. 



505 



S- 



the upper surface of the liver), aud from the walls of the abdomen, from 

 the left side of the thorax, left lung, 

 left side of the heart, and left upper Fig- 322. 



limb, and from the left side of the head 

 and neck. It is from fifteen to eighteen 

 inches long in the adult, and extends 

 usually from the second lumbar vertebra 

 to the root of the neck. Its commence- 

 ment, however, is often as low as the 

 third lumbar vertebra ; and in some cases 

 as high as the first lumbar, or even 

 the last dorsal vertebra. Here there 

 is usually a dilatation of the duct, of 

 variable size, which is called recep- 

 tacidum chyli (Pecquet), and is the 

 common place of junction of the lym- 

 phatics from the lower limb with the 

 trunks of the lacteal vessels. 



Fig. 322. — Sketch of the Thoracic 



THE PkINCIPAL Si'STEMIG VeINS. 



Dpct with 

 (A. T.) 



The full description of this figure will be found 

 at p. 473. 



10, 10, indicate the thoracic duct ; the lower 

 number is close to the receptaculum chyli, the upper 

 is on the fourth dorsal vertebra, above which the 

 duct inclines to the left ; 6, on the left subclavian 

 vein, marks the termination of the duct in the 

 angle of union of the subclavian and iutemal jugu- 

 lar veins ; :>, on the right subclavian vein, indicates 

 the similar termination of the right lymphatic 

 trunk. 



1U 



The lower part of the thoracic duct is 

 generally wider than the rest, being about 

 three lines in diameter ; it lies at first 

 to the right side of or behind the aorta ; 

 it then ascends on the right side of that 

 vessel, in contact with the right crus of 

 the diaphragm, to the thorax, where it is 

 placed at first upon the front of the dorsal 

 vertebra?, between the aorta and the azy- 

 gos vein. The duct ascends, gi'a dually 

 inclining to the left, and at the same time 

 diminishing slightly in size, until it 

 reaches the third dorsal vertebra, where, 

 passing l.iehind the arch of the aorta, 

 it comes into contact with the (Dcsophagus, 

 lying between the left side of that tube 

 and the pleura. Continuing its course '^VlC} 



into the neck to the level of the upper 

 border of the seventh cervical vertebra, "^ 



it changes its direction and turns for- 

 wards, at the same time arching downwards and outwards so as to 



14* 



14 



