LYMPHATIC VESSELS. 



331 



Right Lymphatic Duct. The lymphatic vessels of the right 

 side of the head, neck, and thorax, and of the right arm, 

 right lung, right side of the heart, and a portion of the convex 

 surface of the liver, discharge into the right lymphatic duct, which 

 in turn discharges into the right subclavian vein, at its junction 

 with the right internal jugular vein. It is about 1.25 cm. in 

 length and about 2 mm. in diameter. At its junction with the 

 venous system there are two semilunar valves, to prevent regurgi- 

 tation of the blood. 



Thoracic Duct. All the lymphatics not connected with the 

 right lymphatic duct discharge into the thoracic duct. This vessel 



Scalenusanticus. 



Brachial plexus. 



Superficial cer- 

 vical vein. 



Axillary lym- 

 phatic trunk. 



Esophagus 



Vertebral vein. 

 FIG. 176. Topography of the thoracic duct (Zuckerkandl). 



begins at the receptaculum chyli or reservoir or cistern of Pecquet, 

 which is situated upon the body of the second lumbar vertebra, 

 and terminates in the left subclavian vein, where it joins the left 

 internal jugular vein. The duct is from 38 cm. to 45 cm. long, 

 about the size of a goose-quill at commencement and termination, 

 and somewhat smaller in the middle of its course. 



Structure of the Thoracic Duct (Figs. 176, 177). The thoracic 

 duct is composed of three coats : an internal, composed of a single 



