THE THORACIC DUCT 



691 



Eight 

 lymphat 



a plexiform interlacement. It occasionally divides at its upper part into two 

 branches, right and left; the left ending in the usual manner, while the right opens 

 into the right subclavian vein, in 



x .il-n 



connection with the right lymphatic 

 duct. The thoracic duct has several 

 valves; at its termination it is pro- 

 vided with a pair, the free borders 

 of which are turned toward the vein, 

 so as to prevent the passage of 

 venous blood into the duct. 



The cisterna chyli (receptaculum 

 chyli} (Fig. 600) receives the two 

 lumbar lymphatic trunks, right and 

 left, and the intestinal lymphatic 

 trunk. The lumbar trunks are formed 

 by the union of the efferent vessels 

 from the lateral aortic lymph glands. 

 They receive the lymph from the 

 lower limbs, from the walls and 

 viscera of the pelvis, from the kid- 

 neys and suprarenal glands and the 

 deep lymphatics of the greater part 

 of the abdominal wall. The intes- 

 tinal trunk receives the lymph from 

 the stomach and intestine, from the 

 pancreas and spleen, and from the 

 lower and front part of the liver. 



Tributaries. Opening into the 

 commencement of the thoracic duct, 

 on either side, is a descending trunk 

 from the posterior intercostal lymph 

 glands of the lower six or seven in- 

 tercostal spaces. In the thorax the 

 duct is joined, on either side, by a 

 trunk which drains the upper lumbar 

 lymph glands and 'pierces the crus 

 of the diaphragm. It also receives 

 the efferents from the posterior 

 mediastinal lymph glands and from 

 the posterior intercostal lymph 

 glands of the upper six left spaces. 

 In the neck it is joined by the left 

 jugular and left subclavian trunks, 

 and sometimes by the left broncho- 

 mediastinal trunk; the last-named, 

 however, usually opens indepen- 

 dently into the junction of the left 

 subclavian and internal jugular 

 veins. 



The right lymphatic duct (ductus lymphaticus dexter) (Fig. 601), about 1.25 cm. 

 in length, courses along the medial border of the Scalenus anterior at the root of 

 the neck and ends in the right subclavian vein, at its angle of junction with the right 

 internal jugular vein. Its orifice is guarded by two semilunar valves, which prevent 

 the passage of venous blood into the duct. 



Lum 



FIG. 599. The thoracic and right lymphatic ducts. 



