664 



ABSORPTION. 



branch, its size is sensibly diminished; and when a vein receives a branch, 

 it is enlarged ; but when a lymphatic ramifies, there is generally little 

 change of size, whether the branch given off be large or small. 



The lymphatics consist of two planes, the one superficial, the other 

 deep-seated. The former creep under the outer covering of the organ, 

 or of the skin, and accompany the subcutaneous veins. The latter are 

 seated more deeply in the interstices of the muscles, or even in the 

 tissue of parts; and accompany the nerves and great vessels. These 

 planes anastomose with each other. 



This arrangement occurs not only in the limbs, but the trunk, and in 

 every viscus. In the trunk, the superficial plane is seated beneath the 

 skin; and the deep-seated between the muscles and the serous membrane 

 that lines the splanchnic cavities. In the viscera, one plane occupies 

 the surface; the other appears to arise from the parenchyma. 



The two great trunks of the lymphatic system, in which the lym- 

 phatic vessels of the various parts of the body terminate, are the tho- 

 racic duct, and the great lymphatic trunk of the right side. The 

 course of the thoracic duct has been described already. It is formed 

 of three great vessels; one, in which all the lymphatics and lacteals 

 of the intestines terminate; and the other two, formed by the union of 

 the lymphatics of the lower half of the body. Occasionally, the duct 

 consists of several trunks, which unite into one before reaching the sub- 



clavian vein; but more fre- 

 quently it is double. In ad- 

 dition to the lymphatics of the 

 lower half of the body, the 

 thoracic duct receives a great 

 part of those of the thorax, 

 and all those from the left half 

 of the upper part of the body. 

 At its termination in the sub- 

 clavian, there is a valve so dis- 

 posed as to allow the lymph to 

 pass into the blood; and to 

 prevent the reflux of the blood 

 into the duct. We shall see, 

 however, that its mode of ter- 

 mination in the venous system 

 possesses other advantages. 

 The great lymphatic trunk of 

 the right side is formed by the 

 absorbents from that side of 

 the head and neck, and from 



Fig. 257. 



Lymphatic Vessels and Glands of the Groin of the 

 Right Side. 



1. Saphena magna vein. 2. Veins on the surface of -j^g right arm. It is Very short, 

 abdomen. 3. External pudic vein. 4. Lymphatic ves- . . , , i 



sels collected in fasciculi and accompanying the saphena being little more than an inch, 

 vein on its inner side. 5. External trunks of the same , __._.!.-.., ^.-4. _ 110v +. > , 



set of vessels. 6. Lymphatic gland which receives all and SOmetimCS not a quarter 



these vessels. It is placed on the termination of the. sa- n f an infV) in IpTlD-fh hilt of 



phena vein. 7. Efferent trunks from this gland; they ( Cn > IU *gN| 



become deep-seated and accompany the femoral artery, a diameter nearly aS great aS 



8. One of the more external lymphatic glands of the groin. , J \ 1 



9. A chain of four or five inguinal glands, which receive the tllOraClC UUCt. A ValVO 

 the lymphatics from the genitals, abdomen, and external i P v-it^ at thp mouth of 

 portion of the thigh. aiso 6X1SIS at tne mOUin 01 



