212 THE SURGICAL ANATOMY OF THE HORSE 



posterior aorta. The right vein is related inferiorly near its termina- 

 tion to the external iliac artery, which vessel it crosses to assist in 

 forming the posterior vena cava. 



THE LYMPHATICS 



As in the fore limb, the lymph from the foot is carried by lymphatic 

 vessels which follow the course of the digital veins. Leaving these veins, 

 they run along the course of the metatarsal veins, so that in septic infection 

 of the foot — such as we get in some cases of gathered nail, quittor, &c. — 

 the infection quickly spreads up the limb, and the swelling appears in this 

 limb also on cither side of the tendons of the flexors of the digit. The 

 swelling extends with rapidity from the metatarsal region up the leg, and 

 is particularly evident along the course of the internal and external 

 saphena veins. 



Infection also spreads along the course of the anterior and posterior 

 tibial veins. But these veins are more deeply seated, and, consequently, 

 swelling along their course is not so apparent on the exterior of the 

 limb. 



The Popliteal Lymphatic Glands. — These small glands are placed near 

 the popliteal artery between the biceps femoris and semitendinosus 

 muscles. The group consists of four or five small lobules, and their 

 afferent vessels are derived from the region of the hock. They drain 

 also the lymph from the back and inferior portion of the gluteal 

 region. Efferent vessels from this group pass to the deep inguinal 

 glands. 



The Precrurai Glands. — These glands, which are from twelve to 

 fourteen in number, are arranged in a chain along the course of the 

 circumflex-iliac artery. Their afferent vessels drain the lymph from the 

 anterior and inner aspects of the thigh, and the efferent vessels join the 

 iliac glands. 



