630 CIRCULATORY SYSTEM OF THE PIG 



The arteries of the hip, thigh, and leg are arranged much as in the ox. A few 

 special features may be noted. 



The ilio-lumbar artery gives off a branch to the ciuadriceps femoris. It may 

 also supply the posterior abdominal artery, which otherwise arises from the deep 

 femoral. 



The deep femoral artery is given off above the level of the pubis. The pos- 

 terior abdominal and external pudic arteries may arise from it by a short common 

 trunk or separately. The external pudic gives branches to the prepuce but not 

 to the penis. The popliteal artery gives off the peroneal. 



The femoral artery gives off a short trunk which divides into anterior femoral 

 and external circumflex arteries, the latter being much the larger. 



The saphenous artery is large. It descends on the inner surface of the leg and 

 hock and concurs with the perforating tarsal artery in forming the proximal plantar 

 arch. 



The posterior tibial artery is small, being replaced distally by the saphenous. 

 It gives branches to the muscles on the posterior face of the tibia and supplies the 

 nutrient artery of that bone. 



The anterior tibial artery is continued as the dorsalis pedis on the flexion sur- 

 face of the tarsus. This gives off the perforating tarsal artery, which passes back 

 through the vascular canal of the tarsus and unites with the terminal branches of 

 the saphenous to form the proximal plantar arch. 



The metatarsal and digital arteries resemble in arrangement the corresponding 

 vessels of the fore limb. 



The Veins 



The veins resemble in general those of the ox. Thus there is a hemiazygos 

 vein and two jugular veins, the internal one being relativelj^ larger than in the ox. 

 A few differential features may be noted. 



The buccinator vein resembles that of the horse, and unites with the vena 

 reflexa to form a short common trunk which joins the facial. 



The facial vein resembles in general that of the horse. The dorsal nasal vein 

 is large, receives the veins from the snout, runs backward in the groove of the nasal 

 bone and joins the frontal vein; it is connected with its fellow by a transverse 

 branch, and anastomoses freely with the malar and facial. 



The veins of the distal parts of the limbs naturally present differences which 

 are correlated with those of the arteries. 



The Lymph Vessels and Glands 



The thoracic duct often divides near its termination into two branches which 

 unite to form an ampulla. The latter suddenly contracts and opens into the termi- 

 nal part of the left jugular vein. 



The submaxillary lymph glands are situated in the space between the omo- 

 hyoid and internal i)terygoid muscles in relation to the lower part of the anterior 

 border of the submaxillary salivary gland. There are commonly two on each 

 side, one large, the other small. 



The parotid l)Tnph glands ( Fig. 309) are reddish-brown in color. There are 

 usually four of considerable size on either side. One is situated at the upper part of 

 the posterior border of the masseter, partly covered by the parotid gland. Another 

 large subparotid gland lies below the base of the ear. Ventral to this are two 

 smaller glands, one above and one below the external jugular vein. 



The pharjmgeal (or retropharyngeal) lymph glands (Fig. 310) are situated on 

 the dorsal wall of the pharynx above the external carotid artery and below and 



