740 CIRCULATORY SYSTEM OF THE PIG 



and external pudic arteries may arise from it by a short common trunk or separately. 

 The external pudic gives branches to the prepuce and preputial bursa but not to 

 the penis. In the female it supplies the inguinal and abdominal mammary glands 

 and anastomoses with the external thoracic artery. The popliteal artery gives off 

 the peroneal. 



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

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



The saphenous artery is large. It descends as in the ox on the medial surface 

 of the leg and divides near the hock into lateral and medial tarsal arteries. The 

 latter is the real continuation of the saphenous; it divides into medial and lateral 

 plantar arteries, which concur 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 dorsal 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 plantar arteries to 

 form the proximal plantar arch. 



The metatarsal and digital arteries resemble in arrangement the corresponding 

 vessels of the 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 relatively 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 

 refiexa to form a short common trunk which joins the external maxillary vein. 



The external maxillary 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 veins. 



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

 are correlated with those of the arteries. 



The Lymphatic System- 



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 lymph glands of animals in good condition 

 are almost all embedded in fat. 



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

 hyoid and medial pterj'goid muscles, in relation to the lower part of the anterior 

 border of the mandibular salivary gland. There are commonly two on each side, 

 one large, the other small. 



The parotid lymph glands (Fig. 415) are reddish-brown in color. There are 

 usually four of considerable size and several smaller ones on either side. One is 

 situa.ted at the upper part of the posterior border of the masseter, partly covered 

 by the parotid salivary gland. A large subparotid gland lies below the base of the 

 ear on the terminal part of the brachiocephalicus muscle. A^entral to this are two 

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



The suprapharyngeal lymph glands (Fig. 416) are situated on the dorsal wall 

 of the pharynx, dorsal to the external carotid artery and below and behind the 

 paramastoid process. There are usually two of considerable size on either side. 



