THE yEINS. 329 



2. V. hypogastrica (or iliaca interna) {z). — The hypo- 

 gastric or internal iliac vein joins the medial side of the 

 external iliac to form the common iliac {zu). Its branches 

 follow the branches of the corresponding artery except that 

 the vein from the bladder (umbilical vein) joins the V. hemor- 

 rhoidalis media. Also the vena glutea inferior receives a 

 large superficial communicating branch (Fig. 163, k') from the 

 vena saphena parva. This branch leaves the saphena parva 

 (Fig. 163, k) at the popliteal space, and passes over the lateral 

 surface of the biceps muscle to its proximal end. Here it 

 passes between the biceps and caudofemoralis to jo.in the vena 

 glutea inferior. 



3. V. iliaca externa (Fig. 127, page 310). — This vein fol- 

 lows the corresponding artery, collecting the blood from the 

 posterior extremity. Its branches are the same and have in 

 general the same distribution as those of the artery. The vein 

 has, however, certain branches in addition to those of the 

 artery, resulting in a somewhat different general arrangement 

 of vessels ; it will be necessary therefore to give an account of 

 the system of veins from the foot and lower leg. 



The blood is collected from the foot into tvv'o sets of veins 

 which may be distinguished as the deep and the superficial 

 sets. The veins of the deep set are those which accompany 

 the branches of the popliteal and anterior tibial arteries. Those 

 of the superficial set are larger and carry most of the blood. 

 On the dorsum of the foot blood is collected from the third, 

 fourth, and fifth digits by two or three superficial metatarsal 

 veins, which unite opposite the proximal end of the metatarsus 

 into a single vein. This receives a similar branch coming from 

 the dorsum of the second digit, and has numerous branches in 

 the ankle region which form here a network, communicating 

 with the vena saphena parva (Fig. 163, k), and with branches 

 from the plantar side of the foot. From this network two or 

 three main veins pass proximad on the medial side of the leg, 

 along with the branches of the arteria saphena, and unite with 

 a similar vein from the plantar side of the foot to form the vena 

 saphena magna (Fig. 127, k, page 310), which accompanies 

 the arteria saphena to join the femoral vein {a). 



