VEINS TO THE FOOT. 439 



the posterior extremity, the latter from the hinder part of the 

 trunk. They are lodged in the angles of separation comprised 

 between the external and internal iliac arteries, the right one, 

 the shorter, passing above the external iliac artery to meet the 

 left at the origin of the posterior vena cava. The left one before 

 it joins its fellow passes between the body of the last lumbar 

 vertebra and terminal extremity of the posterior aorta. 



EXTERNAL ILIAC VEIN. 



(Fig. 165. b'.) 



In studying the branches of the external iliac vein, it is advis- 

 able to commence at the foot. The venous plexuses of the foot 

 unite to form two digital veins, and these are succeeded by three 

 metatarsals, the common origin of the four veins of the thigh, 

 Avhich are distinguished as subcutaneous and deep. The deep are 

 continued as the ijopliteal and femoral, the latter being con- 

 tinued by the external iliac vein. 



VEINS OF THE FOOT. 



The veins of the foot are very numerous, and arranged in a 

 superficial and interosseous network. They are valveless, allowing 

 the blood to flow in either direction during sudden emergency. 

 The external or superficial plexuses are the solar, laminal, and 

 coronary. 



The Solar plexus is remarkable for the equality of the dia- 

 meter of its veins throughout the extent of the plantar surface of 

 the foot, as well as for the paucity of anastomoses of them with 

 the deep-seated veins. They chiefly terminate in the large cir- 

 cumflex vein which accompanies the artery of the same name, and 

 receives also descending twigs from the laminal plexus, as it j)asses 

 back to the wing of the bone, and thence into the coronary 

 plexus. The remaining branches of the solar plexus reach the 

 small central vein, situated around the semilunar ridge, on the 

 solar surface, and terminate also in the coronary plexus. 



The Laminal plexus rests on the sensitive wall of the foot. 

 The branches, uniform in the sensitive laminge, gradually increase 

 in size as they approach the coronet, where the majority terminate 

 in the coronary plexus ; the remainder pass down to the circum- 

 flex vein. 



