250 



THE VASCULAR SYSTEM. 



f- 



The vein here gives off the Eamns communicant iliacm to the sciatic 

 vein, and turns forwards and downwards around the M. gliitaeu* 



maximus to reach the floor 

 of the pelvis, near the fe- 

 moral artery. The vein 

 then bifurcates to form the 

 pelvic and iliac veins. 



(1) The liamus commu- 

 nicant iliacus (Fig-. 165 c.i.) 

 forms a communication 

 with the sciatic at the base 

 of the thigh. 



(2) The posterior tibial 

 vein (Vena tibialis postica], 

 of which the femoral is a 

 continuation, arises on the 

 dorsal surface of the toes 

 and foot. It runs super- 

 ficially on the M. extensor 

 longiis digiti primi over the 

 ankle-joint, courses up- 

 wards and winds round 

 the outer surface of the 

 tibio-fibula to the flexor 

 surface. It receives, in its 

 course, muscular branches, 

 and at the knee a large 

 cutaneous branch. 



b. The sciatic vein : 

 this vein has already been 

 described (see p. 247), but 

 the vein from which it 

 arises requires description. 



The anterior tibial 

 vein (7 'en a tibialis fni- 

 tica) arises on the dorsum 

 of the foot by twigs from 

 the toes ; it courses under the M. extensor longus digiti primi y then 

 upwards on the anterior surface of the leg, and enters the canal in 

 the tibio-fibula to appear on its hinder surface. The vein then 



Veins of the hinder extremity, half schematic. 



c.i. Vena comnmnicans iliaca. 



/ Femoral vein. 



i Sciatic vein. 



' Vena cutanea cruris mediiilis. 



r.a. M. rectus anterior. 



s.m. M. semimembranosus. 



v.e. M. vastus externus. 



