OF THE LOWER EXTREMITY. 



473 



Fig. 244. The Internal or 



Long Saphenous Vein 



and its Branches. 



\ 



VEINS OF THE LOWER EXTREMITY. 



The veins of the lower extremity are subdivided, like those of the upper, into 

 two sets, superficial and deep ; the superficial veins being placed beneath the integu- 

 ment, between the two layers of superficial fascia, 

 the deep veins accompanying the arteries, and form- 

 ing the venee comites of those vessels. Both sets of 

 veins are provided with valves, which are more nu- 

 merous in the deep than in the superficial set. These 

 valves are also more numerous in the lower than in 

 the upper limbs. 



The Superficial Veins of the lower extremity 

 are the internal or long saphenous, and the external 

 or short saphenous. 



The internal saphenous vein (fig. 244) com- 

 mences from a minute plexus, which covers the 

 dorsum and inner side of the foot; it ascends in 

 front of the inner ankle, and along the inner side 

 of the leg, behind the inner margin of the tibia, 

 accompanied by the internal saphenous nerve. 

 At the knee, it passes backwards behind the inner 

 condyle of the femur, ascends along the inside of 

 the thigh, and, passing through the saphenous 

 opening in the fascia lata, terminates in the femoral 

 vein, an inch and a half below Poupart's ligament. 

 This vein receives in its course cutaneous branches 

 from the leg and thigh, and, at the saphenous open- 

 ing, the superficial epigastric, superficial circumflex 

 iliac, and external pudic veins. The veins from 

 the inner and back part of the thigh frequently 

 unite to form a large vessel, which enters the . main 

 trunk near the saphenous opening, and sometimes 

 those on the outer side of the thigh join to form a 

 large branch ; so that occasionally three large veins 

 are seen converging from different parts of the thigh 

 towards the saphenous opening. The internal 

 saphenous vein communicates in the foot with the 

 internal plantar vein ; in the leg, with the posterior 

 tibial veins, by branches which perforate the tibial 

 origin of the Soleus muscle, and also with the ante- 

 rior tibial veins ; at the knee, with the articular 

 veins ; in the thigh, with the femoral vein by one or 

 more branches. The valves in this vein vary from 

 two to six in number ; they are more numerous in 

 the thigh than in the leg. 



The external or short saphenous vein is formed 

 by branches which collect the blood from the 

 dorsum and outer side of the foot ; it ascends behind 

 the outer ankle, and along the outer border of the 

 tendo Achillis, across which it passes at an acute 

 angle to reach the middle line of the posterior 

 aspect of the leg. Ascending directly upwards, 

 it perforates the deep fascia in the lower part of 

 the popliteal space, and terminates in the popliteal 

 vein, between the heads of the Grastrocnemius muscle. 

 It is accompanied by the external saphenous nerve. 



