THE SUPERFICIAL VEINS OF THE LOWER EXTREMITY. 855 
course the vein les anterior to the obturator nerve. It is usually provided with 
one bicuspid valve, but sometimes there are two. Its tributaries correspond to the 
branches of the external iliac artery; thus the deep circumflex iliac (v. circumflex 
ihum profunda) and deep epigastric (v. epigastrica inferior) veins open into it close 
to its origin, whilst in addition it frequently receives the pubic vein. 
The pubic vein forms a communication between the obturator vein and the 
external iliac vein. It varies in size, and may form the main-termination of the 
obturator vein from which it arises. Commencing in the obturator foramen, it 
ascends at the side of the pubic branch of the deep epigastric artery, and reaches 
the external iliac vein. 
THE SUPERFICIAL VEINS OF THE LOWER EXTREMITY. 
The superficial veins of the lower extremity terminate in two trunks, one of 
which, the external or short saphenous vein, passes from the foot to the popliteal 
space; whilst the other, the internal or long saphenous vein, extends from the foot 
to the groin. 
The superficial veins of the sole of the foot form a fine plexus, immediately 
beneath the skin, from which anterior and lateral efferents pass. The anterior 
efferents terminate in a transverse arch which lies in the furrow at the roots of the 
toes, and the lateral efferents pass round the sides of the foot to the internal or 
external saphenous veins. The transverse arch also receives small plantar digital 
veins from the toes, and it gives off interdigital efferent branches to the dorsal 
venous arch. 
The superficial veins on the dorsal aspect of each toe unite together to form two 
dorsal digital veins (v. digitales pedis dorsales) which run along the borders of the 
dorsal surface. The dorsal digital veins of the adjacent borders of the interdigital 
clefts unite, at the apices of the clefts, to form four dorsal interdigital veins which 
terminate in the dorsal venous arch. The dorsal digital vein from the inner side 
of the great toe ends in the long saphenous vein, and that from the outer side of 
the little toe terminates in the short saphenous vein. 
The dorsal venous arch (arcus venosus dorsalis pedis) hes in the sub- 
cutaneous tissue, between the skin and the branches of the musculo-cutaneous 
nerve, opposite the lower parts of the shafts of the metatarsal bones. It ends 
internally by uniting with the inner dorsal digital vein of the great toe to form the 
long saphenous vein, and externally by joining the outer dorsal digital vein of the 
little toe to form the short saphenous vein. The dorsal venous arch receives the 
dorsal interdigital veins and interdigital efferents from the plantar transverse arch 
in front, and numerous tributaries from the dorsum of the foot, which anastomose 
freely together, forming a wide-meshed dorsal venous plexus, open into it behind. 
The internal or long saphenous vein (v. saphena magna) is formed by 
the union of the inner extremity of the dorsal venous arch with the inner 
dorsal digital vein of the great toe. It passes upwards in front of the internal 
malleolus, crosses the inner surface of the lower part of the shaft of the tibia, and 
ascends immediately behind the internal border of that bone to the knee, where it 
hes just behind the internal condyle of the femur; continuing upwards, with an 
inclination forwards and outwards, it gains the upper part of Scarpa’s triangle, 
where it perforates the cribriform fascia and the femoral sheath to reach its ter- 
mination in the femoral vein. In the foot and leg it is accompanied by the long 
saphenous nerve, and for a short distance below the knee by the superficial branch 
of the anastomotic artery. In the thigh, branches of the internal cutaneous nerve 
he in close relation with it. It contains from eight to twenty bicuspid valves. 
Tributaries.—It communicates freely through the deep fascia with the deep inter- 
muscular veins. In the foot it receives tributaries from the inner part of the sole and 
from the dorsal venous plexus. As it ascends in the leg it is joined by tributaries from 
the dorsum of the foot, the inner side and back of the heel, the front of the leg and the 
back of the calf, and it anastomoses freely with the short saphenous vein. In the thigh 
it receives numerous tributaries, some of which usually converge to form two superficial 
femoral veins. Of these, one, the external, ascends from the outer side of the knee and 
