5. The =posterior femoral= or =femoro-popliteal= vein (V. femoris
caudalis) is a satellite of the artery. It receives the =recurrent
tarsal= or =external saphenous vein= (V. tarsea recurrens), which arises
at the outer side of the hock, ascends on the deep fascia of the
external surface of the leg in front of the tendo Achillis, passes
between the biceps femoris and semitendinosus, and joins the posterior
femoral vein. It is connected with the recurrent tibial vein by a large
anastomotic branch which crosses in front of the tuber calcis. Usually a
branch from it ascends along the great sciatic nerve and anastomoses
with the obturator vein.
The =popliteal vein= (V. poplitea) lies along the inner side of the
artery (Fig. 459). It is formed by the confluence of anterior and
posterior tibial veins.
Two =anterior tibial veins= (Vv. tibiales anteriores) usually accompany
the artery of like name; the outer vein is much the larger. In other
cases there is a single large vein in the proximal part of the leg, two
lower down. They arise from a number of anastomosing radicles on the
front of the capsule of the hock joint, chiefly as the continuation of
the perforating tarsal vein. The origin of the chief vein is connected
with the saphenous by a large anastomotic branch.
The =posterior tibial vein= (V. tibialis posterior) is commonly double
(Fig. 458). It arises at the level of the tuber calcis, where it has a
communication with the recurrent tibial vein. It is a satellite of the
artery.
The =internal= or =great metatarsal vein= (V. metatarsea dorsalis
medialis) (Figs. 458, 460) arises from the venous arch above the
sesamoids at the fetlock, but is practically the upward continuation of
the internal digital vein. It ascends along the inner border of the deep
flexor tendon, then in the groove on the inner aspect of the proximal
part of the large metatarsal bone to the capsule of the hock joint, and
is continued by the saphenous vein.
The =external metatarsal vein= (V. metatarsea plantaris lateralis)
arises from the venous arch above the fetlock, but appears to be the
upward continuation of the external digital vein. It ascends along the
outer border of the deep flexor tendon in front of the plantar nerve,
and is connected with the deep metatarsal vein at the proximal part of
the metatarsus by a transverse branch. It then passes upward along the
deep flexor tendon in relation to the plantar nerves and the inner
tarsal artery and is continued by the recurrent tibial vein.
The =deep metatarsal vein= (V. metatarsea plantaris medialis) arises
from the plantar venous arch, passes forward between the branches of the
suspensory ligament, and ascends on the posterior face of the large
metatarsal bone. At the proximal end of the metatarsus it is connected
with the external metatarsal vein by a transverse branch. It then passes
(as the perforating tarsal vein) through the vascular canal of the
tarsus and forms the chief radicle of the anterior tibial vein.
The =plantar venous arch= (Arcus venosus plantaris) and the digital
veins are arranged like those of the thoracic limb.