The role of the plantar venous pump can be more clearly understood
by a precise description of the general arrangement of the veins
of the foot. These veins are superimposed on four planes, from
the sole upwards:
Plantar cutaneous venous plexus
This plexus is often wrongly considered to be the blood reservoir
of the plantar pump. In fact, it is composed of subcutaneous
and dermal venous plexuses which constitute Lejars' venous plexus.
Medial and lateral plantar veins
These very large veins travel between the muscles of the sole
of the foot and drain into the posterior tibial veins. They
constitute the real blood reservoir of the plantar venous pump.
These small vessels travel over the dorsal surface of the foot,
between the first and second metatarsals, from the perforating
vein of the first intermetatarsal space, where they communicate
with the medial and lateral plantar veins, at the ankle.
Dorsal veins of the foot
These form the dorsal venous arch, which is continuous medially
with the medial marginal vein, the origin of the long saphenous
vein, and laterally with the lateral marginal vein, the origin
of the short saphenous vein.
The dorsal venous arch (Figure
) is clearly visible underneath the skin. It crosses
the medial segment of the five metatarsals. The convexity of
this arch receives dorsal digital veins and interdigital veins,
which connect, between the toes, the superficial dorsal and
plantar venous plexuses (Braune's arcade), both situated at
the base of the toes. Interdigital perforating veins also anastomose
in the concavity of the dorsal venous arch.
The dorsal venous arch gives rise to two or three veins of the
dorsum of the foot, which sometimes merge to join the long saphenous
vein or to form an accessory saphenous vein.
The dorsal venous arch
continues medially as the medial
marginal vein. After receiving perforating veins from the medial
surface of the foot. the medial marginal vein becomes the long
saphenous vein anteriorly to the medial malleolus.
Laterally, the dorsal venous arch is continuous with
the lateral marginal vein, which receives perforating veins
of the lateral surface of the foot. This vessel then becomes
the short saphenous vein, posteriorly to the lateral malleolus.