White JV, Katz ML, Cisek P, Kreithen J.
Venous outflow of the leg: anatomy and physiologic mechanism of the plantar
venous plexus.
J Vasc Surg 1996 Nov;24(5):819-24

Department of Surgery, Temple University, Philadelphia, PA 19140, USA.

PURPOSE: Mechanisms of venous outflow from the leg and foot have not been clearly
defined. The purpose of this study was to evaluate the anatomy and physiologic
mechanism of the plantar venous plexus and its impact on venous drainage from the
tibial veins. METHODS: Fifty phlebograms that contained complete foot and calf
films were reviewed. On lateral films, the number of veins in the plantar venous
plexus and its tibial outflow tract were counted. The length and diameter of the
longest vein in the plantar venous system and the length of the foot arch were
measured. The ratio of the length of the plantar venous plexus to the arch length
was calculated. The presence or absence of valves within the plexus was recorded.
Plantar venous plexus outflow was evaluated by an duplex ultrasonographic scan of
the posterior tibial, anterior tibial, and peroneal veins during intermittent
external pneumatic compression of the plantar surface of the foot. RESULTS: The
plantar venous plexus was composed of one to four large veins (mean, 2.7 veins)
within the plantar aspect of the foot. The diameter of these veins was 4.0 +/-
1.2 mm. The veins coursed diagonally from a lateral position in the forefoot to a
medial position at the level of the ankle, spanning 75% of the foot arch.
Prominent valves were recognized within the plantar veins in 22 of 50 patients.
The plexus coalesced into an outflow tract of one to four veins (mean, 2.5 veins)
that flowed exclusively into the posterior tibial venous system. Small accessory
veins that drained the plantar surface of the forefoot flowed into either the
posterior tibial or peroneal veins. This pattern of selective drainage of the
plantar venous plexus was confirmed by duplex imaging. Mechanical compression of
the plantar venous plexus produced a mean peak velocity in the posterior tibial
veins of 123 +/- 71 cm/sec, in the anterior tibial veins of 24 +/- 14 cm/sec, and
in the peroneal veins of 29 +/- 26 cm/sec. CONCLUSIONS: The plantar venous plexus
is composed of multiple large-diameter veins that span the arch of the foot.
Compression of the plantar venous plexus, such as that which occurs during
ambulation, is capable of significantly increasing flow through the posterior
tibial venous system into the popliteal vein. Its function may be integral to
venous outflow from the calf and priming of the more proximal calf muscle pump.