The superficial dermal and subdermal venous network,
also called Lejars' plexus, is composed of very fine venules,
less than 1 mm in diameter (
Figures
109 et
110).
They line the entire plantar surface of the feet, including
the plantar arch and heel. The constituent venules of this superficial
network drain into marginal veins of the foot via numerous small
valve-bearing collectors.
The deep plantar venous arch constitutes the true blood
reservoir of the venous pump of the foot. It comprises two very
large pedicles which are often duplicated: medial plantar veins
and lateral plantar veins. Posteriorly, they drain into the
posterior tibial perforating vein, which gives rise to the posterior
tibial vein with a diameter of 5 to 6 mm. Anteriorly, these
veins converge onto the perforating vein of the first intermetatarsal
space. which gives rise to the pedal vein, and then the anterior
tibial vein (diameter: 3 to 4 mm). Note that the much larger
peroneal vein arises in the distal part of the leg.
Medial plantar veins are short (5 to 6 cm), with a caliber not
exceeding 2.5 to 3 mm. In contrast, lateral plantar veins are
long (12 to 1 °3 cm) with a very large diameter (4 to 5
mm). All these collecting veins present fusiform dilatations:
the fusiform sinuses.

Further reading
Gillot V. Veines plantaires et pompe veineuse. Phlébologie, 1995, 48:
49-70.
Scurr J.H., Coleridge Smith P. La pompe musculaire du pied importance physiologique
et clinique. Phlébologie, 1993, 46: 209-16.