Near the base of metatarsal I, the medial plantar artery gives rise to a superficial branch, which divides into three vessels that pass superficial to the flexor digitorum brevis muscle to join the plantar metatarsal arteries from the deep plantar arch.
The dorsalis pedis artery is the continuation of the anterior tibial artery and begins as the anterior tibial artery crosses the ankle joint (Fig. 6.125). It passes anteriorly over the dorsal aspect of the talus, navicular, and intermediate cuneiform bones, and then passes inferiorly, as the deep plantar artery, between the two heads of the first dorsal interosseous muscle to join the deep plantar arch in the sole of the foot. The pulse of the dorsalis pedis artery on the dorsal surface of the foot can be felt by gently palpating the vessel against the underlying tarsal bones between the tendons of the extensor hallucis longus and the extensor digitorum longus to the second toe.
Branches of the dorsalis pedis artery include lateral and medial tarsal branches, an arcuate artery, and a first dorsal metatarsal artery:
The tarsal arteries pass medially and laterally over the tarsal bones, supplying adjacent structures and anastomosing with a network of vessels formed around the ankle.
The arcuate artery passes laterally over the dorsal aspect of the metatarsals near their bases and gives rise to three dorsal metatarsal arteries, which supply dorsal digital arteries to adjacent sides of digits II to V, and to a dorsal digital artery that supplies the lateral side of digit V.
The first dorsal metatarsal artery (the last branch of the dorsalis pedis artery before the dorsalis pedis artery continues as the deep plantar artery into the sole of the foot) supplies dorsal digital branches to adjacent sides of the great and second toes.
The dorsal metatarsal arteries connect with perforating branches from the deep plantar arch and similar branches from the plantar metatarsal arteries.
There are interconnected networks of deep and superficial veins in the foot. The deep veins follow the arteries. Superficial veins drain into a dorsal venous arch on the dorsal surface of the foot over the metatarsals (Fig. 6.126):
The great saphenous vein originates from the medial side of the arch and passes anterior to the medial malleolus and onto the medial side of the leg.
The small saphenous vein originates from the lateral side of the arch and passes posterior to the lateral malleolus and onto the back of the leg.
The foot is supplied by the tibial, deep fibular, superficial fibular, sural, and saphenous nerves:
All five nerves contribute to cutaneous or general sensory innervation.
The tibial nerve innervates all intrinsic muscles of the foot except for the extensor digitorum brevis, which is innervated by the deep fibular nerve.
The deep fibular nerve often also contributes to the innervation of the first and second dorsal interossei.
The tibial nerve enters the foot through the tarsal tunnel posterior to the medial malleolus. In the tunnel, the nerve is lateral to the posterior tibial artery, and gives origin to medial calcaneal branches, which penetrate the flexor retinaculum to supply the heel. Midway between the medial malleolus and the heel, the tibial nerve bifurcates with the posterior tibial artery into: a large medial plantar nerve, and a smaller lateral plantar nerve (Fig. 6.127).
The medial and lateral plantar nerves lie together between their corresponding arteries.