The plantar arch refers not to the arch of the foot but to the union of two blood vessels of the foot's sole: the deep plantar artery and the lateral plantar artery. This union forms a U-shaped curve near the base of the toes where the deep plantar artery, a branch of the dorsalis pedis artery on the top side of the foot, emerges from between the first and second toes and merges with the lateral plantar artery. Smaller vessels known as perforating arteries split off from the plantar arch toward each of the five toes, supplying blood to the ball of the foot and the plantar surface or sole of each toe.
Deep in the underside of the foot between the muscles and bones is a relatively simple network of blood vessels supplying blood to the muscles, skin, and other tissues of the sole of the foot. Fed by the posterior tibial artery, a major vessel of the calf, this network consists of a loop formed by its two branches — the medial and lateral plantar arteries — and the plantar arch. The medial plantar artery runs along the inside of the sole of the foot, and the lateral plantar artery travels along the outside of the sole of the foot.
A short distance from the base of the pinky toe the lateral plantar artery changes directions, curving across the ball of the foot toward the base of the big toe. It is here that the plantar arch is formed by the intersection of the lateral plantar and deep plantar arteries, near where the big toe splits from the second toe. Here the deep plantar artery, after branching off of the dorsalis pedis artery on the foot’s dorsal or top surface, runs between the first two metatarsal bones or those beneath the first and second toes. It then comes out from between the metatarsals on the foot’s plantar surface and joins with the lateral plantar artery to create the plantar arch.
A short perforating or connecting artery links the plantar arch to the medial plantar artery beneath the big toe, thus completing the arterial loop of the sole of the foot. The medial plantar artery, plantar arch, and lateral plantar artery all in turn produce multiple smaller branches that cross the ball of the foot and enter the toes. Those that cross the ball of the foot alongside the metatarsal bones are known as the metatarsal branches, while those that penetrate the toes alongside the phalanx bones are referred to as the digital branches.