Plantar Arterial Supply

Introduction

Introduction to the Plantar Arterial Supply

The arterial supply of the sole of the foot is primarily derived from the posterior tibial artery, which enters the foot through the tarsal tunnel behind the medial malleolus and divides into the medial and lateral plantar arteries. The lateral plantar artery is the larger of the two and forms the deep plantar arch, which is completed by the deep plantar branch of the dorsalis pedis artery (from the anterior tibial artery). This arch gives rise to plantar metatarsal arteries, perforating branches, and digital arteries, providing a rich collateral network to the plantar structures, toes, and the interosseous muscles. The medial plantar artery supplies the medial aspect of the sole. This dual-source supply from both the posterior and anterior tibial systems ensures robust perfusion and is critical for wound healing in the foot, especially in patients with peripheral arterial disease or diabetes. Clinical evaluation of the plantar arterial supply is essential for assessing foot viability, planning revascularization procedures, and understanding the pathology of ischemic foot ulcers.

Study

1. Origin and Course of the Posterior Tibial Artery in the Foot

The posterior tibial artery is the main source of the plantar arterial supply. It descends in the deep posterior compartment of the leg, passes behind the medial malleolus through the tarsal tunnel (deep to the flexor retinaculum), accompanied by the tibial nerve and its terminal branches. At the level of the sustentaculum tali, or just distal to it, it divides into the medial and lateral plantar arteries. The artery gives off the medial calcaneal branches before this bifurcation to supply the heel pad. The posterior tibial pulse is palpable behind the medial malleolus, a critical point in the peripheral vascular examination.

2. Medial Plantar Artery

The medial plantar artery is the smaller of the two terminal branches of the posterior tibial artery. It arises deep to the abductor hallucis muscle and runs forward along the medial side of the sole, between the abductor hallucis and flexor digitorum brevis (first layer), accompanied by the medial plantar nerve. It supplies the muscles of the medial compartment (abductor hallucis, flexor hallucis brevis, and the first lumbrical) and gives off superficial branches that anastomose with the medial tarsal branches of the dorsalis pedis artery. It also gives rise to a superficial digital branch to the medial side of the great toe. Though smaller, it is an important collateral vessel, particularly in the presence of lateral plantar artery disease.

3. Lateral Plantar Artery

The lateral plantar artery is the larger terminal branch. It runs laterally and forward across the sole, deep to the flexor digitorum brevis and superficial to the quadratus plantae, along with the lateral plantar nerve. At the base of the fifth metatarsal, it curves medially to form the deep plantar arch. Before forming the arch, it gives off muscular branches to the lateral compartment muscles (abductor digiti minimi, flexor digiti minimi brevis) and the quadratus plantae. The lateral plantar artery is the main contributor to the deep plantar arch, and its integrity is vital for plantar perfusion.

4. Deep Plantar Arch

The deep plantar arch is a complete arterial arcade lying on the bases of the second, third, and fourth metatarsals and the interosseous muscles (fourth layer). It is formed primarily by the continuation of the lateral plantar artery, and is completed medially by the deep plantar branch of the dorsalis pedis artery, which enters the sole through the space between the first and second metatarsal bases. The arch gives off the following branches: (1) Plantar metatarsal arteries (four in number) that run distally in the intermetatarsal spaces and divide into digital arteries. (2) Perforating branches that pierce the interosseous muscles to anastomose with the dorsal metatarsal arteries. (3) Muscular branches to the interossei, adductor hallucis, and the deep muscles. The arch maintains consistent blood flow to the forefoot and toes, and serves as a critical collateral pathway between the posterior and anterior tibial systems.

5. Plantar Metatarsal and Digital Arteries

Four plantar metatarsal arteries arise from the convexity of the deep plantar arch and travel forward in the second, third, fourth, and fifth intermetatarsal spaces (the first intermetatarsal space receives the first plantar metatarsal artery, which often arises directly from the junction of the arch and the deep plantar branch). At the webs of the toes, each plantar metatarsal artery divides into two plantar digital arteries, which supply the adjacent sides of the toes. Additionally, the first plantar metatarsal artery gives off a branch to the medial side of the great toe (which may also be supplied by the medial plantar artery). The plantar digital arteries are the primary vessels to the toes, forming a rich network with the dorsal digital arteries via small anastomotic branches. These vessels are essential for toe perfusion and are evaluated in digital ischemia.

6. Contributions from the Dorsalis Pedis Artery

The dorsalis pedis artery (anterior tibial artery's continuation) provides a crucial communication to the plantar arch via the deep plantar artery (deep plantar branch). This vessel pierces the first dorsal interosseous muscle and passes between the two heads of the adductor hallucis to join the deep plantar arch. It is the main source of supply to the arch in a significant proportion of individuals, particularly when the posterior tibial artery is hypoplastic. The dorsalis pedis artery also gives off the first dorsal metatarsal artery and the arcuate artery (when present), which contribute to the dorsal metatarsal arteries that anastomose with the plantar metatarsal arteries through the perforating branches. This interconnection between the two systems provides collateral pathways critical for foot salvage in peripheral arterial disease.

7. Clinical Relevance

Peripheral arterial disease (PAD): Atherosclerotic occlusion of the tibial arteries can compromise plantar blood flow. The deep plantar arch's collateral network may maintain toe perfusion even with single-vessel runoff. Angiography of the foot must include both plantar and dorsal views to fully assess the plantar arch's patency.

Diabetic foot: Neuropathy and ischemia combine to produce plantar ulcers, particularly under the metatarsal heads. Assessment of the posterior tibial and dorsalis pedis pulses, ankle-brachial index (ABI), and toe pressures are essential. In the presence of calcified, non-compressible arteries, toe-brachial index or transcutaneous oxygen pressure (TcPO2) are used.

Plantar artery bypass: The lateral plantar artery or the deep plantar arch can serve as distal targets for bypass grafts in limb salvage. Pedal bypass surgery often uses the dorsalis pedis or the common plantar artery as an outflow vessel.

Digital ischemia and blue toe syndrome: Microemboli from proximal atherosclerotic plaques or aneurysms can lodge in the plantar digital arteries, causing sudden toe pain and cyanosis. The plantar arch's perforating connections may limit the extent of ischemia.

Heel pad necrosis: The medial calcaneal branches of the posterior tibial artery are essential for heel perfusion. In calcaneal fractures or pressure ulcers, their integrity is critical for wound healing.

Summary

Summary of the Plantar Arterial Supply

The posterior tibial artery divides into medial and lateral plantar arteries. The medial plantar artery supplies the medial sole and great toe. The lateral plantar artery forms the deep plantar arch, completed by the deep plantar branch of the dorsalis pedis artery. The arch gives off plantar metatarsal and digital arteries, supplying the toes and interossei. The dorsal and plantar systems are interconnected via perforating branches, providing collateral circulation. Clinical applications include PAD assessment, diabetic foot management, and surgical revascularization.