The foot is a complex, highly vascularized extremity that relies on a constant supply of oxygenated blood. This continuous blood flow nourishes the dense network of muscles, bones, tendons, and skin necessary for movement, balance, and shock absorption. The circulatory system in the foot is intricately designed, featuring a sophisticated network of vessels that ensure tissue health and function, especially under the pressure of daily activities.
Major Arteries Supplying the Foot
The blood supply to the foot begins with two main arteries that descend from the lower leg: the Posterior Tibial Artery and the Dorsalis Pedis Artery. These primary conduits supply the sole and the top of the foot, respectively. The Posterior Tibial Artery curves around the inside of the ankle through the tarsal tunnel.
Once it enters the foot, the Posterior Tibial Artery divides into the medial and lateral plantar arteries, which supply the sole, or plantar surface. The Dorsalis Pedis Artery is a continuation of the anterior tibial artery, crossing the ankle joint and traveling across the top, or dorsal aspect, of the foot over the tarsal bones.
The Dorsalis Pedis Artery nourishes the skin and structures on the top of the foot, branching into several small tarsal and metatarsal arteries. Its pathway is straight until it reaches the space between the first and second metatarsal bones, where it dives deeper. These separate pathways ensure both the top and bottom of the foot receive a dedicated supply before they join together in a critical network.
The Intricate Network Within the Foot
The major arteries connect inside the foot to create a fine-tuned distribution system centered on the Plantar Arterial Arch. This arch forms when the lateral plantar artery and a deep branch of the dorsalis pedis artery connect, lying deep within the sole across the bases of the metatarsal bones.
The arch ensures blood flow continues even if a primary route is temporarily compressed, such as during standing or walking. From this Plantar Arch, four plantar metatarsal arteries branch off, running forward between the metatarsal bones toward the toes.
These vessels divide into smaller plantar digital arteries, which supply the adjacent sides of the toes. This arrangement creates an extensive web of interconnected vessels, including dorsal metatarsal arteries that communicate with the plantar system via small perforating branches.
Assessing Circulation and Artery Health
Understanding the location and function of foot arteries is important for assessing overall circulatory health. Healthcare providers routinely check the two main pulses in the foot to evaluate blood flow. The Dorsalis Pedis pulse is felt on the top of the foot, while the Posterior Tibial pulse is checked behind the inner ankle bone (medial malleolus).
A weak or undetectable pulse can signal reduced blood flow, often associated with Peripheral Artery Disease (PAD). PAD occurs when plaque buildup narrows the arteries, restricting the delivery of oxygen-rich blood to the extremities. Common signs of poor circulation include:
- Skin changes like shininess.
- Brittle toenails.
- Lack of hair growth on the lower legs and feet.
- Coldness or numbness in the feet.
- Sores on the toes and feet that are slow to heal.
To diagnose PAD, the Ankle-Brachial Index (ABI) is a common, non-invasive test. The ABI compares blood pressure in the ankle to the blood pressure in the arm to determine if blood flow to the foot is significantly reduced due to arterial blockage.