The lateral plantar artery is one of the two terminal branches of the posterior tibial artery, the other being the medial plantar artery. It supplies blood to the lateral portion of the foot, particularly the sole, and plays a key role in the vascularization of the foot’s structures.
Location
The lateral plantar artery begins at the posterior aspect of the medial malleolus, where it branches from the posterior tibial artery. It runs obliquely across the sole of the foot, initially deep to the abductor hallucis muscle. It continues laterally and forward, passing between the flexor digitorum brevis and quadratus plantae muscles, then curves medially to form the plantar arch, which connects with the deep plantar branch of the dorsalis pedis artery. The artery supplies the lateral side of the sole, the lateral toes, and contributes to the deep plantar arch.
Structure and Anatomy
Origin
The lateral plantar artery arises as one of the two terminal branches of the posterior tibial artery. This branching occurs as the posterior tibial artery passes behind the medial malleolus, located near the inner aspect of the ankle. The lateral plantar artery originates alongside the medial plantar artery at the level of the ankle, just distal to the flexor retinaculum.
Course
After its origin, the lateral plantar artery travels obliquely across the sole of the foot. Initially, it runs deep to the abductor hallucis muscle and then passes laterally under the cover of the flexor digitorum brevis and quadratus plantae muscles. It moves along the lateral side of the foot toward the base of the fifth metatarsal.
Branching and Relationship to Muscles
The lateral plantar artery is closely associated with several muscles of the sole, as it lies deep within the foot:
- Abductor Hallucis Muscle: The artery passes underneath this muscle as it begins its course along the medial aspect of the foot.
- Flexor Digitorum Brevis Muscle: As the artery progresses laterally, it passes deep to the flexor digitorum brevis.
- Quadratus Plantae Muscle: The artery passes superficially to this muscle before reaching the lateral border of the foot.
The lateral plantar artery gives off numerous small branches along its path to supply these muscles and other soft tissues within the sole of the foot.
Formation of the Plantar Arch
One of the most important features of the lateral plantar artery’s anatomy is its contribution to the formation of the deep plantar arch. Upon reaching the lateral side of the foot, near the base of the fifth metatarsal, the artery curves medially and runs across the foot’s sole to form the deep plantar arch.
This arch connects with the deep plantar branch of the dorsalis pedis artery, which descends from the dorsal side of the foot. Together, these vessels form an important arterial network that supplies blood to the toes and deeper structures of the foot.
Terminal Branches
The lateral plantar artery terminates by giving off several branches that contribute to the plantar arch, as well as digital branches that supply the lateral toes. These branches include:
- Plantar Metatarsal Arteries: These arteries emerge from the plantar arch and supply the metatarsals and toe regions.
- Plantar Digital Arteries: These smaller arteries branch from the plantar metatarsal arteries to supply blood to the individual toes, particularly the lateral aspect of the foot and toes.
Size and Appearance
The lateral plantar artery is larger than the medial plantar artery, reflecting its more extensive role in supplying the sole of the foot. It has a tortuous, curving course as it moves from the medial side to the lateral side and then forms the plantar arch across the midfoot. The artery is accompanied by the lateral plantar nerve, which follows a similar course along the foot’s lateral aspect.
Associated Structures
- Lateral Plantar Nerve: The artery runs alongside the lateral plantar nerve, which follows a similar path from the medial ankle across the sole of the foot. The two structures travel together as they supply the lateral part of the foot.
- Posterior Tibial Artery: The lateral plantar artery is a direct branch of the posterior tibial artery, which continues to supply other parts of the foot through its medial plantar artery branch.
- Deep Plantar Arch: The lateral plantar artery forms a significant part of the deep plantar arch, which connects with the dorsalis pedis artery and supplies the deeper structures of the foot and toes.
Surrounding Soft Tissue and Bones
The lateral plantar artery lies deep within the sole of the foot, surrounded by the plantar fascia, muscles, and tendons. As it courses toward the lateral side, it is in close proximity to the metatarsal bones and the bones of the midfoot, including the cuboid and the base of the metatarsals. Its deep location ensures that the artery is well protected by the surrounding muscles and soft tissue layers, reducing its vulnerability to injury during routine movement and weight-bearing activities.
Function
Blood Supply to the Lateral Side of the Foot
The primary function of the lateral plantar artery is to provide oxygenated blood to the lateral aspect of the sole of the foot. As the artery courses from the medial side of the ankle toward the lateral side, it delivers vital blood flow to the muscles, skin, and soft tissues located along the outer side of the foot. This includes the abductor digiti minimi, flexor digitorum brevis, and the lateral lumbricals. Proper blood flow ensures that these structures function optimally, particularly in supporting the movement of the toes and the lateral aspect of the foot.
Contribution to the Plantar Arch
One of the key roles of the lateral plantar artery is forming the deep plantar arch, a crucial arterial structure that supplies the forefoot and toes. Upon reaching the lateral side of the foot, the lateral plantar artery curves medially and connects with the deep plantar branch of the dorsalis pedis artery to create the plantar arch. This arch acts as a central hub, distributing blood to the plantar metatarsal arteries, which further supply the bones and muscles of the forefoot and toes. This extensive vascular network is essential for maintaining circulation in the plantar region of the foot, supporting locomotion and weight-bearing activities.
Supply to the Plantar Muscles
The lateral plantar artery supplies several key muscles within the sole of the foot. These include:
- Abductor Digiti Minimi: This muscle, responsible for abducting the little toe, receives its blood supply from branches of the lateral plantar artery.
- Flexor Digitorum Brevis: The artery also supplies the flexor digitorum brevis, which is important for flexing the toes.
- Quadratus Plantae: Another muscle critical to foot movement, particularly in flexion of the toes, is supplied by the lateral plantar artery.
The blood supply to these muscles ensures that the foot’s dynamic functions, including maintaining balance and executing fine motor movements like toe flexion, are supported by adequate oxygen and nutrient delivery.
Supply to the Plantar Metatarsal and Digital Arteries
Another important function of the lateral plantar artery is to supply blood to the plantar metatarsal arteries, which branch off from the plantar arch. These metatarsal arteries further divide into plantar digital arteries that supply the toes. This arterial network ensures that each toe, especially the lateral toes (fourth and fifth), receives an adequate blood supply to sustain normal function, skin health, and movement.
The plantar metatarsal arteries support the metatarsal bones and surrounding structures, while the plantar digital arteries provide critical blood flow to the toes themselves, including the skin, connective tissue, and small muscles involved in toe movement and balance.
Oxygenation of Foot Structures
By supplying oxygen-rich blood, the lateral plantar artery ensures that all the structures of the foot it serves, including muscles, bones, ligaments, tendons, and skin, receive the necessary oxygen and nutrients for metabolic functions. This is particularly important in maintaining the health of tissues that are under constant pressure and stress during standing, walking, and running. A healthy supply of oxygenated blood helps prevent ischemia, tissue damage, and potential infections, which are essential for overall foot health.
Support for Weight-Bearing and Locomotion
The lateral plantar artery supports the functions of muscles and bones involved in weight-bearing and walking. As the main artery for the lateral part of the foot, it ensures that the foot can sustain prolonged periods of standing and walking by delivering continuous blood flow to the sole. The artery’s distribution to muscles like the quadratus plantae and flexor digitorum brevis helps facilitate the flexion and stabilization of the toes, which are essential for maintaining balance and propulsion during walking.
Collateral Circulation
The lateral plantar artery also plays a role in maintaining collateral circulation within the foot. Through its connections with the dorsalis pedis artery via the plantar arch, it helps ensure continuous blood flow, even if there are disruptions in other arteries supplying the foot. This function is crucial for maintaining circulation and foot viability in cases where there may be vascular blockage or damage to other arterial branches.
Clinical Significance
The lateral plantar artery holds clinical importance due to its role in supplying blood to the lateral side of the foot and contributing to the plantar arch. In surgical procedures involving the foot, particularly in trauma or reconstructive surgeries, the artery’s anatomy and branches must be carefully considered to avoid complications like ischemia. Injuries to the artery can lead to insufficient blood flow to the lateral foot and toes, potentially causing tissue necrosis or delayed wound healing.
The artery is also relevant in conditions like peripheral artery disease (PAD), where impaired blood flow can lead to pain, ulcers, or gangrene in severe cases. Additionally, in diabetic patients with compromised circulation, maintaining the health of the lateral plantar artery is crucial for preventing foot ulcers and infections. Understanding the lateral plantar artery’s role in the plantar arch also helps during procedures like bypass grafting or angioplasty, where restoring blood flow to the foot is necessary.
