The anterior tibial artery is one of the two terminal branches of the popliteal artery, responsible for supplying blood to the anterior compartment of the leg. It plays a crucial role in the blood supply to the muscles and structures of the lower leg and foot.
Location
The anterior tibial artery originates from the popliteal artery just below the knee, at the lower border of the popliteus muscle. It passes through the interosseous membrane between the tibia and fibula, entering the anterior compartment of the leg. The artery runs down the length of the leg, between the tibialis anterior and extensor digitorum longus muscles. It continues down the leg to the ankle joint, where it becomes the dorsalis pedis artery, which supplies the dorsal surface of the foot.
Anatomy
Origin
The anterior tibial artery originates as one of the two terminal branches of the popliteal artery. This bifurcation occurs at the lower border of the popliteus muscle, just below the knee joint, within the popliteal fossa. The artery quickly passes through a gap in the upper part of the interosseous membrane, which separates the tibia and fibula, to enter the anterior compartment of the leg.
Course
Once the anterior tibial artery enters the anterior compartment of the leg through the interosseous membrane, it runs down the length of the leg. It travels deep within the compartment, positioned between the tibialis anterior muscle (medially) and the extensor digitorum longus muscle (laterally). As it descends, it supplies oxygenated blood to the muscles and surrounding structures of the anterior compartment of the leg.
The artery continues downward toward the ankle joint, following a direct and superficial course along the front of the leg. As it approaches the ankle, it becomes more superficial, making it accessible for palpation in some locations.
Branches
Throughout its course, the anterior tibial artery gives off several important branches that supply blood to the muscles and structures of the anterior compartment, as well as to the knee and ankle regions:
- Posterior Tibial Recurrent Artery: This small artery branches off near the origin of the anterior tibial artery and supplies the popliteus muscle and the upper tibiofibular joint.
- Anterior Tibial Recurrent Artery: This branch supplies the knee joint and surrounding structures. It ascends from the artery just as it enters the anterior compartment and participates in the vascularization of the knee region, particularly the anastomosis around the knee.
- Muscular Branches: These small arteries branch off along the length of the anterior tibial artery and supply the muscles of the anterior compartment, including the tibialis anterior, extensor digitorum longus, and extensor hallucis longus.
- Anterior Medial Malleolar Artery: This small branch arises near the distal part of the leg and supplies blood to the medial side of the ankle joint, including the medial malleolus.
- Anterior Lateral Malleolar Artery: Similar to the medial branch, this artery supplies the lateral side of the ankle joint and the lateral malleolus, contributing to the vascular network around the ankle.
Termination
At the level of the ankle joint, just anterior to the talocrural joint, the anterior tibial artery becomes the dorsalis pedis artery. The dorsalis pedis artery is responsible for supplying the dorsal aspect of the foot and forms an important part of the arterial network that provides blood to the foot and toes.
Anatomical Relations
The anterior tibial artery is located deep within the anterior compartment of the leg, running along the anterior surface of the interosseous membrane. It is flanked by muscles, including the tibialis anterior medially and the extensor digitorum longus laterally. These muscles help protect the artery as it descends the leg. As it travels downward, it crosses over the distal tibia and becomes superficial at the level of the ankle, running between the tendons of the tibialis anterior and extensor hallucis longus.
In the distal leg and ankle, the artery lies anterior to the tibia and can be palpated in some individuals as it crosses in front of the ankle joint, just before it becomes the dorsalis pedis artery.
Vascular Relations
The anterior tibial artery is closely associated with the deep fibular nerve (also known as the deep peroneal nerve), which accompanies the artery throughout its course in the anterior compartment of the leg. The nerve runs parallel to the artery and supplies innervation to the same muscles and structures that receive blood from the artery.
Surface Anatomy and Palpation
As the anterior tibial artery passes into the foot, becoming the dorsalis pedis artery, it can be palpated on the dorsal aspect of the foot, just lateral to the extensor hallucis longus tendon. This transition point is often used clinically to assess arterial blood flow to the lower limb.
Function
Blood Supply to the Anterior Compartment of the Leg
The primary function of the anterior tibial artery is to supply oxygenated blood to the muscles and structures of the anterior compartment of the leg. This compartment contains muscles that are critical for dorsiflexion of the foot (lifting the foot upwards), extension of the toes, and stabilization of the ankle. The muscles receiving blood from the anterior tibial artery include:
- Tibialis Anterior: This muscle is responsible for dorsiflexion and inversion of the foot, playing a key role in walking, running, and maintaining balance.
- Extensor Digitorum Longus: This muscle extends the toes and contributes to dorsiflexion of the foot.
- Extensor Hallucis Longus: Responsible for extending the big toe and aiding in foot dorsiflexion.
By supplying these muscles, the anterior tibial artery ensures they receive adequate oxygen and nutrients, allowing for effective movement and stability in activities such as walking, running, and climbing.
Vascularization of the Knee Joint
The anterior tibial artery, through its anterior tibial recurrent branch, supplies the knee joint and surrounding structures. This branch helps form part of the arterial network around the knee, known as the genicular anastomosis, which provides collateral blood flow to the knee. The artery supports the movement and function of the knee by supplying oxygenated blood to the soft tissues, bones, and ligaments of the joint.
Supply to the Ankle Joint
The anterior tibial artery provides important blood supply to the ankle joint through its terminal branches, the anterior medial malleolar artery and the anterior lateral malleolar artery. These branches contribute to the vascular network around the ankle, ensuring proper circulation to the joint structures, including the bones, ligaments, and surrounding tissues. This arterial supply is essential for maintaining ankle stability, supporting movement, and allowing for efficient healing in case of injury.
Transition to the Dorsalis Pedis Artery
As the anterior tibial artery continues distally, it transitions into the dorsalis pedis artery at the level of the ankle. This transition marks a significant functional shift as the artery begins supplying blood to the dorsal surface of the foot. The dorsalis pedis artery provides oxygenated blood to the structures on the top of the foot, including the metatarsal bones, muscles, and toes. The anterior tibial artery’s role in continuing blood flow through the dorsalis pedis artery ensures that the foot’s dorsal aspect has a steady supply of oxygen and nutrients.
Oxygenation of the Muscles and Skin
By providing blood flow to the anterior compartment of the leg, the anterior tibial artery supports the oxygenation of muscles, skin, and soft tissues. Proper oxygenation is essential for muscle contraction, energy production, and tissue repair, particularly in the lower leg, which experiences continuous strain during walking, standing, and running. The artery ensures that the leg’s anterior muscles and skin remain healthy and capable of performing their functions efficiently.
Collateral Circulation
The anterior tibial artery also plays a role in the collateral circulation of the leg and foot. Through its branches, it forms anastomoses (connections) with other arteries, such as the posterior tibial artery, ensuring that if one pathway is obstructed or damaged, there are alternative routes for blood to reach the muscles and tissues. This function is especially important in cases of arterial blockages or trauma, helping to maintain adequate blood flow to the lower limb.
Nutrient Supply for Bone Health
In addition to supplying muscles, the anterior tibial artery delivers blood to the bones of the lower leg, particularly the tibia and fibula, through its smaller nutrient branches. This ensures that these bones receive the necessary nutrients and oxygen to support growth, repair, and maintenance. A healthy blood supply is crucial for preventing bone-related conditions and ensuring the strength and integrity of the lower leg bones during weight-bearing activities.
Removal of Metabolic Waste
Another key function of the anterior tibial artery is to facilitate the removal of metabolic waste products from the muscles and tissues it supplies. By providing continuous blood flow, the artery ensures that carbon dioxide, lactic acid, and other metabolic byproducts generated during muscle activity are efficiently removed. This is essential for preventing muscle fatigue, maintaining endurance, and supporting recovery after physical exertion.
Support for Dynamic Movements
Through its supply of oxygenated blood to the anterior compartment, the anterior tibial artery supports dynamic foot and leg movements, such as dorsiflexion and toe extension, which are vital for activities like walking, running, and maintaining balance. Without the artery’s proper function, the anterior muscles would not receive sufficient oxygen to carry out these movements effectively, leading to weakness, fatigue, or impaired mobility.
Clinical Significance
The anterior tibial artery is clinically significant due to its vital role in supplying blood to the anterior compartment of the leg, ankle, and dorsal surface of the foot. It is frequently assessed in conditions like peripheral artery disease (PAD), where reduced blood flow can lead to ischemia, particularly in the lower extremities. Blockage or injury to the anterior tibial artery may result in compromised circulation, causing pain, muscle weakness, and delayed healing in the leg and foot.
In cases of trauma to the lower leg, such as fractures or crush injuries, the anterior tibial artery can be damaged, leading to compartment syndrome, a condition where increased pressure within the leg compartments restricts blood flow. Additionally, during vascular surgeries or reconstructive procedures, the anterior tibial artery is often monitored to ensure adequate blood supply to the lower leg and foot. Its continuation as the dorsalis pedis artery makes it crucial for maintaining circulation to the foot, and the palpation of the dorsalis pedis pulse can be used to assess the arterial supply in the lower extremity.
