Anterior Tibial Artery
The anterior tibial artery (a. tibialis anterior) is the primary vessel of the anterior fascial compartment of the leg.
It originates from the popliteal artery at the level of the lower border of the popliteus muscle. Immediately after its origin, it pierces the interosseous membrane of the leg (membrana interossea cruris) in its upper portion to reach the anterior compartment. Descending down the leg, it travels alongside the deep fibular nerve (n. fibularis profundus) between the anterior muscle group (initially between the tibialis anterior and extensor digitorum longus, and more distally between the tibialis anterior and extensor hallucis longus).
After passing beneath the inferior extensor retinaculum at the ankle joint, it continues as the dorsalis pedis artery (a. dorsalis pedis). Along its path, it gives off recurrent branches to the knee joint, muscular branches, and anterior malleolar arteries.
Clinical Significance: The anterior compartment of the leg is a closed osteofascial space. Trauma or overuse can cause swelling, leading to compartment syndrome. Increased pressure compresses both the vessel and the nerve. An early sign of ischemia is pain and sensory loss in the first web space of the foot, whereas the loss of dorsalis pedis pulse occurs in later stages when muscle damage is irreversible.
Posterior Tibial Artery
The posterior tibial artery (a. tibialis posterior) is the larger terminal branch of the popliteal artery and serves as the main blood supply to the sole of the foot.
It descends through the cruropopliteal canal (Gruber canal) together with the tibial nerve (n. tibialis). In the lower third of the leg, the vessel emerges from beneath the medial border of the soleus muscle, running superficially beneath the deep fascia. It then curves posterior to the medial malleolus, passing through the malleolar canal beneath the flexor retinaculum. In the sole, it divides into its terminal branches: the medial and lateral plantar arteries.
In addition to robust muscular branches supplying the posterior compartment, it gives off the nutrient artery of the tibia (a. nutricia tibiae), which is the largest nutrient artery of the human skeleton.
Pulse Point: The pulse of the posterior tibial artery is palpated posterior to the medial malleolus, midway between its tip and the calcaneal (Achilles) tendon. This is a critical landmark in diagnosing diabetic angiopathy.
Fibular Artery
The fibular artery (a. fibularis or peronea) is the largest branch of the posterior tibial artery, branching off in the upper third of the leg. It is not an independent direct branch of the popliteal artery.
The vessel courses laterally and inferiorly within the inferior musculofibullar canal (canalis musculoperoneus inferior) between the fibula and the flexor hallucis longus muscle.
Its branches supply the posterior and lateral leg compartments. Clinically, the perforating branch (r. perforans) is vital: it pierces the interosseous membrane in the lower third of the leg to reach the dorsum of the foot. If the dorsalis pedis artery is congenitally hypoplastic, the perforating branch of the fibular artery may take over its function.
The fibular artery is frequently utilized by reconstructive surgeons as a vascular pedicle for fibular autografts.
Compartment Blood Supply and Anastomoses
The leg is divided into three fascial compartments, each with distinct vascular characteristics:
| Fascial Compartment | Major Artery | Nerve |
|---|---|---|
| Anterior | a. tibialis anterior | n. fibularis profundus |
| Posterior | a. tibialis posterior, a. fibularis | n. tibialis |
| Lateral | None proper (supplied by a. fibularis branches) | n. fibularis superficialis |
The lateral compartment is unique because it lacks a dedicated major arterial trunk passing through it; instead, it is nourished by muscular and perforating branches of the fibular artery.
The arteries of the leg form a rich anastomotic network. Around the knee joint, recurrent branches of the anterior tibial artery anastomose with genicular arteries. In the lower third of the leg, the fibular and tibial arteries interconnect to form the malleolar and calcaneal networks (rete malleolare, rete calcaneum). Because of this collateral circulation, blood flow to the foot may be preserved even if one of the main arterial trunks is occluded.