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Body Surface

The primary surface landmarks of the anterior and lateral leg, and dorsal foot are associated with the patella, patellar ligament, tibia (tibial tuberosity and medial malleolus), fibula (head and lateral malleolus), and tendons of the tibialis anterior, extensor hallucis longus and extensor digitorum longus. The skin overlying the anterior and lateral leg and dorsal foot is innervated by the saphenous, lateral cutaneous of calf, superficial peroneal, sural, and medial plantar nerves.

Skeleton and Joints

The bones and joints associated with the anterior and lateral leg and dorsal foot are the femur, patella and tibia articulating at the knee joint, the tibia, fibula and talus articulating at the ankle joint and the tarsals, metatarsals and phalanges articulating at the joints of the foot. The knee joint moves in flexion and extension, and slight medial and lateral rotation (locking and unlocking knee with flexion and extension). The ankle joint moves in dorsiflexion and plantar flexion. The joints of the foot move in inversion and eversion. The phalanges move in abduction and adduction, and flexion/extension.

Fascial Organization

The deep fascia of the leg is continuous with the fascia lata and subdivides the leg into anterior, lateral and posterior compartments. It is very thick anteriorly where it forms attachements for the underlying muscles. There are anterior and posterior intermuscular septa that extend from the deep fascia to the fibula. The anterior intermuscular septum separates the anterior and lateral compartments. The posterior intermuscular septum separates the lateral and posterior compartments. A dense fibrous band, the interosseous membrane, separates the anterior and posterior compartments. A transverse intermuscular septum separates the superficial and deep muscles of the posterior compartment.

There are four retinacula associated with the fascia of the anterior and lateral compartments of the leg. The superior extensor retinaculum is a thickening of the deep fascia in the region of the tibiotalar joint that stabilizes the positions of the tendons of the tibialis anterior, extensor hallucis longus, extensor digitorum longus and peroneus tertius muscles. The inferior extensor retinaculum is a Y-shaped thickening of the deep fascia positioned distal to the superior extensor retinaculum that stabilizes the tendons of the extensor digitorum longus and peroneus tertius muscles. The superior and inferior peroneal retinacula are thickenings of the deep fascia that stabilize the tendons of the peroneus longus and brevis where they pass posterior to the lateral malleolus.

Muscles

The anterior compartment muscles are active in dorsiflexion of the ankle ( tibialis anterior, extensor hallucis longus and extensor digitorum longus), inversion of the foot (tibialis anterior), eversion of the foot ( peroneus tertius), extension of the 1st toe (extensor hallucis longus) and extension of the 2nd-5th toes (extensor digitorum longus). The lateral compartment muscles are active in plantar flexion of the ankle and eversion of the foot ( peroneus longus and peroneus brevis). The muscles of the dorsum of the foot are active in extension of the 1st ( extensor hallucis brevis) and the 2nd to 5th toes ( extensor digitorum brevis).

Innervation

The deep peroneal ( deep fibular) nerve innervates the muscles of the anterior compartment of the leg and dorsum of the foot. The superficial peroneal ( superficial fibular) nerve innervates the muscles of the lateral compartment of the leg.

Blood Supply

The anterior tibial artery supplies the anterior compartment of the leg. The peroneal and anterior tibial arteries supply the lateral compartment of the leg. The dorsalis pedis artery, the distal continuation of the anterior tibial artery, supplies the dorsum of the foot.