Flashcards in Anterior leg Deck (10):
Anterior compartment of the leg
-Extensor hallicus longus
-Extensor digitorum longus
The anterior (extensor) compartment lies between the deep fascia and the interosseous membrane between the tibia and fibula. The muscles in this compartment are ankle extensors or dorsiflexors.
All these muscles are supplied by the deep branch of the common fibular nerve. The toe extensors and ankle dorsiflexors help the foot to clear the ground in walking. There are two extensor retinacula which span the bones to prevent bowstringing of the tendons
Arises from the upper part of the lateral tibial surface and the interosseous membrane, and inserts into the medial cuneiform and the first metatarsal
Produces both dorsiflexion and inversion (inversion at subtalar joint)
Extensor hallicus longus
Arises from the medial part of the anterior surface of the fibula and the interosseous membrane, and inserts into the base of the distal phalanx of the great toe
Its actions are extension of the hallux (great toe) and weak dorsiflexion at the ankle
Extensor digitorum longus
arises from the upper two-thirds of the anterior surface of the fibula and the interosseous membrane, and inserts by four tendons into the bases of the middle and distal phalanges of the four lesser toes, as in the fingers.
Its actions are extension of the toes and weak dorsiflexion at the ankle
Arises in continuity with extensor digitorum longus but inserts into the dorsal surface of the base of the fifth metatarsal.
Dorsiflexes the ankle and everts the foot
What is eversion?
The sole of the foot faces outwards, and the lateral border moves outwards and upwards
occurs at the subtalar joint
Lateral compartment of the leg
The lateral (evertor) compartment of the leg is bounded by the anterior and posterior intermuscular septa.
The muscles in this compartment produce eversion of the foot at the subtalar joint. However, as their tendons run behind the lateral malleolus and hence posterior to the axis of the ankle joint, they are also weak ankle flexors or plantarflexors
Muscles in lateral compartment of leg
Arises from the upper part of the lateral aspect of the fibular shaft. Its tendon passes behind the lateral malleolus, grooves the cuboid to cross the sole obliquely, and inserts into the medial cuneiform and the base of the first metatarsal.
It is the antagonist to tibialis anterior. It also supports the lateral longitudinal and transverse arches of the foot