The ankle joint
The ankle joint is a hinge joint, the talus articulates with the tibia and fibula. This allows flexion and extension (known as dorsiflexion and plantarflexion at the ankle). Ligaments provide additional stability. On the inner side of the ankle there are 5 ligaments and on the outer side of the ankle there are 3 ligaments.
Muscles in the anterior lower leg are primarily ankle dorsiflexors and toe extensors. These muscles include tibialis anterior, extensor digitorum longus, extensor hallucis longus and peroneus tertius.
Muscles of the lateral lower leg are the peroneal group. These being responsible for plantar flexion and eversion.
Muscles of the posterior lower leg include the gastrocnemius, soleus, tibialis posterior, flexor digitorum longus and flexor hallucis longus. These muscles cause primarily plantar flexion and flexion of the toes.
The popliteus muscle, which crosses the knee, unlocks the extended knee in preparation for flexion.