The movements of the foot & ankle are directed by muscles in the foot & foreleg. The ankle is capable of extension (plantarflexion where the toes are pointed), flexion (dorsiflexion where the toes are drawn back towards the shinbone), inversion (where the big toe is drawn towards the medial line, sometimes referred to as supination), & eversion (where the pinkie toe is drawn towards the lateral line, sometimes referred to as pronation).
The foreleg is divided into three regions:
- Anterior: Tibialis anterior attaches along the top of the foot & is responsible for dorsiflexion & inversion of the foot. Together with fibularis longus, these two muscles create a myofascial stirrup that creates balance in the arch of the foot & allows us to balance on a single foot in our standing asanas.
- Lateral: The lateral compartment is comprised of the fibulares muscle group. As the name implies, fibularis longus is the longest of the three muscles. It attaches to the top & side of the fibula (shin bone). This muscle, along with fibularis brevis & fibularis, tertius are responsible for eversion of the foot.
- Posterior: The gastrocnemius & the soleus are two strong muscles in the posterior compartment that attach to the heel bone via the Achilles tendon. The gastrocnemius actually crosses the both the ankle & knee joint & attaches to the femur. When these muscles contract, they pull the heel into plantarflexion.