Due to the complexity of the rearfoot and movement in multiple planes, understanding the motions at the talocrural and subtalar joints can be very difficult. This 3D demonstration break down each joint and discusses movement in both the open and closed chain environments.
A few take home points:
-Movement at the talocrural joint is primarily in the sagittal plane, resulting in dorsiflexion and plantarflexion.
-Movement at the subtalar joint consists of pronation and supination & changes whether it is occuring in open chain or closed chain.
-Open-chain pronation: dorsiflexion, eversion, and abduction of the calcaneous
-Open-chain supination: plantarflexion, inversion, and adduction of the calcaneous
-Closed-chain pronation: calcaneal eversion with plantarflexion and adduction
-Closed-chain supination: calcaneal inversion with dorsiflexion and abduction