Hinges

The joint capsule is often interwoven with ligaments. These are coarse reinforcing strands that directly connect the epiphysis of the two articulating bones and give the joint stability in unfavorable loading situations. These reinforcing cables protect, for example, the inner and outer walls of the upper ankle joint from "bending" the foot.

https://de.wikipedia.org/wiki/Gelenkkapsel _{(Wikipedia CC-by-sa-3.0)}