The Verge offered some details in a post at launch, but not much in the way of specifics beyond calling it an “articulated hinge”. UPDATE: This post was edited to clarify the way that muscle ...

Hinge joint. Articulating bones are femur and tibia (the patella is not classed as part of the joint, nor is the fibula). Allows bending (flexion) and straightening (extension). Muscles which move ...

ii. With loss of bones, switch to bones articulating hinge between upper and lower jaw. Amphibian, reptile: quadrate (upper) and articular (lower) jaw form hinge. 2 small bones form hinge: not very ...