Quadrate
From Academic Kids
The quadrate is a jaw bone in all jawed vertebrates except mammals (in whom it has become a middle-ear bone, the incus). It connects to the quadratojugal and squamosal in the skull, and articulates with the lower jaw bone that is uncreatively called the articular.
In snakes, this bone has become elongated and very mobile, and contributes greatly to their ability to swallow very large prey items.
