So it's been a while since I've seen the Nightmare Before Christmas, but it's come up in my thoughts recently. Or at least one specific background character.
This character is apparently called the Harlequin Demon. As you can see, instead on a mouth that uses a hinge joint, this guy has a ringed mouth that encompasses the circumference of his head. If you haven't seen the film, the rod connecting the top and bottom parts kind of moves the upper cranium up and down and that's how he talks. What would that even be, a piston joint?
When I was looking up references on how a radially symmetrical mouth would work, my mind ended up going to this weird looking design. And then I realized that it's kinda impractical.
That rod between the top and bottom part of the head likely contains the spinal cord. I don't know any way to make the spinal cord stretch up and down like that without damaging it.
Not to mention the potential difficulties with swallowing, breathing, and the fact that the spinal cord is now much more exposed and having to support the entire weight of the brain and top half of the head with no visible muscular support.
Now I'm wondering this: How can a mouth like this actually work?
(As in, how does it move up and down and not instantly snap off from the weight of the upper cranium. Breathing and eating I think could be possible, but somewhat challenging.)