Normal opening of the mouth

This is the basic jaw movement of opening of the mouth. Besides this hinging movement, the jaw can also move forward and backwards, and a bit from side to side, but you can try this yourself. It is just important to keep in mind that the jaw has a very movable joint, and that the condyle moves forward in the opening of the mouth.
Btw the jaw in latin(anatomical language) is called the mandibula, in english mandible.