The temporomandibular joint is the jaw joint, the hinged point in the jaw that is formed by two bones, named the temporal and mandible bones. The temporomandibular joint is also frequently referred to as simply TMJ. There are two temporomandibular joints, one on each side of the face, each one working in concert with the other. TMJ plays a pivotal role in the normal chewing process, and is in fact essential for proper chewing, so that and any disease of this joint compromises the ability to make normal mouth movements and chew food. An affected dog will feel pain when closing or opening the mouth, or both. Diseases and disorders of the TMJ are referred to as temporomandibular joint disorders, which can be simplified with the abbreviation, TMD.