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jaws

Sunday 2 December 2018

jaw

WKP

Definition : The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of most animals.

In mammals, the jaws are made up of the mandible (lower jaw) and the maxilla (upper jaw).

In the ape there is a reinforcement to the lower jaw bone called the simian shelf.

In the evolution of the mammalian jaw, two of the bones of the jaw structure (the articular bone of the lower jaw, and quadrate) were reduced in size and incorporated into the ear, while many others have been fused together.

As a result, mammals show little or no cranial kinesis, and the mandible is attached to the temporal bone by the temporomandibular joints.

Temporomandibular joint dysfunction is a common disorder of these joints, characterized by pain, clicking and limitation of mandibular movement.