Knowra Jaw Jaw A hinged skeletal structure that supports biting or grasping in many vertebrates. In vertebrates with jaws, it bears teeth or other gripping surfaces and moves to handle food.
Temporomandibular joint : The joint connecting the lower jaw to the skull in mammals. It guides the lower jaw’s movements during biting, chewing, and speech.
Skull : The bony or cartilaginous framework that protects the brain and supports the face and sensory organs. The upper jaw is integrated with the skull, while the lower jaw articulates with it.
Gnathostomata : The vertebrate clade comprising jawed vertebrates, including fishes, amphibians, reptiles, birds, and mammals. Jaws define this major vertebrate group and distinguish it from jawless vertebrates.
Mastication : The process of crushing and grinding food with the teeth and jaws. Jaw movement breaks food into pieces that can be swallowed and digested.
Jawless fish : A fish lacking jaws, such as a lamprey or hagfish. Its feeding structures operate without the hinged jaw that defines jawed vertebrates.
Masseter muscle : A major jaw-closing muscle in mammals, extending from the cheekbone to the mandible. Its contraction raises the mandible and contributes strongly to bite force.
Maxilla : The upper jawbone in many vertebrates, forming part of the face and often bearing teeth. It provides the fixed counterpart to the moving lower jaw in many biting actions.
Placodermi : An extinct group of armored jawed fishes that flourished during the Paleozoic Era. Placoderms preserve some of the earliest evidence of jawed vertebrates.
Occlusion (dentistry) : The contact relationship between upper and lower teeth when the jaws close. A jaw’s alignment determines how opposing teeth meet during biting.
Bird beak : A hard, toothless covering of the upper and lower jaws in birds. A beak performs many jaw functions without teeth, using a specialized outer covering.
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