Jawbone pairing in the skull refers to the two bones of the maxilla and the mandible. The maxilla is nonmoveable, fixed and comprises upper jawbone and upper teeth. The mandible, the only bone in the skull that is moveable, is the mandible's companion.
Teeth are not necessary to ingest food, although chewing can certainly aid in swallowing. However, without either the maxilla or mandible, a stomach tube would be necessary for feeding. In addition to absence of one of the bones, misalignment can cause other problems. Temporomandibular joint (TMJ) disorder occurs when the maxilla and mandible don't align. This can cause problems, such as headache, loss of appetite, weight loss, trouble speaking and an inability to consume necessary nutrients to remain healthy.