dentary

The dentary is the major bone of the lower jaw in jawed vertebrates. It is typically the largest component of the mandible and carries the teeth along its tooth-bearing margin. In most non-mammalian vertebrates, the lower jaw consists of several bones, including the dentary, articular, angular, coronoid, and splenial.

In many species the dentary forms the forward and lateral portion of the lower jaw and provides the framework for muscle attachments that drive mastication. The tooth-bearing portion, or alveolar margin, houses the dentition. The dentary articulates with the upper jaw bones to form the jaw joint; in mammals this joint is between the dentary and the squamosal (the temporomandibular joint).

Evolutionarily, the dentary enlarged in the lineage leading to mammals, while the articular and quadrate bones were repurposed into the middle ear as the malleus and incus. This transition marks a major shift from a jaw-supported hearing apparatus to a dedicated auditory system.

In humans, the mandible is the dentary bone on each side, forming the lower jaw with no other independent dentary elements. The term dentary is used in comparative anatomy and paleontology to denote this bone in jawed vertebrates.