Quadrate bone

For other uses, see Quadrate (disambiguation).
See also: Evolution of mammalian auditory ossicles
A schematic of an anapsid skull showing the location of major dermal bones of the upper skull, including the quadrate bone (q).

The quadrate bone is a skull bone in most tetrapods, including amphibians, sauropsids (reptiles, birds), and early synapsids.

In most tetrapods, the quadrate bone connects to the quadratojugal and squamosal bones in the skull, and forms upper part of the jaw joint. The lower jaw articulates at the articular bone, located at the rear end of the lower jaw. The quadrate bone forms the lower jaw articulation in all classes except mammals.[1]

Evolutionarily, it is derived from the hindmost part of the primitive cartilaginous upper jaw.

  1. ^ Romer, Alfred Sherwood, 1894-1973. (1978). The vertebrate body : shorter version. Parsons, Thomas S. (Thomas Sturges), 1930- (5th ed.). Philadelphia: Saunders. ISBN 0-7216-7682-0. OCLC 3345587.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)