The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible, which is also a fusion of two halves at the mental symphysis.
The maxilla assists in forming the boundaries of three cavities:
The maxilla also enters into the formation of two fossae: the infratemporal and pterygopalatine, and two fissures, the inferior orbital and pterygomaxillary.
Sometimes it articulates with the orbital surface, and sometimes with the lateral pterygoid plate of the sphenoid.