Maxilla

The maxilla, or upper jaw bone, is one of the paired irregular bones that form the central portion of the human facial skeleton. Each maxilla articulates with the nasal bones, lacrimal bones, ethmoid, inferior nasal concha, palatine bones, zygomatic bone, frontal bone, and sphenoid bone. It houses the upper teeth in the alveolar process and contributes to the floor of the orbit, the lateral wall of the nasal cavity, and the anterior portion of the hard palate.

Anatomically, the maxilla consists of a body and four processes: the frontal process, zygomatic process, palatine process, and the alveolar process. The palatine process forms the anterior two-thirds of the hard palate by joining the horizontal plate of the palatine bone. The alveolar process contains dental sockets for the upper teeth. The maxillary sinus, an air-filled cavity within the maxillary body, is a notable feature that drains into the middle nasal meatus. The infraorbital groove and infraorbital foramen transmit the infraorbital nerve and vessels (branch of the maxillary division of the trigeminal nerve).

Function and clinical relevance include forming part of the orbital floor and nasal cavity, supporting teeth, and contributing to the facial contour. The infraorbital foramen is a key neurovascular landmark. The maxilla plays a central role in facial trauma patterns, notably Le Fort fractures, and in dental and sinus pathologies that affect the maxillary region. Developmentally, the maxilla forms by intramembranous ossification from the first pharyngeal arch and typically fuses with the opposite maxilla along the intermaxillary suture during early life.