upperjaw

The upper jaw, anatomically known as the maxilla, is the paired central bone of the upper facial skeleton. It forms the upper jaw and the dental alveolar arches that hold the upper teeth, and it contributes to the floor and rim of the orbits, the lateral wall and floor of the nasal cavity, and most of the hard palate. The maxilla contains the maxillary sinuses, which are air-filled spaces within the bone. The two maxillae meet at the intermaxillary suture in the midline.

Key structural features include the alveolar process for tooth sockets, the palatine process that forms the anterior part of the hard palate, and various processes and surfaces for articulation with neighboring bones. The infraorbital foramen on the anterior face transmits the infraorbital nerve and vessels. The maxilla also participates in the formation of the orbital floor, the lateral wall of the nasal cavity, and the anterior portion of the zygomaticomaxillary buttress, while the nasal and zygomatic processes provide articulation with the nasal, zygomatic, lacrimal, inferior nasal concha, frontal, ethmoid, palatine, and vomer bones.

Development and variation: the maxillae arise mainly through intramembranous ossification and traditionally fuse at the intermaxillary suture. Growth continues through childhood and adolescence, influenced by tooth eruption and craniofacial development. Variations in maxillary size or position can affect occlusion, aesthetics, and airway function.

Clinical relevance: maxillary fractures are clinically significant and are categorized in Le Fort fracture patterns (I, II, III) describing horizontal, pyramidal, and craniofacial disjunction injuries, respectively. The maxilla is involved in dental malocclusions, sinusitis involving the maxillary sinus, and in surgical procedures such as tooth replacement or reconstructive grafting.