yläleukaa

Yläleukaa, or upper jaw bone, is the central part of the facial skeleton that forms the upper dental arch. In humans there are two maxillae that together constitute the upper jaw, contributing to the roof of the mouth, the floor of the orbits, and the walls of the nasal cavity. Each maxilla consists of a central body and several processes that connect with neighboring bones.

It has a frontal process that articulates with the frontal bone, a zygomatic process with the zygomatic bone, and a palatine process that forms most of the hard palate. The alveolar process carries the upper teeth, and the maxillary sinus lies within the body.

Relations: It forms part of the orbital floor and the medial wall of the infraorbital groove. It articulates with the nasal, lacrimal, ethmoid, inferior nasal concha, palatine, vomer, and zygomatic bones; the two maxillae meet at the intermaxillary suture.

Development and growth: The maxilla is formed mainly by intramembranous ossification from neural crest cells. Growth continues with tooth eruption and facial development, and variations can occur among individuals.

Clinical relevance: The maxilla is involved in dental implants, trauma and Le Fort fractures, sinusitis of the maxillary sinus, and congenital conditions such as cleft lip and palate. Pathologies affecting the maxilla can influence occlusion and facial aesthetics.