Yläleukaan

Yläleukaan is Finnish for the upper jaw bone of the skull. In anatomical terms, it corresponds to the maxilla, a paired central bone of the facial skeleton that forms much of the middle third of the face.

Anatomy and features: Each maxilla has a body containing the maxillary sinus and an alveolar process that houses the upper teeth. The bone also includes the frontal process, zygomatic process, and palatine process, which together contribute to the orbital floor, the lateral wall of the nasal cavity, and the anterior part of the hard palate. The infraorbital foramen opens on the face to transmit nerves and vessels. The maxilla participates in the formation of the orbit, the nasal cavity, and the palate, and it articulates with several other bones.

Articulations and sutures: The maxilla articulates with the frontal, nasal, lacrimal, ethmoid, inferior nasal concha, palatine, zygomatic, sphenoid, and other nearby bones. The two maxillae meet at the intermaxillary suture along the midline, and the dentition is anchored in the alveolar processes.

Function: The maxilla supports the upper dentition and forms the floor of the orbit, the lateral wall of the nasal cavity, and the anterior portion of the hard palate. It also houses the maxillary sinus, which communicates with the nasal cavity and contributes to the resonance of the voice.

Development and clinical relevance: The maxilla develops from the first pharyngeal arch and undergoes growth that accommodates tooth eruption and sinus formation. Clinically important considerations include facial trauma and midface injuries such as Le Fort fractures, dental implant planning, and sinus health.

Nerve and blood supply: Sensory input to the maxilla is provided by the maxillary nerve (V2) via branches such as the infraorbital nerve. Blood supply largely comes from branches of the maxillary artery, with venous drainage to the pterygoid plexus and related pathways.