Upper jaw

Upper jaw(maxilla) - a paired bone. The upper jaw has a body and four processes: frontal, alveolar, palatine and zygomatic.

The body of the maxilla (corpus maxillae) has an irregular shape and is limited by four surfaces.

The anterior surface of the body (facies anterior) is slightly concave. It is separated from the orbital surface by the infraorbital margin (margo infraorbitalis), under which is the infraorbital opening (foramen infraorbitale). Vessels and nerves pass through this opening. On the medial edge of the anterior surface is the deep nasal notch (incisura nasalis). It participates in the formation of the anterior opening of the nasal cavity (pear-shaped aperture).

The orbital surface (facies orbitalis) participates in the formation of the slightly concave lower wall of the orbit. In its posterior sections, the infraorbital groove (sulcus infraorbitalis) begins, going forward, passing forward into the canal of the same name, opening into the infraorbital foramen.

The infratemporal surface (facies infratemporalis) is separated from the anterior surface by the base of the zygomatic process. On the infratemporal surface is the tubercle of the maxilla (tuber maxillae), on which the alveolar canals (canales alveolares) open through small alveolar openings. Blood vessels and nerves pass through these canals. The greater palatine groove (sulcus palatmus major) is located vertically medial to the tubercle of the maxilla.

The nasal surface (facies nasalis) of the body of the maxilla participates in the formation of the lateral wall of the nasal cavity. It shows the maxillary cleft - a triangular opening that leads to the air-bearing maxillary (maxillary) sinus (sinus maxillaris), located in the thickness of the body of the maxillary bone. In front of the maxillary cleft is the vertically located lacrimal groove (sulcus lacrimalis). This groove participates in the formation of the nasolacrimal canal, which is also limited by the lacrimal bone and the inferior nasal concha.

The frontal process (processus frontalis) extends upward from the body of the maxilla, where it joins the nasal part of the frontal bone. On the lateral surface of the process there is a vertically located anterior lacrimal crest (crista lacrimalis anterior). It limits the lacrimal groove anteriorly. On the medial surface of the process there is a cribriform crest (crista ethmoidalis), with which the anterior part of the middle nasal concha of the ethmoid bone joins.

The alveolar process (processus alveolaris) extends downwards from the upper jaw in the form of a ridge - the alveolar arch (arcus alveolaris). This arch contains depressions - dental alveoli (alveoli dentales) for the roots of eight teeth of one half of the upper jaw. The alveoli are separated by thin bony interalveolar septa (septa interalveolaria).

The palatine process (processus palatinus) is a thin horizontal plate that participates in the formation of the hard palate. The lower surface of this process in the posterior sections has several longitudinally oriented palatine grooves (sulci palatini). In the anterior part of the process, the incisive canal (canalis incisivus) passes along the midline of the hard palate from bottom to top. Behind, the palatine process is connected to the horizontal plate of the palatine bone.

The zygomatic process (processus zygomaticus) extends from the superolateral part of the body of the maxilla towards the zygomatic bone.

Behind the maxilla is the infratemporal fossa (fossa infratemporalis), which is delimited from the temporal fossa at the top by the infratemporal crest of the greater wing of the sphenoid bone. The upper wall of the infratemporal fossa is made up of the temporal bone and the greater wing of the sphenoid bone (infratemporal crest). The medial wall is formed by the lateral plate of the pterygoid process of the sphenoid bone. The anterior wall of this fossa is the tubercle of the maxilla and the zygomatic bone. From the lateral side, the infratemporal fossa is partially covered by the branch of the mandible. In front, the infratemporal fossa communicates with the orbit through the inferior orbital fissure, and medially through the pterygomaxillary fissure (fissura pterygomaxillaris) - with the pterygopalatine fossa.

The pterygopalatine fossa (fossa pterygopalatina) has 4 walls: anterior, superior, posterior and medial. The anterior wall of the fossa is the tubercle of the maxilla, the superior wall is the lower lateral surface of the body and the base of the greater wing of the sphenoid bone, the posterior wall is the base of the pterygoid process of the sphenoid bone, and the medial wall is the perpendicular plate of the palatine bone. From the lateral side, the pterygopalatine fossa communicates with the infratemporal fossa. Below, the pterygopalatine fossa gradually narrows and passes into the greater palatine canal (canalis palatinus major), which is limited below by the maxilla (laterally) and the palatine bone (medially). Five openings open into the pterygopalatine fossa. Medially, this fossa communicates with the nasal cavity through the sphenopalatine foramen, above and behind - with the middle cranial fossa through the round opening, behind - with the area of the lacerated opening by means of the pterygoid canal, and downwards - with the oral cavity through the greater palatine canal.

The pterygopalatine fossa communicates with the orbit via the inferior orbital fissure.