Upper jaw
Last reviewed: 19.11.2021
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Upper jaw (maxilla) is a pair of bones. The upper jaw has a body and four processes: frontal, alveolar, palatine and zygomatic.
The body of the upper jaw (corpus maxillae) has an irregular shape, it is limited to four surfaces.
The front surface of the body (facies anterior) is slightly concave. It is separated from the orbit by the infraorbital margin (margo infraorbitalis), beneath which is the infraorbital foramen (foramen infraorbitale). Through this hole there are vessels and nerves. On the medial edge of the anterior surface there is a deep nasal incision (incisura nasalis). It is involved in the formation of the anterior opening of the nasal cavity (pear-shaped aperture).
The facial surface (facies orbitalis) is involved in the formation of a slightly concave lower orbit wall. In the posterior parts of it, the infraorbital furrow (sulcus infraorbitalis) begins, anterior to the anterior canal opening with the infraorbital foramen.
The subfamily surface (facies infratemporalis) is separated from the anterior surface by the base of the zygomatic process. The jaw of the upper jaw (tuber maxillae), on which the alveolar canals (canales alveolares) are opened by small alveolar holes, is located on the transplant surface. Blood vessels and nerves pass through these channels. The greater palatal sulcus (sulcuspalatmus major) is vertically located medial to the upper jaw.
The nasal surface (facies nasalis) of the body of the upper jaw participates in the formation of the lateral wall of the nasal cavity. On it, the maxillary cleft is visible - a triangular opening that leads to the air maxillary sinus maxillaris, located in the thickness of the body of the maxillary bone. Anteriorly from the maxillary fissure there is a vertically located tear sulcus (sulcus lacrimalis). This furrow is involved in the formation of the nasolacrimal canal, which is also limited by the tear and the lower nasal canal.
The frontal processus (processus frontalis) departs from the body of the upper jaw upward, where it joins the nose of the frontal bone. On the lateral surface of the appendage there is a vertically arranged anterior lacrimal crest (crista lacrimalis anterior). It limits the tear sulcus in front. On the medial surface of the appendage, a crista ridge (crista ethmoidalis) is visible, with which the anterior part of the median nasal shell of the latticed bone joins.
Alveolar processus (processus alveolaris) departs from the upper jaw downwards in the form of a roller-alveolar arc (arcus alveolaris). This arch contains indentations - dental alveoli (alveoli dentales) for the roots of eight teeth of one half of the upper jaw. The alveoli are separated by thin bone interalveolar septa (septa interalveolaria).
The palatine processus (processus palatinus) is a thin horizontal plate that participates in the formation of a solid palate. The lower surface of this appendage in the posterior sections has several longitudinally oriented palatine fissures (sulci palatini). In the anterior part of the process along the middle line of the hard palate, the incisive canalis (canalis incisivus) passes from the bottom upwards. Behind the palatine process is connected with a horizontal plate of the palatine bone.
The occlusal processus (processus zygomaticus) departs from the upper-lateral part of the body of the upper jaw towards the malar bone.
Behind the upper jaw there is a fossa infratemporalis (fossa infratemporalis), which is delimited from the temporal fossa by the dorsal crest of the large wing of the sphenoid bone. The upper wall of the inframammary fossa is formed by the temporal bone and the large wing of the sphenoid bone (trailing 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 upper jawbone and the malar bone. On the lateral side, the pterygoal fossa is partly covered by the branch of the lower jaw. At the front, the pterygoal fossa is communicating through the lower orbital fissure with the orbit, and medially through the pterygoid-maxillary fissure (fissura pterygomaxillaris) - with the pterygoid fossa.
The pterygo-palatine fossa pterygopalatina has 4 walls: anterior, anterior, posterior and medial. The anterior wall of the fossa is the tubercle of the upper jaw, the upper is the lateral surface of the body and the base of the large wing of the sphenoid bone, the posterior is the base of the pterygoid process of the sphenoid bone, the medial is the perpendicular plate of the palatine bone. From the lateral side, the pterygopalatine fossa is associated with the pteryphalic fossa. The pterygo-palatine fossa narrows gradually to the large palatine canal (canalis palatinus major), which below the upper jaw (lateral) and the palatine bone (medially). In the pterygoid palatine, 5 holes are opened. Medially, this fossa communicates with the nasal cavity through the wedge-palatine orifice, from above and backwards - with the middle cranial fossa by means of a round hole, posteriorly with the area of the lacerated hole by the pterygoid canal, downwards - with the oral cavity through the large palatal canal.
With the eye socket, the pterygoid-palatine fossa is reported through the lower orbital fissure.
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