Maxillary and palatine bones
- The maxillary bone : Figure 1
Bone of the upper facial mass, even and asymmetrical. Located between the orbits above, the oral cavity below and the nasal fossae inside.
The two maxillary bones fused together occupy the central part of the facial mass.
Quadrilateral in shape, it has two faces, four edges, four angles, three processes, and a cavity or sinus.
I) the faces:
1) the lateral face (jugal) : Present at the bottom, several vertical projections which correspond to the alveoli of the dental roots (alveolar jugums), the one corresponding to the canine is called the canine boss.
The myrtiform ( incisor) fossa (depression behind the canine bump).
The canine fossa (depression behind the canine hump).
In its upper part this face presents the pyramidal (zygomatic) process.
2) medial (nasal) face: divided into two parts by the palatine process (apophysis) into two parts; Nasal and buccal part.
a) Nasal part: centered by the hiatus of the maxillary sinus, in front of this hiatus is:
The lacrimal groove (lacrimal groove), and the inferior turbinal crest., behind: the greater palatine groove ( posterior palatine canal)
b) Mouth part: narrow.
II) the edges:
1) upper edges: articulates with: the unguis, the ethmoid and the palatine.
2) lower edge: alveolar.
3) posterior border: called the tuberosity of the maxilla, presents the alveolar foramens.
4) anterior edge: presents the nasal notch, it continues upwards with (rising process) :
III) The apophyses:
1) Pyramidal process : projection which extends outwards, articulates with the malar, has three faces, a base and a summit
– the upper or orbital face: forms the floor of the orbit, presents the suborbital groove which becomes a canal at its anterior part.
– Anterior, jugal surface: presents the suborbital hole (infraorbital foramen).
– Zygomatic posterior face
– The summit: articulates with the malar.
2) The palatine apophysis: The palatine process: it is a horizontal blade which joins that of the opposite side to form the palatine vault, presents in its anterior part the anterior nasal spine; and behind the anterior palatine canal and the incisive hole.
3) The ascending apophysis the frontal process : it extends upwards the anterior edge of the maxilla; flattened bony plate whose anterior edge corresponds to the nasal bone and the posterior edge to the unguis. On its medial face is the superior turbinal crest which articulates with the middle turbinate, on its lateral face is the anterior lacrimal crest and the lacrimal groove.
IV) the maxillary sinus (Highmore’s antrum): pneumatic cavity dug in the thickness of the maxillary sinus, it opens into the nasal fossae by the maxillary hiatus at the level of the middle meatus. The sinus has the shape of a triangular pyramid: the upper wall corresponds to the floor of the orbit, the posterior wall: corresponds to the pterygomaxillary region, the anterior wall corresponds to the jugal region, the base opens into the nasal fossae, the summit corresponds to the pyramidal process
Tooth decay can cause maxillary sinusitis.
Figure 1: Maxillary bone
A: lateral face B: medial face
- the palatine bone : Figures (2,3)
Paired and symmetrical bone, located behind the maxilla. Consists of two blades fused together at right angles: horizontal and vertical.
1) The horizontal blade : behind the palatine process of the maxilla it is united with its counterpart on the opposite side to form the posterior part of the bony palate. Quadrangular in shape with two faces and four edges:
The upper nasal and lower buccal surfaces
The edges:
a) anterior: welded to the posterior edge of the palatine process of the maxilla
b) Posterior: limits the choanae below, presents the posterior nasal spine
c) Internal and external.
2) The vertical blade : oriented upwards and backwards, has two faces, four edges and three processes.
The medial face: presents the superior turbinal crest and inferior turbinal crest which articulate successively with the superior turbinate and the middle turbinate.
The lateral face: has two articular surfaces:
Anterior: articulates with the internal face of the maxilla, and posterior: articulates with the internal wing of the pterygoid process; between these two surfaces we find the groove of the posterior palatine canal.
The edges: upper which presents the sphenopalatine notch (incisure), Lower, anterior and posterior.
The apophyses:
a) Pyramidal process: located on the lateral face of the vertical blade, above the union zone with the horizontal blade, articular with the maxillary tuberosity and the wings of the pterygoid process.
b) Orbital apophysis: arises from the upper edge, articulates with the maxilla, sphenoid and ethmoid (presents ethmoid cells)
c) Sphenoid process: behind the orbital process, articulates with the body of the sphenoid.
Figure 2: Palatine bone A. medial view (nasal side) B. lateral view ( maxillary side)
- perpendicular blade b. horizontal blade
1. orbital process 2. ethmoid crest 3. conchal crest 4. nasal crest 5. sphenopalatine notch 6. sphenoid process 7. posterior nasal spine 8. pyramidal process (medial pterygoid m.) 9. greater palatine foramen 10. lesser palatine foramen 11. greater palatine groove 12. maxillary surface 13. sinus surface 14. maxillary process
Figure 3: Palatine bone + maxillary bone (medial view = inferior view)
Maxillary and palatine bones
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