Oral Biology I &II

1. Oral Biology I &II

2. Syllabus

3. The skull The skull refers to all of the bones that comprise the head. The skull has 22 bones, excluding the ossicles of the ear. Except for the mandible, which forms the lower jaw, the bones of the skull are attached to each other by sutures, are immobile, and form the cranium.

5. The skull The cranium can be subdivided into: • an upper part (the calvaria); and • a lower anterior part-the facial skeleton (viscerocranium).

6. The skull The calvaria surrounds the cranial cavity containing the brain; (neurocranium or braincase) The bones forming the calvaria are: • the paired temporal and parietal bones, • and the unpaired frontal, sphenoid, ethmoid, and occipital bones. http://www.gwc.maricopa.edu/class/bio201/skull/latskul.htm http://www.gwc.maricopa.edu/class/bio201/skull/infskul.htm

9. The skull The viscerocranium is that part of the skull derived from the embryogenic pharyngeal arches; it comprises the facial bones of the facial skeleton.

10. The skull The bones forming the facial skeleton are: • the paired nasal bones, palatine bones, lacrimal bones, zygomatic bones, maxillae, inferior nasal conchae, and • the unpaired vomer. • The mandible is not part of the cranium nor part of the facial skeleton. http://www.gwc.maricopa.edu/class/bio201/skull/antskul.htm

13. Dento-Osseous Structures The osseous structures that support the teeth are: the maxilla and the mandible. http://www.gwc.maricopa.edu/class/bio201/skull/antskul.htm

14. The Maxilla The maxillae are the largest bones of the face, excepting the mandible, and form, by the union of the right maxilla and the left maxilla, the whole of the upper jaw.

15. The Maxilla Each assists in forming the boundaries of three cavities, the roof of the mouth, the floor and lateral wall of the nose and the floor of the orbit.

16. The Maxilla Each bone consists of: • a body and • four processes • zygomatic, • frontal, • alveolar, and • palatine.

17. The Maxilla The body (corpus maxillae) is somewhat pyramidal in shape, and contains a large cavity, the maxillary sinus (antrum of Highmore). Orbita Oral cavity

18. The Maxillae The body of the maxilla has four surfaces: • Anterior or facial surface • Orbital surface • Nasal surface • Infratemporal surface

19. The Maxillae They are sutured together at the median line. (intermaxillary suture). Suture:The saw-like edge of a cranial bone that serves as joint between bones of the skull.

20. The Maxillae intermaxillary suture Baby Child Adult

21. Anterior surface of the Maxillae The anterior or facial surface is separated from the orbitalaspect by the infraorbital ridge. Medially it is limited by the margin of the nasal notch.

22. Anterior surface of the Maxillae Posteriorly it is separated from the posterior surface by the anterior border of the zygomaticprocess, which has a confluent ridge directly over the roots of the first molar.

23. Anterior surface of the Maxillae The ridgecorresponding to the root of the canine tooth is usually the most pronounced and is calledthe canine eminence.

24. Anterior surface of the Maxillae Anterior to the canineeminence, overlying the roots of the incisor teeth, is a shallowconcavity known as the incisive fossa.

25. Anterior surface of the Maxillae Posterior to the canine eminence on a higher level isa deeper concavity called the canine fossa. The floor of this canine fossa is formed in partby the projecting zygomatic process. The major portion ofthe canine fossa is directly above the roots of the premolars.

26. Orbital surface of the Maxillae It together with the orbital surface of the zygomatic bone forms the floor of the orbit. The junction of this surface and the anterior surface forms the infraorbital ridge. Zygomatic bone

27. Orbital surface of the Maxillae The infraorbital ridge runs superiorly to form part of the nasal process. Its posterior border or edge coincides with the boundary of the inferior orbital fissure. Zygomatic bone

28. Orbital surface of the Maxillae Its lateral area iscontinuous with the base of the zygomatic process. Traversing the posterior portion of the orbital surface is the infraorbital groove.

29. Orbital surface of the Maxillae Thisgroove begins at the center of the posterior surface and runs anteriorly. The anterior portion of this groove is covered, becoming the infraorbital canal.

30. Orbital surface of the Maxillae The thin medial edge of the orbital surface is notched anteriorly forming the lacrimal groove. Behind this groove it articulates with the lacrimal bone for a short distance, then foragreater length with a thin portion of the ethmoid bone.

31. Orbital surface of the Maxillae The anterior opening of the infraorbital canal, infraorbital foramen, is located directly below the infraorbital ridge and above the canine fossa on the anterior surface.

32. Orbital surface of the Maxillae If the covered portion of this canal were to be laid open, the orifices of the middle and anterior superior alveolar canal would be seen transmitting the corresponding vessels and nerves to the premolars, canines, and the incisors.

34. Nasal surface of the Maxillae This surface is directed medially toward the nasal cavity. It is bordered below by the superior surface of the palatine process; anteriorly it is limited by the sharp edge of the nasal notch.

35. Nasal surface of the Maxillae Above and anteriorly, it is continuous with the medial surface of the frontal process; behind this it is deeply channeled by the lacrimal groove, which is converted into the lacrimalcanal by articulation with the lacrimal and inferior turbinate bones.

36. Nasal surface of the Maxillae Toward the posterior and upper part of this nasal surface a large, irregular opening into the maxillary sinus (antrum of Highmore) may be seen. This opening is partially covered by the inferior nasal concha.

37. Infratemporal surface The posterior or Infratemporal surfaceis bounded above by the posterior edge of the orbital surface.

38. Infratemporal surface Inferiorly and anteriorly it is separated from the anterior surface by the zygomatic process and the zygomatic ridge, which runs from the inferior border of the zygomatic process to the alveolus of the maxillary first molar.

39. Infratemporal surface This surface is more or less convex and is pierced in a downward direction by two or more posterior alveolar foramina. These two canals transmit the posterior superior alveolar vessels and nerves.

40. Infratemporal surface The inferior portion of this surface is more prominent where it overhangs the root of the third molar and is called the Maxillary tuberosity. The maxillary tuberosity is the origin for some fibers of the medial pterygoid muscle.

41. The Maxillae Each maxilla is somewhat cuboidal in shape which consists of a body and the four processes: the • zygomatic process, • frontal process, • palatine process, and • alveolar process

42. Zygomatic process The zygomatic processis a roughly triangular eminence, whose apex is placed inferiorly directly over the first molar roots.

43. The Maxillae Each maxilla is somewhat cuboidal in shape which consists of a body and the four processes: the • zygomatic process, • frontal process, • palatine process, and • alveolar process

44. Frontal process The frontal process arises from the upper and anterior body of the maxilla. Part of this process is formed by the upward continuation of the infraorbital margin.

45. Frontal process Medially, its edge articulates with the nasal bone. Superiorly the process articulates with the frontal bone. The medial surface of the frontal process forms part of the lateral wall of the nasal cavity.

46. The Maxillae Each maxilla is somewhat cuboidal in shape which consists of a body and the four processes: the • zygomatic process, • frontal process, • palatine process, and • alveolar process.

47. Palatine process The palatine process is a horizontal ledge extending medially from the nasal surface of the maxilla. Its superior surface forms a major portion of the nasal floor.

48. Palatine process The inferior surfaces of the combined left and right palatine processes form the roof of the mouth, the hard palate as far posteriorly as the second molar, where they articulate with the horizontal parts of the palatine bone at the transverse palatine suture.

49. Palatine process The inferior surface of the palatine process is rough and pitted for the palatine mucous glands in the roof of the mouth and pierced by numerous small foramina for the passage of blood vessels and nerve fibers.

50. Palatine process The posterior border of the palatine process is traversed obliquely from above downward and slightly medially by a groove which by articulation with the palate bone, is converted into the greater palatine canal and its opening, the greater palatine foramen.