Axial Skeleton Skull

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Slides to accompany an anatomy lecture to introduce axial skeleton and go through each bone of the skull

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<ul><li> 1. Axial Skeleton Part 1</li></ul> <p> 2. There areapproximately206 bones in the adult skeleton, although the exact number varies from individual to individual 3. Theaxial skeleton(dark bones in this picture) are the skull and associated bones, the vertebral column, and the bones of the rib cage.Theappendicular skeleton(pale bones in this picture) are the bones of the extremities and the shoulder and pelvic girdle 4. Hollywood feels that skulls are scary and remind us of our mortality 5. There are typically 8 cranial bones and 14 facial bones. 6. 7. The configuration of thefacial bonescontribute greatly to the individuality of the human face. 8. Cranial cavity(superior portion of dorsal body cavity) houses the brain 9. Thecalvaria , the upper dome-like portion of the skull, consists of portions of the frontal, parietal, and occipital bones. 10. Frontal bone Sphenoid bone Temporal bone Occipital bone Ethmoid bone Thebase of the craniumis composed of portions of the frontal, ethmoid, sphenoid, temporal, and occipital bones 11. Thenasal septum , composed of bone and cartilage, divides the nasal cavity into left and right halves. 12. There are 4 sets ofparanasal sinusesthat all drain into the nasal cavity. 13. 14. WHICH OF THE FOLLOWING ISNOTPART OF THE CALVARIA? A WORMIAN BONES B CORONAL SUTURE C SAGITTAL SUTURE D ETHMOID BONE E OCCIPITAL BONE 15. The author begins with an overview of the entire skull.Feel free to look it over.However, I will go into details as I discuss each bone . 16. The 8cranial bonesare those bones thatdirectlysurround the brain.Injuries that penetrate these bones areoften fatal .In contrast, damage to the facial bones, while disfiguring, are usually not fatal. 17. The singlefrontal boneforms the anterior roof and anterior floor of the cranium, the forehead, a portion of the nasal cavity roof, and the superior arch of the orbits. 18. Anterior view offrontal bone 19. Inferior view offrontal bone . Note central gap where the ethmoid bone is normally located in roof of nose. 20. Lacerations from car crashes can expose thefrontal bone. Bleeding in tissues around eyes possibly suggests intracranial bleeding. 21. Supraorbitalmargin 22. Thesupraorbital foraminaallow passage of small nerves and blood vessels.Forceful pressure at this site can cause great pain! 23. Thefrontal sinusmay or may not be present.When present is contains air, mucous, and ciliated cells.It drains into the nasal cavity. 24. The sinuses, and the nose, are lined withciliated cellswith an overlying layer of mucous. 25. 26. Thedistinctive shape of the frontal sinusescan be used to identify crime victims if a previous dental x-ray has been kept. 27. Theparietal bonesform the lateral walls and roof of the cranium.They are divided along the midline by the sagittal suture and separated from the frontal bone by the coronal suture. 28. The twoparietal bonesform the upper sides and roof of the cranium 29. Note that theparietal boneshave an inner layer of diplo Cancellous bone Compact bone 30. Skull from pre-Columbian Larsen village demonstratingscalping markson parietal bone. 31. 32. 33. 34. First blow Second blow 35. Read aboutcraniosynostosis(premature fusion of the sagittal suture) in you text 36. Thetemporal bonesform the lower sides and part of the floor of the cranium Squamosal suture 37. Thepetrous portion of the temporal bonecontains the carotid canal and the jugular foramen 38. Close-up ofpetrous portion of temporal boneshowing the carotid canal and the jugular foramen.Note that theinternal carotid artery(which brings blood to the brain) enters the carotid canal at an angle and then exits into the cranial cavity via the foramen lacerum.The jugular foramen, located between the temporal and occipital bones, allows theinternal jugular vein(which drains blood from the brain) to exit. 39. Noteinternal auditory canalthat allows nerves and blood vessels to travel to and from the inner and middle ear. 40. Themastoid portion of the temporal bonecontains the hollow mastoid process. 41. 42. 43. Thesquamous region of the temporal boneis the lateral flat surface below the squamosal suture.Included are the zygomatic process and the mandibular fossa. 44. Temporomandibular joint(TMJ) 45. Close-up oftemporomandibular joint(TMJ) 46. Thetympanic portion of temporal bonecontains the external acoustic meatus and the styloid process. 47. ACCORDING TO THE ARTICLE A LIFETIME OF PAIN, WHICH OF THE FOLLOWINGISA SYMPTOM OF TEMPOROMANDIBULAR JOINT (TMJ) DSYFUNCTION? A BLINDNESS B MEDIASTINAL PAIN C RUNNY NOSE (RHINORRHEA) D FACIAL FLUSHING E CERVICAL PAIN 48. The singleoccipital bone(#15) forms the back and much of the base of the skull.Note thelambdoidal sutureas #14. 49. Inferior view ofoccipital bone . Note the formen magnum Foramen magnum 50. Theoccipital condylesrock on the upper surface of the first vertebra 51. There are two prominent horizontal ridges on the posterior of the occipital bone: theinferior nuchal lineand thesuperior nuchal line . 52. The singlesphenoid bone , with its bat-like shape, contributes to the base of the skull. 53. The singlesphenoid boneis often referred to as the bridging bone because it unites many of the cranial bones and facial bones. 54. The sphenoid bone is hollow and contains thesphenoidal sinuses .Because of these sinuses, and the numerous foramina in this bone, it is often fractured by traumatic movements of the brain. 55. Thesella turcicahouses the pituitary gland, which produces a wide variety of hormones, including growth hormone. 56. Traumatic shifts in the brains position can shear the pituitary stalk. 57. Beware head in the dashboard syndrome! 58. There arenumerous foraminain the sphenoid bone. 59. Foramen lacerumis an opening between the sphenoid and the temporal bones. 60. WHICH OF THE FOLLOWINGIS CORRECTABOUT THE SPHENOID BONE? A IT ARTICULATES WITH THE OCCIPITAL BONE B IT CONTAINS THE STAPES C IT ALLOWS PASSAGE OF THE INTERNALJUGULAR VEIN D IT CONTAINS THE CAROTID CANAL E ALL OF THE ABOVE 61. The singleethmoid boneis located in the anterior floor of the cranium between the orbits where it contributes to the roof of the nasal cavity. 62. Theethmoidal sinuses(shown in blue) contain air, mucous, and ciliated epithelial cells.They empty into the nasal cavity. 63. The most inferior portion of the ethmoid is theperpendicular plate , which contributes to the nasal septum. The crista galli (cocks comb) is the most superior portion of the ethmoid 64. Cocks comb 65. 66. Falx means scythe (referring to the shape) 67. Thecribriform plateof the ethmoid contributes to the floor of the cranium and the roof of the nose.It is a weak structure! 68. Cribriformmeans like a sieve. Whatpasses through the holes of the cribriform plate? 69. Branches of the olfactory nerve(cranial nerve I) pass through the holes in the cribriform plate to innervate the roof of the nasal cavity for our sense of smell. 70. Fractured cribriform platecan allow the fluid around the brain to escape into the nose and microbes to enter into meninges 71. If bacteria from the nose enter through a fractured cribriform plate into the cerebrospinal fluid within the meninges,deadly meningitis can result . 72. Egyptian mummiestypically had their brains removed during the embalming process. 73. A small curved rod, with a spoon-like tip at the other end, was punchedthrough the cribriform plateto scoop out the brain through the roof of the nose. The brain was then thrown away. 74. Egyptian embalming tools .Note one used for removing brain. 75. Theperpendicular plateis the most inferior portion of the ethmoid 76. Thesuperior and middle nasal conchae(turbinates), shown in green,are medial projections of the ethmoid into the nasal cavity.The inferior nasal conchae are separate facial bones andnotpart of the ethmoid. 77. 78. Facial Bones 79. Facial bones 80. There are 14facial bones 81. Facial bonesprovide the basic shape of the face 82. Zygomatic bonesform the bony prominence of the cheeks. They also contribute to the zygomatic arch and the lateral margin of the orbits. 83. Zygomatic bone 84. 85. 86. Thetear ductsdrain just inferior to the inferior nasal conchae 87. Nasal bonescontribute to the roof of the nasal cavity.They are easily fractured. 88. Major injury to nasal bones 89. Fractured nasal bones 90. 91. Thevomerbone contributes to the inferior portion of the nasal septum 92. Vomermeans plow 93. Thenasal septumconsists of the perpendicular plate of ethmoid, the vomer, and septal cartilage 94. 95. This killing blow is actually harder to do than fictional novels suggest.Master Longdoesknow how to do it right!Moreover, it isnotthe septal cartilage that does the penetrating but rather is the ethmoid. 96. Mister Miyagi also knows how to do this killing blow, especially when dealing with evil senseis who show no mercy. 97. 98. Inferior nasal conchae(inferior turbinates) 99. Inferior nasal conchae,along with the rest of the inner nose, are covered with highly vascular moist mucous membrane. 100. The left and rightpalatine bonesform the posterior third of the hard palate (the palatine processes of the maxillae form the front two thirds), a portion of the nasal cavity, and, surprisingly, a portion of the orbits. 101. 102. The twomaxillaeunite along the midline to form the upper jaw. 103. Theteethof the maxillae are located in sockets (alveoli). 104. Thepalatine processes of the maxillae , along with the left and right palatine bones, form the hard palate and the floor of the nasal cavity. 105. Noteinfraorbital foramenwhich allows passage of a nerve and blood vessels. 106. (hare lip) 107. Cleft palate and a hare lip repair 108. The hugemaxillary sinusescontain air, mucous, and ciliated epithelial cells.They drain into the nasal cavity through an opening high on the medial side (poor drainage). 109. Note largemaxillary sinuses 110. Note maxillary sinus hasthin overlying boneanteriorly and superiorly. 111. Drainage route Note that thedrainage opening for the maxillary sinuses is high up on the medial side .This allows fluid to accumulate more easily, and infection to happen more easily, than occurs in the other sinuses. 112. Fracture of the maxillary sinuses can occur with blows to the face 113. WHICH OF THE FOLLOWING IS ACORRECTSTATEMENT? A FRACTURE OF THE NASAL BONES WILLTYPICALLY LEAD TO MENINGITIS B THE TEAR DUCTS DRAIN INTO THE MOUTH JUSTBELOW THE TONSILS C NERVE ENDINGS ASSOCIATED WITH THE NASALSEPTUM CAN CHANGE OVULATION D THE ZYGOMATIC BONES CONTAIN ALVEOLI E MUMMIFICATION INVOLVED PUNCHINGTHROUGHTHE FRONTAL SINUS TO REMOVE THEBRAIN 114. Fractured zygomatic bone andfractured maxillary sinusfrom punch to the face.When palpatedcrepituswas noted. 115. A blow to the eye and orbit can fracture the floor of the orbit and the and its muscles may drop down into upper portion of maxillary sinus (blow out fracture). 116. Blowout fracture 117. Blowout fractureof left eye Patient is asked to look up with both eyes, but the muscles of the left eye are trapped Normal eye 118. WHICH OF THE FOLLOWING CONTRIBUTES TO THELATERAL WALLSOF THE NASAL CAVITY? A PALATINE BONES B MAXILLAE C ETHMOID D LACRIMAL BONES E ALL OF THE ABOVE 119. Hamlet is evaluating Opheliasmandible 120. Note the alveoli of the singlemandible(lower jaw) that contain teeth. 121. Themandibular foramenis a target of your dentist when he/she is injecting anesthesia. 122. To numb the lower jaw the dentist will aim for the mandibular foramen 123. Nasal complex 124. Paranasal sinuses 125. Orbital complex 126. Auditory ossiclesare inside petrous portion of temporal bone 127. 128. Relative size of auditory ossicles 129. 130. 131. Besides theobvious bruising, thisstrangulation victimhad a fractured hyoid bone 132. Intramembranous ossification(shown in gold) leads to formation of flat bones of skull, zygomatic (cheek) bone, maxilla (upper jaw), mandible (lower jaw),collar bone (clavicle), and sesamoid bones. 133. Fibrous sutures and many fontanels (soft spots) allow formolding of the headduring birth ( parturition ). 134. Parturition (birth) 135. 136. The fibrous sutures and fontanels alsoallow the cranium to expand to accommodate the growing brainin children. 137. Abulging fontanelcould be a sign of increased intracranial pressure caused by meningitis 138. ACCORDING TO THE ARTICLE ROUNDING IT OUT, WHAT CONTRIBUTES THEMOSTTO CURRENT CASES OF PLAGIOCEPHALY? A LACK OF FOLIC ACID B FEAR OF CRIB DEATH (SIDS) C ILL-FITTING HELMETS D FAILURE OF FONTANELS TO FUSE E BIRTH TRAUMA 139. Tooth loss is associated with erosion of the alveolar processes of the mandible and maxillae. </p>