1. 7
The Skeleton: Part A

2. Composed of bones, cartilages, joints, ligaments 20% of body mass
Skeletal System
Composed of bones, cartilages, joints, ligaments
20% of body mass
Two major parts
Axial
Appendicular
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3. The Axial Skeleton Consists of 80 bones Three major regions Skull
Vertebral column
Thoracic cage
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4. Formed by two sets of bones
The Skull
Formed by two sets of bones
Cranial bones (cranium)
Enclose the brain in the cranial cavity
Cranial vault (calvaria)
Cranial base: anterior, middle, and posterior cranial fossae
Provide sites of attachment for head and neck muscles
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5. The Skull Facial bones Framework of face
Cavities for special sense organs for sight, taste, and smell
Openings for air and food passage
Sites of attachment for teeth and muscles of facial expression
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6. Middle and internal ear cavities Nasal cavity Orbits 85 named openings
Skull Geography
Cranial cavity
Middle and internal ear cavities
Nasal cavity
Orbits
85 named openings
Foramina, canals, fissures
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7. Eight Cranial Bones Frontal bone Parietal bones (2) Occipital bone
Temporal bones (2)
Sphenoid bone
Ethmoid bone
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8. Anterior portion of cranium Most of anterior cranial fossa
Frontal Bone
Anterior portion of cranium
Most of anterior cranial fossa
Superior wall of orbits
Contains air-filled frontal sinus
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9. Parietal Bones and Major Associated Sutures
Superior and lateral aspects of cranial vault
Four sutures mark articulations of parietal bones with frontal, occipital, and temporal bones:
Coronal suture—between parietal bones and frontal bone
Sagittal suture—between right and left parietal bones
Lambdoid suture—between parietal bones and occipital bone
Squamous (squamosal) sutures—between parietal and temporal bones on each side of skull
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10. Most of skull's posterior wall and posterior cranial fossa
Occipital Bone
Most of skull's posterior wall and posterior cranial fossa
Articulates with 1st vertebra
Sites of attachment for ligamentum nuchae and many neck and back muscles
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11. Inferolateral aspects of skull and parts of cranial base
Temporal Bones
Inferolateral aspects of skull and parts of cranial base
Four major regions
Squamous
Tympanic
Mastoid
Petrous
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12. Complex, bat-shaped bone Keystone bone Three pairs of processes
Sphenoid Bone
Complex, bat-shaped bone
Keystone bone
Articulates with all other cranial bones
Three pairs of processes
Greater wings
Lesser wings
Pterygoid processes
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13. Superior part of nasal septum, roof of nasal cavities
Ethmoid Bone
Deepest skull bone
Superior part of nasal septum, roof of nasal cavities
Contributes to medial wall of orbits
Crista galli for dural attachment
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14. Tiny irregularly shaped bones that appear within sutures
Sutural Bones
Tiny irregularly shaped bones that appear within sutures
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15. Fourteen Facial Bones Mandible Maxillary bones (maxillae) (2)
Zygomatic bones (2)
Nasal bones (2)
Lacrimal bones (2)
Palatine bones (2)
Vomer
Inferior nasal conchae (2)
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16. Largest, strongest bone of face Temporomandibular joint
Mandible
Lower jaw
Largest, strongest bone of face
Temporomandibular joint
Only freely movable joint in skull
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17. Contain maxillary sinuses
Maxillary Bones
Medially fused to form upper jaw and central portion of facial skeleton
Keystone bones
Articulate with all other facial bones except mandible
Contain maxillary sinuses
Largest of paranasal sinuses
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18. Inferolateral margins of orbits
Zygomatic Bones
Cheekbones
Inferolateral margins of orbits
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19. Nasal Bones and Lacrimal Bones
Form bridge of nose
Lacrimal bones
In medial walls of orbits
Lacrimal fossa houses lacrimal sac
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20. Palatine Bones and Vomer
Posterior one-third of hard palate
Posterolateral walls of the nasal cavity
Small part of the orbits
Vomer
Plow shaped
Inferior part of nasal septum
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21. Inferior Nasal Conchae
Form part of lateral walls of nasal cavity
Largest of three pairs of conchae
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22. Cavities that encase eyes and lacrimal glands
Orbits
Cavities that encase eyes and lacrimal glands
Sites of attachment for eye muscles
Formed by parts of seven bones
Frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal, and ethmoid
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23. Nasal Cavity
Roof, lateral walls, and floor formed by parts of four bones
Ethmoid
Palatine bones
Maxillary bones
Inferior nasal conchae
Nasal septum of bone and hyaline cartilage
Perpendicular plate of ethmoid
Vomer
Anterior septal cartilage
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24. Mucosa-lined, air-filled spaces Lighten skull
Paranasal Sinuses
Mucosa-lined, air-filled spaces
Lighten skull
Enhance resonance of voice
Warm and humidify air
Found in frontal, sphenoid, ethmoid, and maxillary bones
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25. Does not articulate directly with another bone Movable base for tongue
Hyoid Bone
Not bone of skull
Does not articulate directly with another bone
Movable base for tongue
Site of attachment for muscles of swallowing and speech
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