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PowerPoint® Lecture Slides prepared by Janice Meeking, Mount Royal College

C H A P T E R

Copyright © 2010 Pearson Education, Inc.

7

The Skeleton: Part A


The Axial Skeleton

• Consists of 80 bones

• Three major regions• Skull

• Vertebral column

• Thoracic cage

Copyright © 2010 Pearson Education, Inc. Figure 7.1a

Skull

Thoracic cage(ribs andsternum)

(a) Anterior view

Facial bonesCranium

Sacrum

Vertebralcolumn

ClavicleScapulaSternumRibHumerusVertebraRadiusUlnaCarpals

PhalangesMetacarpalsFemurPatellaTibiaFibula

TarsalsMetatarsalsPhalanges


The Skull

• Two sets of bones

1. Cranial bones

• 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


The Skull

2. Facial bones

• Framework of face

• Cavities for special sense organs for sight, taste, and smell

• Openings for air and food passage

• Sties of attachment for teeth and muscles of facial expression


Bones of cranium (cranial vault)

Lambdoidsuture

Facialbones

Squamoussuture

(a) Cranial and facial divisions of the skull

Coronalsuture

Copyright © 2010 Pearson Education, Inc. Figure 7.2b

Anterior cranialfossa

Middle cranialfossa

Posterior cranialfossa

(b) Superior view of the cranial fossae


Cranial Bones

• Frontal bone

• Parietal bones (2)

• Occipital bone

• Temporal bones (2)

• Sphenoid bone

• Ethmoid bone


Frontal Bone

• Anterior portion of cranium

• Most of anterior cranial fossa

• Superior wall of orbits

• Contains air-filled frontal sinus


Parietal bone

Squamous part of frontal boneNasal boneSphenoid bone(greater wing)Temporal boneEthmoid boneLacrimal boneZygomatic bone

MaxillaMandible

Infraorbital foramen

Mentalforamen

(a) Anterior view Mandibular symphysis

Frontal boneGlabellaFrontonasal sutureSupraorbital foramen(notch)Supraorbital marginSuperior orbitalfissure

Inferior orbitalfissureMiddle nasalconcha

Inferior nasal conchaVomer

Optic canal

Perpendicularplate

Ethmoidbone


Parietal Bones and Major Associated Sutures• Superior and lateral aspects of cranial vault• Four sutures mark the articulations of parietal

bones with frontal, occipital, and temporal bones:1. Coronal suture—between parietal bones and frontal

bone 2. Sagittal suture—between right and left parietal bones 3. Lambdoid suture—between parietal bones and

occipital bone 4. Squamous (squamosal) sutures—between parietal

and temporal bones on each side of skull


Coronal suture Frontal boneSphenoid bone(greater wing)Ethmoid boneLacrimal bone

Lacrimal fossa

Nasal boneZygomaticbone Maxilla

Alveolarmargins

MandibleMental foramen

Parietal bone

Lambdoidsuture

SquamoussutureOccipitalbone

OccipitomastoidsutureExternal acousticmeatusMastoid processStyloid process

Mandibular condyleMandibular notchMandibular ramus

(a) External anatomy of the right side of the skullMandibular angle Coronoid process

Zygomaticprocess

Temporal bone

Figure 7.5a


Occipital Bone

• Most of skull’s posterior wall and posterior cranial fossa

• Articulates with 1st vertebra

• Sites of attachment for the ligamentum nuchae and many neck and back muscles


Lambdoidsuture

Occipital bone

Superior nuchal line

Externaloccipitalprotuberance

Suturalbone

Occipitomastoidsuture

(b) Posterior view

Occipitalcondyle

Externaloccipitalcrest

Inferiornuchalline

Mastoidprocess

Parietalbone

Sagittal suture


Incisive fossa

Median palatine sutureIntermaxillary suture

Infraorbital foramenMaxillaSphenoid bone(greater wing)

Foramen ovale

Foramen lacerumCarotid canalExternal acoustic meatusStylomastoidforamenJugular foramen

Foramen magnum

Occipital condyle

Inferior nuchal line


Foramen spinosum

Maxilla(palatine process)

Hardpalate

Zygomatic bone

Temporal bone(zygomatic process)

Mandibularfossa

Vomer

Styloid process

External occipital crestExternal occipitalprotuberance

(a) Inferior view of the skull (mandible removed)

Mastoid processTemporal bone(petrous part)

Pharyngeal tubercleof basilar region ofthe occipital boneParietal bone

Palatine bone(horizontal plate)


Temporal Bones

• Inferolateral aspects of skull and parts of cranial floor

• Four major regions• Squamous

• Tympanic

• Mastoid

• Petrous

Copyright © 2010 Pearson Education, Inc. Figure 7.8

Mastoidregion

Externalacousticmeatus

Mastoidprocess Styloid process

Tympanic regionMandibular fossaZygomatic process

Squamousregion


Incisive fossa



Foramen ovale


Foramen magnum

Occipital condyle



Foramen spinosum


Hardpalate

Zygomatic bone


Mandibularfossa

Vomer

Styloid process







Hypophyseal fossaof sella turcicaMiddle cranialfossaTemporal bone(petrous part)

Posteriorcranial fossa

Parietal bone

Occipital bone

Foramen magnum

(a) Superior view of the skull, calvaria removed

Frontal bone

Olfactory foramina

Optic canal

Foramen rotundumForamen ovaleForamen spinosum

Jugular foramenHypoglossal canal

Foramen lacerumInternal acousticmeatus

Cribriform plateEthmoidbone Crista galli

Sphenoid

Anterior cranial fossa

Lesser wingGreater wing

View


Sphenoid Bone

• Complex, bat-shaped bone

• Keystone bone• Articulates with all other cranial bones

• Three pairs of processes• Greater wings

• Lesser wings

• Pterygoid processes


GreaterwingHypophysealfossa ofsella turcica

ForamenrotundumForamenovaleForamenspinosumBody of sphenoid

Superiororbital fissure

(a) Superior view

Optic canal Lesser wing


Body of sphenoid

Greaterwing

Superiororbitalfissure

Lesserwing

Pterygoidprocess

(b) Posterior view


Ethmoid Bone

• Deepest skull bone

• Superior part of nasal septum, roof of nasal cavities

• Contributes to medial wall of orbits

Copyright © 2010 Pearson Education, Inc. Figure 7.10

Orbitalplate

Ethmoidalair cells Perpendicularplate Middle nasal concha

Cribriformplate

Olfactoryforamina

Crista galli

Left lateral mass


Parietal bone


MaxillaMandible


Mentalforamen





Optic canal

Perpendicularplate

Ethmoidbone


Hypophyseal fossaof sella turcicaMiddle cranialfossaTemporal bone(petrous part)

Posteriorcranial fossa

Parietal bone

Occipital bone

Foramen magnum

(a) Superior view of the skull, calvaria removed

Frontal bone

Olfactory foramina

Optic canal

Foramen rotundumForamen ovaleForamen spinosum

Jugular foramenHypoglossal canal

Foramen lacerumInternal acousticmeatus

Cribriform plateEthmoidbone Crista galli

Sphenoid

Anterior cranial fossa

Lesser wingGreater wing

View

Figure 7.7a


Sutural Bones

• Tiny irregularly shaped bones that appear within sutures


Lambdoidsuture

Occipital bone


Externaloccipitalprotuberance

Suturalbone

Occipitomastoidsuture

(b) Posterior view

Occipitalcondyle

Externaloccipitalcrest

Inferiornuchalline

Mastoidprocess

Parietalbone

Sagittal suture


Facial Bones

• Mandible

• Maxillary bones (maxillae) (2)

• Zygomatic bones (2)

• Nasal bones (2)

• Lacrimal bones (2)

• Palatine bones (2)

• Vomer

• Inferior nasal conchae (2)


Mandible

• Lower jaw

• Largest, strongest bone of face

• Temporomandibular joint: only freely movable joint in skull


Coronoidprocess

Mandibular foramen

Mentalforamen

Mandibularangle

Ramusofmandible

Mandibularcondyle

Mandibular notch

Mandibular fossaof temporal bone

Body of mandible

Alveolarmargin

(a) Mandible, right lateral view

Temporomandibularjoint


Maxillary Bones

• Medially fused to form upper jaw and central portion of facial skeleton

• Keystone bones• Articulate with all other facial bones except

mandible


Frontal process

Articulates withfrontal bone

Anterior nasalspine

Infraorbitalforamen

Alveolarmargin

(b) Maxilla, right lateral view

Orbitalsurface Zygomaticprocess(cut)


Parietal bone


MaxillaMandible


Mentalforamen





Optic canal

Perpendicularplate

Ethmoidbone


Incisive fossa



Foramen ovale


Foramen magnum

Occipital condyle



Foramen spinosum


Hardpalate

Zygomatic bone


Mandibularfossa

Vomer

Styloid process







Zygomatic Bones

• Cheekbones

• Inferolateral margins of orbits


Parietal bone


MaxillaMandible


Mentalforamen





Optic canal

Perpendicularplate

Ethmoidbone

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