Bones Of The Axial Skeleton
THE SKULL
Figure 7.1a
Skull
Thoracic cage(ribs andsternum)
(a) Anterior view
Facial bonesCranium
Sacrum
Vertebralcolumn
ClavicleScapulaSternumRibHumerusVertebraRadiusUlnaCarpals
PhalangesMetacarpalsFemurPatella
TibiaFibula
TarsalsMetatarsalsPhalanges
Figure 7.4a
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 bone
GlabellaFrontonasal suture
Supraorbital foramen(notch)Supraorbital marginSuperior orbitalfissure
Inferior orbitalfissureMiddle nasalconcha
Inferior nasal conchaVomer
Optic canal
Perpendicularplate
Ethmoidbone
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 muscles2. 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
Figure 7.2a
Bones of cranium (cranial vault)
Lambdoidsuture
Facialbones
Squamoussuture
(a) Cranial and facial divisions of the skull
Coronalsuture
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
Coronal suture Frontal bone
Sphenoid bone(greater wing)
Ethmoid bone
Lacrimal bone
Lacrimal fossa
Nasal bone
Zygomaticbone
Maxilla
Alveolarmargins
MandibleMental foramen
Parietal bone
Lambdoidsuture
SquamoussutureOccipitalbone
OccipitomastoidsutureExternal acousticmeatusMastoid processStyloid process
Mandibular condyleMandibular notch
Mandibular ramus
(a) External anatomy of the right side of the skull
Mandibular angle Coronoid process
Zygomaticprocess
Temporal bone
Figure 7.5a
Notable Features of Cranial BonesFrontal Bone•Anterior portion of cranium•Most of anterior cranial fossa•Superior wall of orbits•Contains air-filled frontal sinusesParietal Bones•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
Figure 7.4b
Lambdoidsuture
Occipital bone
Superior nuchal line
Externaloccipitalprotuberance
Sutural bone (tiny irregular bones within sutures)
Occipitomastoidsuture
(b) Posterior view
Occipitalcondyle
Externaloccipitalcrest
Inferiornuchalline
Mastoidprocess
Parietalbone
Sagittal suture
Figure 7.6a
Incisive fossa
Median palatine sutureIntermaxillary suture
Infraorbital foramenMaxilla
Sphenoid bone(greater wing)
Foramen ovale
Foramen lacerumCarotid canal
External acoustic meatus
Stylomastoidforamen
Jugular foramen
Foramen magnum
Occipital condyle
Inferior nuchal line
Superior 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 process
Temporal bone(petrous part)
Pharyngeal tubercleof basilar region ofthe occipital boneParietal bone
Palatine bone(horizontal plate)
Figure 7.8
Mastoidregion
Externalacousticmeatus
Mastoidprocess
Styloid process
Tympanic region
Mandibular fossa
Zygomatic process
Squamousregion
Notable Features of Cranial BonesOccipital 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
Temporal Bones•Inferolateral aspects of skull and parts of cranial floor•Four major regions
– Squamous– Tympanic– Mastoid– Petrous
Figure 7.9a
Greaterwing
Hypophysealfossa ofsella turcica
ForamenrotundumForamenovaleForamenspinosumBody of sphenoid
Superiororbital fissure
(a) Superior view of Sphenoid bone
Optic canalLesser wing
Figure 7.9b
Body of sphenoid
Greaterwing
Superiororbitalfissure
Lesserwing
Pterygoidprocess
(b) Posterior view
Sphenoid Bone•Complex, bat-shaped bone•Keystone bone
- Articulates with all other cranial bones•Three pairs of processes
Greater wingsLesser wingsPterygoid processes
Ethmoid Bone
Orbitalplate
Ethmoidalair cells
Perpendicularplate Middle nasal concha
Cribriformplate
Olfactoryforamina
Crista galli
Left lateral mass
• Deepest skull bone• Superior part of nasal septum,
roof of nasal cavities• Contributes to medial wall of
orbits
Hypophyseal fossaof sella turcica
Middle cranialfossa
Temporal 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 foramen
Hypoglossal canal
Foramen lacerum
Internal acousticmeatus
Cribriform plateEthmoidbone Crista galli
Sphenoid
Anterior cranial fossa
Lesser wingGreater wing
View
Figure 7.4a
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 bone
GlabellaFrontonasal suture
Supraorbital foramen(notch)Supraorbital marginSuperior orbitalfissure
Inferior orbitalfissureMiddle nasalconcha
Inferior nasal conchaVomer
Optic canal
Perpendicularplate
Ethmoidbone
Facial Bones
• Mandible• Maxillary bones
(maxillae) (2)• Zygomatic bones (2)• Nasal bones (2)
• Lacrimal bones (2)• Palatine bones (2)• Vomer• Inferior nasal conchae (2)
Figure 7.4a
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 bone
GlabellaFrontonasal suture
Supraorbital foramen(notch)Supraorbital marginSuperior orbitalfissure
Inferior orbitalfissureMiddle nasalconcha
Inferior nasal conchaVomer
Optic canal
Perpendicularplate
Ethmoidbone
Figure 7.6a
Incisive fossa
Median palatine sutureIntermaxillary suture
Infraorbital foramenMaxilla
Sphenoid bone(greater wing)
Foramen ovale
Foramen lacerumCarotid canal
External acoustic meatus
Stylomastoidforamen
Jugular foramen
Foramen magnum
Occipital condyle
Inferior nuchal line
Superior 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 process
Temporal bone(petrous part)
Pharyngeal tubercleof basilar region ofthe occipital boneParietal bone
Palatine bone(horizontal plate)
Frontal process
Articulates withfrontal bone
Anterior nasalspine
Infraorbitalforamen
Alveolarmargin
(b) Maxilla, right lateral view
Orbitalsurface Zygomaticprocess(cut)
Maxillary Bones•Medially fused to form upper jaw and central portion of facial skeleton•Keystone bones
– Articulate with all other facial bones except mandible
Coronoidprocess
Mandibular foramen
Mentalforamen
Mandibularangle
Ramusofmandible
Mandibularcondyle
Mandibular notch
Mandibular fossaof temporal bone
Body of mandible
Alveolarmargin
(a) Mandible, right lateral view
Temporomandibularjoint
• Lower jaw
• Largest, strongest bone of face
• Temporomandibular joint: only freely movable joint in skull
Facial BonesZygomatic Bones•Cheekbones•Inferolateral margins of orbitsNasal Bones And Lacrimal Bones• Nasal bones
– Form bridge of nose•Lacrimal bones
– In medial walls of orbits– Lacrimal fossa houses lacrimal
sacPalatine bones
– Posterior one-third of hard palate
– Posterolateral walls of the nasal cavity
– Small part of the orbits
Vomer– Plow shaped – Lower part of nasal septum
Inferior Nasal Conchae• Form part of lateral walls of nasal
cavityOrbits•Encase eyes and lacrimal glands•Sites of attachment for eye muscles•Formed by parts of seven bones
Frontalsinus
Ethmoidalair cells(sinus)
Maxillarysinus
Sphenoidsinus
Frontalsinus
Ethmoidalair cells
Maxillarysinus
Sphenoidsinus
(a) Anterior aspect (b) Medial aspect
• Mucosa-lined, air-filled spaces • Lighten the skull • Enhance resonance of voice• Found in frontal, sphenoid, ethmoid, and maxillary bones
Paranasal Sinuses
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