131, 7 axial skeleton
TRANSCRIPT
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Axial Skeleton Chapter 7
IB 131
Lecturer: Tom Carlson
The Skeleton
Consists of:Bones, cartilage, joints, and ligaments
Composed of 206 named bonesgrouped into two divisions
Axial skeleton (80 bones)Appendicular skeleton (126 bones)
The Axial
Skeleton(in green)
Formed from80 named
bones
Consists ofskull, vertebral
column, and
bony thorax
Figure 7.1a
Skull
Thoracic cage(ribs andsternum)
(a) Anterior view
Facial bonesCranium
Sacrum
Vertebralcolumn
ClavicleScapulaSternumRibHumerusVertebraRadiusUlna
Carpals
PhalangesMetacarpalsFemurPatella
TibiaFibula
TarsalsMetatarsalsPhalanges
The
Axial
Skeleton(in green)
Figure 7.1b
(b) Posterior view
Cranium
Clavicle
Bones ofpectoralgirdle
Bones ofpelvic girdle
Upperlimb
Scapula
RibHumerusVertebraRadiusUlna
CarpalsPhalangesMetacarpalsFemur
Lowerlimb
TibiaFibula
Figure 7.6a
The Skull Formed by cranial and facial bones
Parietal bone
Squamous partof frontal boneNasal bone
Sphenoid bone(greater wing)
Temporal bone
Ethmoid boneLacrimal bone
Zygomatic bone
Maxilla
Mandible
Infraorbital foramen
Mentalforamen
(a) Anterior view of skull
Mentalprotuberance
Frontal bone
Glabella
Frontonasal suture
Supraorbital foramen(notch)
Supraorbital margin
Superior orbital fissure
Inferior orbital fissure
Middle nasal concha
Inferior nasal concha
Vomer
Optic canal
Perpendicular plateEthmoidbone
The CraniumBones of cranium (cranial vault)
Lambdoid
sutureFacial
bones
Squamous
suture
(a) Cranial and facial divisions of the skull
Coronal
suture
Figure 7.2a
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The Cranium
Is the bodys most complex bonystructure
Formed by cranial and facial bones The cranium
Encloses and protects brainProvides attachment for head and neck
muscles
The Face
Facial bones serve toForm framework of the faceForm cavities for the sense organs of sight,
taste, and smell
Provide openings for the passage of airand food
Hold the teeth in placeAnchor muscles of the face
Anterior cranialfossa
Middle cranialfossa
Posterior cranialfossa
(b) Superior view of the cranial fossae
Frontal lobeof cerebrum
Temporal lobeof cerebrum
Cerebellum
Posterior
Middle
Anterior
Cranial
fossae
(c) Lateral view of cranial fossae showing the containedbrain regions
Overview of Skull Geography
Facial bones form anterior aspect Cranium is divided into cranial vault and the
base
Internally, prominent bony ridges divide skullinto distinct fossae
Figure 7.2b, c
Anterior cranialfossa
Middle cranialfossa
Posterior cranialfossa
(b) Superior view of the cranial fossae
Frontal lobeof cerebrum
Temporal lobeof cerebrum
Cerebellum
Posterior
Middle
Anterior
Cranial
fossae
(c) Lateral view of cranial fossae showing the containedbrain regions
Cranial Fossae
Anterior cranial fossa Middle cranial fossa Posterior cranial fossa
Figure 7.2b, c
Small Cavities of Skull
The skull contains smaller cavitiesMiddle and inner ear cavitiesin lateral
aspect of cranial base
Nasal cavitylies in and posterior to thenose
Orbitshouse the eyeballsAir-filled sinusesoccur in several bones
around the nasal cavity
Overview of Skull Geography
The skull contains approximately 85named openings
Foramina, canals, and fissuresProvide openings for important structures
Spinal cord Blood vessels serving the brain 12 pairs of cranial nerves
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Cranial Bones
Formed from eight large bonesPaired bones include
Temporal bonesParietal bones
Unpaired bones includeFrontal boneOccipital boneSphenoid boneEthmoid bone
Figure 7.6a
The Skull Formed by cranial and facial bones
Parietal bone
Squamous partof frontal boneNasal bone
Sphenoid bone(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Infraorbital foramen
Mentalforamen
(a) Anterior view of skull
Mentalprotuberance
Frontal bone
Glabella
Frontonasal suture
Supraorbital foramen(notch)
Supraorbital margin
Superior orbital fissure
Inferior orbital fissure
Middle nasal concha
Inferior nasal concha
Vomer
Optic canal
Perpendicular plateEthmoidbone
Major cavities of skull Lateral aspect of skull
Lateral aspect of skullThe Cranium
Bones of cranium (cranial vault)
Lambdoid
sutureFacial
bones
Squamous
suture
(a) Cranial and facial divisions of the skull
Coronal
suture
Figure 7.2a
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Parietal Bones and Sutures
Parietal bones form superior and lateralparts of skull
Four sutures of the craniumCoronal sutureruns in the coronal plane
Located where parietal bones meet the frontalbone
Squamous sutureoccurs where eachparietal bone meets a temporal boneinferiorly
Lambdoidsuture
Occipital bone
Superior nuchal line
External occipital
protuberance
Sutural bone
Inferior nuchal line
Occipitalcondyle
External occipital crestOccipitomastoidsuture
Parietal bone
Sagittal suture
The Skull Posterior View
Figure 7.5
Parietal Bones and Sutures
Four sutures of the cranium (continued)Sagittal sutureoccurs where right and
left parietal bones meet superiorly
Lambdoid sutureoccurs where theparietal bones meet the occipital boneposteriorly
Sutural Bones
Small bones that occur within sutures Irregular in shape, size, and location Not all people have sutural bones
Lambdoidsuture
Occipital bone
Superior nuchal line
External occipitalprotuberance
Sutural bone
Inferior nuchal line
Occipitalcondyle
External occipital crestOccipitomastoidsuture
Parietal bone
Sagittal suture
The Skull Posterior View
Figure 7.5
Frontal Bone
Forms the forehead and roofs of orbits Supraorbital marginsuperior margin
of orbits
Glabellasmooth part of frontal bonebetween superciliary (eyebrow) arches
Frontal sinuses within frontal bone Contributes to anterior cranial fossa
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Figure 7.6a
Cranial & Facial Bones of Skull
Parietal bone
Squamous partof frontal boneNasal bone
Sphenoid bone(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Infraorbital foramen
Mentalforamen
(a) Anterior view of skull
Mentalprotuberance
Frontal bone
Glabella
Frontonasal suture
Supraorbital foramen(notch)
Supraorbital margin
Superior orbital fissure
Inferior orbital fissure
Middle nasal concha
Inferior nasal concha
Vomer
Optic canal
Perpendicular plateEthmoidbone
Cranial and Facial Bones of Skull
Occipital Bone
Forms the posterior portion of thecranium and cranial base
Articulates with the temporal bones andparietal bones
Forms the posterior cranial fossa Foramen magnum located at its base
Maxilla
(palatine process)Hard
palate
Zygomatic bone
Incisive fossa
Median palatine sutureIntermaxillary suture
Infraorbital foramenMaxillaSphenoid bone(greater wing)
Foramen ovalePterygoid process
Foramen lacerumCarotid canalExternal acoustic meatusStylomastoid
foramenJugular foramen
Foramen magnum
Occipital condyle
Inferior nuchal line
Superior nuchal line
Temporal bone
(zygomatic process)
Mandibular fossa
Vomer
Styloid process
External occipital crestExternal occipitalprotuberance(a) Inferior view of the skull (mandible removed)
Mastoid processTemporal bone(petrous part)
Basilar part ofthe occipital boneOccipital bone
Palatine bone
(horizontal plate)
Foramen spinosum
Inferior Aspect of the Skull
Figure 7.7a
Inferior Aspect of Skull
(b) Photograph of right side of skull
Sphenoid bone
(greater wing)Coronal suture
Parietal bone
Squamous suture
Zygomatic process
Temporal bone
Lambdoid sutureOccipital bone
External occipitalprotuberanceOccipitomastoidsutureExternal acousticmeatusMastoid process Styloid
processMandibular ramusMandibular angle
Mental foramen
Frontal bone
Ethmoid boneLacrimal bone
Nasal bone
Lacrimal fossaZygomatic
bone
Maxilla
Mandible
Coronoidprocess
Alveolarmargins
Mandibularcondyle
Mandibular
notch
Lateral Aspect of the Skull
Figure 7.4b
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Lambdoidsuture
Occipital bone
Superior nuchal line
External occipital
protuberance
Sutural bone
Inferior nuchal line
Occipitalcondyle
External occipital crestOccipitomastoidsuture
Parietal bone
Sagittal suture
The Skull Posterior View
Figure 7.5
Occipital Bone
Features and structuresOccipital condylesHypoglossal foramenExternal occipital protuberanceSuperior nuchal linesInferior nuchal lines
Temporal Bones
Lie inferior to parietal bones Form the inferolateral portion of the
skull
Term temporal comes from Latin wordfor time
Specific regions of temporal boneSquamous, temporal, petrous, and mastoid
regions
Lateral aspect of skull
(b) Photograph of right side of skull
Sphenoid bone
(greater wing)Coronal suture
Parietal bone
Squamous suture
Zygomatic process
Temporal bone
Lambdoid sutureOccipital bone
External occipitalprotuberanceOccipitomastoidsutureExternal acousticmeatusMastoid process Styloid
processMandibular ramusMandibular angle
Mental foramen
Frontal bone
Ethmoid boneLacrimal bone
Nasal bone
Lacrimal fossaZygomatic
bone
Maxilla
Mandible
Coronoidprocess
Alveolarmargins
Mandibularcondyle
Mandibular
notch
Lateral Aspect of the Skull
Figure 7.4b
The Temporal Bone
Figure 7.8
Mastoid
region
External acoustic
meatus
Mastoid process
Styloid process Tympanicregion
Mandibularfossa
Zygomatic
process
Squamous
region
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The Temporal Bone The mastoid process
Site for neck muscle attachmentContains air sinuses
Petrous region (Fig 7.9)Projects medially, contributes to cranial baseAppears as a boney wedge between
occipetal bone posteriorly and sphenoid
bone anteriorly
Houses cavities of middle and internal ear Contributes to the middle and posterior cranial
fossae
Cranial cavity floor
Cranial cavity floorThe Temporal Bone
Foramina of the temporal bone (Fig 7.9)Jugular foramen
At boundary with occipital boneCarotid canalFormane lacerumInternal accoustic meatus
The Sphenoid Bone
Spans the width of the cranial floor Resembles a butterfly or bat Has of a body Has three pairs of processes Contains five important openings Is the keystone of the cranium
The Sphenoid Bone
Body
The superior part of the body bears asaddle-shaped prominence called a
sella turcica
The seat of this saddle holds thehypophyseal fossa , holds the the
pituitary gland (= hypophysis)
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The Sphenoid Bone
Processes (Fig 7.10)
Greater wings Lesser wings Pterygoid processes
(a) Superior view, as in Figure 7.9
Optic
canal
Greater
wingSellaturcica
Lesser wing
Foramen rotundumForamen ovale
Foramen spinosumBody of sphenoid
The Sphenoid Bone
Figure 7.10a
Greaterwing
Body of sphenoid
Superiororbital
fissure
Lesserwing
Pterygoidprocess
(b) Posterior view
The Sphenoid Bone
Figure 7.10b
The Sphenoid Bone
Openings (Figs 7.9, 7.10)
Optic canal: lies just anterior to sella tursica Superior orbital fissure: long slit between greater
and lesser wings
Foramen rotundum: in medial part of greaterwing
Foramen ovale: posteriolateral to foramenrotundum
Foramen spinosum: posteriolateral to foramenovale
Cranial cavity floor Lateral aspect of skull
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Figure 7.6a
Cranial & Facial Bones of Skull
Parietal bone
Squamous partof frontal boneNasal bone
Sphenoid bone(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Infraorbital foramen
Mentalforamen
(a) Anterior view of skull
Mentalprotuberance
Frontal bone
Glabella
Frontonasal suture
Supraorbital foramen(notch)
Supraorbital margin
Superior orbital fissure
Inferior orbital fissure
Middle nasal concha
Inferior nasal concha
Vomer
Optic canal
Perpendicular plateEthmoidbone
The Ethmoid Bone
Lies between nasal and sphenoidbones
Forms most of the medial bony regionbetween the nasal cavity and orbits
Lateral aspect of skull
Figure 7.6a
Cranial & Facial Bones of Skull
Parietal bone
Squamous partof frontal boneNasal bone
Sphenoid bone(greater wing)
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Infraorbital foramen
Mentalforamen
(a) Anterior view of skull
Mentalprotuberance
Frontal bone
Glabella
Frontonasal suture
Supraorbital foramen(notch)
Supraorbital margin
Superior orbital fissure
Inferior orbital fissure
Middle nasal concha
Inferior nasal concha
Vomer
Optic canal
Perpendicular plateEthmoidbone
Midsagittal section through skull Midsagittal section through skull
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Orbitalplate
Ethmoidalair cells
Perpendicularplate
Middlenasal concha
Cribriformplate
Olfactoryforamina
Crista galli
Leftlateralmass
Figure 7.12
The Ethmoid Bone The Ethmoid Bone
Cribiform platesuperior surface of theethmoid bone
Contain olfactory foramina Crista galliattachment for falx cerebri;
falx cerebri is large vertical sheet which
lies in between cerebral hemispheres
Perpendicular plateforms superiorpart of nasal septum
The Ethmoid Bone
Lateral massescontain air cells Superiorand middle nasal conchae
Extend medially from lateral masses
Bones of Nasal Cavity
Bones of Nasal Cavity Facial Bones
Unpaired bonesMandible and vomer
Paired bonesMaxillaeZygomatic bonesNasal bonesLacrimal bonesPalatine bonesInferior nasal conchae
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Parietal bone
Squamous partof frontal boneNasal boneSphenoid bone
(greater wing)Temporal boneEthmoid boneLacrimal boneZygomatic bone
Maxilla
Mandible
Infraorbital foramen
Mental
foramen
(a) Anterior view of skull
Mental
protuberance
Frontal bone
Glabella
Frontonasal suture
Supraorbital foramen
(notch)Supraorbital marginSuperior orbital fissure
Inferior orbital fissure
Middle nasal concha
Inferior nasal concha
Vomer
Optic canal
Perpendicular plateEthmoidbone
Facial Bones
Figure 7.6a
Mandible
The lower jawbone is the largest andstrongest facial bone
Composed of two main partsHorizontal bodyTwo upright rami
Coronoid
process
Mandibular foramen
Mental
foramen
Mandibular
angle
Ramus
ofmandible
Mandibular
condyle
Mandibular notch
Mandibular fossa
of temporal bone
Body of mandible
Alveolar
margin
(a) Mandible, right lateral view
Temporomandibular
joint
Mandible
Figure 7.13a
Maxillary Bones
Articulate with all other facial bonesexcept the mandible
Contain maxillary sinuseslargestparanasal sinuses
Forms part of the inferior orbital fissure Are the keystone bones of the face
Maxillary Bones
Figure 7.13b
Frontal process
Articulates withfrontal bone
Anterior nasalspine
Infraorbitalforamen
Alveolarmargin
(b) Maxilla, right lateral view
Orbital surface
Zygomaticprocess
(cut)
Maxilla
(palatine process)Hardpalate
Zygomatic bone
Incisive fossa
Median palatine sutureIntermaxillary suture
Infraorbital foramenMaxillaSphenoid bone(greater wing)
Foramen ovalePterygoid process
Foramen lacerumCarotid canalExternal acoustic meatusStylomastoid
foramenJugular foramen
Foramen magnum
Occipital condyle
Inferior nuchal line
Superior nuchal line
Temporal bone
(zygomatic process)
Mandibular fossa
Vomer
Styloid process
External occipital crestExternal occipital
protuberance
(a) Inferior view of the skull (mandible removed)
Mastoid processTemporal bone(petrous part)
Basilar part ofthe occipital boneOccipital bone
Palatine bone
(horizontal plate)
Foramen spinosum
Maxillary Bones
Figure 7.7a
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Other Bones of the Face
Zygomatic bonesForm lateral wall of orbits
Nasal bonesForm bridge of nose
Lacrimal bonesLocated in the medial orbital walls
Palatine bonesComplete the posterior part of the hard
palate
Nasal Cavity
Figure 7.14a
Frontal sinus
Superiornasal conchaMiddle
nasal concha
Ethmoidbone
Inferior nasal concha
Nasal bone
Maxillary bone(palatine process)
Palatine bone(perpendicularplate)
Palatine bone(horizontal plate)
Pterygoidprocess
(a) Bones forming the left lateral wall of the nasal cavity(nasal septum removed)
Sphenoidsinus
Sphenoidbone
Superior, middle, andinferior meatus
Anterior nasal spine
Other Bones of the Face
VomerForms the inferior part of the nasal septum
Inferior nasal conchaeThin, curved bones that project medially
form the lateral walls of the nasal cavity
Maxilla
(palatine process)Hard
palate
Zygomatic bone
Incisive fossa
Median palatine sutureIntermaxillary suture
Infraorbital foramenMaxillaSphenoid bone(greater wing)
Foramen ovale
Pterygoid process
Foramen lacerumCarotid canalExternal acoustic meatusStylomastoid
foramenJugular foramen
Foramen magnum
Occipital condyle
Inferior nuchal line
Superior nuchal line
Temporal bone
(zygomatic process)
Mandibular fossa
Vomer
Styloid process
External occipital crestExternal occipitalprotuberance(a) Inferior view of the skull (mandible removed)
Mastoid processTemporal bone(petrous part)
Basilar part ofthe occipital boneOccipital bone
Palatine bone
(horizontal plate)
Foramen spinosum
Maxillary Bones
Figure 7.7a
Special Parts of the Skull
Orbits Nasal cavity Paranasal sinuses Hyoid bone
Vomer
Crista galliCribriformplate
Ethmoidbone Frontal sinus
Nasal bone
Septalcartilage
Alveolar marginof maxilla
Perpendicular
plate of
ethmoid bone
Sella turcica
Sphenoid sinus
Palatine bone
Palatine processof maxilla
(b) Nasal cavity with septum in place showing the contributions of theethmoid bone, the vomer, and septal cartilage
Hardpalate
Nasal Septum
Figure 7.14b
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Paranasal Sinuses
Air-filled sinuses are located withinFrontal boneEthmoid boneSphenoid boneMaxillary bones
Lined with mucous membrane Lighten the skull
Paranasal Sinuses
Figure 7.15a, b
Frontalsinus
Ethmoidalair cells(sinus)
Maxillarysinus
Sphenoid
sinus
(a) Anterior aspect
FrontalsinusEthmoidalair cells
Maxillarysinus
Sphenoidsinus
(b) Medial aspect
Orbit walls
Roof Lateral wall Medial wall Floor
Orbit
Orbit walls formed by parts of
seven bones
Frontal Sphenoid Zygomatic Maxillary Palatine Lacrimal Ethmoid
Orbits
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Orbit wall openings
Superior orbital fissures Inferior orbital fissures Optic canals Lacrimal fossa
Figure 7.17
The Hyoid Bone Associated with skull
but not directly incontact with any other
bone
Lies inferior to themandible in anterior
neck
The only bone with nodirect articulation with
any other bone
Acts as a movablebase for the tongue
Greater horn
Lesser horn
Body
The Vertebral Column
Formed from 26 bones in the adult Transmits weight of trunk to the lower
limbs
Surrounds and protects the spinal cord
The Vertebral Column
Serves as attachment sites for musclesof the neck and back
Held in place by ligamentsAnterior and posterior longitudinal
ligaments
Ligamentum flavum
Posterior longitudinalligament
Anterior longitudinalligament
Body of a vertebra
Intervertebral disc
(b) Anterior view of part of the spinal column
Ligaments of the Spine
Supraspinous ligamentIntervertebraldisc
Anteriorlongitudinalligament
Intervertebral foramen
Posterior longitudinalligament
Anulus fibrosus
Nucleus pulposus
Sectioned body
of vertebra
Transverse process
Sectioned
spinous process
Ligamentum flavum
Interspinous
ligament
Inferior articular process
(a) Median section of three vertebrae, illustrating the composition
of the discs and the ligaments
Figure 7.19a, b
The Vertebral Column
Figure 7.18
Cervical curvature(concave)
7 vertebrae, C1 C7
Thoraciccurvature
(convex)12 vertebrae,
T1 T12
Lumbarcurvature
(concave)5 vertebrae, L1 L5
Sacralcurvature
(convex) 5 fusedvertebrae sacrum
Coccyx4 fused vertebraeAnterior view Right lateral view
C1
T123456789101112
L1234
5
234567
SpinousprocessTransverseprocesses
IntervertebraldiscsIntervertebralforamen
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Regions and Normal
Curvatures
The Vertebral column has five majorregions7 cervical vertebrae of the neck region12 thoracic vertebrae5 lumbar vertebraeSacrumfive fused bonesCoccyxinferior to sacrum
Regions and Normal
Curvatures
Curvatures of the spineCervical and lumbar curvatures
Concave posteriorlyThoracic and sacral curvatures
Convexposteriority
The Vertebral Column
Figure 7.18
Cervical curvature(concave)
7 vertebrae, C1 C7
Thoraciccurvature
(convex)12 vertebrae,
T1 T12
Lumbarcurvature
(concave)5 vertebrae, L1 L5
Sacralcurvature
(convex) 5 fusedvertebrae sacrum
Coccyx4 fused vertebraeAnterior view Right lateral view
C1
T123456789101112
L1234
5
234567
SpinousprocessTransverseprocesses
Intervertebraldiscs
Intervertebralforamen
Regions and Normal
Curvatures
Curvatures increase resilience of spine Thoracic and sacral curvatures
Primary curvatures Present at birth
Lumbar curvatureDevelops when baby begins to walk
Ligaments of the Spine
Major supporting ligamentsAnterior longitudinal ligament
Attaches to bony vertebrae andintervertebral discs
Prevents hyperextensionPosterior longitudinal ligament
Narrow and relatively weakAttaches to intervertebral discs
Posterior longitudinalligament
Anterior longitudinalligament
Body of a vertebra
Intervertebral disc
(b) Anterior view of part of the spinal column
Ligaments of the Spine
Supraspinous ligamentIntervertebraldisc
Anteriorlongitudinalligament
Intervertebral foramen
Posterior longitudinalligament
Anulus fibrosus
Nucleus pulposus
Sectioned body
of vertebra
Transverse process
Sectioned
spinous process
Ligamentum flavum
Interspinous
ligament
Inferior articular process
(a) Median section of three vertebrae, illustrating the composition
of the discs and the ligaments
Figure 7.19a, b
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Intervertebral Discs
Cushion-like pads between vertebraeComposed of
Nucleus pulposusAnulus fibrosus
Intervertebral Discs
Nucleus pulposusGelatinous inner sphereAbsorbs compressive stresses
Anulus fibrosusOuter fings formed of ligamentInner rings formed of fibrocartilageContain the nucleus pulposus
Intervertebral Discs of Spine
Herniated Intervertebral Disc
Figure 7.19c, d
Vertebral spinous process(posterior aspect of vertebra)
Spinal nerve root
Anulus fibrosusof disc
Herniated portionof disc
Nucleuspulposusof disc
Spinal cord
(c) Superior view of a herniated intervertebral disc
Transverseprocess
(d) MRI of lumbar region of vertebral column in sagittalsection showing normal and herniated discs
Nucleus pulposusof intact disc
Herniated nucleuspulposus
General Structure of Vertebrae
PLAY Spine (horizontal)
Figure 7.20
Posterior
Anterior
Lamina
Superiorarticularprocessandfacet
Transverse
process
Pedicle
Spinous
process
Vertebral
arch
Vertebral
foramen
Body
(centrum)
General Structure of
Vertebrae
Common structures to all regionsBodyVertebral archVertebral foramenSpinous processTransverse processSuperior and inferior articular processesIntervertebral foramina
Posterior longitudinalligament
Anterior longitudinalligament
Body of a vertebra
Intervertebral disc
(b) Anterior view of part of the spinal column
Ligaments of the Spine
Supraspinous ligamentIntervertebraldisc
Anteriorlongitudinalligament
Intervertebral foramen
Posterior longitudinalligament
Anulus fibrosus
Nucleus pulposus
Sectioned body
of vertebra
Transverse process
Sectioned
spinous process
Ligamentum flavum
Interspinous
ligament
Inferior articular process
(a) Median section of three vertebrae, illustrating the composition
of the discs and the ligaments
Figure 7.19a, b
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Regions Vertebral
Characteristics
Specific regions of the spine performspecific functions
Types of movement that may occurbetween vertebrae
Flexion and extensionLateral flexionRotation in the long axis
Cervical Vertebrae
Seven cervical vertebrae (C1 C7)are the lightest vertebrae in thespine
Dens of axis
Transverse ligament
of atlasC1 (atlas)
C2 (axis)
C3
Bifid spinous
process
Transverse processes
C7 (vertebra
prominens)
(a) Cervical vertebrae
Inferior articular
process
Cervical Vertebrae
Figure 7.22a
Cervical Vertebrae
Table 7.2a
The Atlas
C1 is termed the atlas Lacks a body and spinous process Supports the skull
Superior articular facets receive theoccipital condyles
Allows flexion and extension of neckNodding the head yes
The Atlas
Figure 7.21a
Anterior arch
Superior articular
facet
Transverse
foramen
Posterior arch
Posterior tubercle
Anterior tubercle
Posterior
Lateral
masses
(a) Superior view of atlas (C1)
C1
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Lambdoidsuture
Occipital bone
Superior nuchal line
External occipital
protuberance
Sutural bone
Inferior nuchal line
Occipitalcondyle
External occipital crestOccipitomastoidsuture
Parietal bone
Sagittal suture
The Skull Posterior View
Figure 7.5
The Atlas
Figure 7.21b
Facet for dens
Transverse
process Lateral
masses
Transverse foramen
Posteriorarch Posterior tubercle
Posterior
Anterior tubercle
Anteriorarch
(b) Inferior view of atlas (C1)
Inferior
articular
facet
C1
The Axis
Has a body and spinous process Dens (odontoid process) projects superiorly
Formed from fusion of the body of the atlas withthe axis
Acts as a pivot for rotation of the atlas and skullParticipates in rotating the head from side to
side
The Axis
Figure 7.21c
C2Posterior
Dens
(c) Superior view of axis (C2)
Inferior
articularprocess
Body
Superior
articularfacet
Transverse
process
Pedicle
Lamina
Spinous process
Dens of axis
Transverse ligamentof atlasC1 (atlas)
C2 (axis)
C3
Bifid spinousprocess
Transverse processes
C7 (vertebraprominens)
(a) Cervical vertebrae
Inferior articular
process
Cervical Vertebrae
Figure 7.22a
Cervical Vertebrae C3 C7 Body: small and wide laterally (side to side) Spinous process: short and bifid (except C7) and
project posteriorally
Vertebral foramen: triangular and large Transverse processes contain foramina Superior facets directed superposteriorly Inferior facets directed inferoanteriorly Spine region with the greatest range of motion
with the following movement allowed: flexion &
extension, lateral flexion, rotation
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Cervical, Thoracic, & Lumbar Vertebrae
Superior View
Cervical, Thoracic, & Lumbar Vertebrae
Right Lateral View
Cervical, Thoracic, & Lumbar VertebraeThoracic vertebrae
Thoracic Vertebrae
All articulate with ribs Body: larger than cervical bodies and heart-
shaped from superior view
Spinous processes are long and pointinferiorly
Vertebral foramen are circular
Costal Facets of Thoracic Vertebrae
which interface with ribs
Inferior costal facet for head of rib Superior costal facet for head of rib Transverse costal facet for tubercle of rib (except
for T11 T12)
Each of these above three facets are present onboth sides of vertebrae, so each vertebrae has a
total of six facets which interface with ribs
Usually, the head of a rib is attached to the bodiesof two vertebrae, the inferior costal facet of the
superior vertebra and the superior costal facet of
the inferior vertebra
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Cervical, Thoracic, & Lumbar Vertebrae
Right Lateral View Ribs
Figure 7.25a, b
Junction withcostal cartilage
ShaftHead Neck
Articular faceton tubercle
Costal angleCostal groove
Facets for articulationwith vertebrae
(a) A typical rib (rib 6, right), posterior view
Transverse costal facet(for tubercle of rib)
Superior costal facet(for head of rib)
Body of vertebra
Head of rib
Intervertebral disc
Tubercle of rib
Neck of rib
Shaft Sternum
Angleof rib
Cross-sectionof rib Costal groove
(b) Vertebral and sternal articulations of a typical true rib
Costal cartilage
Spinous process
Articular faceton tubercle of rib
Shaft
Ligaments
Neck of rib
Head of rib Body of
thoracic
vertebra
Transverse
costal facet
(for tubercleof rib)
Superior costal facet
(for head of rib)
(c) Superior view of the articulation between a rib and athoracic vertebra
Ribs
Figure 7.25c
Connections between Thoracic
Vertebral Bodies
Laterally each side of the vertebral bodybears two facets (demifacets), one at the
superior edge and one at the inferior edge
These demifacets interface with vertebralbodies above and below
Superior articular facets point posteriorly Inferior articular processes point anteriorly Allows rotation and limits flexion and
extension
Thoracic vertebraeThoracic Vertebrae
Table 7.2b
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Cervical, Thoracic, & Lumbar Vertebrae
Superior View
Cervical, Thoracic, & Lumbar Vertebrae
Right Lateral View
The Thoracic Cage
Forms the framework of the chest Components
Thoracic vertebraeposteriorlyRibslaterallySternum and costal cartilageanteriorly
Protects thoracic organs Supports shoulder girdle and upper limbs Provides attachment sites for muscles Intercostalspaces
True
ribs
(17
False
ribs(812)
Jugular notchClavicular notch
Manubrium
Sternal angleBody
Xiphisternal
jointXiphoid
process
L1
VertebraFloating ribs (11, 12)
(a) Skeleton of the thoracic cage, anterior view
Sternum
Costal cartilageCostal margin
The Thoracic Cage
Figure 7.24a
The Thoracic Cage
Figure 7.24b
XiphisternalXiphisternaljoint
Heart
Sternal angle
Jugular notch
(b) Midsagittal section through the thorax, showingthe relationship of surface anatomical landmarks
of the thorax to the vertebral column
T2
T4
T3
T9
Sternum
Formed from three sectionsManubriumsuperior section
Articulates with medial end of claviclesBodybulk of sternum
Sides are notched at articulations forcostal cartilage of ribs 27
Xiphoid processinferior end of sternum Ossifies around age 40
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Intercostal
spaces
Trueribs
(17
False
ribs
(812)
Jugular notchClavicular notch
Manubrium
Sternal angleBodyXiphisternal
jointXiphoidprocess
L1Vertebra
Floating ribs (11, 12)(a) Skeleton of the thoracic cage, anterior view
Sternum
Costal cartilageCostal margin
The Thoracic Cage
Figure 7.24a
Sternum
Anatomical landmarksJugular notch
Central indentation at superior border ofthe manubrium
Sternal angle A horizontal ridge where the manubriumjoins the body
Xiphisternal joint Where sternal body and xiphoid process
fuse
Lies at the level of the 9th thoracicvertebra
Ribs
All ribs attach to vertebral column posteriorlyRib pairs 1-7 (vertebrosternal ribs) - superior
seven pairs of ribs which attach to sternum by
costal cartilage
Rib pairs 8-10, (vertebrochondral ribs) pairsof ribs which attach to the sternum indirectly
Ribs pairs 1112 (floating ribs) are notattached to the sternum
Ribs 8-12 are sometimes called false ribsbecause they attach to the sternum indirectly
(ribs 8-10) or not at all (ribs 11-12)
Intercostal
spaces
True
ribs
(17
False
ribs(812)
Jugular notchClavicular notch
Manubrium
Sternal angleBody
Xiphisternal
jointXiphoid
process
L1
VertebraFloating ribs (11, 12)
(a) Skeleton of the thoracic cage, anterior view
Sternum
Costal cartilageCostal margin
The Thoracic Cage
Figure 7.24a
Ribs
Figure 7.25a, b
Junction withcostal cartilage
ShaftHead Neck
Articular faceton tubercle
Costal angleCostal groove
Facets for articulationwith vertebrae
(a) A typical rib (rib 6, right), posterior view
Transverse costal facet(for tubercle of rib)
Superior costal facet(for head of rib)
Body of vertebra
Head of rib
Intervertebral disc
Tubercle of rib
Neck of rib
Shaft Sternum
Angleof rib
Cross-sectionof rib Costal groove
(b) Vertebral and sternal articulations of a typical true rib
Costal cartilage
Spinous process
Articular facet
on tubercle of rib
Shaft
Ligaments
Neck of rib
Head of rib Body of
thoracic
vertebra
Transverse
costal facet
(for tubercleof rib)
Superior costal facet
(for head of rib)
(c) Superior view of the articulation between a rib and a
thoracic vertebra
Ribs
Figure 7.25c
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Superior
articularprocess
Transverse
process
Spinous
process
Intervertebral
disc
Body
Inferior
articular
process
(c) Lumbar vertebrae
Lumbar Vertebrae
Figure 7.22c
Lumbar Vertebrae (L1L5) Bodies are thick and robust Transverse processes are thin and tapered Spinous processes are thick, blunt, and point
posteriorly
Vertebral foramina are triangular Superior articular facets face posteromedially or
medially
Inferior articular facets face anterolaterally orlaterally
Allows flexion and extensionrotation prevented
Lumbar Vertebrae
Table 7.2c
Cervical, Thoracic, & Lumbar Vertebrae
Superior View
Cervical, Thoracic, & Lumbar Vertebrae
Right Lateral ViewSacrum (S1S5)
Shapes the posterior wall of pelvis Formed from 5 fused vertebrae Superior surface articulates with L5 Inferiorly articulates with coccyx
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Sacrum (S1S5) Anterior View
Sacral promontory: Where theanterosuperior margin of the first sacralvertebrae bulges into pelvic cavity
Human bodys center of gravity is 1 cmposterior to sacral promontory
Four transverse ridges cross the anteriorsurface of the sacrum, marking the lines offusion of sacral vertebrae
The anterior sacral foramina transmit theventral divisions (ventral rami) of the sacralspinal nerves
Sacrum
Figure 7.23
Body offirst
sacralvertebra
Transverseridges (sites
of vertebralfusion)
Coccyx Coccyx
Anteriorsacral
foraminaApexPosteriorsacral
foramina
Mediansacral
crest
Sacral promontorySacral
canal
Sacralhiatus
BodyFacet of superiorarticular process
Lateralsacral
crest
Auricularsurface
Ala
(a) Anterior view (b) Posterior view
Sacrum (S1S5) Posterior View
On the posterior surface in the midline is thebumpy median sacral crest which representsthe fused spinous processes of the sacralvertebrae
Lateral to the medial sacral crest are theposterior sacral foramina which transmit thedorsal rami of the sacral spinal nerves
Just lateral to these is the lateral sacral crest Ala (wing)develops from fused rib elements
Sacrum
Sacral foraminaVentral foramina
Passage for ventral rami of sacral spinalnerves
Dorsal foramina Passage for dorsal rami of sacral spinal
nerves
Sacrum
Figure 7.23
Body offirst
sacralvertebra
Transverseridges (sites
of vertebralfusion)
Coccyx Coccyx
Anteriorsacral
foraminaApexPosteriorsacral
foramina
Mediansacral
crest
Sacral promontorySacralcanal
Sacralhiatus
BodyFacet of superiorarticular process
Lateral
sacralcrest
Auricularsurface
Ala
(a) Anterior view (b) Posterior view
Coccyx
Is the tailbone Formed from 35 fused vertebrae Offers only slight support to pelvic
organs
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Disorders of the Axial
Skeleton
Cleft palateA common congenital disorderRight and left halves of palate fail to fuse
medially
Stenosis of the lumbar spineNarrowing of the vertebral canalCan compress roots of spinal nerves
Cleft palate
Disorders of the Axial
Skeleton
Abnormal spinal curvaturesScoliosisan abnormal lateral curvatureKyphosisan exaggerated thoracic
curvature
Lordosisan accentuated lumbarcurvature; swayback
Abnormal spinal curvatures
The Axial Skeleton Throughout Life
Flat membrane bones begin to ossify insecond month of embryonic
development
Bone tissue grows outward fromossification centers
At birth, skull bones are separated bystill-unossified remnants of membranes
call fontanelles
Fontanelles Fontanelles are unossified remnants of
membranes present at birth
Anterior, posterior, mastoid, and sphenoidalfontanelles
Allows skull to be safely compressed and moldedas infant passes through narrow birth canal
A visible arterial pulse may be seen in thefontanelles
Fontanelles tend to be replaced by bone by theend of the 1st year, however, the anterior
fontanelle may take 1.5 to 2 years to ossify and
close
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Fontanelles
Figure 7.28a
Occipital
bone
Parietal bone
Anteriorfontanelle
Frontal suture
Frontal bone
Ossification
center
(a) Superior view
Posterior fontanelle
Fontanelles
Figure 7.28b
Frontal bone
Sphenoidal
fontanelle
(b) Lateral view
Posterior
fontanelle
Mastoid
fontanelle
Parietal boneOssification
center
Occipital bone
Temporal bone
(squamous
portion)
Bone formation
Many bones of the face and skullcapform by intramembranous ossification
Endochondral bones of the skullOccipital boneSphenoidEthmoid bonesParts of the temporal bone
Skull and face growth
9 months of age: skull adult size 2 years of age: skull adult size 8-9 years: cranium almost adult size 6-13 years: accelerated growth of jaws,
cheekbones, large permanent teeth,
nose, and paranasal sinuses
The Axial Skeleton
Throughout Life
Aging of the axial skeletonWater content of the intervertebral discs
decreases with age
By age 55, loss of a few centimeters inheight is common
Thorax becomes more rigid as costalcartilage gradually ossifies
Bones lose mass with age