Download The Axial Skeleton

Axial Skeleton
3/4/02
S. Davenport ©
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Axial skeleton
• Divided into the
– Skull
– Vertebral column
– Thorax
Axial skeleton
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SKULL
Skull, lateral
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Skull
• Skull is divided into two basic regions
– (1) cranial region
– (2) facial region.
Cranial region
Facial region
Skull, lateral
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Skull
1) Frontal bone
2) Superior orbital foramen
3) Orbital plate of sphenoid bone
4) Inferior orbital fissure
5) Superior orbital fissure
6) Optic foramen
7) Zygomatic bone
8) Inferior orbital foramen
9) Maxilla
10) Mandible
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Skull
1)
2)
3)
4)
5)
6)
7)
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Nasal bone
Lacrimal bone
Orbital plate of ethmoid
Perpendicular plate of ethmoid
Vomer
Body of mandible
Alveolar process (margin) of
mandible
8) Inferior nasal concha
9) Alveolar process (margin) of
maxilla
10)
Mental
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© foramen
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Skull
1)
2)
3)
4)
5)
6)
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Supraorbital foramen
Optic foramen
Orbital plate of ethmoid
Lacrimal bone
Nasal bone
Zygomatic bone
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Skull
1) Orbital plate and greater wing
of sphenoid bone
2) Frontal bone
3) Superior orbital fissure
4) Inferior orbital fissure
5) Infraorbital foramen
6) Maxilla
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Skull
1) Parietal bone
2) Squamous suture
3) Squamous region of temporal
bone
4) Coronal suture
5) Frontal bone
6) Greater wing of sphenoid
7) Nasal bone
8) Lacrimal bone
9) Zygomatic bone
10) Maxilla
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Skull
1) Lambdoidal suture
2) Squamous suture
3) Parietal bone
4) Coronal suture
5) Frontal bone
6) Squamous region of temporal
7) Greater wing of sphenoid
8) Occipital bone
9) Mastoid process of temporal bone
10) Styloid process of temporal bone
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Skull
1) Zygomatic process of temporal bone
2) Temporal process of zygomatic bone
3) Zygomatic bone
4) Nasal bone
5) Lacrimal bone
6) Maxilla
7) Mandibular condyle
8) Mandibular notch
9) Coronoid process
10) Body of mandible
11) Mental foramen
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Skull
1) External auditory meatus of
temporal bone
2) Alveolar process (margin) of
maxilla
3) Ramus of mandible
4) Angle of mandible
5) Alveolar process (margin) of
mandible
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Skull
1)
2)
3)
4)
5)
6)
7)
Palatine process of maxilla
Horizontal plate of palatine bone
Vomer
Occipital condyles
Foramen magnum
Mandible
Pterygoid process of sphenoid
bone
8) Sphenoid bone
9) Styloid process of temporal bone
10) Mastoid process of temporal bone
11) Occipital bone
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Skull
1)
2)
3)
4)
5)
6)
7)
Foramen ovale
Foramen spinosum
Foramen lacerum
Jugular foramen
Carotid foramen
Zygomatic arch
Temporal process of zygomatic
bone
8) Zygomatic process of temporal
bone
9) Mandibular condyle
10) Mandibular fossa
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Skull
1) Crista galli
2) Cribriform plate
3) Optic foramen
4) Frontal bone
5) Lesser wing of sphenoid bone
6) Sella turcica
7) Greater wing of sphenoid bone
8) Temporal bone
9) Petrous portion of temporal bone
10) Occipital bone
11) Foramen magnum
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Skull
1)
2)
3)
4)
5)
6)
7)
8)
9)
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Olfactory foramina
Optic foramen
Foramen rotundum
Foramen ovale
Foramen spinosum
Foramen lacerum
Internal auditory meatus
Jugular foramen
Foramen magnum
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Skull
1)
2)
3)
4)
5)
6)
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Frontal bone
Coronal suture
Sagittal suture
Parietal bones
Lambdoidal suture
Occipital bone
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VERTEBRAL COLUMN
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Vertebral
column,
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©
lateral view
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Vertebral Column (spine)
Consists of five divisions (26 bones)
• Cervical, the first division
– Contains 7 cervical vertebrae (C1 - C7).
• Thoracic, the second division
– Contains 12 thoracic vertebrae (T1 - T12)
• Lumbar, the third division
– Contains 5 lumbar vertebrae (L1 - L5)
• Sacrum, the fourth division
– One bone formed from 5 fused vertebrae
• Coccyx, the fifth division
– One bone formed from 4 fused vertebrae
Vertebral
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Vertebral Column (spine)
Intervertebral discs
– A disc is located between each pair of
vertebrae.
• Consists of fibrocartilage; attach discs together and
provide support, flexibility, and absorb shock
Intervertebral foramina
– formed between each pair of articulating
vertebrae.
Vertebral column
• Passage for spinal nerves
Abnormal spinal curvatures
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– Kyphosis, or hunchback, is characterized by
an increased convexity of the thoracic spine
– Lordosis is characterized by an increased
concavity of the lumbar spine.
– ScoliosisS. Davenport
is a deviation
from the normal 20
©
straight vertical line of the spine
Structures of “Typical” Vertebrae
• Body (centrum)
– Weight bearing portion and forms
anterior boundary of vertebral foramen
• Vertebral arch
– Portion which forms lateral and posterior
boundaries of vertebral foramen
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• Pedicles originate from body and form sides
of arch
• Laminae extend from the pedicles as
flattened plates and fuse medially to form the
spinous process
• Spinous process extends posteriorly from
the medial union of the laminae
• Transverse processes extend from lateral
portions of arch
• Articular processes (superior and inferior)
originate at the pedicle-lamina junctions and
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function in superior and inferior articulations
Structures of Vertebrae
• Vertebral foramen
– Large opening of a single
vertebra through which a
portion of the spinal cord
passes
Vertebral canal
– Canal which is formed by
the vertebrae and houses
the spinal cord
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Cervical Vertebrae
First Division
Vertebral column
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Cervical Vertebrae
• First division of vertebral column
– Contains 7 cervical vertebrae (C1 -C7)
– Atlas is first cervical vertebra, C1
– Axis is second cervical vertebra, C2
Atlas, C1
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Axis, C2
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Cervical vertebra, “typical”
Features of Cervical Vertebrae
• All cervical are characterized
by:
Cervical vertebra, “typical”
3/4/02
– Body (#1) is “oval” in shape
– Transverse foramen (#2), a passage
of the vertebral artery, is located in
each transverse process
– Vertebral foramen (#3) is somewhat
triangular in shape
– Bifid spinous process (#4) (bifid branches into two-parts) are located
on all vertebrae except number seven
(C7)
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Atlas, C1
First cervical vertebra, C1
• Atlas does not have
– Body
Fig. 1, atlas
• has an anterior arch (Fig 1, #1)
– Spinous process
• has a posterior arch (Fig. 2, #6)
Superior articulation (Fig.2, #1) is
with occipital bone of skull
Fig. 2, Articulation of atlas
– Allows “nodding” head movement,
as seen in head movement to indicate
“yes”
Inferior articulation (Fig. 2) is with
the axis, C2
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Atlas, C1
Atlas, C1
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1)
2)
3)
4)
5)
6)
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Anterior arch
Transverse process
Transverse foramen
Vertebral foramen
Superior articular facet
Posterior arch
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Axis, C2
Second cervical vertebra, C2
• Shares typical features of
cervical vertebrae except for
Fig. 1, Axis, C2
– Dens, or odontoid process (Fig. 1,
#2) which originates superiorly
from the body (Fig. 1, #1)
Superior articulation (Fig. 2, #1) is
with atlas
– Allows “rotational” head
movement, as seen in head
movement to indicate “no”
Fig.3/4/02
2, Axis, articulation
Inferior articulation is with third
cervical vertebra
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Axis, C2
Axis, C2
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1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
Body
Dens, or odontoid process
Superior articular surface
Transverse foramen
Transverse process
Vertebral foramen
Bifid spinous process
Vertebral arch
Pedicle
Lamina
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Typical Cervical Vertebra (C3-C7)
Typical cervical vertebra
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1)
2)
3)
4)
5)
6)
7)
8)
9)
Transverse process
Transverse foramen
Body
Superior articular process
Vertebral foramen
Bifid spinous process
Arch
Pedicle
Lamina
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Thoracic Vertebrae
Second Division
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Vertebral
column
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©
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Features of Thoracic Vertebrae
• Body (#1)
– is “heart shaped” in superior view
– has demifacets (half-facets) (#2),,” on
lateral superior and inferior edges for
articulation with ribs (heads)
Thoracic vertebra,
lateral view
• Except T11 and T12 which have complete
facets for rib articulations
• Transverse processes (#3) have facets (#4)
for articulation with ribs (tubercles)
• Spinous process (#5) is long and projects
inferiorly
• Vertebral foramen (#6) is “rounded” in
shape
Thoracic vertebra,
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superior view
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Thoracic Vertebrae Rib
Articulations
• Demifacets (half-facets) (#4) on the
lateral superior and inferior edges for
articulation with heads of ribs (#3)
– Each head of a rib articulates with both
the inferior demifacet of one vertebra and
the superior demifacet of the adjacent
vertebra. Except T11 and T12 which have
complete facets.
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• Transverse processes (#1) have
facets for articulation with tubercles
(facets) of ribs
– Except T11 and T12 do not have rib
articulations with transverse
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processes
Thoracic Vertebra
Thoracic vertebra, lateral view
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1)
2)
3)
4)
5)
6)
7)
8)
Facet of transverse process
Superior articular process
Superior demifacet
Transverse process
Spinous process
Inferior articular process
Inferior demifacet
Body
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Thoracic Vertebra, Superior
Thoracic vertebra,
superior view
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1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
Body
Demifacets
Transverse process
Facet of transverse process
Vertebral arch
Lamina
Pedicle
Spinous process
Superior articular surface
Vertebral foramen
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Lumbar Vertebrae
Third Division
Vertebral column
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Features of Lumbar Vertebrae
Lumbar vertebra, lateral view
3/4/02 vertebra, superior view
Lumbar
• Body (#1) is large and oval in
shape
• Transverse process (#2) is
short and lack facets (no rib
attachments)
• Spinous process (#3) projects
dorsally. They are described as
blunt, broad, and flat, or
“hatchet shaped.”
• Vertebral foramen (#4) is
small and “triangular” in shape
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Lumbar Vertebra, Lateral
Lumbar vertebra, lateral view
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1)
2)
3)
4)
5)
6)
Superior articular process
Transverse process
Spinous process
Inferior articular process
Body
Pedicle
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Lumbar Vertebra, Superior
Lumbar, superior view
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1)
2)
3)
4)
5)
6)
7)
8)
Vertebral arch
Lamina
Pedicle
Spinous process
Superior articular process
Transverse process
Vertebral foramen
Body
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Sacrum and Coccyx
Fourth and Fifth Divisions
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Sacrum and Coccyx
• Sacrum formed from fused sacral
vertebrae (usually five).
Sacrum; anterior view,
location in pelvis
– Superior articulation with fifth
lumbar vertebra (#1)
– Inferior articulation with coccyx
(#2)
– Lateral articulations with coxal
bones (iliac regions, #3) and
forms sacroiliac joints (#4)
• Coccyx (#2) formed from fused
coccygeal vertebrae (usually 4)
– Superior articulation with apex
of sacrum
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Sacrum, posterior view
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Sacrum (posterior)
Sacrum, posterior view
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1)
2)
3)
4)
5)
6)
7)
8)
9)
Sacrum
Coccyx
Body
Sacral canal
Superior articular process
Ala
Sacral foramina
Medial sacral crest
Sacral hiatus
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Sacrum (lateral)
1)
2)
3)
4)
5)
6)
Sacrum, lateral view
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Sacrum
Coccyx
Body
Ala
Medial sacral crest
Auricular surface
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THORAX
Thorax, anterior view
Axial skeleton
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Thorax
Thoracic cage consists of the
– (1) Thoracic vertebrae (T1 - T12)
– (2) Rib cage
• Ribs (12 pairs) and costal cartilages
– (3) Sternum
Thorax, anterior
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Thorax
Thoracic cage consists of the
– (1) Thoracic vertebrae (T1 - T12)
– (2) Rib cage (ribs and costal cartilages)
• Consists of 12 pairs of ribs and the costal cartilage.
• Attach posteriorly to the thoracic vertebrae
• Anteriorly, ribs 1 - 10 are attached to the sternum (#5)
by cartilage called costal cartilage (#6)
Thorax, anterior
– Ribs 1–7 are the true, or vertebrosternal (#1), ribs
– Ribs 8–12 are the false ribs (#2). Additionally, ribs
8-10 are called the vertebrocostal ribs (#3) as they
attach together by costal cartilage, and ribs 11 and 12
are called vertebral ribs, or floating, (#4) as they
have no anterior attachment
– (3) Sternum.
• The anterior boundary of the thoracic cage.
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Thoracic
Vertebrae
Thoracic vertebra, lateral view
Vertebral column
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Thoracic vertebrae (T1 – T12) paired rib attachments,
(T11&T12 do not have transverse process articulations)
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Ribs
Rib #1
Rib #7
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Rib #12
• All ribs articulate
with the bodies of
thoracic vertebrae
• All ribs, except the
vertebral ribs T11 &
T12, articulate with
transverse processes.
T11 & T12 do not
articulate with
transverse processes.
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Sternum
• Manubrium, superior portion
– Articulates with the clavicles at the
clavicular notches
– Articulates by costal cartilage with
the first two pairs of ribs
• Body, middle portion
– Articulates by costal cartilage with
2nd to 7th pairs of ribs
• Xiphoid process, inferior portion
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