the axial skeleton - linkpublishing.com · 3/4/02 s. davenport © 2 axial skeleton • divided into...
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3/4/02 S. Davenport © 1
Axial Skeleton
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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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Skull1) Frontal bone2) Superior orbital foramen3) Orbital plate of sphenoid bone4) Inferior orbital fissure5) Superior orbital fissure6) Optic foramen7) Zygomatic bone8) Inferior orbital foramen9) Maxilla10) Mandible
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Skull1) Nasal bone2) Lacrimal bone3) Orbital plate of ethmoid4) Perpendicular plate of ethmoid5) Vomer6) Body of mandible7) Alveolar process (margin) of
mandible8) Inferior nasal concha9) Alveolar process (margin) of
maxilla10) Mental foramen
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Skull
1) Supraorbital foramen2) Optic foramen3) Orbital plate of ethmoid4) Lacrimal bone5) Nasal bone6) Zygomatic bone
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Skull
1) Orbital plate and greater wing of sphenoid bone
2) Frontal bone3) Superior orbital fissure4) Inferior orbital fissure5) Infraorbital foramen6) Maxilla
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Skull1) Parietal bone2) Squamous suture3) Squamous region of temporal
bone4) Coronal suture5) Frontal bone6) Greater wing of sphenoid7) Nasal bone8) Lacrimal bone9) Zygomatic bone10) Maxilla
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Skull1) Lambdoidal suture2) Squamous suture3) Parietal bone4) Coronal suture5) Frontal bone6) Squamous region of temporal7) Greater wing of sphenoid8) Occipital bone9) Mastoid process of temporal bone10) Styloid process of temporal bone
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Skull1) Zygomatic process of temporal bone2) Temporal process of zygomatic bone3) Zygomatic bone4) Nasal bone5) Lacrimal bone6) Maxilla7) Mandibular condyle8) Mandibular notch9) Coronoid process10) Body of mandible11) Mental foramen
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Skull
1) External auditory meatus of temporal bone
2) Alveolar process (margin) of maxilla
3) Ramus of mandible4) Angle of mandible5) Alveolar process (margin) of
mandible
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Skull1) Palatine process of maxilla2) Horizontal plate of palatine bone3) Vomer4) Occipital condyles5) Foramen magnum6) Mandible7) Pterygoid process of sphenoid
bone 8) Sphenoid bone9) Styloid process of temporal bone10) Mastoid process of temporal bone11) Occipital bone
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Skull1) Foramen ovale2) Foramen spinosum3) Foramen lacerum4) Jugular foramen5) Carotid foramen6) Zygomatic arch7) Temporal process of zygomatic
bone8) Zygomatic process of temporal
bone9) Mandibular condyle10) Mandibular fossa
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Skull1) Crista galli2) Cribriform plate3) Optic foramen4) Frontal bone5) Lesser wing of sphenoid bone6) Sella turcica7) Greater wing of sphenoid bone8) Temporal bone9) Petrous portion of temporal bone10) Occipital bone11) Foramen magnum
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Skull
1) Olfactory foramina2) Optic foramen3) Foramen rotundum4) Foramen ovale5) Foramen spinosum6) Foramen lacerum7) Internal auditory meatus8) Jugular foramen9) Foramen magnum
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Skull
1) Frontal bone2) Coronal suture3) Sagittal suture4) Parietal bones5) Lambdoidal suture6) Occipital bone
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VERTEBRAL COLUMN
Vertebral column, 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 column
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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.• Passage for spinal nerves
Abnormal spinal curvatures– Kyphosis, or hunchback, is characterized by
an increased convexity of the thoracic spine– Lordosis is characterized by an increased
concavity of the lumbar spine.– Scoliosis is a deviation from the normal
straight vertical line of the spine
Vertebral column
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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• 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 function in superior and inferior articulations
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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 VertebraeFirst 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
Axis, C2
Atlas, C1Cervical vertebra, “typical”
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Features of Cervical Vertebrae
• All cervical are characterized by:– 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)
Cervical vertebra, “typical”
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Atlas, C1First cervical vertebra, C1• Atlas does not have
– Body• 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– Allows “nodding” head movement,
as seen in head movement to indicate “yes”
Inferior articulation (Fig. 2) is with the axis, C2
Fig. 2, Articulation of atlas
Fig. 1, atlas
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Atlas, C1
1) Anterior arch2) Transverse process3) Transverse foramen4) Vertebral foramen5) Superior articular facet6) Posterior arch
Atlas, C1
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Axis, C2
Fig. 1, Axis, C2
Second cervical vertebra, C2• Shares typical features of
cervical vertebrae except for– 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”
Inferior articulation is with third cervical vertebraFig. 2, Axis, articulation
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Axis, C21) Body2) Dens, or odontoid process3) Superior articular surface 4) Transverse foramen5) Transverse process6) Vertebral foramen7) Bifid spinous process8) Vertebral arch9) Pedicle10) Lamina
Axis, C2
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Typical Cervical Vertebra (C3-C7)
1) Transverse process2) Transverse foramen3) Body4) Superior articular process5) Vertebral foramen6) Bifid spinous process7) Arch8) Pedicle9) Lamina
Typical cervical vertebra
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Thoracic VertebraeSecond Division
Vertebral column
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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)
• 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, lateral view
Thoracic vertebra, 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.
• Transverse processes (#1) have facets for articulation with tubercles (facets) of ribs– Except T11 and T12 do not have rib
articulations with transverse processes
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Thoracic Vertebra1) Facet of transverse process2) Superior articular process3) Superior demifacet4) Transverse process5) Spinous process6) Inferior articular process7) Inferior demifacet8) Body
Thoracic vertebra, lateral view
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Thoracic Vertebra, Superior1) Body2) Demifacets3) Transverse process4) Facet of transverse process5) Vertebral arch6) Lamina7) Pedicle8) Spinous process9) Superior articular surface10) Vertebral foramen
Thoracic vertebra, superior view
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Lumbar VertebraeThird Division
Vertebral column
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Features of Lumbar Vertebrae• 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
Lumbar vertebra, lateral view
Lumbar vertebra, superior view
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Lumbar Vertebra, Lateral
1) Superior articular process2) Transverse process3) Spinous process4) Inferior articular process5) Body6) Pedicle
Lumbar vertebra, lateral view
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Lumbar Vertebra, Superior1) Vertebral arch2) Lamina3) Pedicle4) Spinous process5) Superior articular process6) Transverse process7) Vertebral foramen8) BodyLumbar, superior view
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Sacrum and CoccyxFourth and Fifth Divisions
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Sacrum and Coccyx• Sacrum formed from fused sacral
vertebrae (usually five).– 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
Sacrum; anterior view, location in pelvis
Sacrum, posterior view
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Sacrum (posterior)1) Sacrum2) Coccyx3) Body4) Sacral canal5) Superior articular process6) Ala7) Sacral foramina8) Medial sacral crest9) Sacral hiatusSacrum, posterior view
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Sacrum (lateral)
1) Sacrum2) Coccyx3) Body4) Ala5) Medial sacral crest6) Auricular surface
Sacrum, lateral view
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THORAX
Thorax, anterior viewAxial skeleton
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ThoraxThoracic 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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ThoraxThoracic 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)– 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.
Thorax, anterior
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Thoracic Vertebrae
Thoracic vertebra, lateral view
Vertebral column Thoracic vertebrae (T1 – T12) paired rib attachments,(T11&T12 do not have transverse process articulations)
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Ribs• 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.
Rib #1
Rib #7
Rib #12
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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