Chapter 7 - The skeleton (part b) provides knowledge of vertebral column and thoracic cage. This chapter describe the structure of the vertebral column, list its components, and describe its curvatures; indicate a common function of the spinal curvatures and the intervertebral discs; name and describe the bones of the thoracic cage (bony thorax); differentiate true from false ribs.
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prepared by Janice Meeking, Mount Royal College
C H A P T E R
Copyright © 2010 Pearson Education, Inc.
7
The Skeleton: Part B
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Vertebral Column
• Transmits weight of trunk to lower limbs
• Surrounds and protects spinal cord
• Flexible curved structure containing 26 irregular bones (vertebrae)
• Cervical vertebrae (7)—vertebrae of the neck
• Thoracic vertebrae (12)—vertebrae of the thoracic cage
• Lumbar vertebrae (5)—vertebra of the lower back
• Sacrum—bone inferior to the lumbar vertebrae
• Coccyx—terminus of vertebral column
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Vertebral Column: Curvatures
• Increase the resilience and flexibility of the spine
• Two posteriorly concave curvatures
• Cervical and lumbar
• Two posteriorly convex curvatures
• Thoracic and sacral
• Abnormal spine curvatures
• Scoliosis (abnormal lateral curve)
• Lordosis (swayback)
Trang 4Copyright © 2010 Pearson Education, Inc. Figure 7.16
Cervical curvature
(concave)
7 vertebrae, C 1 –C 7
Thoracic curvature
Coccyx
4 fused vertebrae Anterior view Right lateral view
Spinous process Transverse processes
Intervertebral discs
Intervertebral foramen
C 1
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Ligaments
• Anterior and posterior longitudinal ligaments
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Intervertebral Discs
• Cushionlike pad composed of two parts
• Inner gelatinous nucleus that gives the
disc its elasticity and compressibility
2 Anulus fibrosus
fibrocartilage
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Supraspinous ligament
Intervertebral disc
Anterior longitudinal ligament
Intervertebral foramen
Posterior longitudinal ligament
Anulus fibrosus Nucleus pulposus
Inferior articular process
Median section of three vertebrae, illustrating the composition
of the discs and the ligaments
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Vertebral spinous process
(posterior aspect of vertebra)
Spinal nerve root
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General Structure of Vertebrae
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General Structure of Vertebrae
• Seven processes per vertebra:
• Spinous process—projects posteriorly
• Transverse processes (2)—project laterally
• Superior articular processes (2)—protrude superiorly inferiorly
• Inferior articular processes (2)—protrude inferiorly
PLAY Animation: Rotatable Spine (horizontal)
PLAY Animation: Rotatable Spine (vertical)
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Vertebral arch
Vertebral foramen Body
(centrum)
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Cervical Vertebrae
• C1 to C7: smallest, lightest vertebrae
• C3 to C7 share the following features
• Spinous processes are bifid (except C7)
• Large, triangular vertebral foramen
• Transverse foramen in each transverse process
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Dens of axis Transverse ligament
of atlas
C1 (atlas)
C2 (axis)
Bifid spinous process
Transverse processes
C7 (vertebra prominens) (a) Cervical vertebrae
C3
Inferior articular process
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Cervical Vertebrae
• C1 (atlas) and C2 (axis) have unique features
• Atlas (C1)
• No body or spinous process
• Consists of anterior and posterior arches, and two lateral masses
• Superior surfaces of lateral masses articulate with the occipital condyles
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Anterior arch
Superior articular facet
Transverse foramen
Posterior arch
Posterior tubercle
Anterior tubercle
Posterior
Lateral masses
C 1
Facet for dens
Transverse process Lateral masses
Transverse foramen
Posterior arch Posterior tubercle
Posterior
Anterior tubercle
Anterior arch
Inferior articular facet
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Dens
(c) Superior view of axis (C2)
Inferior articular process
Body
Superior articular facet
Transverse
process
Pedicle
Lamina Spinous process
Figure 7.19c
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Thoracic Vertebrae
• T1 to T12
• All articulate with ribs at facets and
demifacets
• Long spinous process
• Location of articular facets allows rotation of this area of spine
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Trang 21Copyright © 2010 Pearson Education, Inc. Figure 7.20b
Transverse process
Spinous process
Superior articular process
Transverse costal facet (for tubercle of rib)
Body
Intervertebral disc
Inferior costal facet (for head
of rib) Inferior articular process
(b) Thoracic vertebrae
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Lumbar Vertebrae
• L1 to L5
• Short, thick pedicles and laminae
• Flat hatchet-shaped spinous processes
• Orientation of articular facets locks lumbar vertebrae together so as to prevent rotation
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Trang 24Copyright © 2010 Pearson Education, Inc. Figure 7.20c
Superior articular process Transverse process
Spinous process
Intervertebral disc
Body
Inferior articular process
(c) Lumbar vertebrae
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Sacrum and Coccyx
• Coccyx
• Tailbone
• 3–5 fused vertebrae
• Articulates superiorly with sacrum
Trang 26Copyright © 2010 Pearson Education, Inc. Figure 7.21a
Coccyx
Anterior sacral foramina Apex
Sacral promontory
Ala Body of
first sacral vertebra Transverse ridges (sites
of vertebral fusion)
(a) Anterior view
Trang 27Copyright © 2010 Pearson Education, Inc. Figure 7.21b
Coccyx
Posterior sacral
foramina
Median sacral crest
Sacral canal
Sacral hiatus
superior articular process
Lateral sacral crest
Auricular surface Ala
(b) Posterior view
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• Protects vital organs of thoracic cavity
• Supports shoulder girdle and upper limbs
• Provides attachment sites for many muscles, including intercostal muscles used during breathing
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• Site of muscle attachment
• Not ossified until ~ age 40
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Ribs and Their Attachments
• 12 pairs
• All attach posteriorly to thoracic vertebrae
• Pairs 1 through 7
• True (vertebrosternal) ribs
• Attach directly to the sternum by individual costal cartilages
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Ribs and Their Attachments
• Pairs 8 through12
• False ribs
• Pairs 8–10 also called vertebrochondral ribs
• Attach indirectly to sternum by joining costal cartilage of rib above
• Pairs 11–12 also called vertebral (floating) ribs
• No attachment to sternum
Trang 32Copyright © 2010 Pearson Education, Inc. Figure 7.22a
Manubrium Sternal angle Body
Xiphisternal joint
Xiphoid process
L 1 Vertebra Floating ribs (11, 12)
(a) Skeleton of the thoracic cage, anterior view
Sternum
Costal cartilage Costal margin
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Structure of a Typical Rib
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Transverse costal facet
(for head of rib) Body of vertebra Head of rib
Intervertebral disc Tubercle of rib
Neck of rib Shaft Sternum
Angle
of rib
section
(a) Vertebral and sternal articulations of a typical true rib
Trang 35Copyright © 2010 Pearson Education, Inc. Figure 7.23b
Spinous process
Articular facet
on tubercle of rib Shaft
Ligaments
Neck of rib
thoracic vertebra
Transverse costal facet (for tubercle