Download Ch 5 Vertebral Column

Chapter 5
Skeletal System
Axial Skeleton
Vertebral Column
Functions
• Surrounds/Protects spinal cord
• Provides attachment sites for
– Ribs
– Muscles of neck and back
• Axial support of the trunk (skull to pelvis)
• Discs absorb shock and provide flexibility
Vertebral Column (Spine)
• 26 single vertebral bones
– 7 cervical vertebrae are in the neck
– 12 thoracic vertebrae are in the chest region
– 5 lumbar vertebrae are associated with the lower
back
• REMEMBER: 7, 12, 5, 1/1
• intervertebral discs separate vertebrae
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Sacrum and Coccyx
• 9 vertebrae fuse to form two composite bones
• Sacrum formed by the fusion of 5 vertebrae
• Coccyx (tailbone) formed by the fusion of 3 to
5 vertebrae (most common to have 4 fuse)
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Figure 5.16 The vertebral column.
Anterior
1st cervical vertebra
(atlas)
2nd cervical vertebra
(axis)
Posterior
Cervical curvature (concave)
7 vertebrae, C1 – C7
1st thoracic vertebra
Transverse process
Spinous process
Thoracic curvature (convex)
12 vertebrae, T1 – T12
Intervertebral disc
Intervertebral foramen
1st lumbar vertebra
Lumbar curvature (concave)
5 vertebrae, L1 – L5
Sacral curvature (convex)
5 fused vertebrae
Coccyx
4 fused vertebrae
Curvatures of the Sine
• Primary curvatures (present at birth)
– Spinal curvatures of the thoracic and sacral regions
– Present from birth
– Form a C-shaped curvature as in newborns
• Secondary curvatures (form after birth)
– Spinal curvatures of the cervical and lumbar regions
– Develop after birth
– Form an S-shaped curvature as in adults
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Figure 5.17 The C-shaped spine typical of a newborn.
Primary Curvature: C- Shaped Curvature of the Spine
Figure 5.18 Abnormal spinal curvatures.
(a) Scoliosis
(b) Kyphosis
(c) Lordosis
Anatomy of a Vertebra
• Body (centrum)
• Vertebral arch
– Pedicle
– Lamina
•
•
•
•
Vertebral foramen
Transverse processes
Spinous process
Superior and inferior articular processes
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Figure 5.19 A typical vertebra, superior view.
Posterior
Vertebral
arch
Lamina
Transverse
process
Spinous
process
Superior
articular
process
and
facet
Pedicle
Vertebral
foramen
Body
Anterior
Atlas and Axis- the neck region
• Atlas (C1)
– No body
– Large depressions to accommodate occipital
condyles of the occipital bone
• Allows head to nod
• Axis (C2)
– Dens (large process) provides pivot point for atlas
– Allow head rotation when articulating with atlas
Figure 5.20a Regional characteristics of vertebrae.
(a) ATLAS AND AXIS
Transverse
process
Posterior
arch
Anterior arch
Superior view of atlas (C1)
Transverse
process
Spinous process
Facet on
superior
articular
process
Dens
Body
Superior view of axis (C2)
Figure 5.20b Regional characteristics of vertebrae.
(b) TYPICAL CERVICAL VERTEBRAE
Spinous process
Vertebral
foramen
Facet on
superior
articular
process
Superior view
Superior articular
process
Spinous
process
Transverse
process
Body
Transverse
process
Facet on inferior
articular process
Right lateral view
Transverse foramina of cervical vertebrae are ONLY characteristics of cervical vertebrae
Figure 5.20c Regional characteristics of vertebrae.
(c) THORACIC VERTEBRAE
Only vertebrae to articulate w/ribs
Spinous process
Vertebral
Transverse
foramen
process
Facet on
superior
Facet
articular
for rib
process
Body
Facet on Superior view
superior
Body
articular
process
Facet on
Costal facet
transverse
Spinous
for rib
process
process
Right lateral view
Figure 5.20d Regional characteristics of vertebrae.
(d) LUMBAR VERTEBRAE
Spinous process
Vertebral
Transverse
foramen
process
Facet on
superior
articular
process
Body
Superior view
Superior
articular
process
Spinous
process
Signature short spinous processes
Body
Facet on inferior
articular process
Right lateral view
Figure 5.21 Sacrum and coccyx, posterior view.
Sacral
canal
Ala
Superior Auricular
articular surface
process
Body
Median
sacral
crest
Sacrum
Posterior
sacral
foramina
Coccyx
Sacral
hiatus