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Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Chapter 5 Skeletal System Axial Skeleton Vertebral Column

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Page 1: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Chapter 5Skeletal System

Axial SkeletonVertebral Column

Page 2: 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

Page 3: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

© 2015 Pearson Education, Inc.

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

Page 4: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

© 2015 Pearson Education, Inc.

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)

Page 5: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.16 The vertebral column.

1st lumbar vertebra

Intervertebral foramen

Intervertebral disc

Spinous process

Transverse process

1st thoracic vertebra

1st cervical vertebra(atlas)

2nd cervical vertebra(axis)

Anterior Posterior

Cervical curvature (concave)7 vertebrae, C1 – C7

Thoracic curvature (convex)12 vertebrae, T1 – T12

Lumbar curvature (concave)5 vertebrae, L1 – L5

Sacral curvature (convex)5 fused vertebrae

Coccyx4 fused vertebrae

Page 6: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

© 2015 Pearson Education, Inc.

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

Page 7: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.17 The C-shaped spine typical of a newborn.

Primary Curvature: C- Shaped Curvature of the Spine

Page 8: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.18 Abnormal spinal curvatures.

(a) Scoliosis (b) Kyphosis (c) Lordosis

Page 9: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

© 2015 Pearson Education, Inc.

Anatomy of a Vertebra

• Body (centrum)• Vertebral arch– Pedicle– Lamina

• Vertebral foramen• Transverse processes• Spinous process• Superior and inferior articular processes

Page 10: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.19 A typical vertebra, superior view.

LaminaPosterior

Vertebralarch

Transverseprocess

Spinousprocess

Vertebralforamen

Body

Anterior

Pedicle

Superiorarticularprocessandfacet

Page 11: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

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

Page 12: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.20a Regional characteristics of vertebrae.

Transverseprocess

(a) ATLAS AND AXIS

Posteriorarch

Superior view of axis (C2)

Anterior arch

Superior view of atlas (C1)

Transverseprocess

Spinous process

DensBody

Facet onsuperiorarticularprocess

Page 13: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.20b Regional characteristics of vertebrae.

(b) TYPICAL CERVICAL VERTEBRAE

Right lateral view

Spinous processFacet onsuperiorarticularprocess

Vertebralforamen

Transverseprocess

Superior view

Body

Facet on inferiorarticular process

Transverseprocess

Superior articularprocessSpinousprocess

Transverse foramina of cervical vertebrae are ONLY characteristics of cervical vertebrae

Page 14: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.20c Regional characteristics of vertebrae.

(c) THORACIC VERTEBRAE

Right lateral view

Transverseprocess

Body

Body

Spinous process

Facetfor rib

Vertebralforamen

Facet on transverseprocess

Spinous process

Costal facetfor rib

Superior view

process

Facet onsuperiorarticular

Facet on superiorarticular process

Only vertebrae to articulate w/ribs

Page 15: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.20d Regional characteristics of vertebrae.

(d) LUMBAR VERTEBRAE

Right lateral view

Transverseprocess

Vertebralforamen

Facet on superiorarticular processBody

BodySuperior articularprocess

Spinousprocess

Facet on inferiorarticular process

Superior view

Spinous process

Signature short spinous processes

Page 16: Chapter 5 Skeletal System Axial Skeleton Vertebral Column

Figure 5.21 Sacrum and coccyx, posterior view.

Ala

Sacrum

CoccyxSacralhiatus

Posteriorsacralforamina

Mediansacralcrest

Body

Auricularsurface

SuperiorarticularprocessSacral

canal