Download Axial Skeleton

PowerPoint® Lecture Slide Presentation
by Patty Bostwick-Taylor,
Florence-Darlington Technical College
The Skeletal System:
Axial Skeleton
5
PART B
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Axial Skeleton
 Forms the longitudinal
axis of the body
 Divided into three parts
 Skull
 Vertebral column
 Bony thorax
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The Skull
 Two sets of bones
 Cranium
 Facial bones
 Bones are joined by
sutures
 Only the mandible is
attached by a freely
movable joint
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Human Skull, Lateral View
Figure 5.7
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Human Skull, Anterior View
Figure 5.11
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Paranasal Sinuses
 Hollow portions of bones
surrounding the nasal
cavity
 Functions of paranasal
sinuses
 Lighten the skull
 Give resonance and
amplification to voice
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The Hyoid Bone
 The only bone that
does not articulate
with another bone
 Serves as a moveable
base for the tongue
 Aids in swallowing
and speech
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Vertebral Column
 Each vertebrae is given a name
according to its location
 There are 24 single vertebral
bones separated by intervertebral
discs
 Seven cervical vertebrae are
in the neck
 Twelve thoracic vertebrae are
in the chest region
 Five lumbar vertebrae are
associated with the lower
back
 Nine vertebrae fuse to form
two composite bones:
Sacrum and Coccyx
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Vertebral Column
 The spine has a normal
curvature
 Primary curvatures are
the spinal curvatures of
the thoracic and sacral
regions
Abnormal curvatures of the spine
Can result from
•Unequal muscle tension
•Malformations of vertebrae
•Age
•Degenerative disease
•Poor posture/use
 Present from birth
 Secondary curvatures
are the spinal curvatures
of the cervical and
lumbar regions
 Develop after birth
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A Typical Vertebrae, Superior View
Figure 5.17
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Regional Characteristics of Vertebrae
C3 – C7
Figure 5.18a
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Regional Characteristics of Vertebrae
T1 – T12
L1 – L5
Figure 5.18c
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Sacrum and Coccyx
 Sacrum
 Formed by the fusion of
five vertebrae
 Coccyx
 Formed from the fusion
of three to five vertebrae
 “Tailbone,” or remnant
of a tail that other
vertebrates have
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
The Bony Thorax
 Forms a cage to protect major
organs
 Consists of three parts
 Sternum
 Thoracic vertebrae
 Ribs: identified by how they
attach to sternum

True ribs (pairs 1–7)
 Attach directly to
sternum

False ribs (pairs 8–12)
 Attach indirectly to
sternum

Floating ribs (pairs 11–12)
 Do not attach
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings