Ch08 a.joint
Transcript of Ch08 a.joint
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Human Anatomy & PhysiologySEVENTH EDITION
Elaine N. Marieb
Katja Hoehn
PowerPoint® Lecture Slides
prepared by Vince Austin,
Bluegrass Technical
and Community College
C H
A P
T E
R
8Joints
P A R T A
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Joints (Articulations)
Weakest parts of the skeleton
Articulation – site where two or more bones meet
Functions of joints
Give the skeleton mobility
Hold the skeleton together
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Classification of Joints: Structural
Structural classification focuses on the material
binding bones together and whether or not a joint
cavity is present
The three structural classifications are:
Fibrous
Cartilaginous
Synovial
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Classification of Joints: Functional
Functional classification is based on the amount of
movement allowed by the joint
The three functional classes of joints are:
Synarthroses – immovable
Amphiarthroses – slightly movable
Diarthroses – freely movable
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Fibrous Structural Joints
The bones are joined by fibrous tissues
There is no joint cavity
Most are immovable
There are three types – sutures, syndesmoses, and
gomphoses
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Fibrous Structural Joints: Sutures
Occur between the bones of the skull
Comprised of interlocking junctions completely
filled with connective tissue fibers
Bind bones tightly together, but allow for growth
during youth
In middle age, skull bones fuse and are called
synostoses
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Fibrous Structural Joints: Sutures
Figure 8.1a
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Fibrous Structural Joints: Syndesmoses
Bones are connected by a fibrous tissue ligament
Movement varies from immovable to slightly
variable
Examples include the connection between the tibia
and fibula, and the radius and ulna
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Fibrous Structural Joints: Syndesmoses
Figure 8.1b
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Fibrous Structural Joints: Gomphoses
The peg-in-socket fibrous joint between a tooth
and its alveolar socket
The fibrous connection is the periodontal ligament
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Cartilaginous Joints
Articulating bones are united by cartilage
Lack a joint cavity
Two types – synchondroses and symphyses
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Cartilaginous Joints: Synchondroses
A bar or plate of hyaline cartilage unites the bones
All synchondroses are synarthrotic
Examples include:
Epiphyseal plates of children
Joint between the costal cartilage of the first rib
and the sternum
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Cartilaginous Joints: Synchondroses
Figure 8.2a, b
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Cartilaginous Joints: Symphyses
Hyaline cartilage covers the articulating surface of
the bone and is fused to an intervening pad of
fibrocartilage
Amphiarthrotic joints designed for strength and
flexibility
Examples include intervertebral joints and the
pubic symphysis of the pelvis
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Cartilaginous Joints: Symphyses
Figure 8.2c
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Synovial Joints
Those joints in which the articulating bones are
separated by a fluid-containing joint cavity
All are freely movable diarthroses
Examples – all limb joints, and most joints of the
body
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Synovial Joints: General Structure
Synovial joints all have the following
Articular cartilage
Joint (synovial) cavity
Articular capsule
Synovial fluid
Reinforcing ligaments
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Synovial Joints: General Structure
Figure 8.3a, b
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Synovial Joints: Friction-Reducing Structures
Bursae – flattened, fibrous sacs lined with synovial
membranes and containing synovial fluid
Common where ligaments, muscles, skin, tendons,
or bones rub together
Tendon sheath – elongated bursa that wraps
completely around a tendon
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Synovial Joints: Friction-Reducing Structures
Figure 8.4
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Synovial Joints: Stability
Stability is determined by:
Articular surfaces – shape determines what
movements are possible
Ligaments – unite bones and prevent excessive or
undesirable motion
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Synovial Joints: Stability
Muscle tone is accomplished by:
Muscle tendons across joints acting as stabilizing
factors
Tendons that are kept tight at all times by muscle
tone
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Synovial Joints: Movement
The two muscle attachments across a joint are:
Origin – attachment to the immovable bone
Insertion – attachment to the movable bone
Described as movement along transverse, frontal,
or sagittal planes
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Synovial Joints: Range of Motion
Nonaxial – slipping movements only
Uniaxial – movement in one plane
Biaxial – movement in two planes
Multiaxial – movement in or around all three
planes
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Gliding Movements
One flat bone surface glides or slips over another
similar surface
Examples – intercarpal and intertarsal joints, and
between the flat articular processes of the vertebrae
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Angular Movement
Flexion — bending movement that decreases the
angle of the joint
Extension — reverse of flexion; joint angle is
increased
Dorsiflexion and plantar flexion — up and down
movement of the foot
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Angular Movement
Abduction — movement away from the midline
Adduction — movement toward the midline
Circumduction — movement describes a cone in
space
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Gliding Movement
Figure 8.5a
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Angular Movement
Figure 8.5b
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Angular Movement
Figure 8.5c, d
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Angular Movement
Figure 8.5e, f
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Rotation
The turning of a bone
around its own long axis
Examples
Between first two
vertebrae
Hip and shoulder joints
Figure 8.5g
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Special Movements
Supination and pronation
Inversion and eversion
Protraction and retraction
Elevation and depression
Opposition
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Special Movements
Figure 8.6a
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Special Movements
Figure 8.6b
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Special Movements
Figure 8.6c
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Special Movements
Figure 8.6d
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Special Movements
Figure 8.6e