Download Synovial Joints

PowerPoint® Lecture Slides
prepared by Vince Austin,
Bluegrass Technical
and Community College
CHAPTER
Elaine N. Marieb
Katja Hoehn
Human
Anatomy
& Physiology
SEVENTH EDITION
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
8
Joints
PART A
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
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Figure 8.1a
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
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Figure 8.1b
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
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Figure 8.2a, b
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
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Figure 8.2c
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
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Figure 8.3a, b
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Table 8.2.1
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Table 8.2.2
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Table 8.2.3
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
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Figure 8.4
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
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Figure 8.5a
Angular Movement
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Figure 8.5b
Angular Movement
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Figure 8.5c, d
Angular Movement
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Figure 8.5e, f
Rotation

The turning of a bone
around its own long axis

Examples

Between first two
vertebrae

Hip and shoulder joints
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Figure 8.5g
Special Movements

Supination and pronation

Inversion and eversion

Protraction and retraction

Elevation and depression

Opposition
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Special Movements
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Figure 8.6a
Special Movements
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Figure 8.6b
Special Movements
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Figure 8.6c
Special Movements
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Figure 8.6d
Special Movements
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Figure 8.6e