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Presentation Prior Lake Savage Area Schools

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									  Chapter 8


Articulations
    Part A
     Joints (Articulations)

Weakest parts of the skeleton
Articulation – site where two or more
bones meet
Functions
  Give the skeleton mobility
  Hold the skeleton together
  I. Classification of Joints:
          Structural
Structural classification focuses on:
 the material binding bones together
 whether or not a joint cavity is present
The three structural classifications are:
  Fibrous
  Cartilaginous
  Synovial
          Know for quiz!
 II. Classification of Joints:
         Functional
Functional classification is based on the
amount of movement allowed by the
joint
The three functional class of joints are:
  Synarthroses – immovable
  Amphiarthroses – slightly movable
  Diarthroses – freely movable
     Know for a quiz!
Summary of Joint Classes p.
          213




   Know for a quiz!
   Fibrous Structural Joints
The bones are jointed by fibrous tissues
There is no joint cavity
Most are immovable(synarthrotic)
There are three
types –
1. sutures,
2. syndesmoses,
3. gomphoses




                                           Figure 8.1a
   Fibrous Structural Joints:
           Sutures
                                        p. 211




Occur between the bones of the skull
Comprised of interlocking junctions
completely filled with CT fibers
Bind bones tightly together, but allow for
growth during youth
In middle age, skull bones fuse and are called
synostoses
                  Fibrous Structural
                        Joints
                   “Syndesmoses”


Bones are connected by a fibrous tissue ligam
Movement varies from immovable to slightly
Examples include the connection between the
fibula, and the radius and ulna


 No movement allowed                 Figure 8.1b
   Fibrous Structural Joints:
         Gomphoses


                                p.212




The peg-in-socket fibrous joint between a
tooth and its alveolar socket
The fibrous connection is the periodontal
ligament
      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
      Cartilaginous Joints p.212

Articulating
bones are
united by
cartilage
Lack a joint
cavity
Two types –
synchondrose
s and
symphyses
                              Figure 8.2a
Cartilaginous Joints   p.212




                         Figure 8.2b
       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
Cartilaginous Joints




                       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
   Synovial Joints: General
   p. 214
          Structure
Synovial joints
all have the
following:
  Articular
  cartilage
  Joint (synovial)
  cavity
  Articular
  capsule
  Synovial fluid
  Reinforcing                 Figure 8.3a
                Synovial Joint
                    Quiz
      7.
     6.
     5.

           4.
          1.
3.

2.


                          Figure 8.3a
   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
      Synovial Joints: Friction-
p.213
        Reducing Structures




                                   Figure 8.4a, b
   Synovial Joints: Stability
Stability is determined by:
  Articular surfaces – shape determines what
  movements are possible
  Ligaments – unite bones and prevent
  excessive or undesirable motion
Muscle tone is accomplished by:
 Exercise!
  Muscle tendons across joints are the most
  important stabilizing factor
  Tendons are kept tight at all times by
  muscle tone
 Synovial Joints: Movement


Muscle attachment across a joint
  Origin – attachment to the immovable bone
  Insertion – attachment to the movable bone
Described as movement along
transverse, frontal, or sagittal planes
Synovial Joints: Range of
         Motion
  Know for a quiz!       p.216


Nonaxial – slipping movements only
Uniaxial – movement in one plane
Biaxial – movement in two planes
Multiaxial – movement in or around
all three planes
    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
    Terms to Know for a Quiz
All six types of synovial joints

Cartilaginous, Fibrous, synovial

Diarthroses, Amphiarthosis, Synarthroses

Uniaxial biaxial, nonaxial, multiaxial

								
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