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Joints and Movement - Chapter 8

Terms in this set (40)

*What is a joint?
A point where two structures come together
*What is a tendon?
Band or cord of dense c.t. that connects a muscle to a bone or another structure
Joint structural classification is based off?
major c.t. type that binds bones/is there a fluid filled joint capsule present
*Types of joints
fibrous, cartilaginous, synovial
Joint functions are based off?
Degree of motion
Fibrous joint characteristics
•United by fibrous connective tissue.
•Have no joint cavity.
•Move little or none.
Fibrous Joints: Subdivides based on basis of suture
•Sutures
•Syndesmoses
•Gomphoses
Fibrous joints; Sutures
•Seams found only between the bones of the skull
•Opposing bones interdigitate=stability
•Dense regular collagenous CT between bones with continuous periosteum from one bone to the next=Sutural ligament
•Fully ossified sutures=synostosis
Fibrous joints; syndesmoses
•Slightly movable type of fibrous joint
•Bones farther apart than suture and joined by ligaments.
•Some movement may occur due to ligaments.
Fibrous joints; gomphoses
•Specialized joints.
•Pegs that fit into sockets held in place by fine bundles of regular collagenous connective tissue called:
*Periodontal ligament
Holds teeth in place
~mastication
~braces
Types of cartilaginous joints
Synchondroses
Symphyses
Cartilaginous Joints: Synchondroses
•Joined by hyaline cartilage.
•Little or no movement.
•Temporary and replaced by synostoses or permanent.
•Develop into synovial joints and persist through life
•Examples: Epiphyseal plates, sternocostal, sphenooccipital.
Cartilaginous joints; symphyses
•Fibrocartilage uniting two bones.
•Slightly movable-flexible fibrocartilage.
•Pregnancy
•Examples: symphysis pubis, between the manubrium sternum and the body of the sternum, intervertebral disks.
*Synovial joints
•Allow considerable movement.
•Most joints that unite bones of appendicular skeleton reflecting greater mobility of appendicular skeleton compared to axial.
•Complex compared to other structural joints.
*Articular cartilage in synovial joints
Hyaline; provides smooth surface
*Articular disk
Flat pad of fibrocartilage b/w bones. Improves stability, reduces wear on cartilage
*Meniscus
Articular disk that only partially spans synovial cavity, opening in center
*Joint cavity
Synovial fludi; encloses articular surfaces, holds bones together, allows movement
Synovial joints
•Capsule.
•Outer Fibrous capsule: vascular, continuous with fibrous layer of the periosteum.
•Inner Synovial membrane and fluid: lines inside of joint capsule except at articulation. Produces synovial fluid.
•Sometimes extends as pocket called a bursa to provide cushion between structures that would rub together
•Avascular-receive nutrients via vascular circle at the peripheral margin of the cartilage, underlying spongy bone, or synovial fluid but do not actually penetrate the cartilage or enter the joint cavity
Nerves enter fibrous capsule and synovial membrane, not cartilage or joint cavity.
Synovial fluid has a ?
Complex mixture of polysaccharides, proteins, lipids, cells derived from serum filtrate, and secretions from the synovial cells`
Hyaluronic acid
Provides much of the slippery consistency and lubricating qualities of synovial fluid
*What are the six types of synovial joints?
plane, hinge, pivot, condylar, saddle, ball and socket
*Uniaxial movement
occurring around one axis, can only move front to back or left to right
*Biaxial movement
Occurring around two axes at right angles to each other, can move left and right as well as back to front
*Multiaxial movement
Occurring arounds several axes, ball and socket
Plane or gliding joints
-Uniaxial, some rotation/limited movement
Intervertebral
Saddle joint
Two saddle shaped bones joined together
-biaxial
-Thumb
Hinge joint
Uniaxial
~cylinder shaped bone corresponding concavity in the other
~Ulna/radius and humerous
Pivot joints
Uniaxial
~Cylindrical bony process rotating w/in a circle of a bone and ligament
~Axis and Atlas
Ball and socket joint
Multiaxial
~wide range of movement
Ellipsoid (Condyloid) Joint
~Modified ball and socket, articular surfaces are ellipsoid in shape
~Biaxial, shape of joint limits it's range of movement, almost to hinge in two motions
Three general types of movement
Flexion/extension
Angular
Gliding
Joint structure =
Movement
What is 'normal' when talking about movement?
Anatomical position
Circular rotation
Rotation, pronation/supination, circumduction
*Circumduction
Moving a body part such that the distal end traces a circle while the proximal end stays in one position
~Combination of flexion, extension, abduction, adduction
*Active range of motion
Amount of movement accomplished by muscle contraction
*Passive range of motion
Amount of movement accomplished by some outside force
Active and passive ROM is influenced by
1.Shape of articular surfaces forming joint.
2.Amount and shape of cartilage covering surfaces.
3.Strength and location of ligaments and tendons.
4.Bulk of surrounding tissues, such as muscle and adipose tissue.
5.Amount of fluid in and around joint.
6.Amount of pain in and around joint.
7.Amount of use/disuse of joint.
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