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Joints - Anatomy & Physiology (view source)
Revision as of 09:14, 18 July 2008
, 09:14, 18 July 2008→'''Synovial Joints'''
=='''Synovial Joints'''==
=='''Synovial Joints'''==
*Articulating joints are separated by a fluid-filled joint cavity, which is bounded by a synovial membrane
*Articulating joints are separated by a fluid-filled joint cavity, which is bounded by a synovial membrane
*Often the synovial membrane is reinforced by a fibrous capsule and ligaments restricting joint movement
**Synovial fluid: Nourishes and lubricates [[Joints - normal#Articular cartilage|articular cartilage]]
*Cartilage covers the articular surfaces
***Normally in canine joint - 0.01 - 1.0 ml
***Transparent to light yellow (horses)
***Usually very thick due to high hyaluronic acid, forms strands
***Windrowing of cells on smear
***Normal protein < 25g/l (all species)
***Normal cell count: Large mononuclear cells, <12% neutrophils, <11% lymphocytes
****Small animals - < 3 x 10e9/L
****Horses - < 0.5 x 10e9/L
****Cows - < 1 x 10e9/L
*Often the synovial membrane is reinforced by a fibrous capsule and ligaments restricting joint movement and providing stability
**Outer fibrous layer
***Encloses bone and muscle insertions within joint capsule
***Supplied by blood vessels and nerve endings
**Inner synovial layer
***Covers surfeces except for [[Joints - normal#Articular cartilage|articular cartilage]]
***Very thin
***Has surface projections - villi
*Articular Cartilage covers the articular surfaces
**Usually, this is [[Bones and Cartilage - Anatomy & Physiology#Structure and Function of Cartilage|Hyaline]], although [[Bones and Cartilage - Anatomy & Physiology#Structure and Function of Cartilage|Fibrocartilage]] or fibrous tissue can substitute
**Usually, this is [[Bones and Cartilage - Anatomy & Physiology#Structure and Function of Cartilage|Hyaline]], although [[Bones and Cartilage - Anatomy & Physiology#Structure and Function of Cartilage|Fibrocartilage]] or fibrous tissue can substitute
[[Image:Normal joint cartilage.jpg|right|thumb|100px|<small><center>Normal joint cartilage (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
**Limited response to injury, Little repair capacity
*In large animals - normal bilaterally symmetrical depressions on the surface
*Obtains nutrition from [[Joints - normal#Synovial fluid|synovial fluid]] and less so from subchondral vessels
Microscopically, surface has depressions - for synovial fluid?
*In young animals overlies [[Bones - normal#Bone development|epiphyseal cartilage]]
==Joint Pathology==
==Joint Pathology==
For links to joint pathology, go [[Joints|here]]
For links to joint pathology, go [[Joints|here]]