Joints/Articulations
Contact between bones, cartilage and bone, or teeth and bone
Types of join classifications
Structural and functional
Structural classification
Based on anatomical organization if the joint
Functional classification
Based on range of motion of the joint
Structural Classification of Joints
Fibrous, Cartilaginous, Bony, Synovial
Fibrous
Bones held together by fibrous CT tightly - no joint cavity
Cartilaginous
Bones held together by cartilage - No joint activity
Bony
Two bones fused by issues tissue and the boundary between them disappears
Synovial
- Joint cavity - separates bones and is surrounded by an articular capsule
- Accessory ligaments found around many capsules
- Freely movable joints
Functional Classification of Joints
Synarthroses - immovable joints
Amphiarthroses - slightly moveable joints
Diathroses - Freely moveable joints (all synovial)
Synarthroses
Suture
Gomphosis
Synchondrosis
Synostosis
Suture
Bones are bound by dense connective tissue (only skull bones)
Gomphosis
Bound by periodontal ligaments (binds teeth to sockets)
Synchondrosis
Bound by rigid cartilaginous bridge (epiphyseal cartilage of longe bones; between vertebrosternal ribs and sternum)
Synostosis
Two bones completely fused (epiphyseal lines of long bones)
Amphiarthrosis
Syndesmosis
Symphysis
Syndesmosis
Boned connected by a ligament -allows some flexibility or movement (distal articulations of the tibia and fibula)
Symphysis
Bone connected by fibrocartilage (intervertebral disks & pubic symphysis)
Diathrosis
Most common in adults
Bony surfaces
•enclosed within joint (articular) capsule
•covered by articular cartilage
•lubricated by synovial fluid
Movement limited only by ligaments, tendons, muscles, and shape of articulating bones
Structure of synovial/diathrosis join
Join Capsule
•Dense irregular CT attach periosteum, provides resistance to dislocation
Articular Cartilages
•Pad articulation surfaces within
•Prevent bones from touching
•Smooth surfaves lubricated by synovial. fluid reduce friction
Synovial Membrane
Fibroblasts of the synovial membrane secret synovial fluid that contained slippery proteoglycans
Synovial fluid
•The consistency of egg yolk
Functions of synovial fluid
- Lubrication
- Nutrient distribution
- Shock absorption