Transcript Articulations

Articulations
Articulations- points where two or
more bones come together to form a
joint [ maybe rigid or movable]
Classified by Structure or Function
• Structure- based on material that joins
bones together
Fibrous – fibrous connective tissue
Cartilagenous – hyaline or
fibrocartilage
Synovial – joint cavity with synovial
membrane
Synovial Joint
Capsule is
continuous with
periosteum
Membrane
is 2 layers
Has blood
vessels &
nerves
Synovial Fluid
• Continuously made, circulated – at any time there
is 3 ml [ 0.1 oz] in cavity
• Resembles interstitial fluid, but contains
proteoglycans secreted by fibroblasts  making it
thick / viscous
• Functions: lubricate joint
distribute nutrients and remove
waste products
shock absorber
defense
Accessories of Synovial Joint
• Cartilage – fibrocartilage [articular discs or
meniscus]
• Fat – articular fat pads
• Ligaments [ attach bone to bone]
• Tendons [ attach muscle to bone]
• Bursae – synovial fluid filled ‘pockets’ mini
shock absorbers
•
Function – based on degree of
movement
Synarthroses – immovable
Amphiarthroses – slightly
movable
Diarthroses – freely moveable
Fibrous Articulations
• Bones are held tightly connected by fibrous
connective tissue or cartilage. Joints are rigid and
immoveable.
Sutures – found only in skull. Bones joined by
fibrous connective tissue
Syndesmosis – band of fibrous connective tissue,
holds bones tightly together
distal end of tibia/fibula
Gomphosis – peg in socket
tooth in alveoli- periodontal ligament
Syndesmosis
Cartilagenous Articulations
Hyaline or fibrous cartilage joins bones; limited
motion in response to twisting, compression, stress
Synchondrosis – hyaline cartilage joins bones.
epiphyseal plate, costal cartilages
Symphysis – pad of fibrocartilage separates bones.
intervertebral discs, symphysis pubis
Synchondrosis
Symphysis
Synovial Articulations
•
Freely moveable joints. Include a capsule
lined with a membrane and contains fluid
Range of movement limited by:
1. Structure of bones
2. Strength and tautness of ligaments,
tendons, joint capsule
3. Size, arrangement, action of muscles
Types of Synovial Articulations
• Hinge – concave surface
on one articulates with
convex surface of another.
• Pivot – conical surface on
one articulates with
depression on another
• Condyloid – oval condyle
on one articulates with
elliptical cavity on another
• Gliding- flattened or
slightly curved articulating
surfaces
• Saddle – concave and
convex surface on each
articulating bone
• Ball and Socket – rounded
surface on one articulates
with cuplike socket on
another
Pivot
saddle
Ball & Socket
Condyloid
Gliding
Hinge
•Bursa – fluid filled sacs near diarthrotic joints –
between muscles, skin and bones or tendon and bone.
Reduce friction and stress associated with movement
•Tendon Sheaths – modified bursae that surround and
lubricate tendons of certain muscles, esp. those that
cross wrist and ankle