Articulations

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Articulations

• CH 8

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Outline

• Joint Cavity Components
• Joint capsule
• Articular cartilage
• Synovial membrane
• Joint accessory components
• Selected articulations
• Intervertebral articulations
• Glenohumeral joints
• Tibiofemoral joint
• Talocrural joint

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Synovial Joint

• Space
• Yes!
• Joint cavity
• Space contents
• Synovial fluid
• Held together w/ bands of dense regular CT-
  ligaments
• Degree of motion
• Freely moveable
• Least stable- high motility
• Example
• Knee, elbow, fingers, shoulder

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Synovial Joint

• fluid filled joint
• No direct bone- bone contact
• Joint cavity- persistent space between bones
• Diarthrosis- high degree of mobility

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Joint Cavity Components

• Joint capsule
• Articular cartilage
• Synovial membrane
• Joint accessory components
• Accessory Capsular ligaments
• Extracapsular ligaments
• Intracapsular ligaments
• Bursae
• Menisci
• Fat pads
• Stabilizing bones muscles

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Joint Capsule

• Dense irregular CT encloses cavity
• Function
• Adds joint stability
• Refines joint motility
• Defines joint cavity border

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Joint Capsule
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Joint Capsule
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Articular Cartilage

• Structure
• Hyaline cartilage
• Function
• Reduces friction
• Shock absorption
• Modification
• Synovial fluid storage
• Porous allows synovial fluid to be released
  during compression (joint motion)

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Articular Cartilage
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Clinical- Chondromalacia
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Synovial Membrane

• Structure
• Membrane lining articular capsule
• Stops at articular cartilage
• Function
• Synovial fluid secretion
• Provides lubrication/ reduces friction
• Efficient motion w/out wear on bones
• Nourishes articular cartilage
• Chondrocytes acquire nutrition thru synovial
  fluid
• Why?
• Shock absorption
• Absorbs and distributes shock across articular
  cartilage

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Synovial Membrane
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Joint Accessory Components

• Accessory capsular ligaments
• Extracapsular ligaments
• Intracapsular ligaments
• Articular discs menisci
• Bursae
• Fat pads
• Muscles
• Bones

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Accessory Capsular Ligaments

• Distinct localized thickenings of articular
  capsule
• Work to add strength, refine motion stabilize
  joints
• Component of capsule

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Capsule
Pubofemoral Ligament
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Extracapsular ligaments

• outside capsule
• Fibers comprise the layer of CT that is on the
  outside of the articular capsule

Ulnar Collateral Ligament
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Extracapsular Ligaments
Medial Collateral Ligament (knee)
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Intracapsular ligaments

• Fibers located within the articular capsule

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Intracapsular Ligaments
Anterior Cruciate Ligament- Knee
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Articular Discs Menisci

• Structure
• Fibrocartilage discs
• Function
• Change the shape of the articulating surface
• Refine joint movement- stabilize koint
• Absorb shock
• Channel distribute synovial fluid
• Location
• Articulating bones of knee

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Menisci
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Menisci
Provide better bone-bone fit
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Menisci
Refine movement- stability
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Menisci
Channel distribute synovial fluid
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Bursae

• Fluid filled pouch
• Structure
• CT sacs filled with synovial fluid
• Lined with synovial membrane
• Connected or separated from joint cavity
• Form where ligaments or tendons rub against other
  tissue
• Function
• Reduce friction
• Absorb shock
• Location
• Areas of friction

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Suprapatellar Bursa
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Fat Pads

• Pads of fat
• Structure
• Adipose loose connective tissue proper
• Function
• Reduce friction
• Fill space
• Location
• Areas of friction

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Infrapatellar Fat Pad
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Stabilizing Bones Muscles

• Add stability to joint

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Clinical Applications

• Synovial joint dislocation
• Sprain
• Strain
• Bursitis

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Synovial Joint Dislocation

• Luxation- Full dislocation
• Subluxation- Partial dislocation
• Articulating surfaces forced out of position
• Displacement can cause joint structure damage
• Cartilage, ligaments, menisci

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Synovial Joint Dislocation
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Synovial Joint Dislocation
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Double Jointed

• Weakly stabilized joints
• Permit greater range of motion
• More prone to luxation

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Strain

• Overstretching or tearing of muscle or muscle
  connective tissue
• Results from joint over extension
• Repair 3-4 weeks

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Sprain

• Overstretching or tearing of ligament or capsule
• Result from joint overextension
• Repair- 3-4 weeks

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Bursitis

• Inflammation of the bursa
• Result from
• A direct fall or blow
• Overuse
• Infection

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Bursitis
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Bursitis