Joints

• Joints


  Articulation (articulare = to divide into joints) that connects a bone with another bone, cartilage, or tooth
• Structural classification of joints

  • Fibrous joints
  • Cartilaginous joints
  • Synovial joints
• Fibrous joints


  Dense fibrous connective tissue with strong collagen fibers that hold the joints firmly together with no synovial cavity, little or no movement
• Examples of fibrous joints


  • Skull joints
  • Teeth in sockets
  • Distal joint between tibia and fibula
• Cartilaginous joints


  Hyaline cartilage or fibrocartilage connecting the bones with no synovial cavity, small degree of movement
• Examples of cartilaginous joints

  • Intervertebral joints
  • Pubic symphysis
  • Connection of sternum and manubrium
• Synovial joints


  Have a synovial cavity (space) between the two bones, dense fibrous connective tissue holds the bones together, synovial fluid present
• Examples of synovial joints


  • Shoulder
  • Elbow
  • Hip
  • Knee
• Functional classification of joints

  • Immovable joints (synarthroses)
  • Slightly movable joints (amphiarthroses)
  • Freely movable joints (diarthroses)
• Synarthroses


  Immovable joints like sutures between skull bones and teeth sockets
• Amphiarthroses


  Slightly movable joints like intervertebral joints, tibiofibular joint, pubic symphysis
• Diarthroses


  Freely movable joints, about 90% of joints in the body
• Synovial joints


  • Synovial cavity
  • Articular cartilage
  • Articular capsule (fibrous capsule and synovial membrane)
  • Synovial fluid
• Types of movement at synovial joints

  • Gliding
  • Angular (flexion, extension, hyperextension, abduction, adduction, circumduction)
  • Rotation
  • Special (elevation, depression, protraction, retraction, supination, pronation, inversion, eversion, dorsiflexion, plantar flexion)
• Flexion


  Decrease in the angle of a joint
• Extension


  Increase in the angle of a joint
• Hyperextension


  Excessive extension movement beyond normal anatomical position
• Abduction


  Move appendage away from the midline
• Adduction


  Move appendage toward midline
• Circumduction


  Move a distal part of an appendage in a circular motion
• Rotation


  Turn on a pivot with a circular motion
• Elevation


  Upward movement raising body part vertically
• Depression


  Downward movement lowering body part vertically
• Protraction


  Move a body part forward or anterior on a horizontal plane
• Retraction


  Move a body part backward or posterior
• Supination


  Palm of the hand faces forward or upward
• Pronation


  Palms face backward or downward
• Inversion


  Turn the sole of foot inward
• Eversion


  Turn the sole of foot outward
• Dorsiflexion


  Point the toes upward; stand on the heels
• Plantar flexion


  Point the toes downward; raise the heel