Chapter 8

• Joints are classified structurally and functionally:

  • Structural classification: based on the material that binds the joints and whether a joint cavity is present
  • Functional classification: based on the degree of movement the joint allows
• Three types of fibrous joints:

  1. Sutures: found in the skull

  2. Syndesmoses: between the radius and ulna in the forearm

  3. Gomphoses: between teeth and sockets in the jaw
• Three types of cartilaginous joints:

  1. Synchondroses: joint between the ribs and sternum

  2. Symphyses: pubic symphysis in the pelvis

  3. Intervertebral discs between vertebrae
• General features of a synovial joint:

  • Articular cartilage covering the ends of bones
  • Joint cavity filled with synovial fluid
  • Articular capsule surrounding the joint
  • Reinforcing ligaments
• Weeping lubrication:

  • Process where synovial fluid is squeezed out of the articular cartilage when pressure is applied, providing lubrication
• Bursae: fluid-filled sacs that reduce friction between tissues

  Tendon sheaths: elongated bursae that wrap around tendons
• Three factors influencing the stability of a synovial joint:

  1. Shape of the articular surfaces

  2. Ligament number and location

  3. Muscle tone
• Movements allowed at synovial joints:

  • Flexion and extension
  • Abduction and adduction
  • Rotation
  • Circumduction
• Types of synovial joints:

  • Plane joint
  • Hinge joint
  • Pivot joint
  • Condylar joint
  • Saddle joint
  • Ball and socket joint
• Parts of the knee joint:

  • Femur
  • Tibia
  • Patella
• TMJ (temporomandibular joint) is the most easily dislocated joint in the body
• In sprains, ligaments are stretched or torn

  Cartilage injuries involve damage to the cartilage covering the bone ends

  Dislocations occur when bones are forced out of alignment
• Inflammatory conditions targeting joints:

  • Rheumatoid arthritis
  • Gout

  Degenerative conditions:

  • Osteoarthritis