Chapter 8 Musculoskeletal system

• Bone


  Living tissue
• Person's bone mass


  • Continues to grow until about the age of 30 years
  • After this, the bone gradually begin to deteriorate
• Bone density


  Gradual decrease as the bones lose calcium and other minerals
• Osteoporosis


  Loss of bone mass becomes sufficient to impair normal functioning
• As bone density decreases


  The risk of fractures increases so that even minor bumps or falls can result in serious fractures
• Bones most likely to be effected by osteoporosis

  • Vertebrae
  • Ribs
  • Pelvis
  • Wrist
  • Upper arm
• To prevent osteoporosis


  • People need an adequate calcium intake in their diet
  • An adequate amount of vitamin D
  • Plenty of exercise
• Treatment for osteoporosis


  • Lifestyle changes to increase calcium intake, vitamin D production and exercise
  • Quitting smoking
  • Medication can be used to prevent or treat the condition
• Osteoarthritis


  Gradual change in the joints that occurs over time and is frequently associated with ageing
• Osteoarthritis


  • Joint cartilage deteriorates, and so the bone surfaces are no longer protected
  • Bony spurs or growths may develop from the exposed ends of the bone forming the joint
  • These growths and spurs decrease the space within the joint cavity, restricting movement of the joint
• Symptoms of osteoarthritis


  • Pain and stiffness in the joints, pain is more severe after exercise and when weight or pressure is put on the joint
  • Rubbing, grating or cracking sound when they move the joint
• Treatment for osteoarthritis


  • Medication to relieve pain
  • Physiotherapy to strengthen muscles around the affected joints
  • Surgery to realign bones or joint replacement surgery
• Joint


  Site at which two or more bones come together
• Types of joints


  • Fibrous or fixed joints
  • Cartilaginous or slightly movable joints
  • Synovial or freely moveable joints
• Synovial joint


  • Freely movable joints with space or synovial cavity between the articulating surfaces of the bones
  • Synovial membrane surrounds the synovial cavity, and there is articular cartilage on the bone surfaces
• Structures of a synovial joint

  • Articular capsule
  • Fibrous capsule
  • Synovial membrane
  • Synovial fluid
  • Articular cartilage
  • Articular discs
  • Bursae
  • Ligaments
• Articular capsule


  Surrounds and encloses the joint, comprises two layers: fibrous capsule and synovial membrane
• Synovial fluid


  Secreted by the synovial membrane, lubricates the joint, helps to keep the articulating surfaces from making contact with one another, provides nourishments for the cells of the articular cartilage, and contains phagocytic cells that removes micro-organisms and any debris resulting from wear and tear at the joint
• Articular cartilage


  Covers the articulating surfaces of the bones forming the joint, provides a smooth surface for movement
• Articular discs


  Occur in some synovial joints, divide the synovial cavity into two, meaning that synovial fluid can be directed to the areas of greatest friction
• Bursae


  Little sacs of synovial fluid, positioned to prevent friction between a bone and a ligament or tendon, or a bone and the skin
• Ligaments


  Hold the bones together in many joints
• Factors keeping joints together

  • Fit of the articulating bones
  • Strength of the joint ligaments
  • Tension provided by the muscles around the joint
• Types of joint movements

  • Flexion and extension
  • Abduction and adduction
  • Rotation
• Flexion


  Decreases the angle between articulating bones, meaning that the bones come closer together
• Extension


  Increased the angle between the articulating bones, moving the bones further apart
• Abduction


  Movement away from the midline of the body
• Adduction


  Movement towards the midline of the body
• Rotation


  Movement of the bone around its long axis
• Types of joints


  • Fibrous or fixed joints
  • Cartilaginous or slightly movable joints
  • Synovial or freely moveable joints
• Fibrous or fixed joints


  • No movement occurs between the bones concerned, bones are held in place by fibrous connective tissue
• Cartilaginous or slightly movable joints


  • Held in place by cartilage which allows slight movement
• Synovial or freely moveable joints


  • Most joints of the body, amount of movement limited by ligaments muscles, tendons and adjoining bones
• Types of synovial joints


  • Ball and socket joints
  • Hinge joints
  • Pivot joints
  • Gliding joints
  • Saddle joint
  • Condyloid (ellipsoid) joints
• Ball and socket joints


  Form when the spherical head of one bone fits into a cup-like cavity of another
• Hinge joints


  Allow movements in one plane only, form when the convex surface of the bone fits into the concave surface if another
• Pivot joints


  Formed when the rounded, pointed or conical end of one bone articulates with a ring, formed partly by bone and partly by a ligament
• Gliding joints


  Allow movement in any direction in a side-to-side or back-to-forth motion, restricted only by the ligaments or bony processes surrounding the joint
• Saddle joint


  Two bones forming the joint are both saddle-shaped, concave in one direction and convex in the other, allow both side-to-side and back-and-forth movements
• Condyloid (ellipsoid) joints


  Have one surface of bone slightly convex that fits into a slightly concave depression in another bone, allow movement in two directions, up and down and side to side