anatomy and physiology

• Skeletal System: Bones and Joints
• Opposition


  Movement unique to the thumb and little finger where the tips are brought toward each other across the palm
• Reposition


  Returns the digits to the anatomical position
• Most movements are combinations of individual movements
• Sprain


  Forceful pulling apart of bones and ligament damage around a joint
• Separation


  Bones remain apart after joint injury
• Dislocation


  End of one bone pulled out of socket in ball-and-socket, ellipsoid, or pivot joint
• Hyperextension


  Abnormal, forced extension of a joint beyond its normal range of motion
• Crawl stroke in swimming

  Combination of movements at shoulder and elbow joints
• The most significant age-related changes in the skeletal system affect the joints and the quality and quantity of bone matrix
• Bone matrix in older bones

  • More brittle due to decreased collagen production resulting in relatively more mineral and less collagen fibers
  • Amount of matrix decreases as rate of matrix formation by osteoblasts becomes slower than rate of breakdown by osteoclasts
• Bone mass


  Highest around age 30, men generally have denser bones than women due to effects of testosterone and greater body weight
• Race and ethnicity affect bone mass, African-Americans and Latinos have higher bone masses than caucasians and Asians
• After age 35, both men and women experience a loss of bone of 0.3–0.5% a year, this can increase 10-fold in women after menopause
• Significant loss of bone increases the likelihood of osteoporosis
• Bone matrix


  The organic and inorganic components that make up bone
• Decreased collagen production in older bones

  Results in relatively more mineral and less collagen fibers, making the bone more brittle
• Decreased rate of matrix formation by osteoblasts compared to rate of matrix breakdown by osteoclasts with aging

  Decreases the amount of bone matrix
• Bone mass


  • Highest around age 30
  • Men generally have denser bones than women due to effects of testosterone and greater body weight
  • African-Americans and Latinos have higher bone masses than caucasians and Asians
• After age 35


  Both men and women experience a loss of bone of 0.3–0.5% a year
• After menopause in women

  Bone mass can be lost at a rate of 3–5% a year for approximately 5–7 years
• Significant loss of bone

  Increases the likelihood of bone fractures
• Loss of trabeculae


  Greatly increases the risk of fractures of the vertebrae
• Loss of bone and resulting fractures

  Can cause deformity, loss of height, pain, and stiffness
• Loss of bone from the jaws


  Can lead to tooth loss
• Changes in synovial joints have the greatest effect as a person ages
• Dislocated shoulder


  The shoulder joint is the most commonly dislocated joint in the body
• Relocating a dislocated shoulder


  Carefully pull the humeral head laterally over the inferior lip of the glenoid cavity and then superiorly into the glenoid cavity
• After a shoulder dislocation


  The shoulder joint capsule may be predisposed to future dislocations
• Abduction


  Movement away from the median or midsagittal plane
• Adduction


  Movement toward the median plane
• Pronation


  Rotation of the forearm so that the palm is down
• Supination


  Rotation of the forearm so that the palm faces up
• Eversion


  Turning the foot so that the plantar surface (bottom of the foot) faces laterally
• Inversion


  Turning the foot so that the plantar surface faces medially
• Rotation


  The turning of a structure around its long axis
• Circumduction


  The arm moves so that it traces a cone where the shoulder joint is at the cone's apex
• Protraction


  A movement in which a structure, such as the mandible, glides anteriorly
• Retraction


  The structure glides posteriorly
• Elevation


  Movement of a structure in a superior direction