Lec 3

• What is a joint?

  A joint is a place or junction between two or more bones.
• What is the role of a joint in movement?

  A joint is a passive structure that allows movement to occur but does not create the movement.
• What are the main types of joints?

  • Compound joint
  • Simple joint
• How do muscles relate to joint movement?

  The movement at a joint is created by muscles through muscle contractions that apply force on the bones.
• What role do ligaments and joint capsules play?

  Ligaments and joint capsules function to limit excessive movement at a joint.
• What are the general rules regarding joints, muscles, and ligaments?

  • Joints allow movement.
  • Muscles create movement.
  • Ligaments/joint capsules limit movement.
• Why do weight-bearing joints need to be stable?

  Weight-bearing joints need to be very stable to support the weight that is borne through them.
• What does "Degree of Freedom (DOF)" describe?

  Degree of Freedom (DOF) describes joint mechanics regarding possible movements around fixed or relatively fixed axes.
• What is the significance of the closed-packed position of a joint?

  The closed-packed position is stable and results from the bones being maximally congruent and ligaments being taut, increasing stability.
• What is the open-packed position of a joint?

  The open-packed position is where the bony fit is poor and ligaments are lax, resulting in greater mobility but poorer stability.
• How does axial motion differ from nonaxial motion?

  Axial motion occurs around an axis, while nonaxial motion does not occur around an axis and is known as gliding motion.
• What is nonaxial motion?

  Nonaxial motion is motion of a body part that does not occur about or around an axis.
• What are the five major pairs of directional terms used in joint action terminology?

  1. Flexion/extension
  2. Abduction/adduction
  3. Right lateral flexion/left lateral flexion
  4. Lateral rotation/medial rotation
  5. Right rotation/left rotation
• What are some specific directional terms used for certain actions at specific joints?

  • Plantarflexion/dorsiflexion
  • Eversion/inversion
  • Pronation/supination
  • Protraction/retraction
  • Elevation/depression
  • Upward rotation/downward rotation
  • Anterior tilt/posterior tilt
  • Opposition/reposition
  • Lateral deviation to the right/lateral deviation to the left
  • Horizontal flexion/horizontal extension
  • Hyperextension
  • Circumduction
• What is a reverse action in muscle contraction?

  A reverse action occurs when the origin moves while the insertion stays fixed during muscle contraction.
• What are physiological movements?

  • Flexion
  • Extension
  • Abduction
  • Adduction
  • Rotation
• What are the three specific types of accessory motion?

  The three types of accessory motion are spin, roll, and glide.
• What is axial motion?

  Axial motion is a motion of a body part that occurs about or around an axis.
• How would you describe the action of flexion of the right forearm at the elbow joint?

  This action involves the direction of flexion, the moving body part (right forearm), and the joint involved (right elbow joint).

  
• What are the types of range of motion?

  1. Active range of motion
  2. Active assistive range of motion
  3. Passive range of motion
• What is the spin accessory motion?

  Spin is when a single point on one articular surface rotates about a single point on another articular surface.
• What does the term "Range of Motion (ROM)" refer to?

  Range of Motion (ROM) is the maximum amount of displacement possible at any one joint.
• What is the glide (slide) accessory motion?

  Glide (slide) is when a specific point on one articulating surface comes in contact with a series of points on another surface.
• How does nonaxial motion occur?

  Nonaxial motion occurs as the body part glides along another body part, moving in a linear direction.
• What happens during axial motion regarding points on a body part?

  In axial motion, points closer to the axis move less than points farther from the axis, which move more.
• What is the roll (rock) accessory motion?

  Roll (rock) is when a series of points on one articular surface contacts a series of points on another articular surface.
• What characterizes ball-and-socket joints?

  • Smooth hemispherical head fits within a cuplike depression.
  • Examples: head of humerus into glenoid cavity of scapula, head of femur into acetabulum of hip bone.
  • Multiaxial joint.