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Joint Structure and Function

Objectives¡G After studying this topic, the students will be able to

  1. identify types of the joints and their characteristics
  2. describe the definition and characteristics of a synovial joint
  3. distinguish arthrokinematic movements from osteokinematic movements and explain their relationship

Classification of Joints
Synovial Joint
Joint Mobility
Joint Stability

  1. Neumann, DA (2002)¡G Getting Started.  in Neumann DA (ed)¡G Kinesiology of the Musculoskeletal System - Foundations for Physical Rehabilitation. Philadelphia¡G Mosby.  pp.4-11
  2. Threlkeld AJ (2002). Basic Structure and Function of the Joints.  In Neumann DA: Kinesiology of the Musculoskeletal System: Foundations for Physical Rehabilitation. Philadelphia: Mosby.  Chapter 2, pp. 25-40
  3. Smith LK et al., 1996. pp.11-17.

Classification of Joints

¡@

Classification based on anatomic structure and movement potential

  • diarthrosis¡G an articulation that contains a articular cavity between two bones
  • synarthrosis¡G an articulation between bones that is held together by dense irregular connective tissues
  • amphiarthrosis¡G an articulation between bones that is formed primarily by fibrocartilage and/or hyaline cartilage
    • ¡@ Diarthrosis  Synarthrosis Amphiarthrosis
    prefix di = double syn = together amphi = both
    articular cavity
    capsule
    synovial membrane    		 presence no no
    articular surfaces hyaline cartilage or fibrocartilage linked by fibrocartilage, fibrous tissues, or ligaments linked by fibrocartilage and/or hyaline cartilage
    functions¡G
      to connect two bones
      to transmit forces
      to allow motions
    yes
    yes
    maximum
    yes
    yes
    no or little
    yes
    yes
    some
    examples most joints in the extremities cranial suture or distal tibiofibular ligament intervertebral joint or pubis symphysis

    ¡@

    Classification of diarthrosis

  • plane joint (irregular or arthrodial)
  • non-axial joint
  • only sliding movements present
  • e.g. facet joint of the spine
  • hinge (ginglymus)
  • uniaxial joint
  • degree of freedom = 1
  • e.g. humeroulnar joint
  • pivot (trochoid or screw)
  • uniaxial joint
  • degree of freedom = 1
  • e.g. humeroradial joint
  • condyloid (ovoid or ellipsoidal)
  • biaxial joint
  • degree of freedom = 2
  • Ideal joint surface: ovoid
  • e.g. radiocarpal joint
  • saddle (sellar)
  • biaxial joint
  • degree of freedom = 2
  • Ideal joint surface: sellar
  • e.g. first carpometacarpal joint
  • ball-and-socket (spheroidal)
  • triaxial joint
  • degree of freedom = 3
  • e.g. glenohumeral joint

    • ¡@

    Classificaiton of synarthrosis

  • cartilaginous (synchondrosis)¡G fibrocartilage; bending and twisting
  • fibrous (suture)¡G fibrous tissue; no movement
  • ligamentous (syndesmosis)¡G ligaments; limited or no movement

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    Synovial Joint

    ¡@

    Components of synovial joint

  • intra-articular components
  • articular cartilage (hyaline cartilage)
  • joint capsule and capsular ligament
  • synovial membrane
  • synovial cavity
  • rheumatoid arthritis
  • synovial fluid¡G to provide nutrition and lubrication for the articular cartilage
  • extra-articular components
  • ligament
  • exception¡G anterior/ posterior cruciate ligament of the knee
  • muscle tendon
  • meniscus or disc
  • bursa
  • labrum
  • fat pads
  • synovial plica

    • ¡@

    Functions of synovial joint

  • joint mobility
  • joint stability

    • ¡@

    Factors affecting structure and function of synovial joint

  • aging
  • immobilization
  • trauma
  • disease
  • habit
  • psychological status

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    Joint Mobility

    ¡@

    Osteokinematic movements¡G movements between 2 bony segments
  • synonym¡G physiological movements
  • types
  • swing¡G rotary motion about a fixed axis at the proximal segment e.g. knee flexion
  • spin¡G axial rotation about a longitudinal axis of the distal segment e.g. forearm pronation
  • description of osteokinematic movements
  • plane of motion
  • axis of rotation
  • degree of freedom
  • range of motion
  • open vs. closed kinematic chain
  • concentric vs. eccentric contraction

    • ¡@

    Arthrokinematic movements¡G movements between 2 articular surfaces

  • synonym¡G accessory movements¡F joint play
  • types
  • distraction (traction)¡G separation of two articular surfaces along the longitudinal axis of the distal segment
  • compression¡G meeting together of two articular surfaces along the longitudinal axis of the distal segment
  • glide¡G a combination of roll and slide between two incongruent joint surfaces
  • roll¡G new points on one rotating articular surface meet new points on another articular surface
  • slide¡G same point on one rotating articular surface meet new points on another articular surface
  • In Neumann's book, three fundamental arthrokinematic movements was classified. (Neumann 2002, p.8)
  • roll¡G not really found in human joints
  • slide¡G not really found in human joints
  • spin
  • What if only the roll movement occurs without any slide for the glenohumeral joint?
    -- shoulder impingement syndrome
  • description of arthrokinematic movements
  • joint morphology to establish concave-convex rule
  • plane of motion
  • direction of motion
  • amplitude of motion

    • ¡@

    Concave-convex rule

  • concave on convex (concave surface moving on convex surface) movement¡G
  • The concave articular surface moves in the same direction as the moving bone
  • Glide occurs in the same direction as the physiological movement
  • e.g. tibia on femur motion: knee flexion with posterior glide
  • convex on concave (convex surface moving on concave surface) movement¡G
  • The convex articular surface moves in the opposite direction of the moving bone
  • Glide occurs in the direction opposite to the physiological movement
  • e.g. humerus on scapula motion: shoulder abduction with inferior glide
    •  

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    Joint Stability

    ¡@

    Factors affecting joint stability

  • configuration of the bone
    •
  • components of ligament¡G depending on proportion of different types of fibers in ligament
  • collagen fibers¡G for strength
  • 94% of the anterior cruciate ligament of the knee is composed of collagen fibers
  • 60% of the ligamentum of flavum are elastin fibers
  • elastin fibers¡G for flexibility
  • rectin fibers¡G for mass

  • muscular arrangement

  • fascia and skin

  • atmosphere pressure

    • ¡@

    Close-packed position

  • definition¡G the position that both of the articular surfaces are in the maximum congruency status for a joint, resulting in the greatest mechanical stability for that joint
  • In the close-packed position, most ligaments and capsules surrounding to the joint are taut
  • example¡G for the glenohumeral joint the close-packed position is abduction of 90º and full external rotation
  • loose-packed position¡G all positions other than close-packed position

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    Established on 09/18/2002 and Last Updated 12/06/2004 © 2004 Huei-Ming Chai, PhD PT          All Right Reserved