Lec 8: Joints and Body Movements

• Joints (Articulations)


  Sites where two or more bones meet.

  
• Functions of Joints (Articulations)

  Allows for mobility,

  Holds bones together
• The three structural classifications of Joints

  Fibrosis,

  Cartilaginous,

  Synovial

  
• Fibrosis joint


  connected by dense fibrous connective tissue consisting mainly of collagen;

  no joint cavity

  
• Fibrosis Joint Function (movement)


  Mostly immovable

  (No joint cavity)

  
• Examples of Fibrosis Joints

  Sutures in Skull,

  Ligament only connections such Tibia and Fibula,

  Periodontal ligaments in Alveolar processes

  
• Cartilaginous joint


  Bones held together by cartilage;

  no joint cavity

  
• Cartilaginous Joints Function (movement)


  Both immovable and slightly moveable

  
• Examples of Cartilaginous


  Temporary Epiphyseal Plate,

  Intervertebral Discs,

  Pubic Symphysis,

  
• Synovial Joints


  Adjoining bones covered with articular cartilage,

  Separated by a joint cavity,

  Enclosed within an articular capsule lined with synovial membrane

  
• Synovial Joints Function (movement)

  Freely moveable

  
• Composition of Synovial Joints

  Articular Cartilage,

  Joint Cavity,

  Articular Capsule (fibrous layer & synovial membrane),

  Synovial Fluid,

  Reinforcing Ligaments,

  Nerves and Vessels

  
• What is the weakest part of the skeleton?

  Synovial joints

  
• Where is the oxygen and nutrients contained in synovial joints?

  The synovial fluid

  
• Articular Cartilage


  Covers ends of long bones

  
• Joint Cavity


  the space between two connecting bones,

  contains synovial fluid

  
• Articular Capsule


  Double layered capsule composed of an outerfibrous layerlined bysynovial membrane

  
• Fibrous layer of Articular Capsule


  outer layer of articular capsule

  
• Synovial Membrane of Articular Capsule

  lines the capsule and secretes synovial fluid

  
• Synovial Fluid


  Lubricating fluid secreted by the synovial membrane

  
• nerves in synovial joints

  detect pain, monitor joint position and stretch

  
• Blood Vessels in synovial joints

  Supplies blood, most of which supplies the Synovial membrane.

  
• The 6 Types of Synovial Joints

  Plane,

  Hinge,

  Pivot,

  Condylar,

  Saddle,

  Ball & Socket

  
• Plane joint movement


  Glide movement

  
• Plane joint example


  Intertarsal joints,

  Intercarpal

  
• Hinge Joint movement


  One Axis movement for flexion and extension

  
• Hinge Joint example


  Elbow,

  Ankle,

  Between phalanges

  
• Pivot Joint movement


  One Axis movement for rotation

  
• Pivot Joint example


  Radius & ulna,

  Atlas at dense

  
• Condylar Joint movement


  a shallow ball-and-socket joint with biaxial movement

  
• Condylar Joint Examples


  Metacarpophalangeal (knuckles),

  Wrist

  
• Biaxial Movement


  movement in two planes

  
• Saddle Joint movement


  Biaxial movement

  
• Saddle Joint Examples


  1st carpometacarpal joint (base of thumb)

  
• Ball and Socket Joint movement

  Multiaxial movement

  
• Ball and Socket Joint Examples

  Hip,

  Shoulder

  
• Specialized structures of Synovial Joints

  Meniscus,

  Bursa,

  Tendon Sheath
• Meniscus


  Fibrocartilage that divides Synovial Cavity in two

  
• Meniscus Functions


  Prevents side to side rocking of femur on tibia,

  Absorbs shock transmitted to knee joint,

  Improves fit between articulation bone ends, making joint more stable and minimizes wear and tear on joint surfaces

  
• Bursa


  Flatten fibrous sac lined with Synovial Membrane and containing thin film of synovial fluid