Articulations

Introduction

•      Joints/Articulations: vary in amount of movement allowed

•      Catergorized by type of connection

–  Fluid, Cartilage, connective tissue

•      Freely movable joints in appendicular skeleton

•      Immovable joints in Axial skeleton

Synarthroses (Immovable Joints)

•      Sutures

–  Connective tissue connection

•      Gomphosis

–  Between tooth and bone

–  Periodontal ligaments

•      Synchondrosis – hyaline cartilage

–  Found in growing bone

•      Synostosis – bone that fuses together

–  Frontal bone, mandible

Amphiarthroses (Slightly Movable Joints)

•      Syndesmosis

–  Distal ends of Tibia & fibula

–  Connection by ligaments

•      Symphysis – fibrocartilage connection. 

Diarthroses (Freely Movable Joints)

•       Synovial joints

–    Joint capsule

•    Lined with synovial membrane

•    Filled with synovial fluid

–    Fat pads

–    Articular cartilages

•    Menisci - fibrocartilage

–    Accessory structures

•    Ligaments

–   Intrinsic

–   Extrinsic: intracapsular & Extracapsular

•    Bursae

•    Tendon sheaths

Synovial Fluid

•      Synovial fluid has three functions:

–  Lubricates

–  Nourishes chondrocytes

–  Shock absorbing

Types of Movements

•      Angular movements

–  Abduction

–  Adduction

–  Flexion

–  Extension – hyperextension

–  Circumduction

•      Rotation

–  Lateral rotation

–  Medial rotation

–  Pronation

–  Supination

Special Movements

•      Movements at the ankle include:

–  Eversion/inversion

–  Dorsiflexion/plantar flexion

•      Movement of the vertebral column includes:

–  Lateral flexion

•      Movement of the pollex (thumb):

–  Opposition/reposition

Special Movements

•      Movements that occur at many joints include:

–  Protraction: anterior movement in the horizontal plane

–  Retraction: posterior movement in the horizontal plane

–  Elevation: cranial movement in the vertical axis

–  Depression: caudal movement in the vertical axis

Structural Classification of Synovial Joints

•      Plane joints

•      Hinge joints:

–  flexion and extension

•      Pivot joints:

–  rotational movements

Structural Classification of Synovial Joints

•      Condylar joints:

–  flexion/extension and abduction/adduction

•      Saddle joints:

–  biaxial joints that also allow circumduction

•      Ball and socket joints:

–  triaxial joints

The Knee

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