C h a p t e r 8 The Skeletal System Articulations Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Introduction Joints or articulations are connections between bones that may or may not permit movement Cartilage fluid or dense connective tissues are usually involved in holding joints together Joints are classified functionally by the amount of movement they allow Immovable or slightly movable joints tend to be in the axial skeleton Freely movable joints are more common in the appendicular skeleton Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Synarthroses Immovable Joints Sutures are joints found only in the skull Bony edges interlock and short dense connective tissue fiber holds the bones together A gomphosis is the joint between a tooth and the alveolar fossa of the maxillae or mandible Periodontal ligaments hold the tooth to the bone in the gomphosis A synchondrosis is a joint in which hyaline cartilage separates the ends of the bones involved in the joint A synostosis occurs if bones fuse together to form one bone Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Amphiarthroses Slightly Movable Joints A syndesmosis occurs when bones are connected by relatively long connective tissue ligaments Connecting bones using a fibrocartilage pad forms a symphysis Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Diarthroses Freely Movable Joints Synovial joints are typically found at the ends of long bones in the upper and lower limbs All synovial joints have 6 basic characteristics A joint capsule Articular cartilages A joint cavity filled with synovial fluid A synovial membrane lining the joint capsule Accessory structures Sensory nerves and blood vessels Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Figure 8 1a Structure of a Synovial Joint Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Figure 8 1b Structure of a Synovial Joint Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Classification of Joints Synovial fluid has three functions Lubricates the surfaces of the articular cartilages on the ends of the bones Nourishes the chondrocytes by entering and exiting the articular cartilages due to the forces acting on the joint Acts as a shock absorber Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Types of Movement Linear movements Angular movements Rotation Special movements Movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 2 A Simple Model of Articular Motion Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function 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 Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Special movements that occur at many joints include Protraction is movement anteriorly in the Retraction is movement posteriorly in the horizontal plane horizontal plane Elevation is movement cranially in the vertical Depression is movement caudally in the vertical axis axis Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 3a c Angular Movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 3b d Angular Movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 4 Rotational Movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 5a c Special Movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 5d f Special Movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function A Structural Classification of Joints Plane joints Nonaxial joints Multiaxial joints Hinge joints Flexion and extension Pivot joints Rotational movements Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function A Structural Classification of Joints cont Condylar joints Saddle joints Flexion extension and abduction adduction Biaxial joints that also allow circumduction Ball and socket joints Triaxial joints Joint Structure Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 6a A Structural Classification of Synovial Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 6b A Structural Classification of Synovial Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 6c A Structural Classification of Synovial Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 6d A Structural Classification of Synovial Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 6e A Structural Classification of Synovial Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Articular Form and Function Figure 8 6f A Structural Classification of Synovial Joints Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Representative Articulations Figure 8 7 The Temporomandibular Joint Lateral View Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Representative Articulations Figure 8 7 The Temporomandibular Joint Sectional View Copyright 2009 Pearson Education Inc publishing as Pearson Benjamin Cummings Representative Articulations Figure 8 8 Intervertebral Articulations Copyright 2009 Pearson Education Inc