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8 Joints Part A. Joints (Articulations)  Weakest parts of the skeleton  Articulation – site where two or more bones meet  Functions of joints  Give.

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Presentation on theme: "8 Joints Part A. Joints (Articulations)  Weakest parts of the skeleton  Articulation – site where two or more bones meet  Functions of joints  Give."— Presentation transcript:

1 8 Joints Part A

2 Joints (Articulations)  Weakest parts of the skeleton  Articulation – site where two or more bones meet  Functions of joints  Give the skeleton mobility  Hold the skeleton together

3 Classification of Joints: Structural  Structural classification focuses on the material binding bones together and whether or not a joint cavity is present  The three structural classifications are:  Fibrous  Cartilaginous  Synovial

4 Classification of Joints: Functional  Functional classification is based on the amount of movement allowed by the joint  The three functional classes of joints are:  Synarthroses – immovable  Amphiarthroses – slightly movable  Diarthroses – freely movable

5 Fibrous Structural Joints  The bones are joined by fibrous tissues  There is no joint cavity  Most are immovable  There are three types – sutures, syndesmoses, and gomphoses

6 Fibrous Structural Joints: Sutures Figure 8.1a Occur between the bones of the skull Comprised of interlocking junctions completely filled with connective tissue fibers

7 Fibrous Structural Joints: Syndesmoses  Bones are connected by a fibrous tissue ligament  Movement varies from immovable to slightly variable  Examples include the connection between the tibia and fibula, and the radius and ulna

8 Fibrous Structural Joints: Gomphoses  The peg-in-socket fibrous joint between a tooth and its alveolar socket  The fibrous connection is the periodontal ligament

9 Cartilaginous Joints  Articulating bones are united by cartilage  Lack a joint cavity  Two types – synchondroses and symphyses

10 Cartilaginous Joints: Synchondroses Figure 8.2a, b

11 Cartilaginous Joints: Symphyses Figure 8.2c  Hyaline cartilage covers the articulating surface of the bone and is fused to an intervening pad of fibrocartilage

12 Synovial Joints  Those joints in which the articulating bones are separated by a fluid-containing joint cavity  All are freely movable diarthroses  Examples – all limb joints, and most joints of the body

13 Synovial Joints: General Structure  Synovial joints all have the following  Articular cartilage  Joint (synovial) cavity  Articular capsule  Synovial fluid  Reinforcing ligaments

14 Synovial Joints: General Structure Figure 8.3a, b

15 Synovial Joints: Friction-Reducing Structures  Bursae – flattened, fibrous sacs lined with synovial membranes and containing synovial fluid  Common where ligaments, muscles, skin, tendons, or bones rub together  Tendon sheath – elongated bursa that wraps completely around a tendon

16 Synovial Joints: Friction-Reducing Structures Figure 8.4

17 Synovial Joints: Range of Motion  Nonaxial – slipping movements only  Uniaxial – movement in one plane  Biaxial – movement in two planes  Multiaxial – movement in or around all three planes

18 Gliding Movements  One flat bone surface glides or slips over another similar surface  Examples – intercarpal and intertarsal joints, and between the flat articular processes of the vertebrae

19 Angular Movement  Flexion — bending movement that decreases the angle of the joint  Extension — reverse of flexion; joint angle is increased  Dorsiflexion and plantar flexion — up and down movement of the foot  Abduction — movement away from the midline  Adduction — movement toward the midline  Circumduction — movement describes a cone in space

20 Gliding Movement Figure 8.5a

21 Angular Movement Figure 8.5b

22 Angular Movement Figure 8.5c, d

23 Angular Movement Figure 8.5e, f

24 Rotation  The turning of a bone around its own long axis  Examples  Between first two vertebrae  Hip and shoulder joints Figure 8.5g

25 Special Movements  Supination and pronation  Inversion and eversion  Protraction and retraction  Elevation and depression  Opposition

26 Special Movements Figure 8.6a

27 Special Movements Figure 8.6b

28 Special Movements Figure 8.6c

29 Special Movements Figure 8.6d

30 Special Movements Figure 8.6e


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