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Joints 8.

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Presentation on theme: "Joints 8."— Presentation transcript:

1 Joints 8

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 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

5 Fibrous Structural Joints: Sutures
Occur between the bones of the skull Comprised of interlocking junctions completely filled with connective tissue fibers Bind bones tightly together, but allow for growth during youth

6 Fibrous Structural Joints: Sutures
Figure 8.1a

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: Syndesmoses
Figure 8.1b

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

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

11 Cartilaginous Joints: Synchondroses
A bar or plate of hyaline cartilage unites the bones All synchondroses are synarthrotic Examples include: Epiphyseal plates of children Joint between the costal cartilage of the first rib and the sternum

12 Cartilaginous Joints: Synchondroses
Figure 8.2a, b

13 Cartilaginous Joints: Symphyses
Hyaline cartilage covers the articulating surface of the bone and is fused to an intervening pad of fibrocartilage Amphiarthrotic joints designed for strength and flexibility Examples include intervertebral joints and the pubic symphysis of the pelvis

14 Cartilaginous Joints: Symphyses
Figure 8.2c

15 All are freely movable diarthroses
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

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

17 Synovial Joints: General Structure
Figure 8.3a, b

18 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

19 Synovial Joints: Movement
The two muscle attachments across a joint are: Origin – attachment to the immovable bone Insertion – attachment to the movable bone Described as movement along transverse, frontal, or sagittal planes

20 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

21 Types of Synovial Joints
Plane joints Articular surfaces are essentially flat Allow only slipping or gliding movements Only examples of nonaxial joints Figure 8.7a

22 Types of Synovial Joints
Hinge joints Cylindrical projections of one bone fits into a trough-shaped surface on another Motion is along a single plane Uniaxial joints permit flexion and extension only Examples: elbow and interphalangeal joints

23 Types of Synovial Joints
Figure 8.7b

24 Only uniaxial movement allowed
Pivot Joints Rounded end of one bone protrudes into a “sleeve,” or ring, composed of bone (and possibly ligaments) of another Only uniaxial movement allowed Examples: joint between the axis and the dens, and the proximal radioulnar joint

25 Pivot Joints Figure 8.7c

26 Condyloid, or Ellipsoidal, Joints
Oval articular surface of one bone fits into a complementary depression in another Both articular surfaces are oval Biaxial joints permit all angular motions Examples: radiocarpal (wrist) joints, and metacarpophalangeal (knuckle) joints

27 Condyloid, or Ellipsoidal, Joints
Figure 8.7d

28 Similar to condyloid joints but allow greater movement
Saddle Joints Similar to condyloid joints but allow greater movement Each articular surface has both a concave and a convex surface Example: carpometacarpal joint of the thumb

29 Saddle Joints Figure 8.7e

30 Ball-and-Socket Joints
A spherical or hemispherical head of one bone articulates with a cuplike socket of another Multiaxial joints permit the most freely moving synovial joints Examples: shoulder and hip joints

31 Ball-and-Socket Joints
Figure 8.7f

32 One flat bone surface glides or slips over another similar surface
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

33 Flexion — bending movement that decreases the angle of the joint
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

34 Gliding Movement Figure 8.5a

35 Angular Movement Figure 8.5b

36 Angular Movement Figure 8.5c, d

37 Angular Movement Figure 8.5e, f

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

39 Supination and pronation Inversion and eversion
Special Movements Supination and pronation Inversion and eversion Protraction and retraction Elevation and depression

40 Special Movements Figure 8.6a

41 Special Movements Figure 8.6b

42 Special Movements Figure 8.6c

43 Special Movements Figure 8.6d

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