Articulations Where two bones interconnect Immovable joints Synarthroses

Articulations • Where two bones interconnect • Immovable joints • Synarthroses, or bony • Slightly moveable joints • Amphiarthroses, or fibrous / cartilagenous • Freely moveable joints • Diarthroses, or synovial Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Synarthroses (immovable joints) • Four major types • Suture = skull bones bound together by dense connective tissue • Gomphosis = teeth bound to bony sockets by periodontal ligaments • Synchondrosis = two bones bound by rigid cartilaginous bridge • Syntosis = two bones completely fused Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Amphiarthroses (slightly movable joints) • Two major types • Syndesmosis = bones connected by a ligament • Symphysis = bone separated by fibrocartilage Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Diarthroses (freely movable joints) • Bony surfaces enclosed within articular capsule • Bony surfaces covered by articular cartilage • Bony surfaces lubricated by synovial fluid • Structures include • Menisci • Fat pads • Accessory ligaments • Bursae Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 1 The Structure of a Synovial Joint Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 1

Dynamic motion • Linear motion • Angular motion • Rotation • Joints classified based on type of motion permitted • Monaxial • Biaxial • Triaxial Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 2 A Simple Model of Articular Motion Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 2

Types of movement • Gliding motion • Two surfaces slide past one another • Angular motion • Flexion, extension, hyperextension • Abduction, adduction • Circumduction Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 3 Angular Movements PLAY Animation: Flexion, Extension, Hyperextension Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 3

Rotational movement • Left or right • Medial (internal) or lateral (external) • Pronation or supination in the bones of the forearm only Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 4 Rotational Movements Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 4 a, b

Figure 9. 4 Rotational Movements Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 4 c

Special movement • Movements of the foot • Inversion and eversion • Plantar flexion and dorsiflexion • Movements of the thumb • Opposition Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Other movements • Protraction moves a structure anteriorly • Retraction moves a structure posteriorly • Elevation moves a structure superiorly • Depression moves a structure inferiorly • Lateral flexion bends the vertebrae to one side Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 5 Special Movements Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 5

Structural classification of joints • Gliding joints permit movement in a single plane • Hinge joints are monaxial joints permitting angular motion in one plane • Pivot joints are monaxial joints that permit rotation • Ellipsoid joints are biaxial joints that pit one bone in an oval depression of another • Saddle joints are biaxial joints with one concave and one convex bone face • Ball-and-socket joints are triaxial joints that permit rotation and other movements Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 6 A Functional Classification of Synovial Joints Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 6

Figure 9. 6 A Functional Classification of Synovial Joints PLAY Animation: Joint Motion Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 6

Intervertebral articulations • Gliding joints • Vertebral bodies form symphyseal joints cushioned by intervertebral discs • Outer anulus fibrosus and inner nucleus pulposus • Stabilized by ligaments Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 7 Intervertevbral Articulations Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 7

Figure 9. 8 Damage to the Intervertebral Discs Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 8

Shoulder joint (glenohumoral joint) • Glenoid cavity and head of humerus • Ball and socket diarthroses • Stabilized by ligaments • Strength and stability sacrificed for range of motion Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 9 The Shoulder Joint Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 9 a

Figure 9. 9 The Shoulder Joint Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 9 b

The elbow joint • Permits only flexion and extension • Hinge diarthroses • Reinforced with strong ligaments PLAY Animation: Clavicle & Scapula Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hip joint • Ball and socket diarthroses • Acetabulum and head of femur • Permits flexion/extension, abduction/ adduction, circumduction, rotation • Stabilized by numerous ligaments Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 11 The Hip Joint Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 11

Knee joint • Hinge joint with incomplete articular capsule • Formed by the condyles of the femur and the condylar surfaces of the tibia • Accessory structures help stabilize lateral movements • Permits flexion/extension, limited rotation • Supported by ligaments PLAY Animation: Hip Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Figure 9. 12 The Knee Joint Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 12 a, b

Figure 9. 12 The Knee Joint Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 9. 12 c, d

Joint problems with aging • Joint problems associated with aging • Relatively common • Rheumatism – general term for pain and stiffness in muscular and skeletal elements • Arthritis – all rheumatic diseases affecting synovial joints Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings