1. Joints Articulations of bones Functions of joints
Hold bones together
Allow for mobility
Ways joints are classified
Functionally
Structurally
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2. Functional Classification of Joints
Synarthroses – immovable joints
Amphiarthroses – slightly moveable joints
Diarthroses – freely moveable joints
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3. Structural Classification of Joints
Fibrous joints
Generally immovable
Cartilaginous joints
Immovable or slightly moveable
Synovial joints
Freely moveable
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4. Fibrous Joints Bones united by fibrous tissue Examples Sutures
Syndesmoses
Allows more movement than sutures
Example: distal end of tibia and fibula
Figure 5.27d, e
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5. Cartilaginous Joints Bones connected by cartilage Examples
Pubic symphysis
Intervertebral joints
Figure 5.27b, c
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6. Synovial Joints Articulating bones are separated by a joint cavity
Synovial fluid is found in the joint cavity
Figure 5.27f–h
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7. Features of Synovial Joints
Articular cartilage (hyaline cartilage) covers the ends of bones
Joint surfaces are enclosed by a fibrous articular capsule
Have a joint cavity filled with synovial fluid
Ligaments reinforce the joint
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8. Structures Associated with the Synovial Joint
Bursae – flattened fibrous sacs
Lined with synovial membranes
Filled with synovial fluid
Not actually part of the joint
Tendon sheath
Elongated bursa that wraps around a tendon
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9. The Synovial Joint Figure 5.28 Slide 5.51
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10. Types of Synovial Joints Based on Shape
Figure 5.29a–c
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11. Types of Synovial Joints Based on Shape
Figure 5.29d–f
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12. Inflammatory Conditions Associated with Joints
Bursitis – inflammation of a bursa usually caused by a blow or friction
Tendonitis – inflammation of tendon sheaths
Arthritis – inflammatory or degenerative diseases of joints
Over 100 different types
The most widespread crippling disease in the United States
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13. Range of motion allowed by joints
Non-axial—no motion, immovable
Uniaxial—motion in only one direction—ex: hinge joint
Biaxial—motion in 2 directions—ex: wrist
Multiaxial—motion in all planes and axis—ex: shoulder

14. Joint stability Based on 3 factors
How flat are the articular surfaces—flatter surfaces lead to less stability—deeper sockets lead to more stability
Ligaments—more ligaments = more stability
Muscle tone—for most joints this is the most important factor

15. Ligaments
If other stabilizing factors are weak or absent, the ligaments suffer strain and tension and stretch
Once stretched, they stay stretched and never regain as much stability in the joint
They can only stretch 6% before they tear or break