Chapter 09 Articulations
An Introduction to Articulations Articulations Body movement occurs at joints (articulations) where two bones connect Joint Structure Determines direction and distance of movement (range of motion or ROM) Joint strength decreases as mobility increases
9-1 Classification of Joints Two Methods of Classification 1. Functional classification is based on range of motion of the joint 2. Structural classification relies on the anatomical organization of the joint
9-1 Classification of Joints Functional Classifications Synarthrosis (immovable joint) Amphiarthrosis (slightly movable joint) Diarthrosis (freely movable joint)
9-1 Classification of Joints Structural Classifications Bony Fibrous Cartilaginous Synovial
Table 9-1 Functional and Structural Classifications of Articulations
Table 9-1 Functional and Structural Classifications of Articulations
Table 9-1 Functional and Structural Classifications of Articulations
9-2 Synovial Joints Accessory Structures Cartilages Fat pads Ligaments Tendons Bursae
9-2 Synovial Joints Cartilages Cushion the joint Fat Pads Fibrocartilage pad called a meniscus (or articular disc; plural, menisci) Superficial to the joint capsule Protect articular cartilages Ligaments Support, strengthen joints Sprain ligaments with torn collagen fibers
9-2 Synovial Joints Tendons Attach to muscles around joint Help support joint Bursae Singular, bursa, a pouch Pockets of synovial fluid Cushion areas where tendons or ligaments rub
9-2 Synovial Joints Factors That Stabilize Synovial Joints Prevent injury by limiting range of motion Collagen fibers (joint capsule, ligaments) Articulating surfaces and menisci Other bones, muscles, or fat pads Tendons of articulating bones
9-3 Movements Classification of Synovial Joints by Shape Gliding Hinge Pivot Condylar Saddle Ball-and-socket
9-3 Movements Gliding Joints Flattened or slightly curved faces Limited motion (nonaxial) Hinge Joints Angular motion in a single plane (monaxial) Pivot Joints Rotation only (monaxial)
9-3 Movements Condylar Joints Oval articular face within a depression Motion in two planes (biaxial) Saddle Joints Two concave, straddled (biaxial) Ball-and-socket Joints Round articular face in a depression (triaxial)
9-2 Synovial Joints Injuries Dislocation (luxation) Articulating surfaces forced out of position Damages articular cartilage, ligaments, joint capsule Subluxation A partial dislocation
9-3 Movements Three Types of Dynamic Motion 1. Linear movement (gliding) 2. Angular movement 3. Rotation Planes (Axes) of Dynamic Motion Monaxial (1 axis) Biaxial (2 axes) Triaxial (3 axes)
Figure 9-2 A Simple Model of Articular Movement Initial position Gliding movement Angular movement Circumduction Rotation
9-3 Movements Classification of Synovial Joints by Shape Gliding Hinge Pivot Condylar Saddle Ball-and-socket
9-3 Movements Gliding Joints Flattened or slightly curved faces Limited motion (nonaxial) Hinge Joints Angular motion in a single plane (monaxial) Pivot Joints Rotation only (monaxial)
9-3 Movements Condylar Joints Oval articular face within a depression Motion in two planes (biaxial) Saddle Joints Two concave, straddled (biaxial) Ball-and-socket Joints Round articular face in a depression (triaxial)
Figure 9-6 Synovial Joints Gliding joint Manubrium Clavicle Movement: slight nonaxial or multiaxial Examples: Acromioclavicular and claviculosternal joints Intercarpal and intertarsal joints Vertebrocostal joints Sacro-iliac joints
Figure 9-6 Synovial Joints Hinge joint Ulna Humerus Movement: monaxial Examples: Elbow joint Knee joint Ankle joint Interphalangeal joint
Figure 9-6 Synovial Joints Pivot joint Atlas Axis Movement: monaxial (rotation) Examples: Atlanto-axial joint Proximal radio-ulnar joint
Figure 9-6 Synovial Joints Condylar joint Scaphoid bone Ulna Movement: biaxial Examples: Radiocarpal joint Metacarpophalangeal joints 2 5 Metatarsophalangeal joints
Figure 9-6 Synovial Joints Saddle joint III II Metacarpal bone of thumb Movement: biaxial Examples: First carpometacarpal joint Trapezium
Figure 9-6 Synovial Joints Ball-and-socket joint Humerus Scapula Movement: triaxial Examples: Shoulder joint Hip joint
Figure 9-3a Angular Movements Extension Flexion Hyperextension Flexion Flexion Hyperextension Extension Flexion Extension Hyperextension Extension Flexion/extension
9-3 Movements Angular Movement Abduction Angular motion Frontal plane Moves away from longitudinal axis Adduction Angular motion Frontal plane Moves toward longitudinal axis
Figure 9-3b Angular Movements Abduction Abduction Adduction Adduction Abduction Abduction Adduction Adduction Abduction/adduction
Figure 9-3c Angular Movements Adduction Abduction Adduction/abduction
9-3 Movements Angular Movement Circumduction Circular motion without rotation Angular motion
Figure 9-3d Angular Movements Circumduction
Figure 9-4a Rotational Movements Head rotation Right rotation Left rotation Lateral (external) rotation Medial (internal) rotation
9-3 Movements Types of Movements at Synovial Joints Rotation Pronation Rotates forearm, radius over ulna Supination Forearm in anatomical position
Figure 9-4b Rotational Movements Supination Pronation Supination Pronation
9-3 Movements Types of Movement at Synovial Joints Rotation Direction of rotation from anatomical position Relative to longitudinal axis of body Left or right rotation Medial rotation (inward rotation) Rotates toward axis Lateral rotation (outward rotation) Rotates away from axis
9-3 Movements Special Movements Inversion Twists sole of foot medially Eversion Twists sole of foot laterally Dorsiflexion Flexion at ankle (lifting toes) Plantar flexion Extension at ankle (pointing toes)
Figure 9-5 Synovial Joints Eversion Inversion
Figure 9-5 Synovial Joints Dorsiflexion (ankle flexion) Plantar flexion (ankle extension)
Figure 9-5 Synovial Joints Special Movements Opposition Retraction Protraction
Figure 9-5 Synovial Joints Depression Elevation
Figure 9-5 Synovial Joints Lateral flexion
9-7 Effects of Aging on Articulations Degenerative Changes Rheumatism A pain and stiffness of skeletal and muscular systems Arthritis All forms of rheumatism that damage articular cartilages of synovial joints Osteoarthritis Caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation Generally in people over age 60
9-7 Effects of Aging on Articulations Rheumatoid Arthritis An inflammatory condition Caused by infection, allergy, or autoimmune disease Involves the immune system Gouty Arthritis Occurs when crystals (uric acid or calcium salts) Form within synovial fluid Due to metabolic disorders
9-7 Effects of Aging on Articulations Joint Immobilization Reduces flow of synovial fluid Can cause arthritis symptoms Treated by continuous passive motion or CPM (therapy) Bones and Aging Bone mass decreases Bones weaken Increases risk of hip fracture, hip dislocation, or pelvic fracture
9-8 Integration with Other Systems Bone Recycling Living bones maintain equilibrium between: Bone building (osteoblasts) And breakdown (osteoclasts)
9-8 Integration with Other Systems Factors Affecting Bone Strength 1. Age 2. Physical stress 3. Hormone levels 4. Calcium and phosphorus uptake and excretion 5. Genetic and environmental factors