© 2015 Pearson Education, Inc.

An Introduction to Joints 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 © 2015 Pearson Education, Inc.

9-1 Classification of Joints Functional Classifications Synarthrosis (immovable joint) Amphiarthrosis (slightly movable joint) Diarthrosis (freely movable joint) © 2015 Pearson Education, Inc.

9-1 Classification of Joints Structural Classifications Bony Fibrous Cartilaginous Synovial © 2015 Pearson Education, Inc.

Table 9-1 Functional and Structural Classifications of Joints (Part 1 of 3).

Table 9-1 Functional and Structural Classifications of Joints (Part 2 of 3).

Table 9-1 Functional and Structural Classifications of Joints (Part 3 of 3).

9-1 Classification of Joints Synarthroses (Immovable Joints) Are very strong Edges of bones may touch or interlock Four types of synarthrotic joints Suture Gomphosis Synchondrosis Synostosis © 2015 Pearson Education, Inc.

9-1 Classification of Joints Suture Bones interlocked Are bound by dense fibrous connective tissue Are found only in skull Gomphosis Fibrous connection (periodontal ligament) Binds teeth to sockets © 2015 Pearson Education, Inc.

9-1 Classification of Joints Synchondrosis Is a rigid cartilaginous bridge between two bones Epiphyseal cartilage of long bones Between vertebrosternal ribs and sternum Synostosis Fused bones, immovable Metopic suture of skull Epiphyseal lines of long bones © 2015 Pearson Education, Inc.

9-1 Classification of Joints Amphiarthroses More movable than synarthrosis Stronger than freely movable joint Two types of amphiarthroses Syndesmosis Bones connected by ligaments Symphysis Bones separated by fibrocartilage © 2015 Pearson Education, Inc.

9-1 Classification of Joints Synovial Joints (Diarthroses) Also called movable joints At ends of long bones Within articular capsules Lined with synovial membrane © 2015 Pearson Education, Inc.

9-2 Synovial Joints Articular Cartilages Pad articulating surfaces within articular capsules Prevent bones from touching Smooth surfaces lubricated by synovial fluid Reduce friction © 2015 Pearson Education, Inc.

9-2 Synovial Joints Synovial Fluid Contains slippery proteoglycans secreted by fibroblasts Functions of synovial fluid Lubrication Nutrient distribution Shock absorption © 2015 Pearson Education, Inc.

9-2 Synovial Joints Accessory Structures Cartilages Fat pads Ligaments Tendons Bursae © 2015 Pearson Education, Inc.

9-2 Synovial Joints Cartilages Fat Pads Ligaments Cushion the joint Fibrocartilage pad called a meniscus (or articular disc; plural, menisci) Fat Pads Superficial to the joint capsule Protect articular cartilages Ligaments Support, strengthen joints Sprain – ligaments with torn collagen fibers © 2015 Pearson Education, Inc.

9-2 Synovial Joints Tendons Bursae Attach to muscles around joint Help support joint Bursae Singular, bursa, a pouch Pockets of synovial fluid Cushion areas where tendons or ligaments rub © 2015 Pearson Education, Inc.

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 © 2015 Pearson Education, Inc.

Figure 9-1a The Structure of a Synovial Joint. Medullary cavity Spongy bone Periosteum Components of Synovial Joints Joint capsule Synovial membrane Articular cartilages Joint cavity containing synovial fluid Metaphysis Compact bone a Synovial joint, sagittal section

Figure 9-1b The Structure of a Synovial Joint. Quadriceps tendon Patella Accessory Structures of a Knee Joint Joint capsule Femur Synovial membrane Bursa Fat pad Joint cavity Articular cartilage Meniscus Ligaments Tibia Extracapsular ligament (patellar) Intracapsular ligament (cruciate) b Knee joint, sagittal section

9-2 Synovial Joints Injuries Dislocation (luxation) Subluxation Articulating surfaces forced out of position Damages articular cartilage, ligaments, joint capsule Subluxation A partial dislocation © 2015 Pearson Education, Inc.

9-3 Movements Types of Movement at Synovial Joints Gliding movement Two surfaces slide past each other Between carpal or tarsal bones © 2015 Pearson Education, Inc.

9-3 Movements Angular Movement Flexion Extension Angular motion Anterior–posterior plane Reduces angle between elements Extension Increases angle between elements © 2015 Pearson Education, Inc.

9-3 Movements Angular Movement Hyperextension Angular motion Extension past anatomical position © 2015 Pearson Education, Inc.

Figure 9-3a Angular Movements. Extension Flexion Hyperextension Flexion Flexion Hyper- extension Extension Extension Flexion Hyperextension Extension a Flexion/extension

9-3 Movements Angular Movement Abduction Adduction Angular motion Frontal plane Moves away from longitudinal axis Adduction Moves toward longitudinal axis © 2015 Pearson Education, Inc.

Figure 9-3b Angular Movements. Abduction Abduction Adduction Adduction Abduction Adduction Abduction Adduction b Abduction/adduction

Figure 9-3c Angular Movements. Adduction Abduction c Adduction/abduction

9-3 Movements Angular Movement Circumduction Circular motion without rotation Angular motion © 2015 Pearson Education, Inc.

Figure 9-3d Angular Movements. Circumduction

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 © 2015 Pearson Education, Inc.

Figure 9-4a Rotational Movements. Head rotation Right rotation Left rotation Lateral (external) rotation Medial (internal) rotation a

9-3 Movements Types of Movements at Synovial Joints Rotation Pronation Rotates forearm, radius over ulna Supination Forearm in anatomical position © 2015 Pearson Education, Inc.

Figure 9-4b Rotational Movements. Supination Pronation b Supination Pronation

9-3 Movements Special Movements Inversion Eversion Dorsiflexion Twists sole of foot medially Eversion Twists sole of foot laterally Dorsiflexion Flexion at ankle (lifting toes) Plantar flexion Extension at ankle (pointing toes) © 2015 Pearson Education, Inc.

Figure 9-5 Special Movements (Part 1 of 6). Eversion Inversion

Figure 9-5 Special Movements (Part 2 of 6). Dorsiflexion (ankle flexion) Plantar flexion (ankle extension)

9-3 Movements Special Movements Opposition Reposition Protraction Thumb movement toward fingers or palm (grasping) Reposition Opposite of opposition Protraction Moves anteriorly In the horizontal plane (pushing forward) Retraction Opposite of protraction Moving anteriorly (pulling back) © 2015 Pearson Education, Inc.

Figure 9-5 Special Movements (Part 3 of 6). Opposition

Figure 9-5 Special Movements (Part 4 of 6). Retraction Protraction

9-3 Movements Special Movements Elevation Depression Lateral flexion Moves in superior direction (up) Depression Moves in inferior direction (down) Lateral flexion Bends vertebral column from side to side © 2015 Pearson Education, Inc.

Figure 9-5 Special Movements (Part 5 of 6). Depression Elevation

Figure 9-5 Special Movements (Part 6 of 6). Lateral flexion

9-3 Movements Functional Classification of Synovial Joints Gliding Hinge Pivot Condylar Saddle Ball-and-socket © 2015 Pearson Education, Inc.

Figure 9-2 Joint Movement (Part 7 of 12). Gliding. Slight nonaxial or multiaxial Gliding joint Gliding joints, or plane joints, have flattened or slightly curved surfaces that slide across one another, but the amount of movement is very slight. Clavicle Manubrium

Figure 9-2 Joint Movement (Part 8 of 12). Angular. Monaxial Examples: Elbow joint Knee joint Ankle joint Interphalangeal joint Hinge joint Hinge joints permit angular motion in a single plane, like the opening and closing of a door. Humerus Ulna

Figure 9-2 Joint Movement (Part 9 of 12). Angular. Biaxial Examples: Radiocarpal joint Metacarpophalangeal joints 2–5 Metatarsophalangeal joint Condylar joint Condylar joints, or ellipsoidal joints, have an oval articular face nestled within a depression on the opposing surface. Scaphoid bone Radius Ulna

Figure 9-2 Joint Movement (Part 10 of 12). Angular. Biaxial Examples: First carpometacarpal joint Saddle joint Saddle joints have complex articular faces and fit together like a rider in a saddle. Each face is concave along one axis and convex along the other. III II Metacarpal bone of thumb Trapezium

Figure 9-2 Joint Movement (Part 11 of 12). Rotation. Monaxial Examples: Atlantoaxial joint Proximal radioulnar joint Pivot joint Pivot joints only permit rotation. Atlas Axis

Figure 9-2 Joint Movement (Part 12 of 12). Angular, circumduction, and rotation. Triaxial Examples: Shoulder joint Hip joint Ball-and-socket joint In a ball-and-socket joint, the round head of one bone rests within a cup-shaped depression in another. Scapula Humerus

Table 9-3 Joints of the Appendicular Skeleton (Part 1 of 2).

Table 9-3 Joints of the Appendicular Skeleton (Part 2 of 2).

9-7 Effects of Aging on Joints 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 © 2015 Pearson Education, Inc.

9-7 Effects of Aging on Joints 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 © 2015 Pearson Education, Inc.

9-7 Effects of Aging on Joints 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 © 2015 Pearson Education, Inc.