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Chapter 9: Articulations 1 Slide 2 Articulations Body movement occurs at joints where 2 bones connect Articulation = joints; site where two or more bones meet 2 Slide 3 Joint Structure Determines direction and distance of movement (range of motion) Joint strength decreases as mobility increases 3 Slide 4 Anatomical/Structural Classification of Joints (based on connecting material 1.Fibrous: bones joined by fibrous CT with no space 2.Cartilaginous: bones joined by pad or bridge of cartilage 3.Synovial: bones separated by fluid- filled cavity, surrounded by CT 4 Slide 5 Structural Classification Table 92 5 Slide 6 Physiological/Functional Classifications of Joints: (based on the amount of movement) 1.Synarthrosis: immovable joints - No movement - Fibrous or cartilaginous connections 2.Amphiarthrosis: slightly moveable joint - Little movement - Fibrous or cartilaginous connections 3.Diarthrosis: freely moveable joint - More movement - always synovial connections 6 Slide 7 What common characteristics do typical synarthrotic and amphiarthrotic joints share? A.joint capsules filled with fluids B.non-restricted movement of bony regions C.bony regions separated by fibrous connective tissue D.articular cartilages and bursae 7 Slide 8 Synarthroses (Immovable Joints) Are very strong Edges of bones may touch or interlock 4 Types of Synarthrotic Joints Suture Gomphosis Synchondrosis Synostosis 8 Slide 9 1. Synarthoroses * Immoveable Strength 1.Synotosis: fused bones - Suture of skull and epiphyseal lines of long bones 2.Suture: interlocked bones, sealed with dense CT - Found only in the skull 3.Gomphosis: tooth in alveolar socket, held by peridontal ligament - Binds teeth to sockets 4.Synchrondrosis: hyaline cartilage bridge between bones - Epiphyseal cartilage of long bones and between vertebrosternal ribs and sternum 9 Slide 10 2. Amphiarthroses * Slightly Moveable, strength with some mobility Syndesmosis: bones connected by ligament Symphasis: bones separated by pad of fibrocartilage 10 Slide 11 3. Diarthorses = Synovial Joints Great mobility, less strength and stability At ends of long bones Within articular capsules Lined with synovial membrane 11 Slide 12 Features of Synovial Joints 1.Articular Cartilage 2.Synovial Cavity 3.Articular Capsule 4.Synovial Fluid 5.Accessory Structures - Meniscus, fat pad, accessory ligaments, tendons, bursa, synovial tendon sheath 12 Slide 13 (a) (b) Synovial ligament Bursa ibia Femur Patella Articular cartilage Fat pad Joint capsule Meniscus Joint cavity Intracapsular ligament Quadriceps tendon Patellar ligament T Marrow cavity Spongy bone Periosteum Synovial membrane Articular cartilage Articular capsule Joint cavity (containing synovial fluid) Compact bone 13 Slide 14 1. Articular Cartilages Hyaline cartilage No perichondrium or periosteum Pad articulating surfaces within articular capsules: prevent bones from touching Smooth surfaces lubricated by synovial fluid: reduce friction 14 Slide 15 Features of Synovial Joints 2.Synovial cavity: -Space between/around opposing bones -Has synovial fluid 3.Articular Capsule: 2 layers -Outer -dense irregular connective tissue, continuous with periosteum -Inner -synovial membrane (areolar CT), covers inside surface of cavity except articular cartilage, secretes synovial fluid 15 Slide 16 4. Synovial Fluid filtrate from blood plasma + hyaluronic acid from fibroblasts * Functions: 1. Lubrication 2. Nutrient distribution: diffusion medium 3. Shock absorption 16 Slide 17 Synovial Joints: Accessory Structures Cartilages (Meniscus) Fat pads Ligaments Tendons Bursae Synovial Tendon Sheath 17 Slide 18 Synovial Joints: Accessory Structures 1.Meniscus: -fibrocartilage pad = articular disc -Subdivides cavity or changes shape of articular surface, limits range of motion -Cushion the joint 2.Fat Pad: -Adipose -Superficial to joint capsule, -Function: protection and space filler 18 Slide 19 Synovial Joints: Accessory Structures 3.Accessory Ligaments: -Dense regular connective tissue -Either part of capsule, inside joint, or outside capsule -Function: support and strengthen joint -Sprain: Ligaments with torn collagen fibers 4.Tendons: -Dense regular connective tissue -Attach muscle to bone -Function: Add stability to the joint 19 Slide 20 Synovial Joints: Accessory Structures 5.Bursa: -Synovial fluid filled pocket -Function: reduces friction -Cushion areas where tendons or ligaments rub 6.Synovial Tendon Sheath: - Tubular bursa around a tendon 20 Slide 21 Synovial Joints: Stabilizing Factors 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 21 Slide 22 Functional Classification Table 91 22 Slide 23 In a newborn infant, the large bones of the skull are joined by fibrous connective tissue. Which type of joints are these? The bones later grow, interlock, and form immovable joints. Which type of joints are these? A.synarthrosis; gomphosis B.symphysis; sutural C.synchondrosis; synostosis D.syndesmosis; sutural 23 Slide 24 Why would improper circulation of synovial fluid lead to the degeneration of articular cartilages in the affected joint? A.Synovial fluid nourishes articular cartilage. B.Blood flow follows synovial fluid circulation. C.Articular cartilage is composed of synovial fluid. D.Both A and B. 24 Slide 25 Joint Injuries 1.Sprain: damage to ligament -Some collagen torn, slow to heal 2.Bursitis: -Inflammation of a bursa due to trauma, infection, or repetitive motion ** Synovial joints stabilized by articular capsule and accessory structures to restrict mobility: Increase Mobility = Decrease Stability = Increase chance of dislocation 25 Slide 26 Injuries Luxation: Dislocation articulating surfaces forced out of position Joint Displacement Usually damages articular cartilage, ligaments, and joint capsule Pain receptors in all CT of the Joint, except articular cartilage, to prevent actions Subluxation: Partial dislocation Displacement beyond usual anatomical limitation Double Jointed 26 Slide 27 The dynamic movements of the skeleton. 27 Slide 28 Movements at Synovial Joints 1.Linear Movements: -Gliding: slight movement in any direction 2.Angular Movements: one plane of motion -Flexion: reduce angle in frontal plane -Extension: increase angle in frontal place -Hyperextension: extension past anatomical position -Abduction: move away from longitudinal axis in sagittal plane -Adduction: move toward longitudinal axis in sagittal plane -Circumduction: move in loop without rotation 3.Rotational Movements: turn on axis -Medial Rotation: turn in toward body -Lateral Rotation: turn out away from body 28 Slide 29 Linear Motion Pencil maintains vertical orientation, but changes position Figure 92a, b 29 Slide 30 Angular Motion Pencil maintains position, but changes orientation Figure 92c 30 Slide 31 Circumduction Circular angular motion Figure 92d 31 Slide 32 Rotation Pencil maintains position and orientation, but spins Figure 92e 32 Slide 33 Angular Motion: Flexion Figure 93a 33 Slide 34 Flexion Angular motion Anteriorposterior plane Reduces angle between elements Extension Angular motion Anteriorposterior plane Increases angle between elements Angular Movement: Flexion Vs. Extension 34 Slide 35 Angular Motion: Abduction Vs. Adduction Figure 93b, c 35 Slide 36 Abduction Vs. Adduction Abduction: Angular motion Frontal plane Moves away from longitudinal axis Adduction: Angular motion Frontal plane Moves toward longitudinal axis 36 Slide 37 Circumduction Circular motion without rotation Angular motion Figure 93d 37 Slide 38 Special and Specific Motion Inversion: turn sole inward Eversion: turn sole outward Dorsiflexion: lift toes Plantar flexion: lift heal Opposition: thumb across palm Pronation: medial rotation of radius Superination: lateral rotation of radius Protraction: move anterior (toward front) Retraction: move posterior (toward back) Elevation: move superior (toward head) Depression: move inferior (toward feet) 38 Slide 39 Inversion and Eversion Figure 95a 39 Slide 40 Dorsiflexion and Plantar Flexion Figure 95b 40 Slide 41 Ranges of Motion 1.Monaxial: movement in 1 plane 2.Biaxial: movement in 2 planes 3.Triaxial: movement in 3 planes 4.Multiaxial: gliding joints, all directions 41 Slide 42 When you do jumping jacks, which lower limb movements are necessary? A.flexion and extension B.abduction and adduction C.flexion and abduction D.plantar flexion and eversion 42 Slide 43 The types of synovial joints, and the relationship of motion to structure. 43 Slide 44 Classification of Synovial Joints by Shape Gliding Hinge Pivot Ellipsoidal Saddle Ball-and-socket 44 Slide 45 Gliding/Plane Joints Flattened or slightly curved faces Slide in any direction Figure 96 (1 of 6) 45 Slide 46 Hinge Joints Cylindrical projections in trough-shaped surface Angular motion in a single plane (monaxial) Figure 96 (2 of 6) 46 Slide 47 Pivot Joints Round projection in ring shaped depression Rotation only (monaxial) Figure 96 (3 of 6) 47 Slide 48 Ellipsoidal Joints Oval articular facet within an oval depression Motion in 2 planes (biaxial) Figure 96 (4 of 6) 48 Slide 49 Saddle Joints 2 concave faces into convex Straddled (biaxial) Figure 96 (5 of 6) 49 Slide 50 Ball-and-Socket Joints Spherical head into cup-like socket Round articular face in a depression (triaxial) Figure 96 (6 of 6) 50 Slide 51 KEY CONCEPT A joint cant be both mobile and strong The greater the mobility, the weaker the joint Mobile joints are supported by muscles and ligaments, not bone-to-bone connections 51 Slide 52 How the vertebrae in the vertebral column articulate. 52 Slide 53 Intervertebral Articulations Figure 97 53 Slide 54 Damage to Intervertebral Discs Figure 98 54 Slide 55 Damage to Intervertebral Discs Slipped disc: bulge in anulus fibrosus invades vertebral canal Herniated disc: nucleus pulposus breaks through anulus fibrosus presses on spinal cord or nerves 55 Slide 56 Articulations and Movements of the Axial Skeleton Table 93 (1 of 2) 56 Slide 57 Articulations and Movements of the Axial Skeleton Table 93 (2 of 2) 57 Slide 58 The Elbow Joint Figure 910 58 Slide 59 The Hip Joint Figure 911b, c 59 Slide 60 The Knee Joint Figure 912a, b 60 Slide 61 Articulations of the Appendicular Skeleton Table 94 (1 of 2) 61 Slide 62 Articulations of the Appendicular Skeleton Table 94 (2 of 2) 62 Slide 63 The effects of aging on articulations, and the most common clinical problems. 63 Slide 64 Age Related Changes Rheumatism: Pain and stiffness of skeletal system Arthritis: Rheumatism of synovial joints, caused by damage to articular cartilage 1.Osteoarthritis: - Age 60+, cumulative wear and tear erodes cartilage 2.Rheumatoid Arthritis: - Autoimmune attack, chronic inflammation and damage to joint - Ankylosis: ossification of the joint due to untreated RA 3.Gouty Arthritis: -Crystals of uric acid from nucleic acid metabolism form in synovial fluid, damage cartilage -Due to metabolic disorders 64