Copyright 2010, John Wiley & Sons, Inc. Chapter 7 Joints
Copyright 2010, John Wiley & Sons, Inc. Chapter 8 Joints of the Skeletal System Articulations - Junctions between bones Bind parts of skeletal system together Make bone growth possible Permit parts of the skeleton to change shape during childbirth Enable body to move in response to skeletal muscle contraction 8-2
Copyright 2010, John Wiley & Sons, Inc. Joints Classifications Structurally: by their anatomy Fibrous, cartilaginous, or synovial Functionally: by the degree of movement they permit Immovable, slightly movable, and freely movable
Copyright 2010, John Wiley & Sons, Inc. Structural Classification Based on what is between bones: Space (or not) Type of connective tissue present Types Fibrous joints - no cavity, just dense irregular connective tissue Cartilaginous joints - no cavity, bones held together by cartilage Synovial joints - have synovial cavity, dense irregular tissue of articular capsule, and often ligaments
Copyright 2010, John Wiley & Sons, Inc. Functional Classification Types Synarthrosis: immovable Pelvis, sutures, teeth Amphiarthrosis: slightly movable Epiphyseal plate, tibia-fibula, vertebrae, pelvic symphysis Diarthrosis: freely movable Most joints of the body All diarthrotic joints are synovial
Copyright 2010, John Wiley & Sons, Inc. Fibrous Joints 3 Types Syndesmosis Suture Gomphosis Syndesmosis long fibers connect bones amphiarthrotic distal ends of tibia and fibula 8-4
Copyright 2010, John Wiley & Sons, Inc. Fibrous Joints Suture between flat bones synarthrotic thin layer of connective tissue connects bones Gomphosis cone-shaped bony process in a socket tooth in jawbone synarthrotic 8-5
Copyright 2010, John Wiley & Sons, Inc. Fibrous Joints Interosseous membrane (amphiarthrosis) Has greater amount of dense irregular connective tissue Examples: extensive membranes between shafts of some long bones Radius-ulna Tibia-fibula
Copyright 2010, John Wiley & Sons, Inc. Fibrous Joints
Copyright 2010, John Wiley & Sons, Inc. Fibrous Joints
Copyright 2010, John Wiley & Sons, Inc. Fibrous Joints
Copyright 2010, John Wiley & Sons, Inc. Cartilaginous Joints Symphysis pad of fibrocartilage between bones Compressible “shock absorber” amphiarthrotic Ex: intervertebral discs & symphysis pubis 8-7
Copyright 2010, John Wiley & Sons, Inc. Cartilaginous Joints Synchondrosis (synarthrosis) Cartilage connects two areas of bone Example Epiphyseal (growth) plate connecting epiphysis and diaphysis of long bone (synarthrosis)
Copyright 2010, John Wiley & Sons, Inc. Cartilaginous Joints
Copyright 2010, John Wiley & Sons, Inc. Cartilaginous Joints
Copyright 2010, John Wiley & Sons, Inc. Synovial Joints: Structure Synovial cavity: space containing fluid Articular cartilage Covers ends of bones, absorbs shock Articular capsule Inner layer: synovial membrane that secretes synovial fluid (reduces friction, supplies nutrients) Outer layer: dense, irregular connective tissue diarthrotic
Copyright 2010, John Wiley & Sons, Inc. Synovial Joints: Structure
Copyright 2010, John Wiley & Sons, Inc. Synovial Joints 8-8
Copyright 2010, John Wiley & Sons, Inc. Synovial Joints: Structure In some cases synovial joints include: Ligaments (either inside or outside of joint cavity) A ligament joins a bone to another bone across a synovial Menisci (cartilage discs) Articular fat pads Bursae Sacs made of synovial membranes containing fluid Located where friction can occur Examples: between skin-bone, tendons-bones, muscles-bones, ligaments-bones act as “ball bearings”
Copyright 2010, John Wiley & Sons, Inc. Synovial fluid = viscous lubricating fluid within cavity 1. Reduces friction between cartilages of 2 bones 2. Provide “weeping lubrication” 3. Nourish cartilage 4. Contain phagocytes General Structure of a Synovial Joint
Copyright 2010, John Wiley & Sons, Inc. Skeletal Muscle Actions 9-30 origin – immovable end insertion – movable end * When muscle contracts & shortens its insertion is pulled toward its origin prime mover (agonist) – primarily responsible for movement synergists – assist prime mover antagonist – muscle in opposition to the action of the prime mover’s and cause movement in the opposite direction Antagonist relaxes (stretches) during prime movement Fixators – muscle groups that stabilize the origin of the prime mover so that the prim mover can act more efficiently
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints Gliding Flat bone surfaces moving across each other Flexion Decrease in angle between articulating bones Extension Increase in angle between articulating bones In anatomical position the body is in full extension Hyperextension Bending beyond 180 o degrees, such as moving humerus backwards behind anatomical position
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Movements Abduction Movement of bone away from midline Adduction Movement of bone toward midline Circumduction Movement of distal end in a circle Rotation Bone revolves around its own longitudinal axis
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Special Movements Elevation Movement upward Depression Movement downward Protraction Movement forward Retraction Movement backward into anatomical position
Copyright 2010, John Wiley & Sons, Inc. Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Special Movements Inversion Move soles medially Eversion Move soles laterally Dorsiflexion Bend foot toward dorsum (“stand on heels”) Plantar flexion Bend foot toward plantar surface (“stand on toes”)
Copyright 2010, John Wiley & Sons, Inc. Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Supination Movement of forearm so palms face forward or upward Pronation Movement of forearm so palms face backward or downward Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Special Movements at Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints Saddle joints One side of saddle-shaped, other like a rider astride it Example: trapezium (carpal) to metacarpal-1 (thumb) Movements: triaxial (F, E, ABD, ADD, ROT) Ball-and-socket joints Ball-like surface into cuplike socket surface Example: shoulder, hip Movements: triaxial (F, E, ABD, ADD, CIR, ROT)
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints Condyloid joints Convex oval surface to concave oval surface Examples: wrist, metacarpophalangeal-2 to -5 joints Movements F, E, ABD, ADD 8-9
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Six Types of Synovial Joints Planar joints Articulating surfaces flat or slightly curved Examples: between carpals, tarsals, sternum- clavicle, scapula-clavicle Movements: gliding Hinge joints Convex-to-concave surfaces Examples: elbow, knee, ankle, interphalangeal Movements: flexion (F) and extension (E) only
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints 8-10
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints Pivot joints Rounded surface with ring formed by bone and ligament Examples: atlantoaxial joint (to turn head to say “no”) and radius-ulna for pronation-supination Movement: rotation (ROT)
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints 8-11
Copyright 2010, John Wiley & Sons, Inc. Types of Synovial Joints
Copyright 2010, John Wiley & Sons, Inc. Details of a Synovial Joint: Knee Joint See slides 10a-d Ligaments Tibial and fibular collateral ligaments Anterior cruciate ligament (ACL): 70 % of knee injuries Posterior cruciate ligament (PCL) Menisci (medial and lateral) Fibrocartilage discs that increase stability of knee joint Bursae Arthroplasty Knee replacement: total or partial
Copyright 2010, John Wiley & Sons, Inc. Knee Joint
Copyright 2010, John Wiley & Sons, Inc. Knee Joint
Copyright 2010, John Wiley & Sons, Inc. Knee Joint
Copyright 2010, John Wiley & Sons, Inc. Knee Joint
Copyright 2010, John Wiley & Sons, Inc. Aging of Joints Decrease in production of synovial fluid Thinning of articular cartilage Ligaments shorten and lose flexibility Influenced by genetic factors
Copyright 2010, John Wiley & Sons, Inc. Common Disorders of Joints Common joint injuries Rotator cuff injury Separated shoulder Tennis elbow Dislocation of the radial head Knee injuries: swollen knee, rupture of tibial collateral ligaments, dislocated knee Rheumatism: rheumatoid arthritis, osteoarthritis Ligaments shorten and lose flexibility Influenced by genetic factors
Copyright 2010, John Wiley & Sons, Inc. Life-Span Changes Fontanels of skull harden in first 2 years Epiphyseal plates harden from ages years Fibrocartilage loses water, decreases flexibility of intervertebral joints and knees Collagen changes causes stiffening beginning at age 30 Joint stiffness is an early sign of aging Regular exercise can prevent stiffness Fibrous joints first to strengthen over a lifetime Changes in symphysis joints of vertebral column diminish flexibility and decrease height Synovial joints lose elasticity 8-23
Copyright 2010, John Wiley & Sons, Inc. Clinical Application Joint Disorders Sprains damage to cartilage, ligaments, or tendons associated with joints forceful twisting of joint Bursitis inflammation of a bursa overuse of a joint Arthritis inflamed, swollen, painful joints Rheumatoid Arthritis Osteoarthritis Gout 8-24
Copyright 2010, John Wiley & Sons, Inc. End of Chapter 7 Copyright 2010 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of theses programs or from the use of the information herein.