Joints: Movement & Disease Lecture PDF

Introduction to Articulations Joints: Movement  Articulations & Disease Body movement occurs at joints (articulations...

Introduction to Articulations Joints: Movement  Articulations & Disease Body movement occurs at joints (articulations) where 2 bones connect Dr. Gregory Karapetian  Joint Structure Lecture 9 Determines direction and distance of movement (range of motion) Joint strength decreases as mobility increases Joint Movement Classification of Joints  Functional Classifications  Functional Classifications Synarthrosis (immovable joint)  Fibrous or cartilaginous connections Synarthroses (immovable joints)  May fuse over time  Are very strong  Edges of bones may touch or interlock Amphiarthrosis (slightly movable joint)  Fibrous or cartilaginous connections  Four types of synarthrotic joints: 1. Suture Diarthrosis (freely movable joint) 2. Gomphosis  Also called “Synovial joints” 3. Synchondrosis  Subdivided by type of motion 4. Synostosis Classification of Joints Classification of Joints  Synarthrotic Joints (immovable) Suture  Amphiarthrotic Joints (slightly movable)  Bones interlocked  Bound by dense fibrous connective tissue More movable than synarthrosis  Found only in skull Gomphosis Stronger than freely movable joint  Fibrous connection (periodontal ligament)  Binds teeth to sockets Two types of amphiarthroses Synchondrosis  Syndesmosis:  Is a rigid cartilaginous bridge between 2 bones:  Epiphyseal cartilage of long bones  Bones connected by ligaments  Between vertebrosternal ribs and sternum Synostosis  Symphysis:  Fused bones, immovable:  Bones separated by fibrous cartilage  Frontal suture of skull  Epiphyseal lines of long bones 1 Classification of Joints Classification of Joints  Syndesmosis:  Symphysis: Posterior tibia and fibula Pubic symphysis Classification of Joints Components of Synovial Joints  Diarthrotic Joints (freely movable)  Articular cartilages Known as: Synovial joints Pad articulating surfaces within articular capsules: Wrist Thumb  Prevent bones from touching At ends of long bones Are within articular capsules Smooth surfaces  Lined with synovial membrane lubricated by synovial Shoulder fluid:  Reduce friction Elbow Components of Synovial Joints Components of Synovial Joints  Synovial fluid  Accessory structures Cartilages: Contains slippery proteoglycans secreted by  Cushion the joint: fibroblasts  Fibrous cartilage pad called Functions of synovial fluid: a meniscus (articular disc)  Lubrication Fat pads:  Nutrient distribution  Superficial to the joint capsule  Shock absorption  Protect articular cartilages Ligaments:  Support, strengthen joints  Sprain: ligaments with torn collagen fibers 2 Components of Synovial Joints Components of Synovial Joints  Accessory structures (continued…) Tendons:  Attach to muscles around joint  Help support joint Bursae:  Pockets of synovial fluid  Cushion areas where tendons or ligaments rub  Bursitis of olecranon (elbow) Components of Synovial Joints Synovial Joints  Bunion Inflammation Sesmoid bones of toes shift Components of Synovial Joints Synovial Joint Injuries  Factors that stabilize Synovial Joints: Prevent injury by limiting range of motion:  Collagen fibers of the joint capsule (ligaments)  Shapes of the articulating surfaces may prevent movements  Other bones, muscles, or fat pads  Tendons of articulating bones 3 Synovial Joint Injuries Joint Movement  Injuries  Types of Dynamic Motion Linear motion (gliding) Dislocation (luxation) Angular motion  Articulating surfaces forced out of position Rotation  Damages articular cartilage,  Planes (Axes) of Dynamic Motion ligaments, joint capsule Monaxial (1 axis) Subluxation Biaxial (2 axes)  A partial dislocation Triaxial (3 axes) Simple Model of Articular Motion Simple Model of Articular Motion Types of Movements at Synovial Types of Movements at Synovial Joints Joints  Linear Motion:  Angular Motion: Flexion Also called a Gliding Joint  Anterior–posterior plane Two surfaces slide past each other:  Reduces angle between elements  Between articulating carpal bones Extension  Between articulating tarsal bones  Anterior–posterior plane  Between clavicle and sternum  Increases angle between elements Hyperextension  Extension past anatomical position 4 Angular Movements Angular Movements  Angular Motion: Abduction  Angular motion  Frontal plane  Moves away from longitudinal axis Adduction  Angular motion  Frontal plane  Moves toward the longitudinal axis Angular Movements Angular Movements  Angular Motion: Circumduction  Circular motion without rotation Types of Movement at Synovial Types of Movement at Synovial Joints Joints  Rotation Direction of rotation from anatomical position Relative to longitudinal axis of body May be left or right rotation Medial rotation (inward rotation):  Rotates toward axis Lateral rotation (outward rotation):  Rotates away from axis 5 Types of Movement at Synovial Joints Special Movements (1 of 6)  Rotation (cont…) Pronation:  Inversion:  Rotates forearm Twists sole of foot medially  Radius over ulna  Eversion: Supination: Twists sole of foot laterally  Forearm in anatomical position Special Movements (2 of 6) Special Movements (3 of 6)  Dorsiflexion:  Opposition: Flexion at ankle (lifting toes) Thumb movement toward fingers or palm (grasping)  Plantar flexion: Extension at ankle (pointing toes) Special Movements (4 of 6) Special Movements (5 of 6)  Protraction:  Depression: Moves anteriorly Moves in inferior direction In the horizontal plane (pushing (down) forward)  Elevation: Moves in superior  Retraction: direction (up) Opposite of protraction Moving anteriorly (pulling back) 6 Special Movements (6 of 6) Types of Synovial Joints  Classification of synovial joints by shapes of the articulating surfaces  Lateral flexion: 1. Gliding Bends vertebral column 2. Hinge from side to side 3. Pivot 4. Ellipsoid 5. Saddle 6. Ball-and-socket Types of Synovial Joints (1 of 6) Types of Synovial Joints (2 of 6)  Gliding Joints:  Hinge Joints: Flattened or slightly curved faces Angular motion in a single plane (monaxial) Limited motion (nonaxial) Types of Synovial Joints (3 of 6) Types of Synovial Joints (4 of 6)  Pivot Joints:  Ellipsoid Joints: Rotation only (monaxial) Oval articular face within a depression Motion in two planes (biaxial) 7 Types of Synovial Joints (5 of 6) Types of Synovial Joints (6 of 6)  Saddle Joints:  Ball-and-Socket Joints: Straddled (biaxial) Round articular face in a depression (triaxial) The Shoulder Joint The Shoulder Joint  Also called the glenohumeral joint  Shoulder Ligaments Glenohumeral Coracohumeral Allows greater range of motion than Coracoacromial Coracoclavicular any other joint Acromioclavicular Least stable  Shoulder Muscles (aka rotator cuff) Supraspinatus Supported by skeletal muscles, Infraspinatus Teres minor tendons, ligaments Subscapularis  Shoulder Bursae  Ball-and-socket diarthrosis Subacromial Subcoracoid Subdeltoid  Head of humerus and glenoid cavity of scapula Subscapular The Elbow Joint  A stable and complex hinge joint  2 Articulations of the Elbow Humero-ulnar joint  Largest articulation  Trochlea of humerus and trochlear notch of ulna  Limited movement Humero-radial joint  Smaller articulation  Capitulum of humerus and head of radius 8  The Hip Joint  Also called Coxal joint  Strong ball-and-socket diarthrosis  Wide range of motion  Structures of the Hip Joint Head of femur fits into the socket of acetabulum Which is extended by fibrocartilaginous acetabular labrum  Ligaments of the Hip Joint Pubofemoral Iliofemoral Ischiofemoral Transverse acetabular Ligamentum teres The Hip Joint The Knee Joint  A complicated hinge joint  Transfers weight from femur to tibia  3 Articulations of the knee joint 2 femur–tibia articulations  At medial and lateral condyles 1 between patella and patellar surface of femur The Knee Joint The Knee Joint  Menisci of the Knee  8 Ligaments of the Knee Joint Medial and lateral menisci  Fibrous cartilage pads Patellar ligament (anterior)  At femur–tibia articulations 2 popliteal ligaments (posterior)  Cushion and stabilize joint  Give lateral support Anterior and posterior cruciate ligaments (inside joint capsule) Tibial collateral ligament – MCL (medial) Locking knees  Standing with legs straight: Fibular collateral ligament – LCL (lateral)  “Locks” knees by jamming lateral meniscus between tibia and femur Anterolateral ligament 9 The Knee Joint The Knee Joint The Knee Joint The Knee Joint  Anterolateral ligament (ALL) Discovered in 2013 by Belgian surgeons  ACL replacement graft harvested from tissue in patellar region  Surgeon removes tissue and (small piece of) “bone block” at each end  ACL knee brace  Graft is pulled through two tunnels drilled in the femur and tibia, secures graft with screws or staples 10 Joint Pathology Joint Pathology  Sprain  Rheumatism Partial or complete tearing of the ligaments and the A pain and stiffness of skeletal and muscular systems capsule of a joint  Arthritis Note: “Strain” is the tearing of muscle, not the joint All forms of rheumatism that damage articular cartilages of synovial joints  Rheumatoid Arthritis Chronic autoimmune disease Pain, swelling, stiffness, loss of function in joints Healthy immune system protects the body by attacking foreign bacteria and viruses… … But an autoimmune disease causes the body to mistakenly attack healthy tissue Joint Pathology Joint Pathology  Osteoarthritis Caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation Generally in people over age 60 Rheumatoid arthritis Rheumatoid nodules Joint Pathology  Gouty Arthritis Occurs when crystals (uric acid or Ca2+ salts) form within synovial fluid 11