Transcript Joints
Joints Chapter 8 Classifying Joints Functions • Flexibility for movement • Hold bones together Classification • Structural • Functional Fibrous Joints Cartilaginous Joints Synovial Joints Binding material Joined by fibrous tissue Joined by articular (hyaline) cartilage Separated by synovial fluid cavity Cavity Present No No Yes Functional Type Synarthroses (immovable) Amphiarthroses (slightly movable) Diarthroses (freely movable) Examples Sutures Syndesmoses Gomphoses Synchondroses Symphyses Joints of limbs Fibrous Joints • Sutures – Only b/w skull bones – Bind, but allow growth – As an adult CT ossifies = synostoses • Syndemoses – Longer than sutures – Length of ligament determines mov’t – E.g interosseous membrane and tibiafibula distal ends • Gomphoses – Tooth in alveolar socket – E.g periodontal ligament Cartilaginous Joints • Synchondroses – Temporary, become synostoses – E.g Epiphyseal plates and coastal cartilage • Symphyses – Cartilage fused to fibrocartilage pad/plate – Strength with flexibility – E.g. intervetevbral discs and pubic symphysis Synovial Joint Structure • Synovial cavity filled w/ synovial fluid – Viscous, but thins with mov’t • Articular capsule enloses cavity – Fibrous capsule (ext-) DICT – Synovial membrane (int-) LCT • Articular cartilage (hyaline) • Reinforcing ligaments – Double jointed = looser/stretchier ligaments and capsule Synovial Joints • Prevent friction – Bursae are flattend fibrous synovial sacs – Tendon sheaths are elongated bursa wrapped around a tendon • Provide stability – Articular surface shape • Determine mov’t & some stability – Ligaments • Prevent excessive/undesirable mov’t • Inadequate stabilization stretches (taffy) = snapping – Muscle tone • Tendons stay taut so reactive Synovial Joint Shapes • Plane - intercarpal and –tarsals – Slip 1 or 2 ways (A) • Hinge – elbow and interphalengeal – 1 plane of mov’t (B) • Pivot – C1 & C2 or radius & ulna (C) – 1 plane of mov’t • Condyloid - metacarpophalangeal (knucles) – 2 planes of mov’t (D) • Saddle – carpometacarpal joint (thumb) – 2 planes of mov’t (E) • Ball and socket – shoulder or hip joint – 3 planes mov’t (F) Synovial Joint Movements • Gliding – Slips surfaces across one another • Flexion/extension – Reduces angle of joint/ increases angle • Abduction/adduction – Away from center/ toward midline • Pronation/supination – Face or palm down/ face or palm up • Rotation/circumduction – Turning on an axis/ making small circles • Inversion/eversion – Turn sole medially/ turn sole laterally • Dorsiflexion/plantar flexion (foot and wrist) – Flex/ point • Protraction/retraction – Jaw out/jaw in • Elevation/depression – Lift superiorly/move inferiorly Knee Joint • • • • Single cavity w/ 3 joints Capsule partially encloses Strong vertical force, weak lateral Patellar ligament (knee-jerk) – Prevent hyperextension • Fibular and tibial collateral ligaments anterior cruciate ligament – Prevent lateral and medial rotation w/extension • Anterior and posterior cruciate ligaments (tibial attachment) – ACL: runs up posteriorly & laterally; prevents forward tibia mov’t – PCL: runs up anteriorly & medially; prevents backward tibia & forward femur mov’t • Lateral and medial meniscus Temporomandibular Joint (TMJ) • Mandibular condyle and fossa mismatched shape – Shallow socket = easy dislocation • Reset: thumbs in molars, push inferior and posterior • Pain and disorders from muscles tension – Lateral exclusion, side to side mov’t, unique to mammals – Grinding, clenching, biting Clinical Terms • • • • Sprain: stretching/tearing of a ligament Dislocation (luxation): bones forced out of position Bursitis: inflammation on bursa; blow or friction Arthritis: synovial membrane thickens, production decrease – Osteoarthritis – degenerative; tissue thickens & bone spurs formed – Rheumatoid arthritis - autoimmune – Gouty arthritis – uric acid accumulation in soft tissue joints • Synovitis: inflammation of synovial membrane • Tendinitis: inflammation of tendon sheaths, overuse;