joints and their classification arthrology = study of the joints kinesiology = study of...
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Joints and Their Classification
•Arthrology = study of the joints
•Kinesiology = study of musculoskeletal movement
• Classified how adjacent bones are joined • Fibrous – by fibrous connective tissue with no space between• Cartilaginous – by pad or bridge of cartilage• Synovial – bones separated by fluid- filled cavity covered by connective
tissue
• Classified by freedom of movement• Synarthrosis (little or no movement) – fibrous or cartilaginous• Amphiarthrosis (slightly movable) – fibrous or cartilaginous• Diarthrosis (freely movable) – always synovial
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Synarthroses - immobile joints
1. Synostosis - Bony Joint •Gap between two bones ossifies• frontal and mandibular bones in infants• cranial sutures in elderly• attachment of first rib and sternum
• Can occur in either fibrous or cartilaginous joint
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Synarthroses -Fibrous Joints• Collagen fibers span the space between bones
1. Sutures - bind skull bones together• Serrate - interlocking lines• coronal, sagittal and lambdoid sutures
• Lap - overlapping beveled edges• temporal and parietal bones
• Plane - straight, non-overlapping edges• palatine processes of the maxillae
2. Gomphosis• Attachment of a tooth to its socket • Held in place by fibrous periodontal ligament• collagen fibers attach tooth to jawbone
• Some movement while chewing
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Synarthroses -Cartilaginous Joint• Synchondrosis• Bones are joined by hyaline cartilage• rib attachment to sternum• epiphyseal plate in children binds epiphysis and diaphysis
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Amphiarthroses - fibrous joint
• Syndesmosis• Two bones bound by ligament only• interosseus membrane
• Most movable of fibrous joints• Interosseus membranes unite radius to ulna and tibia to
fibula
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Amphiarthroses - cartilaginous joint
• Symphysis• 2 bones joined by fibrocartilage• pubic symphysis and intervertebral discs
• Only slight amount of movement is possible
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Diarthrosis - Synovial Joint
Joint in which two bones are separated by a space called a joint cavity
Most are freely movable7-7
General Anatomy
•Articular cartilage = hyaline cartilage covering the joint surfaces• Synovial cavity •Articular capsule encloses joint cavity• continuous with periosteum• lined by synovial membrane
• Synovial fluid = slippery fluid; feeds cartilages
•Articular discs and menisci• jaw, wrist, sternoclavicular and knee
joints• absorbs shock, guides bone
movements and distributes forces• Tendon attaches muscle to bone• Ligament attaches bone to bone
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Tendon Sheaths and Bursae
• Bursa = saclike extension of joint capsule • between nearby structures so slide more easily past each other
• Synovial tendon sheaths = cylinders of connective tissue lined with synovial membrane and wrapped around a tendon
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Range of Motion
•Degrees through which a joint can move• Nonaxial – vertebrocostal, sacroiliac• Monoaxial – elbow, knee,ankle, interphalangeal• Biaxial – radiocarpal• Triaxial (multiaxial) – sholder, hip
•Determined by• structure of the articular surfaces• strength and tautness of ligaments, tendons and capsule• stretching of ligaments increases range of motion• double-jointed people have long or slack ligaments
• action of the muscles and tendons• nervous system monitors joint position and muscle tone
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