Joints 7 Unit 1 Chapter 7 Joints 7

Joints 7 Unit 1 Chapter 7

Joints 7 Unit 1 • Places where bones meet • Classified structurally by anatomy • Classified structurally by motion

• Based on material between bones • Fibrous joints- no cavity just fiberous Connective tissue • Cartilaginous joints- bones held together by cartilage • Synovial joints- have synovial cavity and dense irregular tissue of articular capsule and often ligaments 7 Unit 1 Structural Classification

Functional Joints 7 • Synarthrosis- immoveable pelvis , sutures, , teeth • Amphiarthrosis- slight movement • Diarthroses- free movement= synovial defined by movement Unit 1 Epiphysis, tibia-fibula, vertebrae and pelvic symphysis

Fibrous Joints 7 • Little or no movement • Suture- e. g. skull (synarthrosis) joined by thin layer of dense fibrous connective tissue Greater distance and amount of dense fibrous material • Gomphosis- e. g. tooth root in socket = synarthrosis Unit 1 • Syndesmosis- e. g. tibia & fibula= amphiarthrosis

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• Synchondrosis- hyaline cartilage • E. g epiphyseal plate = synarthrosis • Symphysis- fibrocartilage join • E. g. pubic symphysis and intervertebral joints = amphiarthrosis 7 Unit 1 Cartilaginous joint

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Synovial Joints 7 • Synovial cavity • Articular cartilage • Articular capsule • Synovial fluid • Ligaments • Some contain menisci Unit 1 Inner layer = synovial secretory membrane

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• Located where friction can occur • E. g. between skin & bone or bone & tendons, ligaments or other bones • Structurally similar to joint capsules. Contain synovial membrane and fluid. 7 Unit 1 Bursae

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Types of motions at synovial joints 7 • Glidingflat bone surfaces moving across each other • Flexiondecrease in angle between articulating bones Increase in angle between articulating bones • Hyperextension Bending beyond 180 o degrees e. g. moving humerus backwards behind anatomical position Unit 1 • Extension-

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Motion (cont. ) 7 • Abduction. Movement of bone away from midline • Adduction • Circumduction. Movement of distal end in a circle • Rotation. Bone revolves around its own longitudinal axis Unit 1 Movement of bone toward midline

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• Elevation- lift upward • Depression- downward movement • Protraction – movement forward • Retraction- movement back to anatomical position 7 Unit 1 Special Movements

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• Inversion- move of soles medially • Eversion- move soles laterally • Dorsiflexion- bending of foot toward dorsum • Plantar flexion- bend foot toward plantar surface 7 Unit 1 Special Movements (cont. )

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Special Movements (cont. ) 7 Unit 1 • Supination- movement of forearm so palms face forward or upward • Pronation- movement of forearm so palms face backward or downward

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Types of Synovial Joints 7 Only do flexion and extension • Pivot joints- rounded surface with ring formed by bone and ligament e. g. atlantoaxial joint Unit 1 • Planar joints- articulating surfaces flat or slightly curved • Hinge joints- convex to concave surface

Types of Synovial Joints 7 • Condyloid joints- convex oval surface to concave oval surface • Saddle joints- one side saddle shaped other sits astride it • Ball & socket joints- ball like surface into cup like socket surface Can do flexion/extension, adduction/adduction & rotation Unit 1 e. g. wrist & metacarpophyangeal joints

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Aging of Joints 7 Unit 1 • Slowing of synovial fluid production • Thinning of articular cartilage • Ligaments shorten and lose flexibility • Influenced by genetic factors