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Joints (Articulations) Form Connections Between Bones:
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Classified by degree of movement
-Fibrous joint
-immovable
-example: joints between flat bones of skull
-Cartilaginous joint:
-slightly moveable, cartilage connection
-example: joints between adjacent vertebrae
-Synovial joint
-freely moveable
-bones separated by fluid-filled cavity
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Synovial Joints:
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Joint capsule: synovial membrane+ hyaline cartilage
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Synovial membrane secretes synovial fluid as a lubricant
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Hyaline cartilage acts as a cushion
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Types of synovial joints:
-hinge joint: (fingers)
-ball and socket joint: (shoulder)
Fun Fact: bubbles in the synovial fluid popping are what makes the loud cracking sound
when you “pop” or “crack” your knuckles
Ligaments, Tendons, and Muscles Strengthen and Stabilize Joints:
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Ligaments: attach bone to bone in a synovial joint
-example: ACL (anterior cruciate ligament in the knee)
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Tendons: attach muscle to bone
-example: Achilles tendon
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Both tendons and ligaments are composed of tough connective tissue containing
collagen (strong, flexible)
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Muscles further stabilize joints
Diseases and Disorders of Skeletal System:
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Sprains
-stretched or torn ligaments
-heal slowly (few cells and poor blood supply)
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Bursitis and teninitis
-inflammation of bursae or tendons
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Arthritis: inflammation of joints
-osteoarthritis
-rheumatoid arthritis
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Osteoporosis: excessive bone loss
