JOINTS IN THE SKELETAL SYSTEM

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JOINTS IN THE SKELETAL SYSTEM
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What is a Joint?

• The area where two or more bones articulate
  (move).
• Joints give structure and flexibility to the
  skeleton.

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Classification

• Functional Classifications
• 1) Synarthroses Immovable joints
• 2) Amphiarthroses Slightly movable joints
• 3) Diarthroses Freely Movable

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• Structural Classifications
• 1) Fibrous Joints Bones are connected by dense
  fibrous tissue usu. immovable
• 2) Cartilaginous Joints Bones are connected by
  cartilage (vertebral column, pubic bones) - usu.
  Slightly movable or immovable
• 3) Synovial Joints a joint cavity with fluid
  allowing highly movable joints.

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Synovial Joints

• Articular Cartilage covers the ends
• Fibrous Articular capsule is formed by the
  synovial membrane
• Joint cavity has lubricating synovial fluid
• Reinforcing ligaments usually found.

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Rotator Cuff Injury
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Types of Synovial Joints

• Plane Joint Slipping or gliding movement between
  bones (wrist/ankle)
• 2) Hinge Joint Motion on a single plane (elbow)
• 3) Pivot Joint Movement of a bone along its
  longitudinal axis (radius, atlas/axis no)

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Types of Synovial Joints

• 4) Condyloid Joint Oval surfaces
  (concave/convex) on two bones match
  (metacarpal/phalange joint-knuckle)

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Types of Synovial Joints

• 5) Saddle Joint concave/convex surfaces with
  greater range of movement
• (carpo-metacarpal joint
• of your thumb)
• 6) Ball and Socket Joint The head of a bone fits
  into a cuplike socket (femur/acetabulum)

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JOINTS GONE BAD

• Arthritis (ArthJoint itisInflammation)
• Disease that causes pain, stiffness, and
  swelling of a joint.
• 1 out of 7 Americans
• Can be caused by bacterial infection or genetic
• Synovial membranes thicken, less fluid, more
  bone friction

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Three types of Arthritis

• Osteoarthritis (OA) chronic. Cartilage wears out
  between bones, usu. causes bone spurs
• Rheumatoid Arthritis (RA) chronic. An autoimmune
  disorder where the body destroys its own tissue

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• 3) Gouty Arthritis (Gout) Uric acid accumulates
  in the blood and is deposited as needle-shaped
  crystals in the joints.
• Very painful and can cause joints to fuse.

Gout Crystals
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Osteoporosis

• Loss in bone mass
• Leads to thin, brittle bones
• A decrease in estrogen can cause it
• Poor diet, smoking, and lack of vitamin D also
  causes