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Skeletal System


Types of Skeletons
Skeletal Functions
Types of Bones
Structure of Long Bones
Microscopic Structure
Skeletal Development
Axial Skeleton
Appendicular Skeleton
Interactive Skeleton
Diseases, Disorders and Fractures

Joints, or articulations, are places where two or more bones attach. 
There are three basic types of joints classified by the level of allowed movement:
Synarthrotic - are immovable articulations, such as the sutures in the skull, formed by the fusion of two bones
Amphiarthrotic - slightly movable articulations, joined with cartilage between them
      ex: Symphysis Pubis between the two Pubis bones of the Pelvis
Diarthrotic - freely movable articulations, contain joint capsule and layers of cartilage over the ends of the two joining bones
      ex: shoulder, elbow, wrists...
The basic structure of all diarthrotic joints are the same:
      - cartilage lines the ends of the bones meeting at the joint to prevent friction
      - synovial membranes line the joint and secretes synovial fluid for lubrication to aid in smooth movement
      - the individual bones are connected together via ligaments, and attach to the muscles which move them via tendons

Basic Structure of a Joint (Knee)

No-So-Basic Structure of a Diarthrotic Joint

The majority of joints in the human body are diarthrotic.  Each joint is classified by the type of movement it creates: