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Joints intro.
Joints.
Question | Answer |
---|---|
What is the definition of a joint? | Where two or more bones meet. |
What is the general function of a joint? | Facilitate growth and transmit forces. |
What does arthro mean? | A joint. |
What is the approximate amount of joints in the body? | 230. |
What is the approximate amount of joints in each hand? | 27. |
What are the categories of bone by type of movement? | Synarthroses, Amphiarthroses and Diarthroses. |
What are the categories of joint by soft tissue structure? | Fibrous, Cartilaginous and Synovial. |
What are examples of fibrous joints? | Sutures, syndesmosis and gomphosis. |
What are sutures joints? | Joints between skull vault bones. |
What are syndesmosis joints? | A fibrous membrane between bones. E.g. radioulnar interosseous membrane. |
What are gomphosis joints? | "Peg and socket"- teeth in the jaw. |
What are the two types of cartilaginous joints? | Primary cartilaginous joint (synchondrosis) and Secondary cartilaginous joint (symphysis). |
What is the structure of a primary cartilaginous joint? | Bone then hyaline cartilage in the middle and then bone. |
What is the structure of a secondary cartilaginous joint? | Bone then hyaline cartilage then fibrocartilage in the middle then hyaline cartilage then bone. |
What are examples of primary cartilaginous joints? | First costosternal joints and the epiphyseal plates in growing bones. |
What are the properties of primary cartilaginous joints? | Very strong with no movement. |
What are primary cartilaginous joints also known as? | Synchondrosis. |
What are secondary cartilaginous joints also known as? | Symphyses. |
What are examples of secondary cartilaginous joints? | Joints of the sternum. Intervertebral discs. Pubic symphysis. |
What is a synovial joint? | A freely movable joint. The ends of the adjoining bones are covered with a thin cartilaginous sheet, and the bones are linked by a ligament lined with synovial membrane. |
How does a synovial joint deal with stress? | It has a fibrous capsule that consists of collagen fibres. May be thickened along lines of stress to form ligaments. |
What is the function of ligaments? | They restrict movement, protecting the joint from damage. |
Where are intrinsic ligaments located? | They are part of the capsule. |
Where are extrinsic ligaments located? | Outside of the capsule. |
What is the function of articular cartilage in a synovial joint? | Hyaline cartilage, creates frictionless surface. |
Why is cartilage slow to heal? | It has a poor blood supply. |
What is the synovial membrane? | Collagenous tissue that lines the fibrous capsule. Secretes synovial fluid. |
What is synovial fluid made up of? | Hyaluronic acid. Lubricin. A small number of phagocytic cells. |
What is the function of synovial fluid? | Reduces friction between the articular surfaces. |
How does the synovial fluid reduce friction? | Alignment of glycoprotein molecules changes with exercise. Exercise decreases viscosity so that lubrication improves (thixotropic). |
How does the cartilage receive exchange materials? | The synovial fluid provides nutrients (and O2) for articular cartilage and then also removes waste. |
What are intra-articular discs also known as? | Meniscus. |
What are intra-articular discs classified as? | Fibrocartilage. |
Where are intra-articular discs found? | In joints where there are rotatory movements. |
What are bursae? | Closed sacs lined with synovial membrane, lubricated with fluid. |
Where are bursae found? | Found where friction occurs. E.g. between skin and bone/ tendons and bone. |
What are synovial sheaths? | Specialised bursae that surround tendons where they are subject to pressure. |
How many planes can ball and socket joints move in? | 3 planes. |
How many planes can a hinge joint move in? | 1 plane. |
What factors influence the stability of the joint? | Shape of bones. Strength and position of ligaments. Tone of the surrounding muscles. |
What type of disease is osteoarthritis? | A degenerative disease. |
Where does osteoarthritis occur? | In the articular cartilage in weight bearing joints. |
What type of disease is rheumatoid arthritis? | An autoimmune disease. |
What causes RA? | Changes in synovium lead to the destruction of articular cartilage. |