Joint Structure and Function Flashcards
Describe how joints are classified.
Joints are classified by movement and/or by the manner in which the bones are joined. For example, in terms of movement, diarthrosis joints are freely moving and synarthrosis joints have little to no motion.
In terms of articulating surfaces, joints can be classified as fibrosis, cartilaginous, bony, and synovial. It is important to understand also, that any given joint can be classified by both classifications. For example, the glenohumeral joint is a diarthrosis and synovial joint.
Describe characteristics of fibrous joints, cartilaginous joints, bony joints, and synovial joints; and then provide an example of each.
A fibrous joint has collagen fibers spanning the space between the bones (or bone and other structure). Examples are the sutures of the skull and the interosseus membranes found between the ulna and radius and between the tibia and fibula (gomphoses is also another example).
Cartilaginous joints have two bone ends bound together by cartilage. An example of this is the pubic symphisis.
Bony joints have two bones once separate, but become fused upon maturation; they are fused by osseous tissue. An example is early childhood joints such as the anterior mandible.
Synovial joints are classified by two bones separated by a joint cavity. These joints are usually freely moving. An example is the glenohumeral joint.
What characteristics do all synovial joints have?
All synovial joints have an articular capsule, synovial fluid, and articular cartilage (hyaline).
Describe the difference between a ligament and a tendon and provide an example of pathology to each.
A tendon attaches muscle to bone. It has some flexibility, but very little elasticity. Strains occur to tendons if they are “stretch or stressed” beyond their yielding points.
A ligament attaches bone to bone. It has vey little flexibility and very little elasticity. Sprains occur to ligaments. Sprains are a medical term for tearing of the ligamentous fibers.
Synovial joints have specific characteristics that reflect their “make up”. There are several types of synovial joints (e.g., hinge joint); name the types and identify the plane on which they move and the number of axis (e.g., uniaxial) upon which they rotate.
A hinge joint is a uniaxial joint that moves along the sagital plane.
A pivot joint is a uniaxial joint that moves along the transverse plane.
A condyloid joint is a biaxial joint that moves along the sagital and coronal planes.
The saddle joint (there is only one in the body and is located at the first carpometacarpal joint) is biaxial and moves along the coronal plane and in an opposition direction (combination of coronal and sagital planes).
A ball-and-socket joint is multiaxial and moves in all planes and in a combination of planes.
