Other MSK Knowledge Flashcards
What are the 3 main types of joint?
Fibrous
Cartilaginous
Synovial
What are some examples of fibrous joints?
Peridontal ligament
Cranial sutures
Interosseus membranes
What is the difference between a primary and secondary cartilaginous joint?
Primary - only hyaline cartilage.
Secondary - has both hyaline cartilage and fibrocartilage.
What are some examples of cartilaginous joints?
Synchrondrosis (primary) between arm or leg bone ends.
Symphysis (secondary) intervertebral discs.
What are some common features of synovial joints?
Synovial cavity that is fluid filled.
Articular cartilage present between 2 articular heads.
Fibrous capsule
Synovial membrane.
What are some different types of synovial joints?
Plane e.g. acromiocoricoid joint. Hinge e.g. elbow joint Pivot e.g.radiculoulnar joint Condylar e.g. axis of skull Saddle e.g. sternoclavicular joint Ball and socket e.g. glenohumeral joint
What provide joint stability?
Shape of articulating surfaces
Capsule and ligaments
Muscles
What are some characteristics of articular (hyaline) cartilage?
Superficial layer has flattened chondrocytes that produce collagen and glycoproteins e.g. lubricin.
Transitional layer has round chondrocytes that produce proteoglycans such as aggrecan.
> 75% water which makes it incompressible.
What are glycoproteins?
Proteins to which oligosaccharide chains are attached.
More protein than carb.
What are proteoglycans?
Proteins that are heavily glycosylated.
Tend to be more carb than protein. E.g. aggrecan.
What are glycosaminoglycans (GAGs)?
Long unbranched polysaccharides which are highly polar and thus attract water.
E.g. hyaluronic acid
What is the average thickness of articular cartilage?
2-3mm
Interphalangeal joint it is 1mm
Patella it is 5-6mm
How does cartilage get nutrients and remove waste if it is avascular?
Synovial fluid produced by synovial membrane provides these features for cartilage.
What are the features of the synovium?
Synoviocytes produce fluid
Rich capillary network present
No epithelial lining
Direct exchange of oxygen, carbon dioxide and metabolites between blood and synovial fluid.
What are the characteristics of type A synoviocytes?
Look like macrophages
Remove debris from synovial cavity.
Contribute to synovial fluid production.
What are the characteristics of type B synoviocytes?
Fibroblast like
Main producer of synovial fluid.
What is synovial fluid?
Fluid that fills synovial cavity of joints. Mixture of hyaluronic acid and lubricin. Fluid component if from blood plasma.
Very viscous.
What are the functions of synovial fluid?
Provide nutrition for cartilage
Remove waste products from cavity.
Provide lubrication to protect the joint from damage.
How does synovial fluid provide lubrication?
Glycoproteins such as lubricin bind to receptors on articular surfaces to form a thin film.
Surfaces are kept apart by liquid pressure and the viscosity changes with load and velocity of movement.
Fluid present within cartilage is squeezed out into the synovial cavity to increase fluid volume.
What are bursae?
Fluid filled pouch that provides cushioning and protecting to certain joints. Produced by synovial membrane they also help to reduce friction.
How does ageing affect synovial joints?
Viscosity of synovial fluid increases with age so there is slower joint movements and reduced lubrication.
Water content of cartilage decreases so there is reduced shock absorption.
Less protection of articular surface and increased risk of damage.
What are the signs of osteoarthritis?
Bone spurs
Loss of joint space
Loss of articular cartilage
What is an infection in the bone called?
Osteomyelitis
What is an infection in the joint called?
Septic arthritis