Common Joint Pathologies

Question 1

define joint

Answer 1

site at which 2 or more bones articulate

Question 2

what are the characteristics of a synovial joint?

Answer 2

• Articular surfaces of bones are covered by a thin layer of avascular hyaline cartilage
• Joint cavity is lined by synovial membrane (very thin) which produces synovial fluid.
• The function of synovial fluid is lubrication, shock absorption and nutrient distribution within the joint
• Nutrient distribution is especially important as hyaline cartilage does not have its own blood supply.
• Joint is surrounded by a fibrous capsule, reinforced externally or internally (or both) by fibrous ligaments
• Bursae: fluid-filled sacs that facilitate smooth movement between articulating structures.
• Tendons anchor muscle to bone
• The muscles acting over the joint move it through its normal range
• Muscles, ligaments and capsule all provide stability to the joint –> prevent dislocations

Question 3

identify the 4 different structures on the radiograph:

Answer 3

Answer 4

1st tube is pure water (for comparison)
2nd tube is what normal synovial fluid looks like
Straw colour
Relatively clear
3rd tube is what would be aspirated from this case above
straw colour
almost completely opaque
4th tube shows blood incompletely mixed with synovial fluid
Therefore, is this case blood has entered synovial fluid during aspiration procedure
5th tube shows blood completely mixed with synovial fluid.
In this case however the blood present has been present in the joint capsule for some time.