What term describes the accumulation of fluid around a joint, such as the knee, after injury?

What term describes the accumulation of fluid around a joint, such as the knee, after injury?

• A. Edema
• B. Infection
• C. Dislocation
• D. Effusion

Answer: (D)

Effusion is when fluid accumulates inside a joint capsule after an injury. This happens as the body's inflammatory response increases permeability and causes fluid (sometimes blood) to pool within the joint space, leading to swelling, stiffness, and limited movement at the joint like the knee. Edema, by contrast, is swelling from fluid collecting in the soft tissues around the joint, not inside the joint itself. Infection can cause swelling and warmth but is marked by additional signs such as fever or redness and isn’t defined by fluid inside the joint. Dislocation describes bones that are out of place, not fluid buildup within the joint. So the term that best describes fluid within the joint after injury is effusion.

Effusion is when fluid accumulates inside a joint capsule after an injury. This happens as the body's inflammatory response increases permeability and causes fluid (sometimes blood) to pool within the joint space, leading to swelling, stiffness, and limited movement at the joint like the knee.

Edema, by contrast, is swelling from fluid collecting in the soft tissues around the joint, not inside the joint itself. Infection can cause swelling and warmth but is marked by additional signs such as fever or redness and isn’t defined by fluid inside the joint. Dislocation describes bones that are out of place, not fluid buildup within the joint. So the term that best describes fluid within the joint after injury is effusion.