Question

how does compression reduce swelling after an injury?
a. it cools the injured tissue.
b. it keeps the injury elevated.
c. it cuts off blood flow.
d. it narrows blood vessels.

please select the best answer from the choices provided.

○ a
○ b
○ c
○ d

Explanation:

• Option A: Cooling injured tissue is the role of ice (cold therapy), not compression. So A is incorrect.
• Option B: Elevation is a separate method to reduce swelling (by reducing blood flow due to gravity), while compression has a different mechanism. So B is incorrect.
• Option C: Compression does not cut off blood flow completely (which would be harmful), it just reduces the amount of fluid that can leak into the injured area by narrowing blood vessels and reducing capillary permeability. So C is incorrect.
• Option D: Compression applies external pressure, which causes blood vessels (especially small capillaries) to narrow. This reduces the amount of fluid that can leak out of the blood vessels into the surrounding tissue, thereby reducing swelling. This matches the physiological mechanism of how compression works to reduce swelling.

Answer:

D. It narrows blood vessels.