What causes fluid to leak out?

Fluid leaks out when pressure pushes it through tiny holes, just like when you squeeze a toothpaste tube, squeezing makes the paste come out.

Imagine your body is like a big balloon filled with water. When something happens, like you sit on a chair or get bumped, it can make that balloon feel squished in some places and stretched in others. The tiny holes are like the little tears or openings in the balloon, when there's too much pressure, the fluid (like your body’s liquid) pushes through those tiny holes and leaks out.

Think about a plastic bag filled with water. If you squeeze one side hard, the water will come out from the other side, especially if it has a small hole or tear. That's pressure at work! Your body can act like that bag: when there's more pressure on one part (like your leg), fluid might leak through a tiny opening in another place (like around your ankle).

So, fluid leaks out because of pressure, and the tiny holes let it escape, just like toothpaste or water from a squeezed bag.