While playing on the playground, a student accidentally gets kicked in the finger at a joint. She feels pain right away, and when she touches it, she can feel liquid moving around. What might have happened?

A bursa is a small, fluid-filled sac that cushions a joint and reduces friction. A direct kick could damage or rupture it, allowing fluid to move around and causing immediate pain. The meninges in choice B surround the brain and spinal cord, while choices C and D describe structures or fluids that do not fit this joint injury.

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