Bursa

bursa \ˈbər-sə\ noun: a small, fluid-filled sac that provides a cushion between bones and tendons

Etymology: Latin bursa bag, purse (due to the sac’s resemblance to a purse)

Wikipedia states, “Current medical studies have no specific knowledge of the entire bursae system [in the human body].” Is that really true? I would have thought something like that would have been thoroughly catagorized by now.