German words for parts of the body are much more colorful and descriptive than their prettified Latin counterparts in English. Fuck nostril, German gives you 'nose-hole' (Nasenloch). Suck it, placenta, in German you're 'mother-cake' (Mutterkuchen). Don't think about that last one too long.
And now for the synovial bursa. WTF is the synovial bursa? This:
A bursa (plural bursae or bursas) is a small fluid-filled sac lined by synovial membrane with an inner capillary layer of viscous fluid (similar in consistency to that of a raw egg white). It provides a cushion between bones and tendons and/or muscles around a joint.
It comes from the Latin bursa, or purse. This is why people in English get bursitis.
Ooh la-de-da, bur-si-tis!
German, the Moe Szyslak of languages, doesn't bully its speakers with this hifalutin' Latinizing.
What is the 'synovial bursa'? It's a bag.
What's it filled with? Slime.
So the German word is Schleimbeutel — literally, 'slime-bag'. Now, you could also perhaps call it 'mucus-bag', since the German word for mucus is also 'slime'. (Hence the German word for the unpronounceable train-wreck of Latinate fuckwittery we English-speakers have to call mucous membrane is Schleimhaut — 'slime-skin').
But the synovial bursa isn't filled with mucus, is it now? No, it's filled with a 'lawyer of viscous fluid' — er, layer of viscous fluid — similar to an egg white.
In other words, slime. And if your slime-bag gets infected, you have a Schleimbeutelentzündung — slime-bag inflammation.
Now you know that in Germany, there are dozens of slimebags inside your body. In addition to the ones in high office (ba-da-BOOM!)