posted from: https://peakmemory.me/2017/03/03/why-cant-i-snap-my-fingers/

I am unable to snap my fingers. I never really regarded this as any kind of a disadvantage. However, it has been brought to my attention that some people advocate replacing applause with finger snapping. 

When I tell people that I can’t snap my fingers, they often try to instruct me. They assume that I must just be using the wrong technique. But to no avail. The other thing I discover is that I am not alone and that other people are unable to do it.

I have been unable to find an explanation in the medical literature. I suspect that it might have something to do with the mobility of the finger joints.
https://www.youtube.com/embed/pYTrtT1J8HE?version=3&rel=1&fs=1&autohide=2&showsearch=0&showinfo=1&iv_load_policy=1&wmode=transparent