Finger-Trill Symbols
...unspecified alternating of the fingers...

FEW in American Sign Language (one of several ways to write this sign)	Single Finger-Trill From The Middle Joint ...unspecified alternating of the fingers one time only..... One finger opens, then the next finger opens, then the next and the next, all finishing in an open position. This is a single trill. The symbol does not give detailed information. There is no way to know which finger started the trill, or which one finished.
Drumming of the Palm of the Hand Fingers are drumming the palm of the hand, since the movement is only from the middle joint of the fingers, never opening very far, only to close again. So the fingers are opening and closing just a tiny bit, only to fall right back into the position of the handshape, with the fingertips touching the palm of the hand.	Multiple Finger-Trills From The Middle Joint ...unspecified alternating of the fingers many times.... One finger closes, then the next finger closes, then the next and the next, and then it all reverses direction. This is a multiple trill. The symbol does not give detailed information. There is no way to know which finger started the trill, or which one finished.