This covers a variety of movements from having the palm of the hand facing the floor (pronation) or the ceiling (supination) or anything in between. 
This video clip shows forearm pronation and supination:

Wrist and forearm movements also include bending the wrist up (wrist extension) and down (wrist flexion). 
This video clip shows wrist extension and flexion:

We usually use a combination of wrist and forearm movements when we are using our hands but it is important to remember that wrist extension and supination are often quite tricky for people with hemiplegia.

Wrist and forearm movements Toys and Games.