How to create a physical constraint between a arm/hands bones and a plane?

Hi Friends,

How can I create this specific constraint where my live animated character arms/hands cannot go below the plane, when moving the arms up and down? See the image attached.

I’m streaming this animation via live mocap into UE4 and it’s worth to mention that:

The actual movements don’t really go passed the height where the plane is located (it’s a mocap issue that can’t be corrected in the “source”)

Thanks for your guidance!