Measuring from the first crease of the wrist to the very tip of my middle finger I got 195 mm.
I guess the line between my hand and wrist probably means that same crease, and its apex to the thumb side endpoint were the hand were to be cut off along that line. However, I couldn't figure out which point along which side of the hand to use as the other endpoint, so I finally decided to use the spot at the knuckle of the pinky because it's the farthest away.
That gave me "less than 95 mm," which seems a bit weird...