If you want to know the length of a hand.
You can measure from the length of the middle finger.
In addition to raising the middle finger to elevate for annoy other .
It also indicates something more.
One of them is the length of our own hands.
Try to spread your hand the ,then set the base of the middle finger.
It found that the length is measured up to the end of the finger.
It has a length measured down to the wrist or palm size, that is, to us.
The length of the middle finger itself.