HANDBREADTH
The ancient measurement system was based on the human body.
The longest span was the length between the ends of the thumb and little finger with the hand extended, and was equivalent to approximately 22.5 cm. (half a cubit, cf. Ex. 28:16; 39:9, etc.).
The shorter hand was measured with the hand closed except for the thumb, open, taking the width between the little finger and index finger at the base (Ex. 25:25; 37:12, etc.).