Also called: Thumb attachment · Thumb placement on the palm edge

Where on the hand: Judged by where the thumb's inner edge attaches along the side of the palm — nearer the wrist, nearer the index finger, or about midway.

What it looks like: Trace the thumb's inner edge down to the point where it meets the palm's radial border, and note whether that point sits high, low or in the middle of the hand's height.

The set governs the natural angle of opening and, with it, the person's natural breadth. A low-set thumb opens wide and reads as broad and practical; a high-set thumb opens narrow and reads as reserved and self-contained.