information:highlighting, structural:scholar_edition
Ulnar opposition

The ulnar opposition—the contact between the thumb and the tip of the little finger of the same hand—is unique to the genus Homo, including Neanderthals, the Sima de los Huesos hominins and anatomically modern humans. In other primates, the thumb is short and unable to touch the little finger. The ulnar opposition facilitates the precision grip and power grip of the human hand, underlying all the skilled manipulations.