These include carpal tunnel syndrome, a painful condition of the hand and fingers caused by compression of the median nerve, and Dupuytrens contracture, a condition in which fingers bend towards the palm and cannot be straightened. Similarly, injury to the ulnar nerve may result in a condition in which some of the fingers cannot be flexed. A common fracture of the hand is a scaphoid fracture—a fracture of the scaphoid bone, one of the carpal bones. This is the commonest carpal bone fracture and can be slow to heal due to a limited blood flow to the bone. There are various types of fracture to the base of the thumb; these are known as Rolando fractures, Bennets fracture, and Gamekeepers thumb. Another common fracture, known as Boxers fracture, is to the neck of a metacarpal. One can also have a broken finger. Evolution
The prehensile hands and feet of primates evolved from the mobile hands of semi-arboreal tree shrews that lived about 60 million years ago. This development has been accompanied by important changes in the brain and the relocation of the eyes to the front of the face, together allowing the muscle control and stereoscopic vision necessary for controlled grasping. This grasping, also known as power grip, is supplemented by the precision grip between the thumb and the distal finger pads made possible by the opposable thumbs.
The thumbs of Ardipithecus ramidus, an early hominin, are almost as robust as in humans, so this may be a primitive trait, while the palms of other extant higher primates are elongated to the extent that some of the thumbs original function has been lost (most notably in highly arboreal primates such as the spider monkey). In humans, the big toe is thus more derived than the thumb.There is a hypothesis suggesting the form of the modern human hand is especially conducive to the formation of a compact fist, presumably for fighting purposes. The fist is compact and thus effective as a weapon. It also provides protection for the fingers. However, this is not widely accepted to be one of the primary selective pressures acting on hand morphology throughout human evolution, with tool use and production being thought to be far more influential. Additional images
See also
References
External links

Hand anatomy (eMedicine)
Film Board of Canada documentary Faces of the Hand
"The Common Hand" article in the May 2012 National Geographic