Hand. The numerous bones of the hand prove the wonderful structure of the animal frame. It is joined to the radius and ulnus of the arm by the carpus, or wrist, which consists of eight small bones, in two rows; to these are attached four bones within the palm, called metacarpal, and each of the fingers and the thumb contains three bones, connected by cartilages: hence the hand contains twenty-seven bones. It is so important an instrument to man, that without it his reason and speech would not have availed him against other animals.