Mind Map [antikvár]

ForewordOn louking at the palmar, or inner, side of a hand, certain features are apparent to the naked eye. There are four fingers and a thumb. The palm is not completely fiat, but has a number of raised parts or mounds. The palm is traversed by three major creases. There are other creases at the wrist, at the base of the fingers and at the joints between the phalanges of fingers and thumb. With a hand lens (magnifying glass) it can be seen that the entire palmar surface of the hand, including the fingers, is covered with narrow ridges, which in certain areas, for example the fingerballs, are arranged to form patterns. With higher magni-fication, such as a low-power binocular microscope, it is possible to see that the ridges do not continue unbroken across the surface, but are divided into pieces of varying length. Some ridges fork, others rejoin after forking. The width of the ridges also varies, not only on différent individuáis, but in différent parts. Each ridge has a row of pores, the openings of the sweat glands. There are so many variations in the detailed structure of the ridges that the features of even a small area are not repeated either in the same individual or in a différent one. Even the ridge détails of identical twins are not exactly alike.Ridged skin is not limited to hands, but also occurs on soles and toes. It is present on the hands and feet of all primates, man, apes, monkeys and pro-simians (bushbabies). The study of ridged skin is called dermatoglyphics, a word coined in 1926 by Dr Harold Cummins, who was Professor of Anatomy at Tulane University, New Orleans, Louisiana, U.S.A., for many years. Various aspects of the subject are of interest to workers in a number of fields: identification experts, anthropologists, geneticists, cytologists, pae-diatricians, psychiatrists in hospitals for the mentally defective and primatologists, not to mention palmists, or chirologists, to give them their proper title. Some, or all, of the features mentioned in the first paragraph are used by one or other of the above-mentioned workers. The shape of the hand is notable; for one reason, because