Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!rutgers!sunybcs!kitty!larry From: larry@kitty.UUCP (Larry Lippman) Newsgroups: sci.med,sci.bio Subject: Re: Dating age of humans Message-ID: <1960@kitty.UUCP> Date: Mon, 24-Aug-87 23:27:09 EDT Article-I.D.: kitty.1960 Posted: Mon Aug 24 23:27:09 1987 Date-Received: Wed, 26-Aug-87 01:27:36 EDT References: <26333@sun.uucp> Organization: Recognition Research Corp., Clarence, NY Lines: 62 Keywords: Ageing Human Carbon Summary: More measurement techniques avaiable for "dead" humans... :-) Xref: mnetor sci.med:3015 sci.bio:612 In article <26333@sun.uucp>, ram%shukra@Sun.COM (Renu Raman, Sun Microsystems) writes: > Are there any techniques (like carbon dating) to determine a living > human's age (Accurate to within a month/week at least)? My > knowledge of biology and/or human anoanotmy&physilogy is not > more than high-school level. So, anybody know of any techniques > that can succesfully determine the age of a person? There are a number of techniques which may be used to ascertain the approximate age of a human being; unfortunately, most of them can only be applied to _dead_ human beings. :-) First of all, radiocarbon dating (C14) only works on living matter that is now dead. C14 intake stops at death, and the decay of residual C14 is used to determine absolute age. Radiocarbon dating can be used to ascertain age up to about 50,000 years. While radiocarbon dating is accurate to +/- 40 years, specimens which are less than 200 years old cannot be dated by this method. Other techniques for dating bone include: fluorine dating (a purely chemical measurement); uranium dating (isotope decay); nitrogen dating (chemical measurement of collagen in bone); and racemization of amino acids in bones (chemical measurement of amino acid isomer mixtures). Unfortunately, the above techniques only work on dead specimens and determine their absolute age (but not relative age at death). The only satisfactory method of age determination in living and dead contemporary specimens is through examination of skeletal structures. Some techniques which I will describe are only applicable to direct examination of skeletal remains; other techniques may be used through x-ray examination, and therefore could be applied to living humans. In general, the precision to which human age can be determined decreases as the subject becomes older. The most common method of age determination is through the appearance of unique bone structures which are called "ossification centers". Examination of ossification centers can determine age with a precision of +/- 1 month from birth to about 2 years; from 2 to 3 years the precision is +/- 2 months; from 3 to 5 years the precision is +/- 6 months. Vertebral ossification can be used to establish age from about 6 to 12 years with a precision of about +/- 1 year. The emergence of teeth is useful to determine age from about 6 to 14 years, with a precision of about +/- 1 year. The study of epiphysial union can be used to determine age from about 12 years to about 30 years. An "epiphysis" is a piece of bone which is joined to a larger bone via a cartilagenous bridge; after a certain age, union occurs as the cartilage is replaced by bone, and the epiphysis becomes part of the main bone. Examination of closure of cranial "sutures" has been used, but is not considered that reliable. Examination of changes in the scapula (shoulder blade) through transillumination or x-rays can be used to determine age in older persons up to the 80's or more. Other areas of bone "wear" such as the glenoid fossa (part of the skull into which the lower jaw fits), clavicular facet (part of the collarbone), acromial process (the "point" of the shoulder), etc. can be used to determine age in older subjects. The best age determination precision in subjects older than 40 years is +/- 10 years. Generally, as many skeletal points as possible are examined, and a statistical "score" is taken to arrive at a mean age figure. So, to sum up: there is no method of age determination in either living or dead subjects beyond that which I have described above. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"