Describe anthropometry, the Bertillon system and superimposition.

Anthropometry and the Bertillon System

• It rested on eleven measurements, chosen because they were thought to be stable after adulthood: height; the span of the outstretched arms; sitting height (trunk); length and breadth of the head; length of the left middle finger, left little finger and left foot; length of the left forearm (cubit); length and breadth of the right ear
• The left side was used throughout, on the reasoning that it is less affected by occupational use and therefore less variable
• It also incorporated the portrait PARLE ("spoken portrait") — a standardised verbal description of the features, particularly the ear — together with standardised full-face and profile photographs, which are the origin of the modern police "mugshot", and a record of scars, marks and deformities
• Why it failed — the measurements change with age and are not fixed in the young; they require skilled and consistent technique, and different operators obtained different results; two people may coincidentally share several measurements; and it is not applicable to children or to the dead. The decisive failure was the west case (Leavenworth, 1903), in which two unrelated prisoners named Will West and William West were found to have nearly identical Bertillon measurements and closely similar appearance, but entirely different fingerprints
• It was superseded by dactylography, which is unique, permanent, unaffected by age, easily recorded by anyone, and applicable to the dead

Superimposition

• Method — the photograph is enlarged to life size using a known reference such as the interpupillary distance; the skull is photographed or displayed in the identical orientation; and the two images are superimposed photographically or, in modern practice, by video superimposition with digital fading between them
• Points compared — the outline of the skull against the head; the orbits against the eyes; the nasal aperture against the nose; the position of the teeth against the mouth and the smile line; the relation of the external auditory meatus to the ear; the angle of the mandible; the supraorbital ridges and the chin
• Its evidential value is negative rather than positive — a mismatch excludes the individual reliably, whereas a good match is corroborative and consistent, not conclusive, since many skulls will fit a given photograph acceptably
• The classical Indian case is the Ravana Elangovan case, and internationally the Ruxton case (1935) in Britain, in which superimposition of the skulls of two dismembered victims onto their photographs was a notable element of the evidence
• Facial reconstruction is the reverse procedure — building a face onto a skull, in clay or digitally, using average soft-tissue depths at defined landmarks, to produce a likeness for public appeal. It generates a lead; it does not identify

Other Comparative Methods and Applied Aspects

• Radiographic comparison is far more reliable than superimposition, and is a positive method of identification where antemortem films exist. The frontal sinus pattern is unique to the individual, including in identical twins, and is stable after about 20 years of age; the trabecular pattern of bone, the shape of the sella turcica, healed fractures, surgical implants and prostheses with serial numbers are similarly conclusive
• Forensic odontology — comparison with antemortem dental records and radiographs is conclusive and is the workhorse of mass-disaster identification, because teeth survive fire and decomposition
• Iris and retinal patterns, and voice — biometric methods used in the living; iris recognition is a component of the Aadhaar system in India
• A method that excludes is more useful than one that merely does not exclude; superimposition, hair microscopy and blood grouping are all far stronger as exclusionary evidence, and reports should say so plainly
• Obtain antemortem records early — dental charts, radiographs, photographs and prosthesis details; identification depends entirely on having something to compare against, and these records are often destroyed or lost within weeks
• Bertillonage is historically important and practically obsolete, but its two surviving legacies — the standardised photograph and the systematic verbal description — remain in daily use in every police force
• Superimposition excludes reliably and includes weakly, and a report should say exactly that rather than implying that a good fit identifies the person
• The frontal sinus is unique even in identical twins, and an antemortem skull radiograph is therefore a conclusive identifier where one exists
• Facial reconstruction produces a lead, not an identification; it is published to prompt recognition, and any resulting candidate must then be confirmed by a primary method
• Ask for the antemortem records immediately; dental charts and radiographs are routinely destroyed within a few years, and identification fails for want of something to compare against far more often than for want of technique