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Photography of bite marks

Dr Richard Bassed, Dr Pratik Tarvadi, photography of bite marks, distortion, parallax error
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The very act of taking a photograph of a bite mark injury immediately produces further distortion into the process. Every single body surface is curved to a greater or lesser extent. Some places commonly bitten are extremely curved- arm, shoulder, neck, breast. Converting a three dimensional object into a two dimensional image via photography distorts the real dimensions of the injury. For example, any part of the injury closer to the camera lens will be magnified. Any part where the scale is not in the exact plane of the injury will return false distance measurements. So it is virtually impossible to get a distortion free, dimensionally accurate image of a bite mark using standard photographic techniques.
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This series of images shows how an injury will change shape and size as a body part, in this case, the neck is moved to different positions for imaging. Attempting to match an injury to a dentition here would be impossible as there is no way of knowing what position the neck was in at the time of biting.
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Photography plays key role in bite marks evidence collection. Any fault in photography done will lead to dire consequences. Photograph has to be taken before the bite mark fades away or it gets inflamed to such an extent that we cannot elicit the bite mark properly. It should always be with a scale which is numbered as ABFO No. 2 scale- American Board of Forensic Odontology scale, that is, has to be in line with the bite mark. Third, the scale and the bite mark should be in the same plane and the photograph should be correctly perpendicular it so that direct photograph is taken. As shown in this picture, you can see the three circles in the scale.
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These circles, even if there is a slight angulation change, the lines will not be as clear as we’re seeing in the photograph. So that gives us the analysis of the photograph being taken correctly or not.

How does photography of bite marks lead to further unreliability in bite mark analysis and comparison? Watch Dr Bassed and Dr Tarvadi discuss the challenges with photography of bite mark injuries.

After watching this video, think about any report on bite mark comparison that you have seen in casework. Do you have access to the photographs of bite marks? Reflect on the following points:

  • What was the quality of the photographs? Were these photographs coloured? Was the bite mark clearly visible in these photographs?
  • Are you aware of the time gap between the biting incident and the photography of the bite mark?
  • Was the bite mark inflicted on a curved body part? Were the inherent distortions due to photography visible to you?
  • Were the photographs clicked using ABFO No 2 scale?

Share your reflections in the comments section.

*References for images

Certain images in this video are sourced from ‘Jane A. Taylor and Jules A. Kieser (ed), Forensic odontology: Principles and practice (2016)’.

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Decoding Forensics for Legal Professionals

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