Medical opinion sought in relation to injury interpretation is probably the commonest reason that an Expert Medical report is commissioned from a Forensic Physician. Forensic physicians regularly see fresh injuries both before and after they treatment, in addition to seeing injuries that have started to heal spontaneously in the absence of treatment.
The forensic physician can offer expert opinion relating to possible causation by determining whether the injury is likely to have resulted from a blunt impact or force from a sharp implement. The appearance of injuries caused by a specific weapon varies depending upon the site on the body, particularly if there are any hard underlying bony structures. Cuts caused by blunt trauma are referred to as lacerations, and this often highlights forensic naevity on the part of doctors not trained in the field of forensics, who often use the term ‘laceration’ incorrectly to describe cuts likely to have been caused by sharp edged objects (such as knives, scissors or glass). Such injuries are more accurately referred to as incised or stabbed wounds depending on whether the cutting edge runs tangentially or perpendicular to the skin surface respectively.
With careful consideration, the FP may be able to determine the likely orientation of direction of injury and therefore likely positioning of the assailant. It is also possible to give an indication as to how much force was likely to have been involved which is likely to influence the likely gravity of offence.
Appearance and distribution of injuries might suggest consistency with ‘defence type injuries’ that typically involve the forearms if the arms are raised to protect the head, or knife cuts to the palm of the hand in blade attacks.
Self inflicted injuries also tend to have a characteristic appearance and distribution usually on the non dominant side of the body, and often found to be a cluster of fairly trivial almost parallel superficial scratches.
Colouration of bruising is of notoriously limited value in age determination of injuries with the exception of yellow discolouration that is scientifically accepted to correlate to injuries older than 18hours. (Based on work by Langlois and Gresham 1991).
The relatively rare finding of patterned bruising is of particular forensic interest since a specific object (such as a trainer with patterned sole seized from a suspect thought to be involved in assault by ‘kicking’ ) may on occasions be confidently linked to observed injuries.
Detailed consideration of reported history in witness statements relating to suspect / assailant injuries is vital in establishing whether the account is consistent with or inconsistent with observed injuries.
In relation to serious sexual offences, it is well established that the presence or absence or overt genital injury neither supports nor absolutely refutes an allegation of non-consensual vaginal penetration.
Research undertaken by Slaughter in 1997 (Ref. The Pattern of genital injury in female sexual assault victims. Am J Obstet Gynecol 176:609-611) suggested that forced non consensual intercourse can very well result in NO injury, and similarly visible injuries can result from intercourse considered to be entirely consensual.
The implication is that when victims of alleged rape are examined, careful whole body examination is essential in order to record the presence or absence of any possible recent injuries (no matter how trivial). Such injuries could well be the subject of subsequent courtroom deliberation as potential evidence suggesting that the victim may have put up some resistance to the assaliant.