External examination of either a corpse, injured victim, or suspect includes a careful verbal and visual record of any body marks. These include features such as birthmarks, moles, body piercings, tattoos, and scars. Body marks can be characteristic of an individual and can be used to support an identification , in conjunction with medical or police records and with identification given by family members.
Tattoos are patterns on the skin formed by injection of dyes into a pattern of prick marks. The presence of tattoos can signify a number of meanings—sometimes people are tattooed with the name of a loved one, or it may be a sign of belonging to a gang. There are even a few remaining instances of tattoos from World War II (1939–1945) concentration camps among elderly victims or suspects. Semi-permanent make-up is another form of tattoo that might be used for identification purposes. It is sometimes possible to link a tattoo to a particular tattoo artist by analyzing the materials used in creating the tattoo. The chemical composition of the dyes can be determined by extracting a small amount from the tattoo and subjecting it to thin layer chromatography or high performance liquid chromatography . Generally, a tattoo is a permanent feature and it might be possible to identify a suspect by looking for a record of the tattoo in police records. A tattoo might also be mentioned in a missing person's record that could help identify a victim or suspect. Tattoos survive partial decomposition of the body; they can still be seen even if the outer layer of the skin has been sloughed off.
Body piercing is fashionable and related items of jewelry like earrings can be used as evidence , possibly aiding identification via the evidence from relatives. The site and number of piercings may be matched to existing records if they have been present for some time. Birthmarks are another important body mark. Birthmarks are benign tumors involving the blood vessels just under the skin. They are often present at birth, as the name suggests, although they may fade with time. They are sometimes known as strawberry marks or port wine stains and these names are very characteristic of their appearance. The shape and positioning of a birthmark can be important in helping identify an individual involved in a crime. Moles and warts are other important skin features, although they are more common and less individual than a birthmark.
Scars are another important type of body mark. A scar is a healed wound and it may arise from surgery, accident, or assault. Needle tracks in drug users make characteristic scars that may be informative in the context of many crimes. Severe acne during adolescence may leave scars that persist into adult life and may be a useful identification aid. Many people have scars from common operations such as appendix or gall bladder removal. The dates of such operations should be in the person's medical records and the medical examiner will try to relate this to the age of the scar. The internal examination will relate the scar to the operation because the relevant organ will be missing. Operation scars are an aid to identification, but are not usually sufficient alone for identification as they are fairly similar and common. It is also possible to remove some scars with modern laser surgery, so expected scars may no longer be present.
Any wound, however it was acquired, follows the same course of healing. Serious knife wounds , deep or jagged accidental cuts, and surgical wounds need stitches to repair them. For several months after the wound was inflicted, a telltale pattern from the stitches will be apparent and this can help age the wound. The healing process involves tiny blood vessels supplying the wounded area with blood and this gives a characteristic pink to reddish brown color to the wound. Later, the body will create scar tissue by laying down collagen, a protein found in connective tissue. This makes the scar fade and shrink. Four to six months after the wound occurred, it will have the appearance of a faint white line. After this, the appearance of the scar won't change much, although it will still be present. This means it is possible to be precise about recent surgery, accidents, or assaults. However, older wounds cannot be dated with much precision although the presence of a scar can still be a useful aid to the identification of an individual.
It is important that the pathologist distinguishes between body marks and injuries that have been sustained during the crime. Often the difference between new and old injuries is obvious. If a body is partially decomposed, dating body marks and assessing their significance may be more of a challenge.
see also Autopsy; Wound assessment.