Significance of Tattoo Marks in Forensic Medicine

Definition and Mode of Production

• Voluntary - deliberately imprinted with pigments (Indian ink/carbon - black; cinnabar/vermilion - red; indigo/Prussian blue - blue; chromic acid - green)
• Involuntary - e.g., gunpowder tattooing around firearm entry wounds

Medicolegal Significance

1. Identification (Most Important)

• Unknown or unidentified bodies - especially in decomposed, mutilated, or burned bodies
• Name of person, relatives, spouse, or friends written as part of the design
• Date of birth, marriage, or service entry
• Bodies recovered from water - after removing loose epidermis, the tattoo on the dermis can be photographed

Tattoo marks seen in a decomposed body - the name "APPU NAMA" remains legible even after putrefaction:

2. Race / Nationality

• Extensive tattooing of the chest and limbs is common among Japanese
• Tribal communities use characteristic patterns

3. Religion

• Design of Hanuman, Lord Krishna (Hindu), Cross or Christ (Christian), etc. indicate religious affiliation

4. Profession / Occupation

• Coal miners leave involuntary tattoo marks (carbon dust) on hands and face
• Certain criminal gangs have specific emblem tattoos identifying membership

5. Behavioural Characteristics / Social Habits

• Erotic tattoos suggest sexual deviation
• Blue bird design on the extensor surface of the thumb web - associated with homosexuality
• Number 13 inside the lower lip - associated with drug pushers
• Tattoos over injection sites (antecubital fossa) - used by drug addicts to conceal needle marks
• Tattoos on genitalia or excessive sex-oriented designs suggest sexually deviant orientation

6. Social Status / Political Conviction

• In India, tattooing is more common in the lower socioeconomic class
• Political symbols (cow and calf, sword and sickle) may indicate political affiliations

7. Mental Makeup

• The nature of the design (flower, obscene figure, idol) reflects the personality and inclinations of the individual

Permanency and Durability

• Most permanent when dye is deposited into the dermis (may last a lifetime)
• Fading occurs if pigment is in the subepithelial layer, on exposed parts (sunlight), or on areas of constant friction (hands) - may fade in 8-10 years
• Vermilion and ultramarine may disappear after ~10 years

Recognition of Faded/Old Tattoos

• Lymph nodes near a tattoo mark always show a deposit of the pigment used - helpful even when the skin tattoo has faded

Attempts to Conceal / Obliterate Tattoos

1. Dermabrasion (leaves scar)
2. Application of caustic substances or CO₂ snow (leaves scar)
3. Electrolysis
4. Surgical excision with skin grafting (less obvious scar)
5. Laser beams (destroys pigment without structural damage - most modern method)

Note: Chronic eczema may cause tattoo designs to disappear; confluent smallpox can obliterate them in children.

Complications (Medicolegal Relevance)

• Sepsis / local infection
• Syphilis, leprosy, tuberculosis
• Hepatitis B and C
• HIV/AIDS
• Keloid formation, ulcers

Key Forensic Points to Record

1. Anatomical situation (location on body)
2. Size
3. Color
4. Design (sketch or photograph - more reliable than written description)
5. Possible origin (tattooist, gang, country)

"The possibility of the same emblem in the same situation in more than one person due to the same tattooist executing the design must be kept in mind." - Parikh's Textbook