Medical aspects of human identificationPresentation Transcript
MEDICAL ASPECTS OFHUMAN IDENTIFICATION
• The determination of a person based on certain physical characteristics.• Establishing identity of a person whether dead or alive is of paramount importance.• This is because an individual exists as an entity in society, and is dealt with as such by the legal system
Reasons for establishing identity:• Use of identity certificate in criminal or civil cases eg Insurance benefits to next of kin Identification of offenders Age determination in criminal liability Identification of bodies for burial purposes. Interchange of newborn babies in hospital Disputed sex.
• At least 2 identification marks should be noted by the doctor in all medico-legal cases.• Visual identification becomes difficult or impossible in cases of fire, explosion, advanced decomposition, mutilation, air craft accidents or earthquakes.
• Identification of the bodies may be a problem in mass disasters eg air crush or bomb blast, in charred remains found in a burnt vehicle or building.• Identification of a dead victim often helps the police to trace the victim’s movement, to know his background, talk to his friends and find out his enemies.
Laws relating to identification: Penal Code ( Cap 16). Determination of age and criminal responsibility. Personation of a person living or dead. Births and Deaths Registration Act ( Cap 108) Inquest Act (Cap 24)-evidence procurable as to the identity of deceased is a requirement in inquest.
Identification in the living: – Usually done by the police to identify perpetrators of crime. – By using trace evidence such as bloodstains, hair, bite marks, finger prints etc. – Functions such as speech, handwriting, walking gait may be used. – Estimation of age of living persons is frequently done for court purposes – Also to determine the appropriate charges laid eg for a minor accused. Or to determine the sentence to be imposed after verdict.
Identification in the dead:The body may be in one of the following states: – Fresh and intact – Putrefying – Mutilated or dismembered – Charred – Skeletonized.
• May be a problem in: – Mass disaster such as bomb blast, air crash, charred remains – In buried or hidden bodies unearthed after a long time.• Accurate identification of bodies is essential for personal and religious reasons.• Completion of official records , burial or cremation purposes or for statistics.
• Settlement of legal claims eg estate, debts, property, insurance.• To facilitate legal investigations, police enquiries and court cases.
Characteristics useful in identifying the dead:1. Race and Religion:• Complexion: of limited value. Black, white, brown skin.• Eyes - dark in Indians, blue or grey Europeans.• Clothes- dress may be helpful
2. Sex:• Has to be determined in case of heirship, marriage, divorce, legitimacy, impotence, rape. Sex chromatin ( Barr body), Davidson body ( in neutrophils) useful for female identity. Fluorescent body in males. Skeleton: male pelvis android, female gynaecoid. Attachmenmt of muscles- pelvis, skull, and long bones- rough in males.
3. Age determination:• Can be determined from teeth, ossification of bones, secondary sex characteristics and general development in case of children.Age group: Foetus and young infant: Look at the appearance of ossification centres in growing cartilage ( complete by 5 years.
Child to young adult: Look at fusion of the epiphyses ( secondary ossification centres up to 25 years). Also note appearance of milk and permanent teeth. Adult > 25 years: Look at wear and tear changes in teeth and bones.
Medico-legal importance of age:2.Criminal responsibility.o Any act which is done b a child under 7 years of age is not an offenceo A child between 7 and 12 years is presumed to be capable of committing an offence,
• if he attained sufficient maturity of understanding to judge the nature and consequences of his conduct on that occasion• A child under 12 years cannot give valid consent to suffer any harm which can occur from an act done in good faith and for its benefit
• A person over 18 years can give valid con sent to suffer any harm which may result from an act not intended or not known to cause death or grievous harm 2. Judicial punishment A juvenile is a boy who is below 16 years, or a girl below 18 years
• When a juvenile commits an offence, the court my direct that such a person be kept in a juvenile home, or special home, established by government, where there are facilities for education, vocational training and rehabilitation• No deliquent juvenile shall be sentenced to death or improsonment
3. Rape. Sexual intercourse by a man with a girl under 15 years even if she is your wife, or with any other girl under 16 years even with her consent is rape 4. Kidnapping Means taking away a person by illegal means
• It is an offence to kidnap a child with intention taking dishonestly any movable property, if the child is under 7 years• To kidnap a minor for purposes of maiming or begging• To procure a girl for prostitution
5. Employment A child below 14 years cannot be employed to work in any factory or mine or any other risky employment6. Evidence Competence for giving evidence depends on understanding but not age
• A child at any age can give evidence if the court is satisfied if the child is truthful
4. Forensic Odontology( Forensic Dentistry) – Useful in routine identification. – Identification when normal means of identification fail eg charred bodies, drowning, fragmentation of bodies, decomposition, skeletonization. – Mass disasters.
– Bite mark evidence– Child abuse– Race, age and gender determination
It is important for ;• Age estimation• Anomalies of tooth in form and number• Defects due to occupation or habits• Lesions produced by accidents• Crimes, changes occurring after death etc
Identification by dentistry.• Unrecognized individuals killed in accidents- in comparison with dental charts and records important eg gold crowns, on teeth, fixed bridge or partial dentures• Age changes and age estimation
Phases in tooth development and eruption:1. utero ( from 16 weeks) to eruption of 1st tooth at 6 months2. Primary dentition (milk teeth) from 6 months to 6 years.3. Mixed dentition: 6 to 12 years.4. From 12 years on- look at the root development and eruption of wisdom teeth.
5. Identification of skeletal remains:Questions to be answered !!!• Are the remains actually bone ?• Are they human ?• How many sets are there ?• Are they mixed with bones of another person or animal?
• What is the orientation of bones,? left or right• How old is the person ?• What was the gender of the person ?• What race was the person ?
• How tall was the person ?• What was the condition of the teeth ?• How long has the person been dead and/or concealed ?• What was the cause of death ?
When determining gender as many bones as possible should be used.The percentage accuracy of sexing skeletal remains: Skull used alone 90 % Pelvis alone 95 % Skull & pelvis 98 % Long bones alone 80 % Entire skeleton + 100 %.
6. Tattoos:• Huge diversity of skin tattoos.• Main use is their recognition on bodies of unknown persons• Photographs should be taken or drawings made for circulation.• Significance- homosexuals, prostitutes, drug pushers, religion, social status.
7. Finger-prints, palm , foot and lip prints:• Science of print taking is a matter dealt with by the police.• Are impressions of the patterns formed by the papillary or epidermal ridges of finger tips.• No two finger prints identical.• Even identical twins have different finger prints.
• Even after decomposition (skin slippage) has set in the skin of degloved finger remains, and by treating the skin, a finger print can still be obtained• In some circumstances palm, foot and lip prints may be used in identification.
8. DNA finger printing:• Unique sequences of bases in DNA strands are used to compare one blood or tissue sample with another, to investigate genetic relationship.• Blood , hair , saliva and semen can be used for this purpose.
• The technique may be used in the following cases: – To identify a person in cases where conventional means of identification are not possible eg charred body.
– To link a suspect to a crime scene or victim.– In disputed paternity/maternity cases.– In rape and sexual offences.– Mass disasters– Blood or tissue mix-ups in clinical pathology– Ritual murders ( human sacrifice).
9. Facial Reconstruction from skulls (Superimposition). – Technique applied to determine whether the skull is that of the person in the photograph. – The photograph need not be front view of the face, even lateral and semi-lateral view of face can be useful – A recent photograph is much preferred.
• Photograph is enlarged to natural size.• If negative of photograph is not available, negative of available photograph is prepared by copying it.
Identification of a charred body.• Is difficult exercise and the following signs/tests may be used to determine identity.• Radiology- xrays of the body can be used to exclude missile injury, identifying prostheses, parts of a weapon and dental work.• Teeth- antemortem records of dental work compared with postmortem remains. Is a good indicator of age.
• Characteristic features of individual( stigmata)- congenital anomalies, scars, absent organs and prostheses.• Clothing- fragments of clothing may be found in hidden areas of armpits and groin.• Finger prints- can be extracted from a charred body.• Internal viscera- presence of prostate or uterus- gender of victim.