بسم الله الرحمن الرحيم

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بسم الله الرحمن الرحيم. Objectives. 1- To know the definition and value of identification of living and dead persons. 1-To know how to identify living persons 2- To know how to identify dead bodies. 3- To know the characters useful in identification of dead persons - PowerPoint PPT Presentation


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Objectives1- To know the definition and value of identification of living and dead persons.1-To know how to identify living persons2- To know how to identify dead bodies.3- To know the characters useful in identification of dead persons4-To know how to identify age ,sex ,stature ,race, time pass since death ,and cause of death from the skeletal remains.

IdentificationDefinition:-The application of forensic science and technology to personalize someone through specific criteria that individualizes him than others throughout his life.The medicolegal expert may be asked to examine for identification a living , a dead person or even parts of dead bodies or collection of bones.Medicolegal importance of identificationI-Civil cases:-1- In unconscious patients admitted to hospital.2-Amnesia( memory loss).3- Unknown persons and those reported to be lost.4- Persons having no authentic records when facing any legal situation.5- Inheritance.6- Military services.7- Emigration at exit ports.8- Controversy about a prominent , important persons .II- In criminal cases:-1- In criminals who impersonate others.2- Offenders below age of 18 having no official records of age to be tried in the related court eg:- juvenile court.Identification of livingPrimarily a matter for police investigation.Methods of identification:-1-Personal impression (visual identification) Basis of identification parades but is notoriously unreliable. Witness in court may be asked to point out the accused. Identikit is a composite picture of a person from a witness account. Personal impression depends on features such as hair, moustache and beard, all of which can be changed easily. Plastic surgery can easily alter other features.

2-Photography More useful in identifying the living than the dead. 3-Handwriting Possible for experts to identify a person . Methods used include photographic enlargement, analysis of ink, analysis of paper.

4-Fingerprints (Dactylography) How fingerprints are produced: friction skin (i.e. palms and soles) have a ridge pattern. Sweat glands open through minute openings on the summits of the ridges. The sweat contains fat. When the skin is applied to a smooth surface a greasy impression is left behind.

Principles of fingerprint identification: Fingerprint patterns are unique (1 in 64 billion chance of 2 prints being identical). FBI has over 100 million records, no two of which are alike. Fingerprint pattern of an individual remains unchanged throughout life. Reversible atrophy occurs in certain diseases (eg; dermatitis).

Permanent impairment occurs in leprosy and after exposure to radiation. Attempts to mutilate fingerprints are sometimes made. If only the epidermis is destroyed there is no alteration in ridge pattern. If dermis is destroyed additional points of identification are created. 6-DNA:- This is forensically useful in the living (strong evidence of involvement in assault, rape, disputed paternity)

Identification of the deadPrimary Physical Characteristics :-(characteristics which are very difficult for a person to change during life. Some of these characteristics will appear to alter post mortem):Sex - usually obvious. Age - external appearances, internal degenerative disease, bones, joints.

Height or stature: - N.B. height of corpse differs from that in life by up to 2-3 cm, due to joint and muscle relaxation. Race DNA (unique to every individual) except monozygous (identical) twins. DNA comparisons allow for definitive identification of an individual

This is forensically useful in dead (DNA survives in bone for many years, comparison of DNA with family members) as well as in living.Samples may be taken from blood of dead bodies (on EDTA),or from spleen, or organs or from bone marrow( without fixation).

Secondary physical characters:-(characteristics which can change during life, Some of these characteristics will appear to alter post mortem): Skin :-Color in undamaged unputrified bodies only (alters post mortem) Eyes - :-Iris color can be useful in fresh corpse only, but color can alter PM.Teeth :- very resistant and bear much useful information. Hair color and structure - color, style, length, beard/moustache give an idea about sex , race, type of crime and identification of the victim or assailant Scars - surgical procedures and prosthesesTattooing - seen even if the body is putrefied. Fingerprints :- from the palm or sole

External peculiarities - circumcision, moles, warts. Deformities Clothing and other objects (as:-Jewelers )Occupational stigmata :-( eg:-shoe maker kyphosis ,and sternum, blue scars of coal miners).

Identification of decomposed or skeletal reminants

1- Are they really bones? (wood, stones) 2-Are the remains human or animal? 3-Are they human? 4-How many bodies?

5-Time pass since death? - recent or ancient (e.g. construction or digging at an old burial site) 6-Cause of death? 7-Sex? 8-Age? 9-Race? 10-Stature?

Identification of sex

I- In intact bodies:- Straight forward in intact bodies except in adrenogenital syndrome and hermaphrodites. In mutilated/dismembered or charred bodies the internal sex organs, especially the uterus, cervix and prostate are resilient.

II- In skeleton remnant: Based on appearance of pelvis, skull, sternum, long bones. Pelvis is the most important bone for sex determination. Subjective and objective differences are seen between male and female pelvis.

MALEFEMALEPelvis as a wholeThick, heavy, markedlySmoother, lighter, moremuscularspaciousBrimHeart shapedCircular or ellipticalBody of pubisTriangular shapeQuadrangularSub pubic archInverted V shapedInverted U shapedGreater sciatic notchDeep and narrowBroad and shallowSacro iliac jointLargeSmallSacrumLong and narrowShort and wideThe differences between male and female pelvis

III-Sex determination from the skull :- Supra orbital ridges Mastoid process condylar processRace determination from bones The skull is the only reliable bone. Cheekbones (Zygomatic arches): determine facial width. More prominent in Mongoloids. Width between eyes greater in mongoloids.Nasal openings: Wider and flatter in Negroids. Narrow in Caucasians.

Determination of stature from bones

Long bone length (femur, tibia, humerus) is proportional to height. Tables are used. Fairly reliable up to the age of epiphyseal fusion. There are sex, race, nutrition and personal variations to consider.

Age determination from skeleton

Sex has to be taken into account as bone development and epiphyseal fusion is different between the sexes. Epiphyseal fusion :- The pattern of fusion of bone ends (epiphysis) to bone shaft (metaphysis) in each bone indicates age. Charts & tables are used. Cranial suture fusion is less reliable. Arthritic changes, osteophytes and osteoporosis give further clues.Identification of ageThe age can be determined from :-1- Skull including mandible and teeth.2- Appearance of ossific centers.3- Union of epiphysis.1- SkullA- Dimensions :-In the full term infants , the circumference is 13 inches,length is 5 inches and width is 4 inches.

B- Fontanells:-The posterior fontanel is closed at full term while the anterior fontanel can admit the tips of the middle 3 fingers and closed at 18 months after birth. C- Sutures:-- Frontal suturre closes at 3 years ( 30 years in negroid). - Basioccipital basisphenoidal sutures closes at 23 years.Saggital sutures closes at 30 years.Coronal sutures closes at 40 years.Lamboid sutures at 50 years.

D-Age detection from teeth:-A- temporary teeth:-

ToothEruption TimeLower Central Incisors ( CI )Upper central incisors(UI)6-8th month9-12 monthLateral Incisors ( LI )18-24th month(10)Canine ( C )18-24th month(18)Temporal Molar 1 (TM1)12-24th monthTemporal Molar 2 (TM2)24-36th month b- Permanent teeth :-

ToothE.TCentral Incisors ( CI )6-7TH yearLateral Incisors ( LI )7-8th yearCanine ( C )9-11th yearPremolar 1 (PM1)9-12th yearPremolar 2 (PM2)9-12th yearMolar 1 (M1)5-7th yearMolar 2 (M2)10-13th yearMolar3 (M3)18-25th yearTEMPORARY TEETHPERMANENT TEETH - small, narrow, light & delicate - china white crown - constricted neck - serrated edges - - big, broad, heavy & strong - ivory white crown - less constricted - not serrated Bite marksCaused by front teeth with gap at either sideMay be contusion, abrasion & lacerationSwab of bite marks & victims saliva should be takenMatched by photographic method & casts

E- Mandible:- The angle of the mandible is obtuse in infants and old ages and right angle in adults.The alveolar margin is resorbed in senile mandible.

Mandible can now be easily examined, photographed, and X-rayed.

Medicolegal importanceIdentification of individual in accidental or homicidal casesDifferential identification in mass disasterEstimation of ageDetermination of sex & blood groupIdentification of criminal through bite marksDetection of poison

II- Ossific centersThese are centers of bone growth that appears as a dark area inside a translucent cartilage.Ossification centers :- Useful only in fetus and babies. May be determined radiologically or by cutting into ossification centers. Most important center in medico-legal work is the distal center of the femur. This is present at birth and indicates a full term baby.

Ossific centers that appear after birth :- 1 year at the head of the humerus , femur and tibia.2 years at the lower end radius.3 years patella.4 years upper fibula ,greater trochanter of femur5 years at lower fibula.6 years at head of radius , lower ulna.

III- Union of epiphysisEPIPHYSISAGEThe pubic ramus of ischial bone is united with the ischial ramus of pubic bone. 6 ye