Forensic Identity (Human Identity) PDF

Forensic Identification (Human Identity)  Forensic Identity Defined as: ▪ Recognition of the individuality of a person live or dead. ▪ Recognition of a person through certain features that distinguish him from all other individuals.  classified into :- – Complete (positive)...

Forensic Identification (Human Identity)  Forensic Identity Defined as: ▪ Recognition of the individuality of a person live or dead. ▪ Recognition of a person through certain features that distinguish him from all other individuals.  classified into :- – Complete (positive) Identity: full identity is possible. – Incomplete (presumptive) Identity: Here the full identity can not be established but, certain aspects of identity can be recognized. – Legal Identity: An unknown body recovered and labeled by a number of symbols.  Medico legal investigator ask to identify ▪ A living person. ▪ Fresh, intact corpse. ▪ Putrefying (decomposing) bodies. ▪ Mutilated, dismembered or charred (fragmentary) remains. ▪ Skeletonised material. Identification of unknown person is :important in cases of.In cases of impersonation of other individuals.A comatose without identity cards.Mentally retarted.A person accused for assault, rape or murder Mix-up of newborns in the hospitals.Claims of disputed paternity  Identification may become a problem in: – Mass disasters: air crash, inferno (building), disaster at sea, … – identification of burns – explosion accidents (terrorism). – high putrefied bodies – mutilated cadavers recovered in fragments…etc.  Identification of a person can be established in general by: ▪ General Facial Appearance, Personal impression, visual identification. ▪ Photography. ▪ Anthropometry. ▪ Hand writing. ▪ Eye colour. ▪ Skin Pigmentation. ▪ Hair Colour, Structure. ▪ Fingerprints ( dactylography), Palm, Foot And Lip Prints. ▪ Other External Features: Scars Birthmarks, Tattoos, Occupational stigmata, Diseases. Comparison of the remains with antemortem records and information from those thought to be the victims. ▪ The individuality of the cell: blood grouping “ABO, MN, Rh,….etc.”; protein complex, haptoglobins, blood enzyme, DNA.  Fingerprints, Palm, Foot And Lip Prints Fingerprint: Skin ridges alternating with grooves at the palmer surface of the distal phalanges. In the epidermis and dermis. Reversible atrophy in certain diseases e.g. dermatitis. Permanent impairment: leprosy& radiation. It is 100% accurate in establishing identity even between uniovular twins. Incidence: 1/64 billion. Identification of finger prints is made by similarity of more than16 comparison points. Sweat glands open on the surface of the ridges by pores. The size, shape, spacing, and their distribution is examined by poroscopy. Sir Henry Galton (1892), finger prints clasifieds into four types:- – Arch (6%) – Loop: – Radial (3%). – Ulnar (65%) – Whorls (25%) – Compound (1-2%).  Fingerprints, Palm, Foot And Lip Prints Foot Print (Sole print): Tracers can follow the pathway of the thieves or missed people by tracing their foot-print or shoes on the ground. MLI: identification through: congenital anomalies ( flat foot, extratoe ---). distance B/W 2 print: Height. impression in the anterior part: Running. Impression on one side: Carrying heavy object. Wearing shoes: pattern & its brand. Other types: iris, sound, lip, hard plate, ear, DNA.  Identification of the Dead Bodies I-Dead/ unmutilated corpse: same as living except in gait, voice, mentality and hand writing. II-Dead/ mutilated corpse: Presumptive identification: including visual, anthropometric, personal data (race, sex, age, blood grouping, hair color, eye color, tattoos) Positive identification: is a legal identification based on comparison of pre and postmortem information, including dental examination, fingerprints, palmprints, footprints or DNA profiling.  III- Identification of Decomposed/ Skeletalized Remains 1) Are the remains actually bone? 2) Are they human bone? By anatomical features, precipitin test (saline extract of the bone is examined against known antisera) 3) Do they belong to one person? 4) What is the Sex? 5) What is the Age? 6) What is the Height? 7) What is the Race? 8) How many time pass since death or concealed? 9) What is the cause of death?  Identification of Sex from Bones (after puberty)/ Skull Male Female General Big & heavy Small & light Parietal eminence Well marked Less marked Superciliary ridges Prominent Less prominent Frontonasal angle Angular Smooth curve Occipital condyles Long & narrow Short & broad Mastoid process Long& bulky Short& small Styloid process Long Short  Identification of Sex from Bones/ pelvis Male Female Subpubic angle Acute Obtuse Iliac crest High arched Less arched Sacrum Long, narrow & curved Short, wide & straight sacroiliac joint Occupies 3 segments Occupies 2 segment promontory projecting Not projecting Obturator foramen Oval Triangular Acetabulum Wide & deep Narrow& shallow Greater sciatic notch Deep& narrow Shallow& wide  Identification of Sex from Bones ❖ Sternum: Male Female General Long & broad Short & narrow Length of body body > 2X manubrium body < 2X manubrium  Identification of Age from Bones ❖ Skull: Dimensions. Fontanelles. Sutures. The mandible. Teeth. ❖ Appearance of ossification centers. ❖ Union of epiphyses. ❖ The extent of the medullary cavity.  Dimensions: in full term infants, the circumference is 13 inches, length is 5 inches, and width is 4 inches. Fontanelles: the posterior fontanelle is closed at full term while the anterior is 3 fingers at full term and closed at 18 months after birth (1finger every 6 months).  Sutures: ▪ frontal suture closed at 2years (30 years in Negroid). ▪ Sagittal suture closed at 25- 30 years. ▪ Coronal suture closed at 40 years. ▪ Lambdoid suture closed at 50 years. ▪ At 70 years all sutures are united except the suture between the parietal and temporal bones which closes at extreme old ages.  The mandible: the angle of the mandible is: ▪ Obtuse in infants (mental foramen is near lower margin). ▪ Right in adults ( mental foramen is midway). ▪ Obtuse in old age together with atrophied alveolar margin ( mental foramen is near alveolar margin). Milk dentition (temporary teeth = milk teeth): ▪ 20 in number (4 incisors, 2 canines, 4 molars, each jaw has 10 teeth). ▪ Start to erupt at six month and begin to shed at six years. Erupt in the following orders: ▪ The central incisors at 6th month. ▪ The lateral incisors at 9th month. ▪ The first molar teeth at 12th month. ▪ The canine teeth at 18th month. ▪ The second molar teeth at 24th month. ▪ Space behind the last molar 3 – 5 years. Permanent dentition: ▪ 32 teeth; 4 incisors, 2 canines, 4 premolars, 6 molars in each jaw. ▪ erupt from six year of age throughout life in the following orders: ▪ The first permanent molars at 6th year. ▪ The central incisors at 7th year. ▪ The lateral incisors at 8th year. ▪ The first pre-molars (bicusped) at 9th year. ▪ The second pre-molars (bicusped) at 10th year. ▪ The canine teeth at 11th year. ▪ The 2nd molars at 12th year. ▪ The 3rd molars (Wisdom tooth) at 18- 25th year.  Appearance of ossification centers ❖ During Intrauterine Life: ❖ O.C calcaneus at 5th month. ❖ O.C talus at the 7th month. ❖ Lower end of the femur at 8th month. ❖ The upper end of the tibia, the cuboid and the Lower end of the femur reaches 5mm in diameter at 9th month (full term). ❖ After Birth: ❖ The upper end of the humerus& femur at end of 1st yr. ❖ Lower end of the radius& tibia at end of 2nd yr. ❖ Upper end of the radius at end of 6th yrs. ❖ Lower radius 2/3 breadth at 7th yrs. ❖ Upper ulna at end of 12th yrs.  Union of epiphyses In the upper limb: – The humerus: The trochlea with capitulum at 14 yrs. Both bones with shaft at 15 yrs. Lateral epicondyle unite with shaft at 16 yrs. Medial epicondyle unite with shaft at 17 yrs. Head of the humerus unite with shaft at 20 yrs. – The ulna and radius: Upper end of ulna with shaft at 16 yrs. The upper end of radius with shaft at 17 yrs. The lower end of ulna & radius with shaft at 20 yrs. – The hand: The distal end of the metacarpal bones & phalanges unite with their shaft at 18 yrs.  Union of epiphyses In the lower limbs: – The femur: The lesser trochanter unites with shaft at 16 yrs. The greater trochanter unites with shaft at the 17 yrs. The head of the femur unites with shaft at 18 yrs. The lower end of the femur unites with shaft at 21 yrs. – The tibia and fibula: The lower ends of both unites with shaft at 18 yrs. The upper ends of both unites with shaft at 21 yrs. the clavicle: – The proximal (medial) end unites with shaft at 23 yrs.  Union of epiphyses The pelvis: – The pubic ramus unites with the ischial ramus at 6yrs. – The Y-shape suture at acetabulum close at puberty 14-15 yrs. – The iliac crest units with the iliac bone at 23 yrs. the sternum: _ The body unites with the xiphoid process at 40 years. _ The body unites with the manubrium at 60 years. The hyoid bone: _ The body unites with the greater cornu at 40 years  Miscellaneous Data:- Pubic hair. Voice. Scalp hair. Arcus senilis. White ring around the pupil along he margin of the cornea, usually seen after the age of 50 years. Cataract in the eyes. Wrinkles over the face. ❖ The ideal sites recommended for radiological study of ages of medico-legal importance: – Infancy and childhood; wrist and elbow. – Adolescence; pelvis, hips, shoulder and elbow joints. – Adulthood and old age; skull.  Height and Weight Data:- Age can be determined from tables according to heights and weight according to sex (♂- ♀). Identification of height height = span (between outstretched finger tips). From pearson’s formula: Femur =25% of the height. Humerus = 18% of the height.  The time passed since death: before 6 months: soft tissues are found on bones. 6 – 12 months: bones are attached by ligaments. after one year: bones only are present. bones get lighter, whiter, less smelly, and more brittle the more time passed.  Sex and Identity Sex is a very important aspect in determining identity. Medicolegal importance of sex identity: inheritance. marriage. intersex. Identification if dead. It is determined by: – Physical examination (in dead autopsy) – Gonadal biopsy. – Sex chromatin. – Other advanced methods.  In a dead body sex determination is achieved by: – Careful autopsy examination and dissection of internal genital system. – Skeletal examination the accuracy varies with the amount of bones present.  Sex Chromation:- – The x-chromosome in a female is seen microscopically in the form of chromatin condensation towards the nuclear membrane. – It is called sex chromation or Barr body. – Usually better seen in the cells of the buccal mucosa, cartilage, nerves, aminotic fluid, polymorphs and lymphocytes. – In a buccal smear to diagnose sex as female the smear should contain 20-30 percent Barr bodies at least, as 0-4 percent Barr bodies often detected in normal male. – The sex chromation can also be seen as Davidson body which is stalked drumstick projection of the polymorph nucleus attachment to one of the nuclear lobes, seen in peripheral blood smear. (diagnose as female). DNA Profiling:- Described by Dr. Alec Jeffreys a British geneticist DNA is so specific to the individual. DNA (Deoxyribo Nucleic Acid) has repetitive sequences of bases which are unique to each person.  Applications:- – Blood on a weapon – Hair roots in a blunt instrument – Seminal fluid from a vagina of raped victim – In paternity testing.  Samples:- – Semen – blood – hair – buccal smears – mouth scrubs – bone marrow The sample should be frozen solid at -20ºC.q  Medicolegal Application of DNA Typing 1. Personal identification. 2. Parentage testing. 3. Identification & match of body remains. 4. Identification of sex and species. Age