FM4.1-5,FM14.{4,8} | Identification — Practice Quiz

Corpus delicti = 'body of the crime' — the material evidence proving a crime occurred. In murder, it includes proof of death, identity of deceased, and criminal agency, not just the physical body.

Corpus delicti: proof that a crime occurred. In suspicious death: (1) proof of death, (2) identity established, (3) criminal agency implicated. Absence of body does not prevent conviction if corpus delicti is established.

Corpus delicti is a legal concept meaning 'body of the crime,' not literally the physical body. It encompasses all material facts that prove the crime took place.

Pelvis is the most reliable single bone for sex determination: female has wider sub-pubic angle (> 90°, obtuse), broader sciatic notch, oval pelvic inlet, and wider sub-pubic arch compared to male.

Sex from skeleton: pelvis most reliable (sub-pubic angle: female > 90°, male < 90°); skull second (mastoid process, supra-orbital ridge, orbital shape); femur head diameter useful when pelvis absent.

Femur and skull show sexual dimorphism but with less reliability. Sternum is least reliable for sex. Pelvis has the highest accuracy (> 95%) because it is directly shaped by reproductive function.

Femur gives the most accurate stature estimate because it contributes the largest proportion of total stature and has the smallest standard error in regression formulae (Trotter and Gleser, Pearson, or Indian formulae).

Stature from bones: femur best, then tibia, fibula, humerus, radius, ulna. Use Indian regression formulae for Indian populations. Standard error ± 2.5–3.5 cm for femur.

All long bones can estimate stature, but femur has the highest correlation with total stature. Radius and fibula have larger standard errors. Use Indian-specific formulae (Rao, Kolte) for Indian populations.

Gustafson's six criteria: Attrition (A), Periodontosis (P), Secondary dentin (S), Cementum apposition (C), Root resorption (R), Root transparency (T). Enamel hypoplasia is not part of Gustafson's original method.

Gustafson's 6 criteria (AP SCRT): each scored 0-3, total 0-18. Age = regression formula on total score. Best for adults 20-70 years from a single tooth (canine preferred).

Enamel hypoplasia indicates childhood nutritional stress/illness but is not one of Gustafson's six age criteria. The mnemonic AP SCRT covers all six: Attrition, Periodontosis, Secondary dentine, Cementum, Root resorption, Root Transparency.

Third molar erupts between 17-25 years (wide variation), so its full eruption indicates adulthood (≥ 18) with limitations. Useful in medico-legal age assessment when documents are absent.

Third molar: erupts 17-25 years; full eruption suggests ≥ 18 years for legal purposes; impaction or agenesis is common. Use alongside other skeletal markers for age estimation in contested age cases.

Third molar eruption has high variability (17-25 years) and is absent in 25% of populations. It confirms adult age (≥ 17-18) when erupted but cannot give exact age. Exact calculation from root length is unreliable.

Reddy's Indian tables are specifically derived from Indian populations and account for earlier eruption patterns and nutritional differences. Schour/Massler and Gustafson were derived from Western populations.

Population-specific formulae are essential: use Reddy's Indian dental tables and Indian long-bone regression formulae (Rao, Kolte) — NOT Western charts — for Indian subjects. Systematic bias occurs otherwise.

Saunders-Risser staging is for skeletal (epiphyseal) age, not dental. Western dental charts overestimate age in Indians due to earlier eruption patterns. Use Reddy's or Kashyap-Koteswara Rao tables for Indians.

Iliac crest fuses at 20-21 years. This is medico-legally significant for determining if an individual has attained majority (18 years) or reached full skeletal maturity (~21 years).

Key epiphyseal fusion ages: femoral head ~18 years; iliac crest 20-21 years; medial clavicle 25-30 years (last to fuse). Medial clavicle is the best indicator for 25-30+ years.

Iliac crest appears as epiphysis at 13-15 years, begins fusing around 20 and is complete by 21 years. Not 15-16 (too early) or 25-26 (too late).

DNA profiling (STR — Short Tandem Repeat analysis) is the gold standard for personal identification, even with decomposed/skeletonised remains; it offers the highest discriminatory power (1 in billions).

Identification methods ranked: DNA (gold standard, works on bone/teeth) > fingerprints (requires skin) > dental records > radiological comparison > facial superimposition (presumptive).

Fingerprints are gold standard only when fingerprint skin is present (not skeletonised/decomposed). Facial superimposition and dental charting are complementary methods. DNA works on bone, teeth, and hair root.

Nasal index and degree of facial prognathism are most useful for racial determination from skull: Caucasoid (narrow nose, orthognathous), Negroid (wide nose, prognathous), Mongoloid (intermediate, flat malar).

Race from skull: Nasal index (Leptorrhine < 47 = Caucasoid; Platyrrhine > 53 = Negroid; Mesorrhine 47-53 = Mongoloid) + facial prognathism. Overlap between populations limits certainty.

Mastoid and orbital features are more useful for sex determination. Parietal bossing is developmental. Nasal index + prognathism are the key racial markers in forensic craniometry.

Facial superimposition is a presumptive method — it can support but not definitively establish identity in court. It is accepted as corroborative evidence but requires additional confirmatory evidence.

Identification hierarchy: positive (DNA, fingerprints, dental records) vs presumptive (superimposition, facial reconstruction, anthropological traits). Only positive methods are independently court-admissible.

Facial superimposition cannot stand alone as positive proof (unlike DNA or fingerprints). It is a scientifically valid but presumptive method accepted as supporting evidence in Indian courts.

The medial end of the clavicle is the last epiphysis to fuse (25-30 years), making it the only reliable skeletal marker for the 25-30 year age bracket when all other epiphyses have already fused.

Epiphyseal fusion sequence ends at medial clavicle (25-30 years). If all other epiphyses are fused but medial clavicle is still open → age 20-25 years. If fully fused → age > 25 years.

Femoral head fuses ~18; iliac crest ~20-21; distal femur ~18-19. All these fuse before 25. The medial clavicle epiphysis (25-30 years) is uniquely useful for late adult age estimation.

Adipocere (saponification of body fat into waxy material) preserves the external contours of the body — wounds, face, hands — for months to years, enabling identification and injury analysis.

Adipocere: conditions — warm + moist + anaerobic; time — 3-4 weeks minimum; significance — preserves shape for identification and wound analysis; also helps estimate post-mortem interval.

Adipocere actually aids identification by preserving features. It takes weeks to months to form (not 24 hours), and occurs in warm, moist, anaerobic environments, not in all buried bodies.