Skeletal Remains: Species, Sex, Age, Stature and Identification

The first rung is to confirm the fragment is bone, and then ask whether it is human. Gross examination is the start. Bone has a hard cortex, a cancellous interior and characteristic surface landmarks (linea aspera on the femur, intertrochanteric crest, nutrient foramina). Wood, plastic and shell get ruled out by weight, hardness, fracture pattern and the response to a hand lens. Burnt bone retains a recognisable trabecular pattern even when calcined and shrunk.

Once the fragment is confirmed as bone, the species question divides into human versus animal. Three lines of evidence run in parallel.

• Gross morphology. Adult human long bones have characteristic proportions and articular surfaces; the femur head and neck angle, the sigmoid notch of the ulna, and the obturator foramen of the pelvis carry quick recognition value. Veterinary skeletons (dog, sheep, goat, cow, pig) have distinctive condyle shapes and a horizontal axis of the spine.
• Histology. Cut a thin transverse section and read it under the microscope. Human compact bone shows Haversian (secondary osteon) remodelling throughout the cortex, with osteon diameters of roughly 200 to 300 micrometres and a fairly regular concentric pattern. Large mammals (cattle, horse, sheep, deer) also show Haversian remodelling but typically have plexiform (laminar) bone in the outer cortex, a brick-like pattern of alternating vascular layers that is absent in adult humans. Small mammals (rodent, rabbit) and birds have very thin cortices and largely lamellar non-Haversian bone. The combination of plexiform bone in the outer cortex and osteon size and density is the standard exam answer for human-versus-animal histology.
• Cortical thickness. Human long-bone cortex is typically 4 to 8 mm at midshaft; large quadruped long bones often have proportionally thicker cortices.

The molecular line is the precipitin (Uhlenhuth) test for species, originally applied to bloodstains and equally usable on bone-extract proteins. A saline extract of powdered bone is layered against anti-human, anti-cow, anti-dog and other species-specific antisera; a ring of precipitation identifies the species. Modern labs supplement precipitin with mtDNA cytochrome b sequencing for species ID.

The pelvis is the most reliable sex indicator in the human skeleton, with accuracies above 95 per cent when the bone is complete and adult. The reason is obstetric: the female pelvis is shaped to allow childbirth, the male pelvis is shaped for locomotion and load.

• Greater sciatic notch. Wide and shallow in females (greater than 60 degrees, often close to 90), narrow and deep in males (less than 45 degrees).
• Subpubic angle. Greater than 90 degrees in females, less than 90 (typically 60 to 70) degrees in males.
• Pelvic inlet and false (greater) pelvis. Wider and shallower in females; narrower and deeper in males.
• Obturator foramen. Triangular and small in females, oval and large in males.
• Pre-auricular sulcus. Present and well marked in females (a parturition trace), absent or faint in males.
• Ventral arc and subpubic concavity (Phenice traits, 1969). Present in females, absent in males; Phenice's three traits give over 95 per cent accuracy on the pubis alone.

The skull is the second-best indicator, with accuracies of about 80 to 90 per cent when complete. The exam-grade landmarks are five.

• Glabella and supraorbital ridges. Prominent in males, smooth and rounded in females.
• Mastoid process. Larger, longer and more rugged in males; smaller and smoother in females.
• Mental eminence (chin). Square and prominent in males, pointed and rounded in females.
• Frontal bone. Sloping and receding in males, vertical and rounded ("bossed") in females.
• Nuchal crest and external occipital protuberance. Rugged and projecting in males, smooth in females.

Long bones supplement the pelvis-and-skull verdict, especially when the cranium or pelvis is fragmentary. Femoral head diameter above about 47 mm is male, below about 43 mm is female (the indeterminate band runs between).

Age estimation runs across the whole life course and uses different bones at different stages. The exam-grade framework is in five age bands.

Fetal and infant. The number and location of primary ossification centres dates a fetus to within a few weeks. Most long-bone primary centres appear between the 7th and 12th week of intrauterine life; the calcaneus centre appears by the 5th to 6th lunar month and the talus by the 7th, classical landmarks taught from Krogman onwards. Crown-heel and crown-rump length and long-bone diaphyseal lengths give fetal age via standard tables (Olivier and Pineau, Fazekas and Kosa).

Childhood (1 to 12 years). Tooth eruption is the most powerful single criterion. Deciduous teeth erupt between 6 months (lower central incisor) and about 24 months (second molar). Permanent teeth erupt from 6 years (first molar and lower central incisor) onward, ending with the third molar (wisdom tooth) at 17 to 21 years. Epiphyseal appearance at named centres (head of humerus by 1 year, capitulum of radius by 4 years and similar) provides a parallel scale. Hand-wrist radiographs are read against the Greulich-Pyle or Tanner-Whitehouse atlases for skeletal age.

Adolescent and young adult (12 to 25 years). Epiphyseal fusion at named joints carries the bulk of the work. The clinically useful order, with approximate fusion ages in Indian populations:

• Elbow: 14 to 17 years (medial epicondyle last in the elbow, around 16 to 17).
• Hip: head of femur and greater trochanter fuse 16 to 19 years.
• Knee: distal femur and proximal tibia fuse 17 to 20 years.
• Ankle: distal tibia and fibula fuse 16 to 19 years.
• Shoulder: head of humerus fuses 19 to 22 years.
• Iliac crest fuses 20 to 23 years.

Stature is estimated from long-bone length using a linear regression equation of the form Stature (cm) = a + b × bone length (cm) ± standard error, with coefficients fitted on a population of known living height. Coefficients are population-specific and sex-specific, which is why so many Indian authors published their own formulae.

Trotter and Gleser (1952, 1958). The reference set for American Whites, Blacks (1952, World War II dead) and Mongoloids and Mexicans (1958, Korean War dead). Femur is the single most accurate bone, followed by tibia and fibula. Standard error for the femur is about ±3 to 4 cm. Trotter and Gleser later acknowledged a measurement error in their tibia values, an exam-grade limitation. Their formulae overestimate stature when applied to non-American populations and so should not be used uncorrected on Indian remains.

Pearson (1899). Older English-population regression, taught for historical context.

Indian regression formulae (the most testable list in this topic):

• Pan 1924. Bengali males and females, the oldest Indian skeletal-stature regression and a frequent MCQ name.
• Nat 1931. North Indians (Punjabi).
• Siddiqi and Kumar 1965. Uttar Pradesh.
• Athawale 1963. Maharashtrian, especially upper-limb formulae.
• Saxena 1984. North Indian, often-cited general-Indian regression.
• Mehta and Khanna. Punjabi and North Indian, used for tibia and humerus.
• Singh and Sohal 1952. Punjabi, foot-length based.

Approximate multipliers used as a quick-and-dirty estimate on Indian adults (commit to memory):

• Stature ≈ humerus length × 5.30 (male), × 5.43 (female).

The biological profile narrows the search list to "adult male, 25 to 35 years, 168 to 174 cm, Mongoloid features"; individual identification then matches that profile to one named missing person. Five lines of evidence run in parallel.

• Skeletal anomalies and variants. Wormian (sutural) bones in the lambdoid suture, metopic suture persistence, sacralisation of L5 (fifth lumbar fused to sacrum), lumbarisation of S1 (first sacral free), supernumerary ribs, bipartite patella, and any old healed fracture (callus, malunion) are individuating when antemortem records exist.
• Dental work. Restorations, root-canal treatments, crowns, bridges, implants and orthodontic brackets are highly individuating. The forensic odontologist compares the post-mortem dental chart against antemortem dental records; this is the cornerstone of mass-disaster identification.
• Surgical hardware. Orthopaedic plates, screws, intramedullary nails, hip and knee prostheses, pacemakers and cochlear implants carry serial numbers and manufacturer codes, traceable to the implanting hospital and patient. Post-2000 hardware is almost always traceable.
• Antemortem radiograph comparison. The frontal sinus pattern is unique to each adult and stable from late adolescence onwards; a single antemortem skull radiograph matched against a post-mortem radiograph is admissible identification (the classic Schuller 1921 method). Other comparable features include vertebral body shape, trabecular pattern of the hand, and old healed fracture lines.
• DNA from bone. Cortical bone (femur, tibia, petrous portion of the temporal bone) and teeth preserve nuclear DNA and mtDNA well, even after years of burial. The standard workflow is decontamination, mechanical milling to powder, EDTA decalcification and proteinase K digestion, organic or column extraction, STR profiling for nuclear DNA and HV1 and HV2 sequencing for mtDNA. The

Forensic anthropology in India sits across four institutional anchors. The AIIMS Delhi Department of Forensic Medicine and Anthropology runs the senior teaching unit and handles high-profile skeletal casework for Delhi NCR. The Anthropology Division at CFSL Kolkata is the oldest in the CFSL network and serves the eastern region; CFSL Chandigarh has a parallel division for the north. The National Forensic Sciences University (NFSU) Gandhinagar offers MSc and PhD programmes in forensic anthropology with dedicated osteology labs. The Anthropological Survey of India (AnSI), Kolkata (under the Ministry of Culture) holds the largest comparative skeletal collection in the country and publishes population-specific standards used by Indian examiners.

The legal frame for skeletal-remains casework now runs through the Bharatiya Nagarik Suraksha Sanhita (BNSS) 2023. Section 194 (inquest, formerly CrPC 174) directs the investigating officer to draw up an inquest report and forward the body or remains for medical examination. Section 196 (formerly CrPC 176) authorises the magistrate's inquiry into the cause of death. The medical examiner's opinion on sex, age, stature and cause of death enters evidence under BSA 2023 Section 39 (expert opinion). Postgraduate teaching standards rest on Krogman and Iscan, The Human Skeleton in Forensic Medicine (the field standard), Burns, Forensic Anthropology Training Manual (laboratory protocols), and Indian texts including Modi's Medical Jurisprudence and Toxicology.