Forensic Medicine & Toxicology
High-yield MBBS Forensic Medicine & Toxicology question bank — medical jurisprudence, identification, thanatology, injuries, asphyxia, forensic sexology and toxicology, at Reddy’s / Parikh depth.
12chapters144questions77High-Yield
Definition
Rape is defined under Section 375 IPC as sexual intercourse by a man with a woman against her will or without her valid consent.
Legal Framework
- Section 375 IPC — definition; Section 376 IPC — punishment (minimum 10 years to life)
- Consent invalid if obtained by fear, fraud, impersonation, intoxication or unsoundness of mind
- Consent of a girl below 18 years is immaterial — statutory rape
- Criminal Law (Amendment) Act 2013 widened the definition beyond penile-vaginal penetration
- Section 164-A CrPC — medical examination must be done within 24 hours of receiving the information
- Two-finger test is prohibited by the Supreme Court; past sexual history is irrelevant
Medical Examination & Evidence
- Written informed consent of the victim (or guardian if under 12); female attendant present; examination without delay
- Never comment on ‘habituation to sex’ — only on findings
- Examine general injuries (struggle marks, bruises on thighs and breasts) and genital injuries
- Collect: clothing, pubic hair combings, vaginal, cervical and anal swabs, nail clippings, blood for DNA and alcohol, foreign material
- Laboratory: spermatozoa and acid phosphatase in swabs; DNA profiling is confirmatory
- Absence of injury does not exclude rape; the doctor gives an opinion on findings, the court decides the offence
Prompt examination and correct sampling preserve the crucial evidence. Sample Purpose Vaginal swab Spermatozoa, DNA Nail clippings Assailant DNA Clothing Stains, fibres Applied
- Treatment takes priority — injuries, emergency contraception, HIV and STI prophylaxis
- Maintain the chain of custody; hand samples to the police under seal
🔑KEY POINTS TO REMEMBER- Rape is defined in Section 375 IPC; consent below 18 years is immaterial.
- Section 164-A CrPC governs examination; the two-finger test is prohibited.
- Absence of injury does not exclude rape; DNA is the confirmatory evidence.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Virginity means a woman has never had sexual intercourse; defloration is the loss of virginity.
Signs of Virginity (unreliable)
- Intact hymen — the traditional but unreliable sign
- Labia firm and closely apposed; narrow vaginal orifice with rugosity
- Firm, hemispherical breasts with undilated ducts
- All signs are unreliable — the hymen may be ruptured by exercise, cycling, tampons, medical examination or masturbation
- Conversely a distensible (elastic) hymen may remain intact despite repeated intercourse
Signs of Recent Sexual Intercourse
- Freshly torn, bleeding, tender hymen with red margins
- Spermatozoa in the vagina — motile up to about 3–6 hours, non-motile up to 3 days; may be detected in the cervix up to a week
- Seminal stains on body and clothing — detected by ultraviolet fluorescence, acid phosphatase and Florence and Barberio tests
- Genital injuries, abrasions, bruising of the fourchette
- Sexually transmitted infection or pregnancy — signs of previous intercourse
- Absence of all signs does not exclude intercourse
Findings must be reported factually without any comment on chastity. Evidence Detection period Motile sperm 3–6 hours Non-motile sperm Up to 3 days Cervical sperm Up to a week Applied
- Never certify a woman as ‘virgin’ or ‘habituated to sex’ — professionally and legally improper
- The two-finger test is prohibited and has no scientific value
🔑KEY POINTS TO REMEMBER- An intact hymen is an unreliable indicator of virginity.
- Non-motile spermatozoa persist in the vagina up to 3 days, cervix up to a week.
- Doctors must report findings only, never opine on virginity or habituation.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Unnatural sexual offences are sexual acts considered against the order of nature, historically covered by Section 377 IPC.
Categories & Legal Position
- Sodomy — anal intercourse; bestiality — with an animal; buccal coitus
- Section 377 IPC — read down by the Supreme Court in Navtej Singh Johar (2018): consensual acts between adults in private are no longer an offence
- Section 377 still applies to non-consensual acts, acts with minors and bestiality
- Offences against children are covered by the POCSO Act
- Paraphilias: sadism, masochism, fetishism, voyeurism, exhibitionism, necrophilia, frotteurism
Examination Findings
- Passive agent (habitual) — funnel-shaped anus, loss of anal folds, lax sphincter, thickened skin
- Recent act — anal fissures, abrasions, bruising, tenderness, bleeding
- Collect anal swabs for spermatozoa, acid phosphatase and DNA
- Active agent — faecal matter, hair or lubricant on the penis; injuries to the penis
- Examine for sexually transmitted infection in both
- Same protocol as for rape — consent, requisition, chain of custody
The examination protocol is identical to that for other sexual offences. Party Findings Passive Anal fissures, lax sphincter Active Penile injury, faecal matter Applied
- Consensual adult acts in private are no longer criminal since 2018
- Never record moral judgements — document findings only
🔑KEY POINTS TO REMEMBER- Section 377 was read down in Navtej Singh Johar (2018) for consenting adults.
- It still applies to non-consensual acts, minors and bestiality.
- Findings: anal fissures in recent acts, funnel-shaped anus in habitual passive agents.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Abortion is the expulsion of the products of conception before viability; the MTP Act permits legal termination under specified conditions.
Signs of Pregnancy & Criminal Abortion
- Presumptive — amenorrhoea, nausea, breast changes; probable — uterine enlargement, Hegar and Goodell signs, positive hCG
- Positive — fetal heart sounds, fetal parts, ultrasound
- Criminal abortion — termination outside the MTP Act; punishable under Sections 312–316 IPC
- Methods used illegally cause haemorrhage, sepsis, uterine perforation, air embolism and shock — major causes of maternal death
- Autopsy in suspected criminal abortion: examine uterus and genital tract, preserve viscera, look for instrumentation injury
MTP Act Provisions
- MTP Act 1971, amended 2021
- Up to 20 weeks — opinion of one registered medical practitioner
- 20–24 weeks — opinion of two practitioners; for specified categories (survivors of rape, incest, minors, disability, change of marital status)
- Beyond 24 weeks — only for substantial fetal abnormality, on the approval of a Medical Board
- Grounds: risk to the woman’s life or physical/mental health, fetal abnormality, pregnancy from rape, contraceptive failure
- Consent of the woman alone (guardian if below 18 or mentally ill); confidentiality is mandatory
Gestational age determines how many opinions are required. Gestation Requirement Up to 20 weeks One doctor 20–24 weeks Two doctors Beyond 24 weeks Medical Board Applied
- Husband’s consent is NOT required
- Sex determination is prohibited under the PCPNDT Act
🔑KEY POINTS TO REMEMBER- MTP Act 1971 (amended 2021): one doctor up to 20 weeks, two for 20–24 weeks.
- Beyond 24 weeks only for substantial fetal abnormality, via a Medical Board.
- Only the woman’s consent is needed; confidentiality is mandatory.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Infanticide is the unlawful killing of a child under one year of age; in India it is dealt with as murder.
Establishing Live Birth & Viability
- Viability — capacity for independent existence, generally after 28 weeks (about 210 days)
- Signs of live birth — the crucial question
- Respiration — hydrostatic (lung float) test; lungs expanded, mottled, crepitant, margins rounded
- Changes in circulation — closure of foramen ovale and ductus arteriosus
- Gastrointestinal — air in stomach and intestines (Breslau’s second life test)
- Umbilical cord changes, caput succedaneum, vernix caseosa, meconium passage
Causes of Death & Legal Aspects
- Acts of commission — smothering, strangulation, drowning, head injury, poisoning, burial alive
- Acts of omission — failure to tie the cord, not clearing air passages, exposure, starvation, neglect
- Death may also be natural — prematurity, birth trauma, congenital anomaly
- Section 315 IPC — act preventing a child being born alive; Section 318 — concealment of birth
- Female infanticide and foeticide — major social problem; PCPNDT Act prohibits sex determination
- Examine the mother for signs of recent delivery
The sequence of questions — viable, live-born, cause — governs the whole examination. Question Method Viability Length, weight, ossification Live birth Hydrostatic test Age Cord, vernix, meconium Applied
- Live birth must be proved before a charge of infanticide can stand
- A stillborn child cannot be murdered — hence the central importance of the float test
🔑KEY POINTS TO REMEMBER- Infanticide is killing a child under one year; treated as murder in India.
- Viability is generally after 28 weeks; live birth proved by the hydrostatic test.
- Death may follow acts of commission or omission; Sections 315 and 318 IPC apply.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
The hymen is a thin fold of mucous membrane partially closing the vaginal orifice, of considerable but often overstated medicolegal importance.
Types & Normal Variation
- Annular, semilunar (crescentic), cribriform, septate, fimbriated, infantile
- Imperforate hymen — causes cryptomenorrhoea and haematocolpos at puberty
- Distensible (elastic, fimbriated) hymen — may remain intact despite repeated intercourse
- Considerable normal variation in shape and size
- Carunculae myrtiformes — tags remaining after childbirth
Rupture & Medicolegal Value
- Fresh tear — red, bleeding, swollen, tender margins; usually posterior or posterolateral
- Heals in 7–10 days leaving permanent notches or tags
- May be ruptured by cycling, athletics, tampons, masturbation, medical instrumentation, accident — not only by intercourse
- An intact hymen does not prove absence of intercourse, and a torn hymen does not prove intercourse
- Never certify virginity on the basis of the hymen
- The two-finger test is prohibited and has no diagnostic value
Findings must be described factually, never used to judge chastity. Finding Interpretation Fresh tear Recent penetration possible Old notch Past event, undatable Intact Does not exclude intercourse Applied
- Examine in the lithotomy position with good light and gentle traction
- Document with a diagram; avoid the word ‘virgin’ altogether
🔑KEY POINTS TO REMEMBER- Types include annular, semilunar, cribriform, septate and fimbriated.
- Rupture may follow many non-sexual causes; heals in 7–10 days.
- An intact hymen does not exclude intercourse — never certify virginity.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Impotence is the inability to perform sexual intercourse; sterility is the inability to produce children.
Impotence
- In the male — inability to achieve or sustain erection
- Causes: psychological (commonest), endocrine (diabetes, hypogonadism), neurological, vascular, drugs (antihypertensives, alcohol), local disease (hypospadias, Peyronie disease)
- In the female — vaginismus, atresia, rigid hymen, painful lesions, psychological aversion
- May be temporary or permanent, absolute or relative (quoad hanc — towards a particular person)
Sterility & Medicolegal Importance
- Male — azoospermia, oligospermia, obstruction, undescended testis, mumps orchitis, vasectomy, irradiation
- Female — tubal block, ovarian failure, uterine and endocrine causes, tuberculosis
- A person may be potent but sterile, or impotent but fertile
- Medicolegal relevance: nullity of marriage and divorce (impotence is a ground), disputed paternity, legitimacy, adoption and inheritance
- Also relevant in rape allegations (an impotent accused may still be capable of the offence as defined) and in compensation claims
- Examination: history, general and genital examination, semen analysis, hormonal studies
The two are independent — a man may have one without the other. Condition Meaning Impotence Cannot perform intercourse Sterility Cannot produce children Quoad hanc Impotent to one person only Applied
- Impotence is a ground for nullity of marriage, sterility generally is not
- Psychological causes account for most cases of male impotence
🔑KEY POINTS TO REMEMBER- Impotence is inability to perform intercourse; sterility is inability to procreate.
- A person may be potent but sterile, or impotent but fertile.
- Impotence is a ground for nullity of marriage; relevant to disputed paternity.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
The Medical Termination of Pregnancy Act, 1971 (amended 2021) legalises abortion in India under defined conditions, by registered practitioners at approved places.
Gestational Limits & Grounds
- Up to 20 weeks — opinion of one registered medical practitioner
- 20–24 weeks — opinion of two practitioners, for specified categories (survivors of rape or incest, minors, disability, widowhood or divorce during pregnancy)
- Beyond 24 weeks — only for substantial fetal abnormality, with approval of a State Medical Board
- Grounds: risk to the life of the woman, grave injury to her physical or mental health, substantial fetal abnormality
- Pregnancy from rape and failure of contraceptive (now for any woman, not only married) are presumed to cause grave mental injury
Requirements & Safeguards
- Performed by a registered medical practitioner with prescribed training
- At a government hospital or an approved place
- Consent of the woman alone; guardian’s consent if below 18 years or mentally ill
- Husband’s consent is NOT required
- Confidentiality of identity is mandatory — breach is punishable
- Records maintained in Form III; termination in good faith is protected from prosecution
The Act protects the doctor acting in good faith within its terms. Gestation Opinions needed Up to 20 weeks One 20–24 weeks Two >24 weeks Medical Board Applied
- Termination outside the Act is criminal abortion (Sections 312–316 IPC)
- The Act does not permit sex-selective abortion — PCPNDT Act applies
🔑KEY POINTS TO REMEMBER- One doctor up to 20 weeks; two for 20–24 weeks; Medical Board beyond 24 weeks.
- Only the woman’s consent is required — not the husband’s.
- Confidentiality is mandatory; termination outside the Act is criminal abortion.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
The hydrostatic (lung float) test determines whether a newborn breathed after birth, by testing whether the lungs float in water.
Principle & Technique
- Unexpanded (unrespired) lungs sink — specific gravity about 1.04–1.05
- Respired lungs float — specific gravity falls to about 0.94 after air entry
- Performed in four steps: whole thoracic block (with heart and thymus), then lungs together, then each lung separately, then small pieces
- Finally pieces are squeezed under water — escaping air bubbles confirm respiration
- Respired lung is pink, mottled, voluminous, crepitant with rounded margins
Fallacies
- False positive (floats though never breathed) — putrefaction gases, artificial respiration, ventilation
- False negative (sinks though breathed) — atelectasis, pneumonia, hyaline membrane disease, drowning of a live-born infant, feeble breathing
- Putrefaction is the commonest fallacy — the test is unreliable in decomposed bodies
- Must be corroborated by other signs of live birth — Breslau’s test (air in stomach), circulatory changes, histology of lung
- Never rely on the float test alone
Multiple steps and corroboration guard against the well-known fallacies. Result Interpretation Fallacy Floats Breathed Putrefaction Sinks Not breathed Atelectasis Applied
- Essential in alleged infanticide — proof of live birth is legally required
- Histology showing expanded alveoli is more reliable in doubtful cases
🔑KEY POINTS TO REMEMBER- Unrespired lungs sink (SG 1.04–1.05); respired lungs float (SG 0.94).
- Performed in four steps, ending with squeezing pieces under water.
- Putrefaction is the commonest fallacy — always corroborate with other tests.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Signs of recent delivery are the physical and physiological changes present in a woman who has recently given birth.
Immediate and Early Signs
- Breasts — enlarged, tender, colostrum then milk expressible; areola pigmented; Montgomery tubercles
- Abdomen — lax wall, striae gravidarum (pink and fresh if recent, silvery-white if old)
- Uterus — immediately after delivery at the umbilicus (about 1 kg); involutes to the pelvis by 2 weeks, near-normal by 6 weeks
- Lochia — rubra (red) 1–4 days, serosa (pale) 5–9 days, alba (white) 10–15 days
- Vulva swollen, perineal tears or episiotomy, lax vagina, carunculae myrtiformes
- Cervical os transversely slit (parous os)
Medicolegal Importance
- Establishing concealed pregnancy and delivery in suspected infanticide or criminal abortion
- Disputed maternity and cases of exchanged or stolen babies
- Claims relating to legitimacy and inheritance
- Cases of alleged feigned pregnancy or delivery
- DNA profiling settles maternity conclusively
- Signs are most reliable in the first 1–2 weeks and become unreliable later
Lochia and uterine size give the closest estimate of how recent the delivery was. Lochia Days Rubra (red) 1–4 Serosa (pale) 5–9 Alba (white) 10–15 Applied
- Examine the alleged mother whenever a newborn body is found
- DNA is conclusive where physical signs are equivocal
🔑KEY POINTS TO REMEMBER- Signs: breast changes, lax abdomen with fresh striae, involuting uterus, lochia.
- Lochia rubra 1–4 days, serosa 5–9 days, alba 10–15 days.
- Important in infanticide, concealed delivery and disputed maternity.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
The Protection of Children from Sexual Offences (POCSO) Act, 2012 is special legislation protecting children below 18 years from sexual offences.
Key Provisions
- ‘Child’ means any person below 18 years; the Act is gender-neutral
- Offences: penetrative sexual assault, aggravated penetrative sexual assault, sexual assault, sexual harassment, use of a child for pornography
- Consent of a child is irrelevant
- Mandatory reporting — failure to report is itself an offence (Section 21); applies to doctors
- Presumption of guilt — burden of proof lies on the accused
- Trial by Special Courts, in camera; identity of the child must not be disclosed
Duties of the Medical Officer
- Emergency medical care must be given without insisting on police requisition or legal formalities
- Examination within 24 hours; consent of the child’s parent or guardian
- A female child must be examined by a woman doctor, in the presence of a person the child trusts
- Collect samples as in the sexual assault kit; document injuries with diagrams
- Report to the police or Special Juvenile Police Unit — mandatory
- Avoid repeated examinations; child-friendly, non-judgemental approach
Treatment and reporting come before any legal formality. Feature POCSO Age Below 18 years Gender Neutral Reporting Mandatory Applied
- Failure to report is punishable with imprisonment — doctors are not exempt
- Never delay treatment for police formalities
🔑KEY POINTS TO REMEMBER- POCSO 2012 protects all children below 18 and is gender-neutral.
- Consent of a child is irrelevant; guilt is presumed against the accused.
- Reporting is mandatory for doctors; emergency care precedes legal formalities.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.Definition
Battered baby syndrome (Caffey-Kempe syndrome) is repeated non-accidental physical injury inflicted on a child, usually by a parent or caregiver.
Characteristic Findings
- Injuries of different ages — bruises in various stages of healing; the hallmark
- Discrepancy between the history and the injuries; changing or implausible explanations
- Delay in seeking medical attention
- Multiple fractures at different stages of healing; metaphyseal (bucket-handle and corner) fractures and posterior rib fractures are highly suggestive
- Shaken baby syndrome — subdural haematoma, retinal haemorrhages and encephalopathy without external injury
- Cigarette burns, immersion scalds with sharp margins, bite marks, torn frenulum
Risk Factors & Management
- Child: under 3 years, unwanted, disabled, premature, difficult to console
- Caregiver: young, immature parents, poverty, alcohol or drug abuse, mental illness, themselves abused as children, unrealistic expectations
- Full skeletal survey and fundus examination are essential
- Photograph all injuries; document meticulously
- Admit the child to ensure safety; report to Child Welfare Committee and police
- Covered by Juvenile Justice Act and POCSO where sexual abuse coexists
Injuries of differing ages with an inconsistent history is the key pattern. Finding Significance Differing-age bruises Repeated abuse Metaphyseal fracture Highly suggestive Retinal haemorrhage Shaking injury Applied
- Admission may be life-saving — abused children returned home are at risk of further injury
- Reporting is a legal duty, not a discretionary choice
🔑KEY POINTS TO REMEMBER- Battered baby syndrome is repeated non-accidental injury to a child.
- Hallmark is injuries of different ages with a history inconsistent with the findings.
- Metaphyseal fractures and retinal haemorrhages are highly suggestive; reporting is mandatory.
📚SOURCES: The Essentials of Forensic Medicine and Toxicology (K.S. Narayan Reddy); Textbook of Forensic Medicine and Toxicology (V.V. Pillay); Modi’s Textbook of Medical Jurisprudence and Toxicology.