Forensic Medicine

Forensic Medicine (also called Legal Medicine or Medical Jurisprudence) is the branch of medicine that applies medical knowledge to legal issues.It is used primarily to: Help solve criminal cases Interpret injuries or deaths Assist courts with expert medical opinion

Blog Oct 3, 2025 1 272 Add to Reading List

"The use of medical and paramedical expertise to support the administration of justice is known as forensic medicine."

“It deals with the application of medical science in detecting and interpreting crime and civil wrongs involving the human body.”

Importance of Forensic Medicine

Purpose	Examples
Assist in solving unnatural deaths	Murder, suicide, accidents
Provide medical opinion in court	Injury analysis, age estimation
Detect sexual offences	Rape, molestation, child abuse
Conduct post-mortem (autopsy)	Determine cause, time, and manner of death
Deal with toxicology	Poisoning, alcohol influence
Handle medico-legal cases (MLC)	Assault, burns, drowning, gunshot wounds

Key Areas of Forensic Medicine

1. Medico-Legal Autopsy

In cases of suspicious or unusual deaths, a post-mortem examination is performed to ascertain the cause of death. carried out by forensic physicians rather than ordinary pathologists.

2. Injury and Wound Analysis

identifies homicidal, suicidal, and accidental injuries. classifies wounds, such as contused, lacerated, and incised.

3. Sexual Offences Examination

In cases of rape or sexual assault, the victim and the accused are examined medically. gathering of biological evidence, such as hair, saliva, sperm, etc.

4. Age Estimation

Age determination using secondary sexual traits, teeth, and bones is crucial in cases involving child marriage and juvenile justice.

5. Toxicology

Study of poisons and their effects on the human body. Includes alcohol, drugs, pesticides, snake venom, etc.

6. Death Investigation

identifies the cause of death, such as poisoning, strangling, or gunshot wounds. uses body temperature, decomposition, and rigor mortis to estimate the time since death.

7. Identification

Identification of unknown bodies using:
- Fingerprints
- Dental records
- DNA profiling
- Tattoo marks, scars, etc.

Role in Legal System

Forensic doctors provide expert testimony in court. Their opinion is often critical in:

Murder trials
Custodial death investigations
Dowry death cases
Medical negligence lawsuits

Legal basis (India)

Indian Evidence Act, Section 45 – allows medical experts to give opinion in court.
CrPC Sections 174 & 176 – deal with inquest and magistrate inquiry.

Who Practices Forensic Medicine?

Forensic pathologists
Medico-legal officers (MLOs)
Medical examiners
Toxicologists

They usually work in:

Government hospitals
Forensic Science Laboratories (FSLs)
Medical colleges (teaching + post-mortems)
Courts (as expert witnesses)

Causes of Death – Forensic Medicine Perspective

Asphyxial Death

Asphyxia refers to lack of oxygen in the body due to interference with breathing, leading to unconsciousness or death.

Types of Asphyxia

Type	Cause	Example
Hanging	Compression of neck by a ligature using body weight	Suicidal hanging
Strangulation	Manual or ligature compression of neck	Homicidal strangulation
Suffocation	Blockage of external airways	Smothering with a pillow
Drowning	Lungs filled with water, air exchange blocked	Accidental or suicidal drowning
Choking	Internal airway blocked	Food lodged in trachea
Burking	Combination of smothering + traumatic asphyxia	Seen in homicidal cases

Forensic Signs

Cyanosis (bluish skin)
Petechial hemorrhages (tiny blood spots in eyes/skin)
Congestion of face
Marks on neck (ligature or finger marks)
Froth in nose/mouth (in drowning)

Starvation

Death due to prolonged lack of food (caloric intake) and/or water, leading to failure of vital organs.

Duration

Death from acute starvation: 10–12 days (without water)
Chronic starvation: 6–8 weeks (with water but no food)

Forensic Features

Extreme weight loss, muscle wasting
Sunken eyes, dry skin, brittle hair
Empty stomach and intestines
Shrinkage of fat and internal organs
Bone marrow turns gelatinous

Causes

Neglect (child or elder abuse)
Imprisonment or torture
Mental illness (anorexia)
Fasting (extreme religious or political fasting)

Electrocution (Death by Electric Shock)

Death resulting from electric current passing through the body, disrupting vital functions.

Factors Affecting Severity

Voltage (high tension vs low tension)
Resistance of skin (wet or dry)
Path of current (hand to foot is fatal)
Duration of contact

Forensic Findings

Electric marks (Joule burn) at entry/exit points
Burning of internal tissues
Charring or explosive injuries (high voltage)
Cardiac arrhythmia or respiratory arrest
Metallization (in industrial exposure)

Types

Type	Description
Low voltage (<1000V)	Domestic accidents
High voltage (>1000V)	Industrial/electric pole injuries
Lightning	Natural electrocution (special burns like Lichtenberg figures)

Accidental Deaths

Unintentional deaths due to sudden external forces or hazardous environments.

Types of Accidental Deaths

Cause	Examples
Road traffic accidents (RTA)	Car, bike, pedestrian injuries
Falls	From height, stairs, construction sites
Fire/Burns	Domestic fires, workplace accidents
Poisoning	Industrial chemicals, gas leaks
Machinery accidents	Industrial equipment injuries
Animal attacks	Snakebite, dog attacks, wild animals

Forensic Considerations

Nature and pattern of injuries
Scene investigation
Alcohol or drug use
Use of seatbelts/helmets
Skid marks, vehicle speed estimation

Determination of Time Since Death (TSD)

Time since death refers to the interval between the moment of death and the time the body is discovered or examined. Estimating TSD is crucial in:

Criminal investigations (alibi verification)
Identification of the time of murder
Death certification

Methods for Estimating Time Since Death

A. External Physical Changes

Method	Onset	Duration/Significance
Algor Mortis (Body cooling)	Immediately after death	Body cools ~1.5°C/hr in temperate climate; unreliable after 24 hrs
Rigor Mortis (Muscle stiffening)	1–2 hrs after death	Fully developed by 6–12 hrs, passes off in 24–36 hrs
Livor Mortis / Hypostasis (Blood settling)	Starts within 30 min–2 hrs	Fixed after 6–8 hrs; helps indicate position of body after death
Putrefaction (Decomposition)	24–48 hrs	Depends on temperature, humidity, and environment
Adipocere formation	3–6 months (in moist environment)	Indicates death occurred weeks to months earlier
Mummification	Weeks to months	Occurs in hot and dry conditions

B. Internal Examination (Autopsy Findings)

Indicator	Observation
Stomach contents	Degree of digestion helps estimate time of last meal
Bladder	Fullness can suggest time since last urination
State of organs	Tissue autolysis or decomposition signs
Vitreous humour potassium level	Increases postmortem; useful up to ~100 hrs

C. Histopathological Methods

These involve microscopic examination of tissues to estimate time since death. They are useful when other methods are unreliable or in early postmortem interval (0–48 hrs).

Organs Commonly Examined

Liver
Heart
Lungs
Kidneys
Skin and muscles
Brain

Changes Observed Over Time

Organ	Histological Changes Postmortem	Time Frame
Heart	Loss of striations, nuclear changes in myocardial fibers	6–12 hrs
Liver	Cell swelling → vacuolation → disintegration of hepatic cords	6–24 hrs
Kidney	Tubular epithelial degeneration, nuclear fading	12–24 hrs
Lungs	Congestion, hemorrhage, alveolar collapse	6–12 hrs
Brain	Edema, neuronal shrinkage, nuclear disintegration	Starts at ~12 hrs
Skin	Loss of nuclei in epidermis, collagen breakdown	24–36 hrs
Muscles	Loss of cross-striations, fiber degeneration	Starts at 6–12 hrs

D. Chemical & Biochemical Methods

Method	Details	Useful Time Frame
Vitreous Potassium (K⁺)	Increases steadily after death	2–100 hrs
Hypoxanthine in eye fluid	Marker for oxygen deprivation	Up to 48 hrs
pH changes in CSF/blood	Becomes acidic postmortem	Early changes
Enzyme degradation (LDH, CK)	Follows predictable decline	<24 hrs

E. Entomological Evidence (For Long TSD)

Used in advanced decomposition stages:

Indicator	Use
Type of insects	Certain species arrive at specific decomposition stages
Life cycle stage	Eggs, larvae, pupae indicate time since colonization (postmortem interval)

Determination of Age of a Living Person

Age estimation in a living person is the process of determining a person's chronological age using physical, physiological, radiological, and dental examinations.

1. Radiological Examination (Skeletal Age)

Based on appearance and fusion of ossification centers in bones.

Age Group	Commonly Used Bones	Imaging Method
0–5 years	Skull, long bones, epiphysis appearance	X-ray
6–13 years	Elbow (CRITOE Rule: Capitellum → Olecranon)	X-ray elbow
14–18 years	Wrist, iliac crest, shoulder	X-ray wrist, pelvis
18–25 years	Clavicle, iliac crest fusion	X-ray shoulder, pelvis

2. Dental Examination (Dental Age)

Used in children and adolescents.

Parameter	Details
Eruption of milk/permanent teeth	Standard eruption timelines used (e.g., Gustafson’s chart)
X-ray of teeth (OPG)	Examines root and crown development
Wear and tear of teeth	Useful in adults, but less accurate

3. Secondary Sexual Characteristics

Based on Tanner staging (sexual maturity rating):

Feature	Approx. Age Range
Pubic and axillary hair	Begins around 11–13 years
Breast development (girls)	Starts ~10–12 years
Voice change, beard (boys)	13–15 years
Menarche (girls)	Typically 12–14 years

4. Histological and Biochemical Methods

(Not commonly used, more experimental or confirmatory.)

Method	Usefulness
Tooth cementum annulation	Age estimation by counting growth layers
Amino acid racemization (dentin)	Lab-based, useful in dead or teeth samples
Bone biopsy	Used in rare scientific cases