Forensic Medicine & Toxicology – A comprehensive study -1

Dr  Sanil Kumar BHMS MD(Hom)
Department of Forensic Medicine & Toxicology
Govt Homeopathic Medical College. Calicut
Email : drsakumkumar@yahoo.co.in

The general public is fast becoming law conscious and the doctors are being sued from time to time in a Court of law for their acts of omission or commission. Therefore, it is incumbent upon doctors must  have a good knowledge of the law governing their profession, in order not to transgress the law.

History: The Code of Hammurabi, King of Babylon (about 4000 to 3000 B.C) is the oldest known medico-legal code. The first medico-legal autopsy was done in Bologna (Italy) in 1302, by Bartolomeo De Varignana. The first book on Forensic Medicine was published in 1602 by an Italian physician, Fortunato Fedele. Orfila (professor of chemistry and legal medicine at Paris) is considered the founder of modern toxicology. Paulus Zacchias — written “medico-legal questions”, questions Medico legalis.”

a. In the 18th century, study in legal Medicine as a subject was established by appointing professorship in Germany.
b. In England Mc Naughten’s (who was aschizophrenic) rule has been established to deal with legal matters in cases of insanity or like situations whatsoever

Forensic medicine: is the application of medical and paramedical knowledge in the administration of law and justice. Legal medicine and state medicine are other names for it.

Medical jurisprudence: deals with the legal rights, privileges, duties and obligations of medical practitioner.

LEGAL PROCEDUREInquest: is the legal or judicial inquiry to ascertain matter or fact. (Cr.P.C. 174)
It is the investigation into the cause of death. It is conducted in cases of murder, suicide, accidents and suspicious deaths.
1) Police inquest: done by the Officer-in-charge of the police station (S.174, Cr.P.C). Medico-legal autopsy is ordinarily done on requisition of the sub-inspector of police. The inquest report is signed by the police officer and two witnesses.
2) Coroner’s inquest: in Bombay till 1999. Coroner’s court is a court of enquiry and not of trial.
3) Magistrate’s inquest: done by an Executive Magistrate (Collector, Deputy collector, Tahsildar, etc) in cases of death in police custody, death due to police firing, death in prison, dowry death & exhumation (S.176, Cr.P.C).

Courts of law: Criminal and Civil.

1. Supreme Court: is the highest court and has power of supervision over all courts of law. It is purely an appellate court. A supreme court Judge can pass any sentence authorized by law.
2. High Court: highest court for state. It may try any case and pass any sentence authorized by law.
3. Sessions Court: can pass any sentence authorized by law, but a death sentence passed by it must be confirmed by the High court (S.366, Cr.P.C). An Assistant Sessions court can pass a sentence of imprisonment up to 10 years.
4. Magistrate Courts are of 3 types:

a) Chief Judicial Magistrate: can pass a sentence of imprisonment up to 7 years and any amount of fine.
b) I Class Judicial Magistrate: can pass a sentence of imprisonment up to 3 years and fine up to 5000 rupees.
c) II Class Judicial Magistrate: can pass a sentence of imprisonment up to 1 year and fine up to 1000 rupees.

Offence may be Cognisable or non-cognisable.
Cognisable offence: It is an offence in which a police officer can arrest a person without warrant from the Magistrate, e.g., rape, murder, robbery, etc.

The common punishments allowed by law awarded are:
(i) Death (hanged by neck till death)
(ii) Imprisonment for life. (Max. up to 20 years)
(iii) Imprisonment of sometime but less severe than life imprisonment. This may be the form of simple or rigorous imprisonment.
(iv) Monetary fine (Sec.53, I.P.C)
(v) Detentions in reformatories. DRC

The death sentence can be commuted by the President of India (on mercy appeal), by Supreme Court of India (on appeal or by the High Court by merits).

Subpoena or Summons: is a written document issued by the court and served on the witness under a penalty in all cases by the Police officer to attend the court for giving evidence on a particular day and time (S.174, I.P.C; S. 87, Cr.P.C). It may be served from a criminal or civil court. The witness will be excused from attending the court, if he has a valid and urgent reason. If the witness fails to attend the Court: (1) in a civil case, he will be liable to pay damages, and (2) in a criminal case, to fine or imprisonment (S. 172, I.P.C).

Conduct money is fee paid to a witness at the time of serving the summons to cover the expenses for attending the court. Given only in civil cases. In no case the medical practitioner should insist on conduct money when he receives a subpoena from Criminal court because he is liable to be charged with contempt of court.

Perjury means giving willful false evidence while under oath, or failure to tell what he knows or believes to be true (S.191, I.P.C). The witness is liable to be prosecuted for perjury, and the imprisonment may extend to 7 years (S. 193, I.P.C).

Record of evidence: (S. 137, I.E.A)
(1) Oath
(2) Examination-in-chief (direct examination)
This is the first examination of a witness and consists of questions put to him by the lawyer (counsel or advocate) for the side which has summoned him. In government prosecution cases, the public prosecutor first examines the witness. Leading questions are not allowed except when the witness is hostile.
(3) Cross-examination
In this, the witness is questioned by the lawyer for the opposite party, i.e., lawyer for the accused (defense lawyer). Leading questions are allowed. The court has the power to disallow questions which are intended to insult or annoy or offensive in form (S. 152, I.E.A)
(4) Re-examination (Re-direct examination) (S. 137, I.E.A)
This is conducted by the lawyer for the side which has called the witness. The opposite lawyer has the right of re-cross examination on the new point raised. Leading questions are not allowed.
(5) Questions by judge
The court is also empowered (S. 311, Cr.P.C), to recall and reexamine any witness already examined, if his evidence appears to the Court to be essential to the just decision of the Court. The judge may ask any questions at any stage of the examinations to clear up doubts.

Medical evidence: Evidence means all legal means, which help to prove or disprove any matter in question.
Types: Oral, Documentary, Direct, Indirect or circumstantial, Hearsay

A. Documentary evidence. 3 types: MC, DC, Dying declaration.
1. Medical certificate: it refers to ill-health, insanity, death, etc. they are accepted in a Court of law, only when they are issued by a qualified RMP. A medical practitioner is legally bound to give a death certificate, stating the cause of death without charging fee, if a person whom he has been attending during his last illness dies (Registration of Birth and Deaths Act, 1970). The certificate should not be given if the doctor is not sure of the cause of death, or if there is the least suspicion of foul play. In such cases, the matter should be reported to the police. Issuing or signing a false certificate is punishable under S. 197, I.P.C.
Death certificate: In India, the International Statistical Classification of Death,
Injuries and Causes of Death is used.

2. Medico-legal reports: are reports prepared by a doctor on the request of the investigating officer for his guidance, usually in criminal cases, e.g., assault, rape, murder, poisoning, etc. These are admitted as evidence in court only when the doctor gives oral evidence on oath.

3. Dying declaration: It is a written or oral statement of a person, who is dying as a result of some unlawful act, relating to the material facts of cause of his death or bearing on the circumstances. A magistrate should be called to record the declaration. If the patient’s condition is serious, and there is no time to call a Magistrate, the doctor should take the declaration in the presence of two witnesses. The person need not take oath, because of the belief that a dying person tells the truth. Leading questions should not be asked. It should be read over to the declarant, and his signature or thumb impression is taken. The doctor and the witness should also sign the declaration. If the declarant survives, the declaration is not admitted, and the person is called to give oral evidence.

4. Dying deposition is a statement of a person on oath, recorded by a Magistrate in the presence of the accused or his lawyer, who is allowed to cross-examine the witness. It has greater value than dying declaration bcoz the accused has an opportunity of cross-examining the dying person. Not followed in India.

B. Oral evidence: it includes all statements which the Court permits, or which are required to be made before it by the witness, in relation to matters of facts under enquiry (S. 60, I.E.A). it must be evidence of a person who saw, heard or percieved it by that sense or in that manner. Oral evidence is more important than documentary evidence, as it permits cross-examination.
Exceptions to oral evidence:
(1) Dying declaration (S. 32 & 157, I.E.A)
(2) Expert opinion expressed in treatise (S. 60, I.E.A)
(3) Evidence of a doctor recorded in a lower Court (S. 291, I.E.A)
(4) Evidence of a witness in a previous judicial proceeding (S. 33, I.E.A)
(5) Reports of certain govt. scientific experts: Chemical examiner, Chief Inspector of Explosives, Director of Finger Print Bureau, Director of CFSL or SFSL, Director of Haffkine institute, Bombay and Serologist to the Govt. (S. 293, Cr. P.C)
(6) Public records, E.g., Birth and death, certificates of marriage.
(7) Hospital records: Routine entries are admissible without oral evidence.

Types of Witness
Common and Expert.
Common witness: (witness of fact; occurrence witness) is a person who gives evidence about the facts observed or percieved by him. “ First hand knowledge rule”

Expert witness: is a person who has been skilled in technical or scientific subject, and capable of drawing opinions and conclusions from the facts observed by himself, or noticed by others, e.g., doctor, firearms expert, finger prints expert, hand-writing expert, etc (S.45, I.E.A)
Hostile witness: is one who is supposed to have some interest or motive for concealing part of the truth, or for giving completely false evidence (S.191, I.P.C)

MEDICAL LAW AND ETHICS
The medical profession is governed by legislation and by a Code of ethics and Etiquette. Medical ethics deals with the moral principles which should guide members of the medical profession in their dealings with each other, their patients and state. Enforcement of the code is done by the medical councils. (CCH).

Central Council of Homoeopathy Act, 1973. (19th December, 1973)
Amendment vide Homoeopathy Central Council of Amendment Act, 2002. Gazette of 9th December, 2002.
Schedule I: No: of elected members from each state.
(a) No: of RMP exceeds 100 – not exceeding 10000 = 1 seat
(b) No: of RMP exceeds 10000 – not exceeding 20000 = 2 seats
(c) No: of RMP exceeds 20000 – not exceeding 30000 = 3 seats
(d) No: of RMP exceeds 30000 – not exceeding 40000 = 4 seats
(e) More than 40000 RMP = 5 seats.

Schedule II: Recognized medical qualifications granted by Universities, Board or Medical Institutions in India.
Schedule III: Qualifications granted by medical institutions outside India.

Functions:
1. Medical Register: the council maintains a register of medical practitioners who are enrolled on any State Medical Register.
2. Medical Education:
3. Recognition of foreign medical qualifications
4. Appeal against disciplinary action
5. Warning notice for serious misconduct.

Serious professional misconduct: (Infamous conduct in professional respect)
It is any conduct of the doctor which might reasonably be regarded as disgraceful or dishonourable. The conduct of the doctor is judged by professional men of good repute and competence. The main cause for penal erasure is serious professional misconduct. It deprives the doctor of all the privileges of a registered practitioner.

Warning notice
The following are some of the offences contained in the warning notice:-
1. Adultery (voluntary sexual intercourse between a married person, and a person married or not, other than his or her spouse)
2. Conviction by a court of law
3. Issuing false certificates
4. Performing criminal abortions or illegal operations
5. Dichotomy or fee splitting, i.e., receiving or giving commission to a professional colleague or a manufacturer or trader in drugs or appliances, or a dentist, chemist etc.
6. Covering, i.e., assisting some person who has no medical qualification to attend, treat or perform an operation on some person.
7. Advertisement – Repeated advertisement in a newspaper by a medical practitioner is an example of ethical negligence.
8. Using touts or agents for procuring patients.

Duties of Medical Practitioners
A. Doctor should:
1. Exercise reasonable degree of skill and knowledge
2. Attend a patient as long as he requires treatment
3. Prescribe or furnish suitable medicines
4. Warn patients of the dangers involved in the use of a prescribed drug or device
5. Inform patient of risk
6. Notify communicable diseases to the health authorities.
7. Maintain professional secrecy.

Privileged communication: It is a statement made bonafide upon any subject matter by a doctor to the concerned authority, due to his duty to protect the interests of the community or of the State.

Examples of privileged communication
1. A syphilitic taking bath in public pool
2. Engine or bus driver found to be colour blind
3. A person with infectious diseases working as a cook.
4. A doctor’s duty is to notify birth, death, infectious disease to public health authority.

Professional negligence (Malpraxis)
It is defined as absence of reasonable care and skill, or willful negligence of a medical practitioner in the treatment of a patient, which causes bodily injury or death of the patient. Negligence is defined as doing something that is not supposed to do, or failing to do something that one is supposed to do.

Medical negligence falls under following section – sec. 304 A, IPC 312, Indian contract act. (except – IPC 351.)
I. Civil negligence: Liability for negligence arises if the following conditions are satisfied:
a) Duty – Existence of a duty of care by the doctor
b) Dereliction – Failure of the doctor to maintain care and skill
c) Direct causation – The failure to exercise a duty of care must lead to damage
d) Damage – the damage which results must be reasonable anticipated.
A civil wrong is known as – ‘Tort”

The doctrine of res ipsa loquitor: It means the thing or fact speaks for itself.

Novus actus interveniens: It means an unrelated action intervening. A person is responsible for his actions and also for its consequences. This principle applies to cases of assault and accidental injury. If the doctor is negligent, which results from the logical consequence of events, then the responsibility for the subsequent disability or death may pass from the original incident to the later negligent action of the doctor by the principle of “novus actus interveniens”.

II. Criminal negligence: (Sec. 304A IPC). It occurs when the doctor shows lack of competency, gross inattention, criminal indifference to the patient’s safety, or gross negligence in the selection and application of remedies. It is practically limited to cases in which the patient has died. The doctor may be prosecuted by the police and charged in criminal court with having caused the death of the patient by a rash or negligent act not amounting to culpable homicide. The doctor can be punished with imprisonment up to 2 years, or with fine, or with both.

Contributory negligence: It is any reasonable conduct or absence of ordinary care on the part of the patient, or his personal attendant, which combined with the doctor’s negligence.

Therapeutic misadventure: It is a case in which an individual has been injured or had died due to some unintentional act by a doctor or agent of the doctor or hospital.
It may be subdivided into:
1) Therapeutic (when treatment is being given)
2) Diagnostic (where diagnosis only is the objective at the time)
3) Experimental (where the patient has agreed to serve as a subject in an experimental study).

Vicarious liability: (liability for act of another) An employer is responsible not only for his own negligence but also for the negligence of his employees, if such acts occur in the course of the employment and within its scope, by the principle of respondent superior (let the master answer).

Euthanasia (Mercy killing): It means producing painless death of a person suffering from hopelessly incurable and painful disease. It has no legal sanction in India.

Consent: means voluntary agreement, compliance or permission.
It may be: (i) Express (verbal or written) or (ii) Implied.

Reasons for obtaining consent:
(i) To examine, treat or operate upon a patient without consent is assault in law.
(ii) If there is no informed consent the doctor may be charged for negligence.

Rules for consent:
1. Oral consent should be obtained in the presence of a third party, e.g., nurse.
2. Written consent should be taken for court presentation.
3. The consent should be free, voluntary, clear, intelligent, informed, direct, and personal.
4. In medico-legal cases such as rape, pregnancy, delivery, abortion the woman should not be examined without her consent.
5. In case of a female, the examination should be made only by a or under the supervision of a female medical practitioner (S. 53, IPC)
6. An arrested person at his request may be examined by a doctor to detect evidence in his favour (S.54, IPC)
7. A person above 18 years can give consent to suffer any harm, which may result from an act not intended or not known to cause death or grievous hurt (Sec. 87, IPC).
8. A person can give valid consent to suffer any harm which may result from an act, not intended or not known to cause death, done in good faith and for its benefit (S.88 IPC)
9. Consent is not a defense in cases of professional negligence.
10. A child under 12 years cannot give valid consent to suffer any harm which may result from an act done in good faith and for its benefit. The consent of parent or guardian is taken (S. 89, IPC)

Malingering or shamming means conscious, planned feigning or pretending a disease for the sake of gain. Malingering can be diagnosed by keeping the patient under observation and watching him without his knowledge.

Consumer Protection Act (COPRA) passed on 1986, came into force in 1987.

IDENTIFICATION
Identification is the determination of the individuality of a person based on certain physical characteristics, i.e., exact fixation of personality.

Corpus delicti: (body of offence, essence of crime) means, the elements of any criminal offence. E.g., murder. The main part of corpus delicti is the establishment of identity of the dead body, and infliction of violence in a particular way, at a particular time and place, by the person or persons charged with the crime and none other.

Race: It can be determined by complexion, colour of eyes, hair, clothes and skeleton.
Cephalic index = Maximum breadth of skull / Maximum length of skull x 100.
It divides skull into (DOMBA)
1. Dolico-cephalic (long-headed) C.I. 70 to 85 – seen in pure Aryans, Aborigines and Negroes.
2. Mesati-cephalic (medium-headed) C.I. 75 to 80 – seen in Europeans and Chinese.
3. Brachy-cephalic (short-headed) C.I. 80 to 85 – seen in Mongolisms (Max C.I)

Sex: It has to be determined in cases of (1) Heirship, (2) Marriage, (3) Divorce, (4) Legitimacy, (5) Impotence, (6) Rape, etc.

Sex chromatin: is a small plano-convex mass, lying near nuclear membrane (Barr body).
Accuracy of sex determination from pelvis and skull is 98%. Barr body was first demonstrated by Dixon and Tarr. In buccal smear, barr body is present in 20 to 80 % of cells in the female (more than 25% cells are determined) and 0 to 4% in males. Buccal smear is used in determination of sex. Examination of blood is used in determination of sex. Neutrophil leucocytes contain a small nuclear appendage of drumstick form (Davidson body – help in sexing) in upto 6% of cells in the female but is absent in males.
Sex of a developing foetus can be determined at the end of 4th month of I.U life.

Intersex: It is an intermingling in one individual of characters of both sexes, in varying degrees, including physical form, reproductive organs and sexual behaviour. It results from some defect in the embryonic development.
It can be divided into four groups:
1) Gonadal agenesis – In this the testes or ovaries have never developed. The nuclear sex is negative.
2) Gonadal dysgenesis – External sexual structures are present, but at puberty the testes or ovaries fail to develop.
a) Klinefelter syndrome – The anatomical structure is male but the nuclear sexing is female. Sex chromosome is XXY (47 chromosomes). There is delay in onset of puberty, behavioral disorders and mental retardation. Small testis, infertility, gynaecomastia, azoospermia. Increased urinary gonadotropins.
b) Turner’s syndrome – The anatomical structure is female but the nuclear sexing is male. The sex chromosome pattern is XO (45 chromosomes). Earliest feature in newborn girl is oedema of hands and feet and loose nuchal folds. Other features – short stature, webbed neck – shield chest, renal defects – horse shoe kidney and duplication of renal pelvis, cardio-vascular defect – co-arctation of pelvis, skeletal disorder – cubitus vulgus, gonodal streaks – seen in turner’s syndrome, mental status – normal.
3) True hermaphroditism – In this an ovary and testis or two ovotestis are present within the external genitalia of both sexes.
4) Pseudo-hermaphroditism – Internally gonadal tissue of only one sex is seen, but external appearance is of the opposite sex.
a) Male pseudohermaphroditism: Nuclear sex is XY, but sex organs and sexual characteristics deviate to female form, because of testicular feminisation.
b) Female pseudohermaphroditism: Nuclear sex is XX, but deviation of sex organs and sexual characteristics towards male are seen, due to adrenal hyperplasia.
Skeleton: Recognizable sex differences do not appear until puberty except in pelvis, and the accuracy from this bone is about 75 to 80%. The determination of sex is based mainly upon the appearance of the pelvis, skull, sternum and the long bones.

AGE
Age can be determined from teeth, ossification of bones, secondary sexual characteristics, and general development in case of children.

1. Teeth: Teeth are useful for age determination (a) by the stage of development, and (b) by secondary changes.
Temporary teeth: these are 20 in number – 4 incisors, 2 canines, 4 molars in each jaw.
In ill-nourished children and in rickets, dentition may be delayed. In syphilis, dentition appears premature or even present at birth. Eruption of temporary teeth is for 2 – 2½ years. The temporary teeth begin to fall at about the sixth or seventh year after the eruption of first permanent molar. In children mixed dentition remains at 6 – 12 years of age.
Age 9: 12 permanent teeth, 8 I, and 4 1st molars + deciduous molars and canines.
Age 11: 20 permanent teeth, 8 I, 8 Pm and 4 M.
Age 14: 28 permanent teeth, and no deciduous teeth.
Permanent teeth are 32 in number: 4 incisors, 2 canines, 4 premolars, and 6 molars in each jaw.
Developmentally, teeth are divided into two sets:
(1) Superadded permanent teeth: Are those which do not have deciduous predecessors. (all permanent molars, 6 in each row)
(2) Successional permanent teeth: are those which erupt in place of deciduous teeth. (Permanent premolars in place of deciduous molars, 10 in each row).
Temporary teeth eruption (in months) – Total 20.
Eruption of permanent teeth (in years) – Total 32.

Gustafson’s method – The age estimation of adult over 21 years 9between 25 – 60 years) depends on the physiological age changes in each of the dental tissues such as attrition, pqaradentosis, secondary dentin, cementum apposition, root resorption, transparency of the root (The most reliable criteria).

2. Growth of individual bones:
The bones of skeleton are performed in hyaline cartilage. The earliest centres of ossification appear at the end of second months of pregnancy. At the eleventh intrauterine week, there are 806 centres of bone growth, at birth about 450, while the adult skeleton has 206 bones. Tarsus and carpus bones ossify from a single centre. Typically, a long bone such as tibia, has become ossified throughout its shaft (diaphysis) at birth; whereas its two ends (epiphysis) are later ossified by secondary centres. The process of union of epiphysis and diaphysis is called fusion. In an individual bone once union has begun, it will be completed by 12 to 18 months.

For determining the age, skiagrams of the shoulder, elbow, wrist, hip, knees, ankle, pelvis and skull, should be taken in antero-posterior position. Union of epiphysis in cartilaginous bones occurs slightly earlier by about 1 year in the female than in the male, but reverse is seen in the closure of the sutures of the skull.
The symphysis pubis is probably the single best criterion for determining age from third to fifth decades. If male criterion is used for females, the age would be underestimated by about 10 years.

Sternum: Four pieces of body of the sternum fuses with one another from below upwards between 14 and 25 years. At about 40 years the xiphoid unites with the body. The manubrium fuses with the body in old age.

The greater cornu of the hyoid bone unites with the body between 40 and 60 years.
Skull: Bones of calvaria are 8 in number: parietal 2, frontal 1, temporal 2, occipital 1.
Bones of the face and jaw are 14 in number: maxilla 2, zygomatic 2, nasal 2, lacrimal 2, palatine 2, inferior nasal concha 2, mandible 1, and vomer 1. Lateral and occipital fontanelles usually close within the first two months. The anterior fontanelles and the two halves of the mandible unite at the second year. The basioccipital fuses with the basisphenoid at about 18 to 21 years. In the vault of the skull, closure of the sutures begins on the inner side 5 to 10 years earlier than on the outer side. Closure of all sutures indicates age more than 60 years. Suture closure in skull occurs later in females than in males.
Sacrum: the sacrum becomes a single bone between 21 and 25 years.

3. Secondary sexual characters:
In males:
(i) At about 14 years – fine hair begins to appear at pubis.
Testes – large, firmer.
Penis – begins to enlarge.
(ii) At about 15 years – pubic hair thick, extends upto umbilicus, dark
– axillary hair appears.
(iii) At about 16 years – appearance of hair at face.
(iv) Between 16 – 18 years – voice becomes deep.
In females:
(i) At 13 – 14 years – Sequence of puberty is (i) breast begins to develop (ii)
hair on mons veneris (iii) menstruation starts.
(ii) At 14 – 15 years – Female public hair thin; straight tops above mons veneris;
hair appears in axilla.

Doctor’s estimation of age is not proof but merely an opinion.

Medico-legal importance of age:
1) Criminal responsibility: Any act done by a child under 7 years is not an offence (S. 82, IPC). It is an offence if done before 7 years according to Railways act. A child between 7 and 12 years is presumed to be capable of committing an offence, if he attains sufficient maturity (S. 83, IPC).

2) Judicial punishment: According to the Juvenile Justice Act, 1986, “juvenile” means a boy who is below the age of 16 years, or a girl who is below 18 years. No delinquent juvenile shall be sentenced to death or imprisonment.

3) Rape: Sexual intercourse by a man with a girl under 15 years even if she is his own wife, or with any other girl under 16 years even with her consent is rape (S. 375, IPC)

4) Kidnapping: It is an offence
(a) to kidnap a child with the intention of taking dishonestly any movable property, if the age of child is under 10 years (S. 369, IPC)
(b) to kidnap a minor from lawful guardianship if the age of a boy is under 16 and that of a girl under 18 years (S. 361, IPC)
(c) to procure a girl for prostitution, if her age is under 18 years (S. 366-A, IPC), and
(d) to import into India from a foreign country a female for the purpose of illicit intercourse, if her age is less than 21 years (S. 366-B, IPC).

5) Employment: A child below 14 years cannot be employed to work in any factory or mine or in any other risky employment. A person completing 15 years (adolescent) is allowed to work in a factory as an adult.
6) Attainment of majority: A person attains majority on the completion of 18 years. (S. 3, Ind. Majority Act, 1875)
7) Evidence: A child of any age can give evidence if the court is satisfied that the child is truthful (S. 118, IEA)
8) Marriage contract: A female under 18 years and a male under 21 years, cannot contract marriage (Child marriage restraint act, 1978)
9) Infanticide: The charge of infanticide cannot be supported, if the infant can be proved under the age of 6 months of intra-uterine life.
10) Criminal abortion: A woman who has passed the child-bearing age cannot be charged of procuring criminal abortion.

Rule of Haase: A rough method of calculating the age of the foetus.
(1) Upto 5 months, age of foetus = √length (in months)
(2) › 5 months = length (in cm)/ 5 = (months).
Length of an infant: At birth = 50 cm, end of 6 months = 60 cm, end of 1st year = 68 cm, end of 4 years = 100 cm (double).
Birth weight doubles by 5months, triples by 1 year.
For the confirmation of age between 6 and 12, best means is dental examination.

Fusion of bones / joints:
(ii) 15 to 16 years – Elbow joint.
(iii) 16 to 17 years – Ankle joint
(iv) 17 to 18 years – Hip joint
(v) 18 to 19 years – Knee, shoulder, knee joint. Centre appears for inner end of clavicle.
(vi) 18 to 20 years – Iliac crest fuses.
(vii) 21 years – Fusion of ischial tuberosity and inner end of clavicle. Patella completely ossifies at 14 years.
(viii) 2nd and 5th decades – Age of 20 years is determined by pubis.
(ix) 14 to 25 years – Sternum fusion takes place below upwards.
(x) Bertellion system – for greater than 21 years.
(xi) Epiphseal union of sternal end of clavicle occurs at the age of 22 years.

1st ossification centre to appear is clavicle, and lower jaw at 2nd week of intra uterine life.
In post – maturity, ossification centres appear in capitate, hamate.

Stature: By applying Karl – pearson formula, we will be able to calculate stature of the individual from long bones. Multiplying factor of estimating stature: from femur (males) is 3.6 to 3.8, from humerus (males) is 5 to 6.

Dactylography, (finger-print system, dermatoglyphics, Galton system)
Most reliable method of identification of a person. Finger prints are impressions of pattern formed by the papillary ridges of the fingertips.
Finger prints are classified primarily as: (i) Loops 67%, (ii) whorls 25%, (iii) arches 6 to 7% (iv) composite forms – 1 to 2% (least common).

In practice, 16 to 20 points of fine comparison are accepted as proof of identity. The patterns are not inherited. The pattern is different in identical twins.
Ridge alterations occurs in eczema, acanthosis nigricans and scleroderma.
Permanent impairment of the finger print pattern occurs in leprosy, electric injuries, and after exposure to radiation.

Poroscopy – This is the further study of fingerprints described by Locard.
M.L.I:
(i) Recognition of impression at the scene of crime.
(ii) Identification in case of accidental exchange of new-born infants.
(iii) Prevention of impersonation
(iv) Cheques, bank notes and other legal documents.

Cheiloscopy: is the study of lip-prints.
Superimposition: It is the technique applied to determine whether the skull is that of the person in the photograph. A life sized negative of the skull is prepared. The negatives of the photograph and the skull are superimposed by aligning the characteristic point in negative. A negative result is having more credibility because, it can definitely be stated that the skull and the photograph are not those of the same person.

Hair: Study of hair is known as Trichology.
Medullary index of hair is used to determine the species.
Human hair is fine, thin, cuticular scales are short, broad, not continuous; cortex – thick, 4 to 10 times as broad as medulla; medulla – thin, pigment evenly distributed; precipitin test specific for human.
Animal hair is coarse, thick, cuticular scales very large, step-like projection; cortex thin.

Scalp hair grows at 3 mm a week.
Hair becomes loose after 72 hours of death.
ABO groups can be determined in a single hair from any part of the body by a modified absorption – elution technique with 100 % accuracy.

DEATH AND ITS CA– USE
Thanatology deals with death in all its aspects. Death is of two types: (1) somatic, systemic or clinical, and (2) molecular or cellular.
Somatic death is the complete and irreversible stoppage of the circulation, respiration and brain functions, but there is no legal definition of death.
Autopsy means, post-mortem examination of a body (whole body).

Objectives:
(1) To find out the time since death.
(2) To find out the cause of death.
(3) To find out the manner of death, whether accidental, suicidal or homicidal.
(4) To establish the identity.
(5) In new-born infants to determine live birth and viability.

Rokitansky’s method is autopsy technique for infants.
Before doing the post-mortem, body should be identified by policeman.
Exhumation: is the digging out of an already buried body from the grave. There is no time limit for exhumation in India. The body is exhumed only when there is a written order from the First Class Magistrate (Chief Judicial Magistrate). It should be conducted in natural light in early morning. Average number of sample of earth taken is 6 to 7. Disinfectants should not be sprinkled on the body. In suspected mineral poisoning, hair, nails and long bones, e.g., femur should be preserved for chemical analysis. It is not done for Hindus. Performed for Christians, Muslims and Parsies.

Molecular death means the death of cells and tissues individually, which takes place usually one to two hours after the stoppage of vital functions.

Braindeath consists of: (1) Deep unconsciousness with no response to external stimuli or internal need; (2) No movements, no spontaneous breathing; (3) Cessation of spontaneous cardiac rhythm without assistance; (4) No reflexes (except occasionally spinal reflexes), (5) Bilateral dilatation and fixation of pupils; (6) Flat iso-electric EEG; provided that (a) all of the confirmatory mentioned are present for a 24 hour period; (b) patient’s body temperature should not be below 320C. (c) metabolic and endocrine disturbances, which can be responsible for coma should be excluded.

Modes of death: (1) Coma, (2) Syncope, (3) Asphyxia.
Coma is the insensibility, which involves the central portion of the brain stem, and may result in death.
Syncope is sudden stoppage of action of the heart, which may prove fatal. It is due to vaso-vagal attacks resulting from reflex parasympathetic stimulation.

Asphyxia is a condition caused by interference with respiration or due to lack of oxygen in respired air due to which the organs and tissues are deprived of oxygen. (together with the failure to eliminate CO2 ), causing unconsciousness or death.

The cause of death is the disease or injury responsible for starting a sequence of events, which are brief or prolonged and which produce death. It may be divided into: (1) Immediate cause, (2) Basic cause, (3) Contributory cause.

Negative autopsy:
When gross and microscopic examination, toxicological analysis and laboratory investigations fail to reveal a cause of death, the autopsy is considered as negative. It may be due to (1) Inadequate history, (2) Inadequate external examination, (3) Inadequate or improper internal examination, (4) Insufficient laboratory examinations, (5) Lack of toxicological analysis, (6) Lack of training of the doctor.

Obscure autopsies: are those which do not show a definite cause for death, in which there are minimal, indefinite or obscure findings, or even no positive findings at all.
Sudden death: Death is said to be sudden or unexpected, when a person not known to have been suffering from any dangerous disease, injury or poisoning is found dead or dies within 24 hours after the onset of terminal illness.

Natural death means that the death was caused entirely by the disease, and the trauma or poison did not play any part in bringing it about.

POST-MORTEM CHANGES
The signs of death appear in the following order:
(I) Immediate (somatic death).
(1) Insensibility and loss of voluntary power
(2) Cessation of respiration
(3) Cessation of circulation.
(II) Early (cellular death).
(4) Pallor and loss of elasticity of voluntary power
(5) Changes in the eye
(6) Primary flaccidity of muscles
(7) Cooling of the body
(8) Post-mortem lividity
(9) Rigor mortis
(III) Late (decomposition and decay)
(10) Putrfaction
(11) Adipocere formation
(12) Mummification.

Complete stoppage of respiration for more than 4 minutes usually causes death.
Suspended animation: In this condition, signs of life are not found, as the functions are interrupted for sometime, or are reduced to minimum. However, life continues and resuscitation is successful in such cases. Voluntarily, practitioners of yoga can pass into a trance, death like in character. Involuntary suspension of animation lasting from a few seconds to half-an-hour may be found in new-born infants, drowning, electrocution, cholera, after anesthesia, shock, sunstroke, cerebral concussion, insanity, etc.

Changes in skin: Skin becomes pale and ashy-white and loses elasticity within a few minutes of death. Lips appear brownish, dry and hard due to drying.
Changes in eye: Loss of corneal reflex is not a reliable sign of death. Opacity of cornea may occur in diseases like cholera, wasting diseases before death. If the lids are open, cornea remains clear for about 2 hours. The retina is pale for the first 2 hours. At about 6 hours, the disk outline is hazy and becomes blurred in 7 to 10 hours.

Cooling of the body (Algor mortis): The body heat is lost by conduction, convection and radiation. The curve of cooling is sigmoid in pattern. Internal organs take 24 hours to cool. The temperature of the body rises up for the first two hours after death by sunstroke, septicemia, tetanus, strychnine poisoning called post-mortem caloricity.

A rough idea of time in hours after death can be obtained by the formula, (Normal body temperature – Rectal temperature) / Rate of temperature fall per hour.

The rate of cooling of the body in first six hours is 2.50F per hour, the rate in next hours is 1.5 – 20F.
Factors affecting rate of cooling: In India, during summer, cooling is very slow. In tropical climates, the heat loss is roughly 0.5 to 0.70C per hour. Children and old people cool more rapidly than adults. Fat bodies cool slowly than lean bodies. Cooling is more rapid in humid atmosphere than in dry atmosphere. A body immersed in cold water cools rapidly; the rate of fall being almost twice as fast as by air cooling. Bodies buried in earth cool rapidly than that in air, but more slowly than those in water.

Post-mortem hypostasis: This is the bluish-purple or purplish-red discoloration which appears under the skin of the dependent parts of the body after death, due to capillo-venous distension. Also called post-mortem staining, sub-cutaneous hypostasis, livor mortis, cadaveric lividity, suggilations, vibices and darkening of death. The intensity of the colour depends on the amount of reduced haemoglobin in the blood.

Post-mortem lividity begins shortly after death, but it may not be visible for about half to one hour after death in normal individuals, and for about one to 4 hours in anaemic persons. It is usually well developed within 4 hours and reaches a maximum between 6 and 12 hours. It is more marked in asphyxia and is less marked in death from wasting diseases, hemorrhage and from anaemia and lobar pneumonia.

In a body lying on its back, it first appears in the neck, and then spread over the entire back except parts directly pressed on, i.e., shoulder-blades, buttocks, calves and heel.

Post-mortem stains can occur in some cases before death in cholera. The location of the lividity indicates the position of the body during post-mortem interval. Hypostasis lasts for hours. Blood clots after ½ hour of death.

Post-mortem staining gets fixed after 5 – 6 hours. A contusion can be differentiated from post-mortem staining by doing incision test.

•  In carbon-monoxide poisoning, the colour is cherry-red.
•  In hydrocyanic acid poisoning, the colour of stain is bright-red.
•  In poisoning by nitrates, potassium chlorate, potassium bicarbonate, nitrobenzene and aniline (causing methaemoglobinaemia) the colour is red-brown, or brown
•  In poisoning by phosphorus, the colour is dark – brown. (Blue in P.V.Chadha)
•  In case of aniline or CO2 poisoning, it is deep blue, due to excess of reduced Hb.
•  In asphyxia, the colour of stains is deeply bluish-violet or purple.
•  In septic abortion caused by Cl. Welchii, the colour is often greyish-brown.
•  In hanging, hypostasis, will be most marked in the legs, and hands. In drowning, PM staining is usually found on the face, the upper part of chest, hands, lower arms, feet and calves, as they are the dependent parts. If the body is constantly moving its position, as after drowning in moving water, the staining may not develop.
• As decomposition progresses, the lividity becomes dusky in colour and turns brown and green before finally disappearing with destruction of the blood.

Muscular changes: After death, muscles of body pass through three stages:
(1) Primary relaxation or flaccidity,
(2) Rigor mortis or cadaveric rigidity,
(3) Secondary flaccidity.
Primary flaccidity: During this stage, death is somatic only, and it lasts for one or two hours.

Rigor mortis (cadaveric rigidity): This is a stage of stiffening of muscles, sometimes with slight shortening of the fibres. Individual cell death takes place at this stage.

Mechanism:
ATP is responsible for elasticity and plasticity of muscle. The lost ATP (during muscle contraction) during life is resynthesized. After death there is no resynthesis of ATP. The PM alteration of ATP is due to dephosphorylation and deamination. When ATP is reduced to a critical level (85% of the normal) the overlapping portions of myosin and actin filaments combine as a rigid link of actomyosin, which is viscous and inextensible, and causes hardness and rigidity of muscle rigor. The rigidity is maximum, when the level of ATP is reduced to 15%. Rigor persists until decomposition of the proteins of the muscle fibres makes them incapable of any further contraction.

The order of appearance of rigor mortis:
All the muscles of the body, both voluntary and involuntary are affected. It first appears in involuntary muscles; the myocardium becomes rigid in an hour. It begins in the eyelids, neck, and lower jaw, and passes upwards to the muscle of the face, and downwards to the muscles of the chest, upper limbs, abdomen and lower limbs. It passes off in same order.

When rigor is fully developed, the entire body is stiff, the muscles shortened, hard and opaque. Rigor of erector pilae muscles may cause roughness of skin – known as cutis anserina or goose skin. Rigor is tested by trying to lift the eyelids, depressing the jaw, and gently bending the neck and various joints of the body. RM may occur in amputated limbs and diseased parts.

Time of onset of RM:
In India, it begins 1 to 2 hours after death and takes further 1 to 2 hours to develop.
Duration of RM:
In India, usually it lasts for 24 to 48 hours in winter and 18 to 36 hours in summer. When rigor sets in early, it passes off quickly and vice versa.

Conditions altering duration and onset:
In death from diseases causing great exhaustion and wasting, e.g., cholera, typhoid, tuberculosis, cancer, etc and in violent deaths as by cut-throat, firearms or by electrocution, the onset of RM is early and duration is short.
In Strychnine and other spinal poisons, the onset is rapid and the duration is longer. In deaths from asphyxia, severe haemorrhage, apoplexy, pneumonia, nervous disease causing paralysis of muscle, and perfusion with normal saline, the onset is delayed.
The onset is slow and duration is long in cold weather. The onset is rapid due to heat, because of the increased breakdown of ATP but the duration is short. RM may persist for 3 to 4 days in refrigerated conditions.

Conditions simulating RM:
(1) Heat stiffening: When a body is exposed to temperatures above 650C rigidity is produced, which is much more marked than that found in RM. It is seen in deaths from burning, high voltage electric shocks and from falling into hot liquid. The stiffening remains until the muscles soften from decomposition.
(2) Cold stiffening: When the body is exposed to freezing temperatures, the tissues become frozen and stiff, simulating rigor.
(3) Cadaveric spasm or Instantaneous rigor or cataleptic rigidity: In this condition, the muscles that are contracted during life, become stiff and rigid immediately after death without passing into the stage of primary relaxation. It occurs especially in cases of sudden death, excitement, fear, severe pain, exhaustion, sudden asphyxial death, cerebral haemorrhage, injury to the nervous system, firearm wound of the head, etc. this is usually limited to a single group of muscles and frequently involves the hands. No other condition simulates cadaveric spasm and it cannot be produced by any method after death. It may be explained on the basis of diminished or exhausted ATP in the affected muscles.

MLI: in case of suicide the weapon, e.g., pistol or knife is seen firmly grasped in victim’s hand which is a strong presumptive evidence of suicide. In case of drowning, materials such as grass, weeds or leaves may be found firmly grasped in the hand which shows ante mortem drowning.

Secondary relaxation: Muscle becomes soft and flaccid due to breaking down of actinomyosin due to putrefaction

Putrefaction: It is the final stage following death, mainly by the action of bacterial enzymes, mostly anaerobic organisms derived from the bowel.
Putrefaction is delayed after death due to poisoning by: Carbolic acid, Zinc chloride, Strychnine, Heavy metal poisoning e.g. Arsenic, Antimony.

The chief destructive bacterial agent is Cl. Welchii which causes marked hemolysis, liquefaction of post-mortem clots and of fresh thrombi and emboli, disintegration of tissue and gas formation in blood vessels and tissue spaces. Enzyme Lecithinase produced by Cl. welchii is most important.

The characteristic features of putrefaction are : (i) changes in the colour of the tissue,
(ii) collection of gases in the tissues, (iii) liquefaction of tissues.
(i) changes in the colour of the tissue: The first external sign of putrefaction in a body lying in air is a greenish discolouration of skin over caecum i.e. right iliac fossa, where the contents of the bowel are more fluid and full of bacteria.

The colour appears in 12 to 18 hours in summer and one to two days in winter. The greenish discoloration then spreads over the entire abdomen, external genitals and then patches appear successively on the chest, neck, face, arms and legs. The patches become dark-green and later purple and dark blue. The marbled appearance is prominent in 36 to 48 hours. The earliest internal change is reddish brown discolouration of the inner surface of the vessels, especially the aorta.

(ii) Collection of gases in the tissue: Gases collect in the intestines in 6 to 12 hours in summer. From 18 to 36 hours after death, the gas collects in the tissues, cavities and hollow viscera under pressure and the features become bloated and distorted. After 3 days, the face is so discoloured and bloated that identification becomes difficult. The hair becomes loose and is easily pulled out.

(iii) liquefaction of the tissues: Colliquative putrefaction begins from 5 to 10 days or more after death.

Skeletonisation: In India, an unconfined buried body is reduced to a skeleton within a year.
Internal phenomenon:
The organs show putrefactive changes in the following order :
1. Larynx and trachea, 2. Stomach, intestines, spleen, 3. Liver and lungs, 4. Brain,
5. Heart, 6. Uterus, prostate, kidney, 7. Skin, muscle, tendon, 8. Bone.
In putrefaction, when bubbles appear the organ has a honey combed, foamy appearance. Prostate and virgin uterus resists putrefaction for a very long time. Putrefaction begins above 10°C and optimum between 21 °C and 38°C. A body decomposes in air twice as rapidly as in water and eight times as rapidly as in earth; formula is given by Taylor. Putrefaction is the surest sign of death. After death, the onset of putrefaction is in the stage of secondary relaxation. Gas rigidity appears after 72 hours.

Entomology of cadaver: Is the study of insects and maggots that infest the dead body.
Bones begin to decompose after death in 3-10 years. Less than 7 amino acids in bone suggest the age of bone to be (after death) more than 100 years. Total ultraviolet fluorescence of cut surface of bones is seen in 35-100 years. Foamy liver is due to bubbling up of gas. Putrefaction is affected by age, clothing and moisture. Maggots in a dead body do not appear before 48 hours.

Adipocere (Saponification)
In this, the fatty tissues of the body changes into a substance known as adipocere. The change is due to gradual hydrolysis and hydrogenation of pre-existing fat such as olein, into higher fatty acids, which combine with calcium and ammonium ions to form insoluble soaps, which being acidic, inhibit putrefactive bacteria. Adipocere is delayed by cold and formed rapidly by warm humid climate and moist damp soil.

Fresh adipocere is soft, moist, whitish and translucent but old samples are dry, hard, cracked, yellowish and brittle. It is inflammable and burns with a faint yellow flame. It floats in water and dissolves in alcohol and ether. It is formed first in subcutaneous tissue. The face, buttocks, breast, abdomen are the usual sites. In temperate country, the shortest time for its formation is about 3 weeks in summer. Foetuses under 7 months do not show this change. In India, it has been observed within 3 days.

Mummification: It is a modification of putrefaction.

Dessication or, Dehydration or drying and shrivelling of the cadaver occur due to evaporation of water but the natural appearance and features of the body are preserved. It begins in the exposed parts of the body such as face, hands and feet and then extends to the entire body including the internal organs. A mummified body is practically odourless. The time required for complete mummification of a body varies from three months to a year or two. Two factors are necessary for the production of mummification: (1) The absence of moisture in the air, and (2) The continuous action of dry or warmed air.

Embalming:
In this, the contents of the body cavities are removed and the vascular system is injected with an embalming fluid containing 40% formaldehyde and 10% methyl alcohol.
MECHANICAL INJURIES

Mechanical injuries (wound) are injuries produced by physical violence.

An injury is any harm, whatever illegally caused to any person in body, mind, reputation or property (S. 44, IPC)
A wound or injury is a break of the natural continuity of any of the tissues of the living body.

Classification:
(I). Mechanical:
1. Abrasions 2. Contusions 3. Lacerations 4. Incised wounds 5.Stab wounds 6. Firearm wounds 7. Fractures and dislocations

(II) Thermal:
1. Due to cold-
(a) Frost bite (b) Trench foot (c) Immersion foot.
2. Due to heat—
(a) Burns (b) Scalds.

III. Chemical: (a) Corrosive acid (b) Corrosive alkalies.

IV. Injuries due to lightning, electricity, X-ray and radio-active substances..

Abrasions
An abrasion is a destruction of the skin, which involves super¬ficial layers of epidermis only. They are caused by a blow, a fall on a rough surface, by being dragged in a vehicular accident, finger nails, thorns or teeth-bite. The exposed raw surface is covered by exudation of lymph and blood, which produces a protective covering known as scab or crust. They are simple injuries, bleed slightly, heal rapidly and leave no permanent scar.

Types: Abrasions are of four types.
1. Scratches: These are caused by a sharp object passing across the skin, such as finger nails, pin or thorn.
2. Grazes (sliding, scraping or grinding abrasion): They are most common type of abrasions. They show uneven, longitudinal parallel lines (grooves or furrows) with the epithelium heaped up at the ends of these lines, which indicate the direction in which the force is applied.
An abrasion caused by violent friction against a broad rough surface as in dragging over the ground is called brush burn.
3. Pressure abrasion (Crushing or friction abrasion): Ligature mark. They are caused by crushing of the superficial layers of the epidermis and are associated with a bruise of the surrounding area.
4. Impact abrasions or Imprint abrasions— they are caused by impact of a rough object, such as a person knocked down by a motor car. They are also called pattern abrasions.

Age of Abrasions:
1. Fresh — Bright red.
2. 12 to 24 hours — Lymph and blood dries up leaving a bright scab.
3. 2 to 3 days — Reddish-brown scab.
4. 4 to 7 days — Epithelium grows and covers defect under the scab.
5. After 7 days — Scab dries, shrinks & falls off.
In ante-mortem abrasions, intravital reaction and conges¬tion is seen.

Erosion of the skin produced by ants, excoriations of the skin by excreta and pressure sores resemble abrasions.

Contusions (BRUISES)
A contusion is an effusion of blood into the tissues, due to rupture of the subcutaneous vessels, caused by blunt trauma. This is accompanied by a painful swelling and crushing or, tearing of the subcutaneous tissues usually without destruction of the skin. A contusion is a superficial injury. When a large blood vessel is injured, a tumour-like mass called haematoma is formed. The size of the bruise is slightly larger than the surface of the agent which caused it, as blood continues to escape into the area.

If the part is vascular and loose, such as face, vulva, scrotum, a slight degree of violence may cause a large bruise. If the tissues are strongly supported and covered by thick dermis, such as abdomen, back, scalp, palm and soles, moderate violence may produce a small bruise.

Bruising is more marked on tissue overlying bone. Children and old people bruise more easily. Hemorrhages in the soft tissues around the eyes and in the eyelids (black-eye) may be caused by blunt impact to the forehead.

The Age of Bruise:
A bruise heals by destruction and removal of the extra-vasated blood.
At first (1-2 hours)—Red.
Few hours to 3 days—Blue
4th day — Bluish-black to brown (haemosiderin).
5 to 6 days — Greenish (haematoidin).
7 to 12 days—Yellow (bilirubin).
2 weeks—Normal.

In ante-mortem bruising there is swelling, damage to epithelium, extravasation, coagulation and infiltration of the tissue with blood and colour changes.
Bruises are of less value than abrasions. In self inflicted bruises, typical colour changes are not seen.
Artificial bruises: Some irritant substances when applied to skin produce injuries, which simulates bruises. Artificial bruises are dark brown and true bruises show typical colour change.

Incised wounds
An incised wound (cut, slash or slice) is a clean cut through the tissues, which is longer than it is deep. It is produced by pressure and friction against the tissue by object having a sharp cutting edge such as knife, razor, scalpel, sword, etc.

Incised wound appears lacerated on testes. Incised wounds are deeper at their beginning, because more pressure is exerted on the knife at this point, known as the head of the wound.
Towards the end of the cut, the wound becomes shallow, called tailing of the wound.

Age of incised wound:
Fresh—Hernatoma formation.
12 hours—Edges are red, swollen, adherent with blood and-lymph.
24 hours—A continuous layer of endothelial cells cover the surface.
36 hours—The capillary network is complete.
48 to 72 hours—The wound is filled with fibroblasts.
3 to 5 days—Definite fibrils running parallel to the vessels are seen; vessels show thickening and obliteration.
1 to 2 weeks—Scar tissue is formed.

Hesitation marks or tentative cuts or trial wounds—They are cuts which are multiple, small and superficial, often involving the skin and seen at the beginning of the incised wound. They are seen in suicidal wounds.
Chop wounds: They are wounds caused by a blow with the sharp cutting edge of a fairly heavy weapon like a hatchet, axe, a sword etc.
Wound produced by a curved weapon such as sickle is both stab & incised wound.

Stab or Puncture Wounds
Stab wound is a penetrating injury caused by sharp-pointed objects, such as knife, dagger, nail, needle, arrow, screw driver, etc. penetrating the skin and underlying tissues that is deeper than its length and width of the skin.
Most important dimension in stab wound is depth. Punctured wound is deeper than its width and length on skin. The length of wound is less than width. If a single edged weapon is used, the surface, triangular or wedge shaped, one angle of the wound will be sharp, the other blunt or torn.

Harakiri: It is an unusual type of suicide, in which the victim inflicts a single large wound on the abdomen with a short sword while in a sitting position or falls forward upon a ceremonial sword and pulls out intestines. The sudden evisceration of the internal organs causes a sudden decrease of intra-abdominal pressure and cardiac return, producing sudden cardiac collapse.

Lacerations
They are open wound.
Lacerations are tears or splits of skin, mucous membrane, muscle or internal organs produced by application of blunt force to the broad area of the body. Displacement of tissues occurs most commonly when soft tissues are crushed against bone, e.g., scalp, shins, shoulders, and face. They are caused by blows from blunt objects, by falls on hard surfaces, by machinery, traffic accidents, etc.

If the force produces bleeding into adjacent tissues, the injury is a ‘contused-laceration’ or ‘bruised tear’. If the blunt force produces extensive bruising and laceration of deeper tissues, it is called ‘crushing’ injury.
Incised like or incised looking wounds: Lacerations produced without excessive skin crushing may have relatively sharp margins. The sites are the scalp, eyebrows, cheek bones, lower jaw, iliac crest, perineum, and shin.

Stretch lacerations: is seen in the running over by a motor vehicle, and the flap may indicate direction of the vehicle.

Avulsion is a laceration produced by sufficient force (shearing force) delivered at an acute angle to detach (tear off) a portion of a traumatised surface or viscus from its attachments.

Defense wounds
It results due to immediate and instinctive reaction of the victim to save himself, either by raising the arm to prevent the attack or by grasping the weapon.
Self-inflicted wounds are those inflicted by a person on his own body.
Fabricated wounds (fictitious, forged or inverted wound) are those which may be produced by a person on his own body or by another with his consent.

REGIONAL INJURIES
Most fragile bone in the skull to get fractured is — temporal bone.
Depressed fractures -» The outer table is driven into the diploe and inner table is fractured irregularly. Depressed fracture is also called signature fracture. Localised depressed fracture are caused by blows from heavy weapon with a small striking surface e.g. stone, stick, axe. hammer etc.
Pond or Indented fractures —> They occur only in skulls which are elastic i.e. the skulls of infants.
Gutter fractures – They are formed when part of the thickness of the bone is removed so as to form a gutter e.g. oblique bullet wound.
Countre-coup lesions fracture means that the lesion is present in an area opposite the side of impact in head injury.
Concussion is a state of temporary unconsciousness, which results from violence applied to the skull. Concussion of the spinal cord is called railway spine.
In fracture, X-ray examination, callus is not readily visible for 3 weeks.
Whip lash injury is due to violent acceleration or deceleration force.
In Boxing injuries fracture of the skull is rare but sub-dural hemorrhage occurs. It is most common type of hemorrhage. Deterioration of speed and co-ordination are the chief symptoms of the onset of punch-drunk (traumatic encephalopathy) condition. Repeated blows to the head produce small hemorrhages and degenerative changes in brain.
— The specific pulmonary injury of air blast is called ‘blast lung’.
— Most common mechanism of fracture of spine is hyperflexion.
— Most common site of spinal cord injury is thoracolumbar junction (T10- L1).
— Best method of assessing spinal cord injury is MRI.

Intracranial Hemorrhage
1. Extradural hemorrhage: — It is caused always due to trauma.
Most common artery causing extradural hemorrhage is anterior branch of middle meningeal artery. Most common site of extradural hemorrhage is Temporo-parietal area where main source of bleeding is middle meningeal artery. There is a history of head injury which causes the bleeding and temporary unconsciousness usually. This is followed by a period of normal consciousness, the lucid interval of few hours to a week.

2. Subdural hemorrhage:
May occur from relatively mild trauma. It is essentially venous or capillary, not arterial.
3. Subarachnoid hemorrhage
This is the most common form of traumatic intracranial hemorrhage.

4. Intracerebral hemorrhage
Most common cause of intracerebral hemorrhage is hypertension.
Most common site of intracerebral hemorrhage is putamen (corpus striatum).
Most common blood vessel leading to intracerebral hemorrhage is lenticulo striate branch of middle cerebral artery.                                                                                                                                                                                                                                                                                                                       MEDICO-LEGAL ASPECTS OF WOUNDS

Homicide: is killing of a human being by another human being.

Types of homicide:
(1) Lawful (a) Excusable (b) Justifiable
(2) Unlawful (a) Murder (b) Culpable homicide (not amounting to murder/ amounting to murder) (c) Rash or negligent homicide.
Justifiable homicide: This is the homicide which is justified in the circumstance which led to the killing of a person. This may occur; (a) In the administration of justice, like execution of sentence of death (b) The maintenance of justice, e.g., in suppressing riots, or executing arrest, or killing in course of violent crime, e.g., a woman who kills a person who attempts to rape her.

Excusable homicide: This is the homicide caused unintentionally by an act done in good faith. This includes: (a) Killing in self-defense when attacked, provided there is no other means of defense (b) Causing death by accident or misadventure (c) Death following a lawful operation (d) Homicide committed by an insane person.

Murder: S. 300, IPC
Culpable homicide: S. 299, IPC
Punishment for murder: S. 302, IPC – Imprisonment for life, and also fine.
Punishment for culpable homicide: S. 304, IPC – Imprisonment for life, or for a term which may extend to 10 years and also fine.
Causing death by negligence: S. 304 – A, IPC – Imprisonment for a term, extend to 2 years or/with fine, or with both.

Grievous Injury
According to 320 I.P.C., anyone of the following injuries is grievous:
1. Emasculation (Ioss of potency).
2. Permanent privation (loss) of sight of either eye.
3. Permanent privation of hearing of either ear.
4. Privation of any member or joint.
5. Destruction or permanent impairing of the power of a member or joints
6. Permanent disfiguration of the head and face.
7. Fracture or dislocation of a bone or tooth.
8. Any hurt which endangers life or, which causes the victim to be in the severe bodily pain or, unable, to follow his ordinary pursuits for a period of 20 days.

Hurt means bodily pain, disease or infirmity caused to any person (S. 319, IPC)
Punishment for voluntarily causing hurt: Imprisonment up to one year, or with fine up to one thousand rupees or both (S. 323, IPC)
Injury is any harm whatever illegally caused to any person in body, mind, reputation or property (S. 44, IPC)
Punishment for voluntarily causing grievous hurt: Imprisonment for a term extending to seven years and also fine (S. 325, IPC)
Punishment for voluntarily causing grievous hurt by dangerous weapons or means: Imprisonment for a term up to 10 years and also fine (S. 326, IPC)

Dangerous weapons or means: According to Sec. 324 and 326, IPC, dangerous weapons or means include any instrument for shooting, stabbing or cutting or any instrument, which used as a weapon of offence, is likely to cause death; fire or any heated substance; poison or any corrosive substance; explosive substance or any substance which are harmful to human body to inhale, to swallow, or to receive in to the blood or by means of any animal.

Voluntarily causing hurt by dangerous means: Imprisonment for a term up to 3 years or with fine, or both (S. 324, IPC)
Assault is an offer or threat or attempt to apply force to body or another in a hostile manner (S. 351, IPC)

Dowry death
Sec. 304 B, I.P.C., where death of the women occurs under abnormal circumstances within seven years of her marriage. Punishment: imprisonment not less than 7 years, but may extend to life imprisonment. Sec. 498-A, IPC “Whoever, being the husband or relatives of the husband of a woman, subjects such women to cruelty shall be punished with imprisonment up to 3 years”.

Causes of death from wounds: (1) Immediate or direct (2) Remote or indirect
(1) Immediate causes: (a) hemorrhage (b) reflex vagal inhibition (c) shock (d) mechanical injury to a vital organ
(2) Remote causes: (a) infection (b) gangrene or necrosis (c) crush syndrome (d) neglect of injured person (e) surgical operation (f) natural disease (g) supervention of disease from a traumatic lesion (h) thrombosis (i) fat embolism (j) air embolism.
Causes of fat embolism: (1) Fracture of a long bone (2) an injury to adipose tissue which forces liquid fat into the damaged blood vessels, (3) injecting oil into circulation, e.g., in criminal abortion (4) occasionally due to natural disease without trauma as in sickle cell anaemia (5) in case of burns.

FIRE-ARM INJURIES
A firearm is any instrument which discharges a projectile by the expansive force of the gases produced by burning of an explosive substance. Forensic ballistics is the science dealing with the investigation of firearms, ammunition and the problem arising from their use.

Classification:
(I) Rifled weapons: (1) Rifles: (a) Air and gas-operated rifles (b) 0.22 rifles (c) Military and sporting rifles (2) Single-shot target practice pistols (3) Revolvers (4) Automatic pistols (5) True automatic weapons (machine guns)
(II) Smooth-bored weapons (shotgun) (1) Single barrel (2) Double barrel (3) Slide action (4) Bolt – action (5) Semi-automatic (6) Automatic.

Choking is a constricting device at the muzzle end of shot gun.

Muzzle-loading guns are loaded entirely from muzzle end with the help of a rod using gunpowder, pieces of cloth, stones, metal fragments, seeds, bolts, wood, screws, etc. When the entire barrel from breech to the muzzle end is of same diameter, it is called cylinder-bore. In choke-bore, the distal 7.5 to 10 cm. of the barrel is narrow. There are some shotguns which have small portion of their bore near the muzzle end rifled, which are called “paradox guns”. A musket is a military shoulder arm. It has a long fore-stock and usually takes a bayonet at the muzzle. Shot guns are effective up to 30 metres (30-40 yards). 12 bore gun means that a sphere of 1/12 pound of lead will exactly fit the bore of the gun. Markings in projectile occur in Rifle.

Rifle:
A Rifle is a gun with a long barrel, the bore of which is rifled. A Carbine is a short barrelled rifle or a musket. It is effective upto 300 metres. The military rifle has a magazine and bolt action and can kill at a range of 3,000 metres. The pressure in the firing chamber is about 20 tonnes per square inch. The bullet as it leaves the barrel rotates at about 3,000 revolutions persecond. Rifles may be single-shot, repeating, semi-automatic and automatic.

Revolver:
Revolvers are so called because the cartridges are put in chambers in a metal cylinder, which revolves or rotates before each shot, to bring the next cartridge opposite the barrel, ready to be fired. It has a cylindrical magazine situated at the back of the barrel, which is capable of revolving motion. The bores vary from 5.6 to 11.4 mm (0.22 to 0.45 inch). The muzzle velocity is 150 to 180 metres per second. The effective range is 100 metres.

Air rifle and Air pistol
In these compressed air is used to fire lead slugs. Their range is about 40 metres.
Cartridge: is used in shot gun. Detonator cap is situated at the base of the rim. Soiling in a gun shot wound is due to lead content, more marked in distant shot gun wound. Ring of grease occurs at a distance beyond 2 feet.

Powders
1. Black gun powder—It consists of potassium nitrate 75%, sulphur 10% and charcoal 15%.
Except— Lead peroxide.
2. Smokeless: it consists of nitrocellulose (single base) or, nitroglycerine and nitrocellulose (double base) powder which produces much less flame and smoke and are more completely burnt than black powder.

Bullets:
The traditional bullet is made of soft metal and has a round nose. This is known as the round-nose soft bullet, and is usually used in rifles and revolvers. In revolver and pistol, the bullet is short and the point usually round or ogival. In rifle, the bullet is elongated with pointed end. Rifle bullet weight ranges from 2 to 33 grams. The extent of muscle damage by a bullet depends primarily on the velocity.

A dumdum bullet, so called because tip is chiselled out, is one which fragments extensively upon striking and produces extensive wounds with ragged margins.

Incendiary bullets contain phosphorus. Gun shot wound is a perforated wound. Glance bullet causes gutter fracture. In case of shot by bullet, the presence of singeing (of hair) and charring (of skin) indicates a distance up to 6 inches.

Near wound caused by fire-arms is characterised by— (i) Tattoing by unburnt powder,
(ii) Presence of grease collar and abrasion collar, (iii) Presence of carbon monoxide in the blood of the injured tissues in the track of the bullet.
Bevelling of the skull in bullet injury:
(i) At broad end of the entry point, inner table shows bevelling, (ii) At exit point of bullet, outer table shows bevelling.

In close shot, the victim is within the range of the frame i.e. few feets.
The term point blank is used when the range is very close to or in contact with the surface of the skin. Blasting effect is usually seen.

The entrance wound is circular, with inverted edges and is surrounded by blackened and singed area. Abraded collar and grease or, dirt collar are present in gun shot entrance injury. Some contusion is present in abraded collar, called contusion collar. The abrasion collar and contusion collar are proof of an entrance wound.

Skull—In the skull, the wound of entrance shows a punched hole in the outer table. Opening in the inner table is large and shows beveling (sloping). At the point of exit, a punched-out opening is produced in the inner table and beveled opening on the outer table. Greater damage is produced by Dumdum bullet, larger bullet and round bullet.

A bullet traveling in an irregular fashion instead of traveling nose-on is called a yawning bullet. A bullet that rotates end-on-end during its motion is called a tumbling bullet.

Ricochet bullet is one which before striking the object aimed at, strikes some intervening object first, and then after ricocheting and rebounding from these, hits the object.

Tandem bullet or piggyback bullet (one behind the other).

Souvenir bullets: if a bullet is present for a long time in the body, there will be no fresh bleeding in the surrounding area.
                                                                     
THERMAL DEATH
Cold:
Trench foot and Immersion foot are the result of prolonged exposure to severe cold (5 to 8°C) and dampness. The term Immersion foot is used for cases with frost bite. In frost bite, skin becomes hard & black in about 2 weeks. Frost bite occurs due to exposure to extremes of cold (- 2.5°C).

Heat:
1. Heat cramps (miner’s cramps or, fireman’s cramps): They are caused by rapid dehydration of body through the loss of water and salt in the sweat.
2. Heat hyperpyrexia or Heat stroke: The term thermic fever or sunstroke is used when there has been direct exposure to the sun. High temperature, increased humidity, minor infections, muscular activity, and lack of acclimatisation are the principal factors of the initiation. Failure of cutaneous blood flow and sweating leads to breakdown of heat regulating centre of hypothalamus.

C/F: In some cases, symptom are headache, giddiness, nausea, vomiting, weakness, staggering gait, mental confusion, muscle cramps, restlessness and excessive thirst occur. The skin is dry, hot and flushed with complete absence of sweating.

3. Heat prostration (heat exhaustion and heat syncope): Heat prostration is a condition of collapse without increase in body temperature, which follows exposure to excessive heat. Main cause of death is vascular collapse and syncope. Muscle cramp is due to loss of Na+ ion.

BURNS
A burn is an injury which is caused by application of heat or chemical substances to the external or internal surfaces of the body.

Burns due to X-rays and radium vary from redness of the skin to dermatitis, with shedding of hair (epilation) and pigmentation of surrounding skin. Curling ulcer is seen in burn patient.

Degrees of Burns
Dupuytren recognised six degrees of burns but they were merged into three groups by Wilson.
1. Epidermal (First and Second degree Dupuytren): Usually a blister (vesicle or bulla) is formed which is covered by white, avascular epidermis, bordered by red, hyperaemic skin. These burns are very painful. Repair is complete without scar formation.
2. Dermo-epidermal (Third and Fourth degree Dupuytren): Whole thickness of skin is destroyed. Skin and subcutaneous tissue is affected. In Dermo-epidermal, pain and shock are greater than in first degrees burns (most painful).
3. Deep (Fifth and Sixth degree Dupuytren): In this, there is gross destruction not only of the skin and subcutaneous tissue but also of muscles and even bone. Nerve endings are also destroyed and as such, the burns are relatively painless.

The extent of the surface
The estimation of the surface area of the body involved is worked out by the ‘rule of nine by Wallace.

• 9% for head and each upper limb,
• 9% for front of each lower limb,
• 9% for back of each lower limb,
• 9% for front of chest,
• 9% for back of chest,
• 9% for front of abdomen,
• 9% for back of abdomen i.e. 99% of the body.
• Remaining 1% for external genitalia.
• Involvement of 50% of burn proves fatal, even of first degree.

Causes of death in burns
(i) Primary (neurogenic) shock due to pain,
(ii) More, than half of deaths from burns occur from secondary shock due to fluid loss from burnt surface.
(iii) Toxaemia.
(iv) Sepsis —> It is late cause of death due to burn.
(v) Acute renal failure,
(vi) Pyemia.
(vii) Suffocation.

Flash burns refer to thermal burns due to sudden exposure to flame.
Presence of carbon particles in trachea and an elevated CO saturation together are absolute proof that the victim was alive when fire occurred. The exudate begins to dry in 12-24 hrs. from dry brown crust within 2-3 days; pus may form under slough in 36 to 72 hours; slough falls off in 4 to 6 days.

Pugilistic attitude (boxing, fencing, or defence attitude)
Pugilistic attitude is due to heat stiffening, seen both in AM and PM burns. This stiffening is due to coagulation of protein albumin of the muscles which causes contraction. Heat stiffening is due to exposure of the body to temperature above 75°C. Pugilistic attitude is seen in those dying due to burns, and sudden immersion in boiling liquid. In heat stiffening, body assumes a posture of generalised flexion.

Scalds:
A scald is an injury which is caused by application of liquid above 60°C or from stream.
Electrical injuries: The electric mark (Joule burn) is specific and diagnostic of electrical bum. Joule burn is both exogenous and endogenous burn. High tension electric currents may produce multiple burns or punched out lesions due to arching from conductor to the body without contact, which present crocodile flash burns. Crocodile flash burn is due to high voltage flash burn. Most common cause of death in electrocution is ventricular fibrillation.
Death may occur from paralysis of medullary (respiratory centre) or from ventricular fibrillation and cardiac arrest.

Lightning stroke
A flash of lightning is due to an electrical discharge from a cloud to the earth. The burns may be Arborescent or Filigree burns (Lichtenberg’s flowers). Arborescent burns are superficial, irregular, thin, resembling the branches of a tree.

STARVATION
In acute starvation, there is a feeling of hunger for the first 30 to 48 hours, followed by pain in the epigastrium which is relieved by pressure. After 4 to 5 days of starvation, general emaciation and absorption of the subcutaneous fat begins to occur. The tongue is coated and dirty and thirst is intolerable. Usually the loss of 40% of body weight is fatal. The intellect remains clear till death. Death occurs from exhaustion, circulatory failure due to brown atrophy of the heart, or intercurrent infection. Ammonia in brain is detoxified in to Glutamine. During starvation the substance which heart uses as energy source is acetoacetate. If starvation exceeds 7 days then the major nutritional supply of brain comes from ketone-bodies. Absorption of Vit. B12 occurs in ileum.

The changes in starvation seen are Hypoglycemia, Hyper-triglyceremia and Ketoacidosis. (except—Hyper cholesterolemia). Iron absorption is decreased by phosphates, phytates, oxalates (except—ascorbic acid).

Fatal period: If both water and food are completely stopped, death occurs in 10 to 12 days.
If food alone is stopped, death occurs in 6-8 weeks or even.
On P-M examination, the heart is small (from brown atrophy), and chambers are empty. The gall bladder is distended with bile.

MECHANICAL ASPHYXIA
Asphyxial deaths:
1. Suffocation—Mechanical obstruction to airways other than by hanging, strangulation and throttling. MC cause is inhalation of irritant gas.
2. Smothering—Closing the external respiratory orifice by hand or by other means.
3. Gagging—Closing mouth and nose with cloth etc. and tying around head or stuffing it into mouth.

Hanging:
Hanging is that form of asphyxia which is caused suspension of the body by a ligature, which encircles the neck, the constricting force being the weight of the body.
In partial hanging, the bodies are partially suspended; the weight of the head (5-6 kg) acts as the constricting force.
Typical hanging: In typical hanging, the ligature runs from the midline above the thyroid cartilage symmetrically upward on both sides of neck to the occipital region.

Causes of Death:
1. Asphyxia: A tension of 15 kg on ligature blocks the trachea.
2. Venous congestion: The jugular vein is closed by a tension in the rope of 2 kg.
3. Combined asphyxia and venous congestion: this is the commonest cause.
4. Cerebral anemia: A tension of 4 to 5 kg on ligature blocks carotid arteries, and 20 kg
blocks the vertebral arteries.
5. Reflex vagal inhibition from pressure on the vagal sheath or carotid bodies.
6. Fracture or dislocation of the cervical vertebrae.
Fatal period: The usual period is 3 to 5 minutes.

Post-mortem appearance:
The ligature mark in the neck is the most important and specific sign of death from hanging. The ligature mark is situated above the level of thyroid cartilage between the larynx and the chin in 80 percent cases. In partial hanging, the feet touch the ground. Le facie sympathique (it the ligature knot presses on cervical sympathetic, the eye on the same side may remain open and its pupils dilated) is seen in ante-mortem hanging. The eyes are frequently protruded and firmer and the conjunc¬tiva congested, the pupils are usually dilated. Saliva may be found dribbling from the angle of the mouth (due to stimulation of the salivary glands by the ligature). Seminal emission is common. In rare cases (5 to 10%), the intima of the carotid arteries show transverse split. Hyoid bone is fractured in 15 to 20% cases. Are seen in persons above 40 years; involves the great horn at junction of the inner two-thirds and outer one-third.

Judicial hanging: Justifiable homicide is judicial hanging and death of a suspected criminal while executing arrest. Legal death sentence is carried out by hanging the criminal. The cause of death in judicial hanging is fracture dislocation at the level of second and third or third and fourth cervical vertebra.
Lynching is a type of homicidal death by hanging by large group of people.

Strangulation:
Strangulation is that form of asphyxia, which is caused from constriction of the neck by a ligature without suspending the body.
It is of two types: (1) Strangulation by ligature, and (2) manual strangulation or throttling.
Cause of death: Death may be due to (1) asphyxia, (2) cerebral anoxia or venous congestion (3) combined asphyxia and venous congestion, and (5) rarely fracture – dislocation of cervical vertebrae.
The mark in strangulation completely encircles the neck transversely. Classical signs of asphyxia are seen in about 50% of victims.

Doing a post-mortem on a suspected case of strangulation in situ examination of neck structures is done after opening the skull and the chest, to allow blood to drain from the neck blood vessels. Most important sign of strangulation is ligature mark. Hyoid bone may be fractured in older persons in 10 to 15% cases.

The common methods of homicidal strangulation are: (1) Strangulation by ligature, (2) Throttling, (3) Bansdola, (4) Garrotting, and (5) Mugging
Mugging is homicidal strangulation caused by holding the neck of the victim in the bend of the elbow.
Bansidola is a type of homicidal strangulation caused with sticks.
Garroting is type of homicidal strangulation caused by twisting a lever like torniquet.

(Signs of Strangulation) Signs of Asphyxia:
Intense maximum congestion and deep cyanosis of the head and neck is seen in strangulation. The eyes are wide open and pupils dilated. The tongue is swollen and protruded. Petechial hemorrhages are common in to the skin of the eyelids, face, forehead, behind the ears and scalp. Blood stained froth may escape from the mouth and nostrils and there may be bleeding from nose and ears. There is severe congestion and hemorrhage into the subcutaneous tissue in and above the area compressed. The intima of the carotid artery are not usually damaged. Injury of hyoid bone is not common in strangulation because the level of constriction is below the bone. Fracture of the thyroid cartilage is more common. Pulmonary oedema may be present.

Throttling
Throttling is manual strangulation. Fracture of the hyoid bone in 30-50% cases. Fracture of the thyroid cartilage and hyoid bone are usually found in above 40 years. Hyoid bone fracture does not occur in choking. It is always homicidal.

Hyoid bone fractures can be classified in to three groups: (1) Inward compression fractures, (2) Antero-posterior compression fractures, (3) Avulsion fractures.

Inward compression fracture is seen in throttling, where the main force is an inward compression acting on the hyoid bone. Antero-posterior compression fractures is seen in case of hanging, the hyoid bone is forced directly backwards, due to which the divergence of greater horns is increased which may fracture with outward displacement of the posterior small fragment. Avulsion fractures occur due to muscular over-activity, without there being direct injury to the hyoid bone. They are also called “tug” or “traction” fractures.

Suffocation:
Suffocation is a general term to indicate that form of asphyxia, which is caused by deprivation of oxygen, either due to lack of oxygen in the environment or from obstruction of the air-passages.

Smothering:
Smothering is a form of asphyxia which is caused by closing the external respiratory orifices either by the hand or by any other means, or blocking up the cavities of the nose and mouth by the introduction of a foreign substance, such as mud, paper, cloth, etc.

Gagging: is a form of asphyxia which results from forcing a cloth into the mouth, or the closure of mouth and nose by a cloth or similar material, which is tied around the neck.

Overlaying:It is a type of smothering. Overlaying or Compression suffocation results due to compression of the chest, so as to prevent breathing. Overlaying by mother is common in European countries. The usual findings are those of asphyxia.

Burking:It is a method of homicidal smothering and traumatic asphyxia.

Homicidalchoking
In choking, there is obstruction within airways. It is very rare and is practicable only when the victim is an infant or suffering from disability or, disease or, under the influence of alcohol.

Cafe Coronary:
This is a condition in which a healthy but grossly intoxicated person, who begins a meal, suddenly turns blue, coughs violently, then collapse and dies due to asphyxia. Death appears to be due to sudden heart attack. A blow on the back or on the sternum may cause coughing and expel the foreign body.

Traumatic Asphyxia
Traumatic asphyxia results from respiratory arrest due to mechanical fixation of the chest, so that the normal movement of the chest wall is prevented. Common cause is crushing by falls of earth in a coal mine or during tunneling or in a building collapse. An intense cyanosis of deep purple or purple-red colour of the head, neck and upper chest, above the level of compression is the prominent feature.

Sexual Asphyxia
Partial asphyxia causes cerebral disturbance with feeling of sexual gratification. These cases are associated with some form of abnormal sexual behavior, usually masochism and transvestism.

Drowning
Drowning is a form of asphyxia due to aspiration of fluid into air-passages, caused by submersion in water or other fluid. Commonest type of drowning is accidental.

In immersion syndrome, death occurs by vagal inhibition and cardiac arrest. Cold water drowning causes immersion syndrome. In secondary drowning, death occurs in half an hour to two days after resuscitation due to secondary changes in lungs. In secondary drowning, sign of asphyxia absent. Victim of drowning in a state of suspended animation can be revived in as long as 10-20 minutes. The extent and direction of the exchange through the alveolar lining depends on the difference between osmotic pressure of the blood and the water.

The drowning in fresh water, water passes rapidly from the lungs to the blood, leading to hemolysis and dilution of the blood with an abrupt increase in blood volume. Fresh water alters or denatures the protective surfactant which lines the alveolar wall. When water is inhaled, vagal reflexes cause increased peripheral airway resistance with pulmonary vaso-constriction, development of pulmonary hypertension, decreased lung compliance and fall of ventilation perfusion ratios. The concentration of serum electrolytes (sodium and calcium) decreases, serum potassium increases. The heart is subjected to hypoxia, overfilling, sodium deficit and potassium excess. Cardiac arrhythmias leading to ventricular tachycardia and fibrillation occur, probably due to hypoxia and hemodilution. Hemodilution leads to hemolysis, haemoglobinemia, and haemoglobinuria, marked hyponatraemia and hyperkalaemia. The potassium and chloride content of the left side of the heart is decreased.

Drowning in Sea water — Due to high salinity of sea water (usually over 3% NaCI), water is drawn from the blood into the lung tissue, and produces severe pulmonary oedema and hypernatraemia and increase in magnesium ion. This causes haemoconcentration. In sea water drowning, chloride content of the left side of the heart is higher (as is Mg concentration).

Causes of Death: (1) Asphyxia, (2) Ventricular fibrillation (3) Laryngeal spasm (4) Vagal inhibition (5) Exhaustion (6) Injuries.

Fatal period: Death usually occurs in 4 to 8 minutes of complete submersion. Hyper-ventilation before drowning can cause death.

Post-mortem appearance:
Gettler’s test is used in drowning. Gettler’s test is based on the biochemical changes in blood in a case of typical drowning. Gettler devised, a test to estimate the chloride content of blood from both sides of the heart. A difference of 25 percent in chioride content is considered significant.

— Limitations of Gettler’s test:
1. There is progressive loss of chloride from blood after death. To be maximal value therefore the test has to be made within a reasonably short time after death.
2. Has no value in atypical drowning.
3. Has no value in congenital cardiac defects such as shunts & patent foramen ovale where admixture of blood freely occurs between two sides of the heart.
4. Has no value if drowning medium and blood contain the same amount of chloride.

In homicidal drowning, multiple injuries may or may not be present. Chloride estimation is not of any help after 12 hours. Absence of foam in drowning can be found in death due to laryngeal spasm and immersion syndrome.

Regurgitation of gastric contents into the larynx and trachea in cases of drowning is due to vomit reflex due to medullary hypoxia. Cutis-anserina is seen in drowning. Cutis-anserina proves that molecular death present at the time of drowning. Wrinkling of limbs indicate that body was in water. Most important evidence for drowning is water in lungs and stomach. In drowning in unconscious state, there is no ballooning of lungs. Water can be absent in stomach in cases of drowning due to sudden death due to vagal inhibition. Presence of water in stomach in case of drowning is found in 70% cases. Deep inspiration above the water level and air pockets in clothing may cause early floatation of the body. Post-mortem staining is usually found on the face, the upper part of chest, hands, lower arms, and feet. The colour of PM stain is light-pink due to oxygenation, but in some cases it is dusky and cyanotic. Petechial hemorrhages are seen in subpleural tissues of lungs.

A fine white leathery froth is seen at mouth and nostrils, most characteristic external sign of drowning. The inhalation of water irritates the mucous membrane of air passages; mucous gland produces large quantity of tenacious mucous. Froth without mucous is seen in death due to strangulation, acute pulmonary oedema, electrical shock, during an epileptic fit, in opium poisoning and putrefaction.

Cutis anserina (goose skin or. goose flesh) in which the skin has granular and puckered appearance may be seen. Weeds, grass, sticks, leaves etc. floating in water may be firmly grasped in the hands due to cadaveric spasm. It indicates antemortem drowning. Bleaching of the cuticle becomes quite evident after 12 hours of immersion. The skin becomes sodden, thickened, wrinkled and white in colour, known as “Washer-women’s” hands, within 12-18 hours.

Wet drowning is due to entry of water into lungs. In wet drowning, lungs are overdistended and alveolar walls are torn. On section, an oedematous condition is seen. This has been described as “emphysema aquosum”.

In dry drowning, death occurs due to laryngeal spasm. There is no water entry into lungs. The alveolar walls may rupture due to increased pressure during forced expiration and produce sub-pleural haemorrhage known as ‘Paltauf’s haemorrhages’. They are shining, pale bluish – red, and may be minute or 3 – 5 cm in diameter. Usually present in the lower lobes.

The stomach contains water in 70% of cases. The small intestine may contain water in 20% cases. This sign is regarded as positive evidence of death by drowning as it depends on peristaltic movement which is a vital act. Haemorrhages are found in middle ear and temporal bone. Temporal bone haemorrhages are also seen in deaths due to hanging, head injury and CO poisoning.

Diatoms : Presence of  of diatoms in tissue is a sign of ante-mortem drowning. Diatoms are microscopic, unicellular, silica coated algae. The bone marrow of long bones such as femur, tibia, and humerus or sternum is examined for diatoms. Diatoms are examined by acid digestion technique.

Diagnosis
The reliable signs of drowning at autopsy are:
1. Antemortem drowning is best demonstrated by fine, white froth at the mouth and nose.
2. The presence of weeds, stones etc. grasped in hand, shows ante-mortem drowning.
3. The presence of fine froth at lungs and air passages.
4. The voluminous water-loaded lungs.
5. The presence of water in stomach and intestine.
6. Finding of diatoms in the tissues.
The above signs are not found if death occurs due to vagal-inhibition. In dry – drowning, the PM appearances are those of asphyxia.
The body floats in about 12 to 18 hours in summer and 18 to 36 hours in winter in India.

…….Continued in Part.II

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