Forensic Medicine and Toxicology(FMT) - AIM4PG

Medicolegal Application of Blood Groups: (1) Disputed Paternity: The question of disputed paternity arises in the Court in the following conditions. (1) When a child is born in lawful marriage, but the husband denies that he is the father of the child. (2) When a child is born out of lawful marriage, and the mother accuses a certain man of be in cr the father of the child, while the man denies the accusation. (3) When a woman pretends pregnancy and deli very and obtains a child claiming it as her own, in order to obtain a share in her husband's property. (4) In suits for nullity of marriage. (2) Disputed Maternity: When the same child is claimed by two women, or when two children are interchanged either by accident or by design in maternity home or hospital, or supposititious child, and when a woman kidnapping a child and claiming to be the mother of that child, blood grouping tests are helpful. (3) Crimes: Blood stains may be found on clothing and person of suspect. If the accused alleges that the stain is of his own blood, it will have similar blood group systems and haptoglobins. If the victim has similar characters, the test is not conclusive. If there is difference in blood group of the stain and the accused's blood, then the stain is of some other person's blood. If the characteristics of the victim's blood coincide with those of the stain, an association is established between the suspect and the victim (4) Stains due to Body Fluids: The blood group can be demonstrated in stains on clothes due to semen, sweat, saliva, nasal secretion, urine or faeces in persons who are "secretors". This may be a corroborative evidence of the accused. (5) Identity: The specificity of various blood group combinations is like that of the fingerprints. When an individual has some rare blood group, he can be identified with certainty. But when they are of common type, they are not of use. (6) Cause of Death: In certain cases, cause of death can be established, e.g., incompatible blood transfusion. Poisons can be detected in the blood.

CHEMICAL EXAMINATION OF BLOOD STAINS The chemical tests depend on the presence in the blood stains of an enzyme peroxidase, which in the presence of hydrogen peroxide, oxidises the active ingredient of the reagent and produces the characteristic coloured compound. (1) Benzidine Test : Cut out a small piece of stained material or tease out fibres from the stained fabric and place it on porcelain tile. Add a drop of saturated solution of benzidine in glacial acetic acid, and then a drop of 10 volumes hydrogen peroxide. If blood is present, dark blue colour is produced immediately. A positive reaction is given by blood of almost any age, blood that has been exposed to heat or cold, and blood stains treated with cleaning agents. This is the best preliminary test for blood and it detects blood when present in a dilution of one part of blood in three lakhs. A positive reaction is not proof of the presence of blood, but a negative reaction rules out of the presence of blood. A weaker reaction is obtained from certain other substances, e.g. pus, saliva, milk, rust, formalin, certain vegetable and animal juices, oxidising agents, bacteria, etc. (2) Phenolphthalein Test (Kastle-Meyer Test): To a solution extracted from the stain with distilled water, add ten to twenty drops of phenolphthalein reagent (phenolphthalein 2g. + sodium hydroxide 20g. + zinc+ distilled water 100 ml), and then a drop or two of 10 volumes hydrogen peroxide. If blood is present, a pink or purple colour develops immediately. The test is more specific for blood than benzidine test, but comparatively less sensitive. Traces of copper give positive reaction. The tests employing guaiacum (deep blue) and green are rarely used in medico-legal work.

Collection of Blood Stains: (1) A clean piece of white filter paper or a piece of clean white cloth or gauge or cotton swab may be used, allowing blood to soak into it, then drying it at room temperature. A control filter paper, etc. should also be sent for examination. (2) If the object is porous, a portion of unstained area should also be taken. (3) If the object is non-porous and particularly if it is metallic, stains can be removed by scraping and placed in small glass containers. They should not be placed in envelopes where they will be reduced to powder. (4) Stains on clothing may be scraped off or a fragment of the material cut. (5) If blood is liquid, a sample can be pipetted and placed in a bottle and refrigerated. Solvents: The solvents for blood stains are: (1) 10% solution of potassium cyanide. (2) 10% solution of glycerine in distilled water. (3) A weak solution of ammonia. A coloured solution is obtained immediately with any of the above solvents. Otherwise, the material must be covered and left for from 12 to 24 hours at room temperature.

Acts of Omission or Neglect: A woman is guilty of criminal negligence, if she does not take ordinary precautions to save her child after birth. The following acts of omission amount to crime. (1) Failure to provide proper assistance during labour may cause death by suffocation or head injury. (2) Failure to tie the cord after it is cut usually does not cause death by haemorrhage. Tearing of the cord within the uterus during delivery may cause massive haemorrhage and foetal death. (3) Failure to clear the air-passages which may be obstructed by amniotic fluid or mucus. (4) Failure to protect the child from exposure to heat or cold. (5) Failure to supply the child with proper food. THE ABANDONING OF INFANTS: (1) If the father or mother of a child under the age of twelve years, or anyone having the care of such child, leaves such a child in any place with the intention of abandoning the child, shall be punished with imprisonment up to seven years. (2) If the child so exposed or abandoned is a girl child, the person doing so shall be punished with rigorous imprisonment for a term which may extend to ten years and shall also be liable to fine which may extend to one lakh rupees (Sec. 317, I.P.C.). CONCEALMENT OF BIRTH: (1) Whoever, secretly buries or otherwise disposes of the dead body of child, whether such child dies before or after or during its birth, intentionally conceals the birth of such child, shall be punished with imprisonment up to two years. (2) If the child whose dead body is so disposed off is of a girl child, the person committing such offence shall be punished with rigorous imprisonment for a term which may extend to five years and shall also be liable to fine which may extend to fifty thousand rupees (Sec. 318, I.P.C).

Legal Problems associated with artificial insemination :- There is no statutory law in India for artificial insemination. Artificial insemination with the semen of the husband is justifiable and unobjectionable, since the child is actually the biologic product of both husband and wife, but it does not constitute evidence of proper consummation of marriage. The following are the legal apects of A.I.D. as applicable to India. (1) Adultery : The donor and recipient cannot be held guilty of adultery in India, as S. 497, I.P.C. requires sexual intercourse as necessary part of adultery. Adultery is punishable with imprisonment up to five years. (2) Legitimacy : The husband is not the actual father of the child, and as such, the child is illegitimate and cannot inherit property. (3) Nullity of Marriage and Divorce: Mere A.I. is not a ground for nullity of marriage or divorce, because sterility is not a ground for it. However, if A. I. is due to impotence, it is a ground. Consent of husband has no bearing on this. When A.I. was done due to the impotence of the husband, the wife may ask for nullity or divorce, even if a child was born out of A.I. If A.l. is done without the consent of the husband, he can sue his wife for divorce and the doctor for damages. (4) Natural Birth: If a child is born naturally some time after the birth of a child by A.I., the status of the child born after A.I. remains illegitimate unless it is adopted, and the status of the natural born child remains legitimate. But, if the parents do not declare A.l., the child remains to be a natural child for practical purposes. (5) Unmarried Woman or Widow : An unmarried woman or widow may have a child from A.I. but that child would be illegitimate. (6) Incest : There is risk of incest between the children born by A.I and children of the donor, but this is not an offence in India.

Precautions of artificial insemination : Certain recommendations have been made when a donor is used. They are : (1 ) Consent of the donor and his wife is essential. (2) The identity of the donor must remain secret. (3) The donor should not know to whom the semen is donated and the result of insemination. (4) The donor must be mentally and physically healthy and should not be suffering from any hereditary or familial disease. He should be screened with all available tests including chromosomal studies for possible genetic defects. (5) The donor must not be a relative of either spouse, he should have had children of his own. (6) The race and characteristics of the donor should resemble those of the husband of the woman as closely as possible. (7) The donor should be of the same blood group as that of the husband. (8) There should not be any Rh incompatibility between the donor and recipient. (9) The physician should have permission to use his own best judgement in selecting the donor. (10) The couple should be psychologically fit and emotionally stable. (11) The woman to be inseminated and her husband must give consent in writing that an unknown donor should be used. (12) A witness must be present, when insemination is done. (13) It is usually wise to use "pooled" semen. When husband's semen is mixed with that of a donor, there is the technical possibility that the husband may, in fact be the father of the child. ( 14) The physician who administers the artificial insemination should avoid delivering the child. This will avoid the necessity of either falsifying the birth records or disclosing the true paternity in those records. (15) Usually, a single donor's semen is not used to produce more than ten children.

DEATHS WHICH OCCUR DURING THE ADMINISTRATION OF AN ANAESTHETIC BUT WHICH ARE NOT DUE TO ANAESTHETIC: (1) The injury or disease which necessiate the operation is sufficiently serious to cause death, though the anaesthetic may have precipitated the death. (2) A patient suffering from a serious disorder, e.g., valvular disease of the heart, may have to undergo an operation for another disease or injury, in which the operation or anaesthetic may have only precipitated death. (3) The patient may be suffering from undiagnosed serious lesion, e.g. coronary artery arteriosclerosis which could have been an important contributory factor in causing death. (4) Surgical shock and exhaustion may be the major factors in causing the death of patient under anaesthesia. This can occur when the pre-operative condition of the patient was poor, or operation has been unduly prolonged. (5) A surgical accident during the administration of anaesthesia, e.g.,damage to a large blood vessel or aneurysm may cause death.

Lungs in fresh water drawning: In fresh water drowning, the lungs are ballooned but light in weight (about double the normal weight). They are pale- pink or pale grey due to squeezing out of blood from compression of the vessels in interalveolar septa by the trapped air and water in the alveoli and appear uniformly emphysematous. They retain their normal shape and do not collapse when they are removed from the chest. A crepitus is heard on sectioning and each portion retains its normal shape. On compression, little froth is squeezed out, and there is no fluid in the tissue unless there is oedema. Lungs in salt water drowning: In salt water drowning, the lungs are ballooned and heavy, weighing up to 2 kg. They are purplish or bluish in colour, sodden and jelly-like in consistency and pit on pressure. When removed and placed on a flat surface, they tend to flatten out. On sectioning of the lung, crepitus is not heard . Copious amounts of fluid pour out of the cut sections even without compression. The shape of the sectioned portion is not retained. When squeezed, the tissue is found to be filled with fluid in most parts of the lungs, i.e., they are wet and sudden. Occasionally,· small intra-alveolar haemorrhages are seen in both fresh water and sea water drowning which cause the red staining of the foam in the respiratory tract. The pleura may be discoloured by haemorrhages, but petechial haemorrhages of asphyxial type are not found. Petechial haemorrhages n:ay be present in the subepicardial region of the heart posteriorly. If the body remains in water for several hours, or if the postmortem is delayed for several hours after removal of the body from the water, these changes become less marked, and the difference in appearance between the fresh water and sea water drowning lungs are not clear. If there has been delay between death and examination, froth in the lungs and overdistension of the lungs is not seen in most cases of drowning.

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Immersion syndrome (hydrocution or submersion inhibition): Death results from cardiac arrest due to vagal inhibition as a result of (a) cold water stimulating the nerve endings of the surface of the body, (b) water striking the epigastrium, (c) cold water entering ear drums, nasal passages, and the pharynx and larynx which cause stimulation of nerve endings of the mucosa. Falling or diving into the water, feet first, or "duck-diving" by the inexperienced, or diving involving horizontal entry into the water with a consequent blow on the abdomen cause such accident. Alcohol increases such effects, due to the general vasodilation of skin vessels, and possibly by some central effects on the vasomotor centre. This type of very rapid death on immersion is also said to occur in emotionally tense individuals, such as intending suicides, in whom the nervous reflex arcs seem more active. This is seen in one to two percent of cases of drowning. Deprivation of oxygen caused by obstruction of alveolar spaces is a factor in all types of drowning, especially as the time of immersion lengthens.

Accidental Choking : Choking is almost always accidental. (1) Choking from objects being lodged in the posterior hypopharynx, blocking glottis and oesophagus is commonly seen in the very young, elderly, psychiatric patients or in the infirm, particularly where the ability to swallow or masticate is severely impaired. (2) Choking commonly occurs during a meal when food is accidentally inhaled, especially when the victim is laughing or crying. (3) Vomited matter may be inhaled by a person under the influence of drink or of an anaesthetic, during a fit of epilepsy, or while in a state of insensibility from other causes. (4) Infants usually regurgitate clotted milk after a meal, and this may fall into the larynx. (5) Choking may occur due to inhalation of blood from facial injuries, such as a broken nose, or dislodged teeth, and laceration of the lips and gums inflicted during fight, if the victim becomes unconscious and lies on his back. Sometimes, blood may be found as far as the smaller bronchioles. (6) Impaction of solid bodies, such as a large bolus of food, piece of meat, fruitstone, onion, potato, corn, button, coin, rag, rubber teat, seeds, live fish, mud, leaves, cotton, or a set of false teeth, extracted teeth in dentistry, blood and cloth after ENT operation, such as tonsillectomy may cause asphyxia. (7) Gauze packs inserted during an operation can be inhaled and cause death. (8) Children often place objects like marbles or coins in their mouths, which may pass into larynx or trachea during a sudden deep inspiration. (9) Objects like rubber balloons may be inhaled by children during play. (10) Choking due to regurgitation of food may occur during rape or violent sexual intercourse. (11) In head injury, irritation of the brain causes vomiting, which may be inhaled. (12) Food aspiration following suppression of the gag reflex by tranquilizing drugs is sometimes seen in lunatic asylums. The foreign body becomes arrested at, or just below the vocal cords and may produce an inflammatory reaction with oedema. (13) Insect bites especially those of bees, wasps and hornets, and drug reaction from penicillin, etc., can cause swelling of the lining membranes of the larynx and death within a few minutes due to an allergic reaction. (14) A blow to the front of the neck may cause severe swelling of the mucosa of the airway due to oedema and haemorrhage. Death may occur due to reflex vagal inhibition

Suicide by Smothering : ( 1) Suicidal smothering by the hand is impossible. (2) Suicide is possible by burying the face in a mattress or lying against the bed clothing to obstruct the nose and the mouth. It is usually seen in the mental patients or prisoners. (3) Sometimes, in cut-throat wounds, the trachea may be completely cut and the soft parts may obstruct the trachea and the victim is smothered. ( 4) Suicidal smothering can be effected by tying a polythene or similar bag over the head.

ENVIRONMENTAL SUFFOCATION: Death from hypoxic hypoxia may usually result from breathing in a vitiated atmosphere. A vitiated atmosphere is deficient in oxygen which is caused by displacement of oxygen from the atmosphere by inert gases or by gases generated in the atmosphere. CO, C02 , methane, sulphuretted hydrogen and sulphur dioxide are commonly found in vitiated atmosphere. CO displaces oxygen from the atmosphere, and sulphur dioxide prevents haemoglobin from combining with oxygen. Deaths are almost always accidental. The concentration of oxygen in air is about 21%, nirogen 79%, and C02 is 0.033%. An oxygen concentration of 16% or less is dangerous, and with 5% concentration, consciousness is lost rapidly and death occurs within a few minutes. (1) Smothering occurs in airtight place or one in which ventilation is negligible. This may occur when children become locked in old disused refrigerators or when they lock themselves into large boxes or trunks during play. (2) Suffocation due to lack of oxygen in the atmosphere may occur in the vicinity of lime kilns and wells or excavations in chalk rock, where the oxygen is displaced by C02• (3) In a confined space, such as tanks, grain-bins, silos, deep tanks of a ship, fermenters, tanrung vats, unused wells, sewers, etc., hazardous gases, vapour, dust or fumes may accumulate or the oxygen may be deficient. A person may be suffocated on entering such a confined space. ·(4) Inhalation of irrespirable gases, such as C0 CO, hydrogen sulphide or smoke from a bruning house , or entering into disused wells produce suffocation. C02 and methane are the most commonly encountered suffocating gases. Death occurs due to lack of oxygen. (5) Reduction of atmospheric oxygen as in decompression, such as cabin failure of aircraft at high altitudes. (6) It also occurs in ship's tanks or other industrial metal chambers, in which oxygen is replaced by nitrogen. (7) In deaths associated with replacement of oxygen with an inert gas, such as helium, rapid death is common before hypoxia had any physiological effect. In hypoxic death petechial haemorrhages are absent. Congestion and cyanosis may or may not be present.

Pseduo-Strangulation: (1) Occasionally marks are seen on the dead bodies of infants and children in whom the neck is short. These depressed marks are produced from folds in the skin due to bending of the head. (2) A similar mark of depression is found in short-necked persons after death, across front of the neck. (3) It can also be seen in decomposing bodies with tight collars, buttoned shirt at the neck or other clothing round the neck. In these cases, a deep groove simulating ligature mark of strangulation is produced due to the swelling of the tissues around the tight- fitting garment, as the body decomposes.

SPONTANEOUS HUMAN COMBUSTION: (Preturnatural combustion) : This is very rare. During putrefaction, inflammable gases are produced in abdomen due to the action of microorganisms upon organic matter. These gases are ignited if a flame is nearby. A human body may sometimes burn away almost completely, with minimal damage to the surrounding area. This occurs invariably near a hearth, or open fire-grate or chimney. The burning may be confined to the body, its clothing and a narrow zone of floor or carpet. It appears that when a person collapses and falls, and part of the body comes in contact with a source of heat, clothing catches fire and burns the limited amount of oxygen available in the room, after which that part is ignited, and adjacent body fat melts and soaks into clothes. The clothing acts as a wick, melts the next zone of adjacent fat, and the process is repeated along the length of the body, till the extremity joints are" reached, and the burning stops because of less fat and also covered with less layers of the clothes. The smoldering process causes deposit of oily film that coats the walls and ceiling.

Thermal fractures of the skull: The skull fractures occur most commonly in areas where the skull has been severely burned. There are two types of thermal fractures of the skull. (1) Intracranial increase of steam pressure causes separation of ununited sutures or an intracranial explosion occurs, producing fractures with gaping defects and widely separated bony margins. (2) The fracture occurs due to rapid drying of the bone with contraction, and only involves the outer table of the skull. In this type there is no displacement, and the lines of fracture are frequently stellate. Skull fractures are usually seen on either side of the skull above the temples. Sometimes they may be bilateral. They consist of several lines which radiate from a common centre and in some cases may fragment . The skull is often friable with flaking of the outer table. Heat fractures usually do not involve the sutures of the skull even in young persons with un-united sutures. Heat fracture may cross a suture line. Prolonged application of heat to the neck can make the hyoid bone so fragile that it breaks on gentle manipulation. In fire victims fractures of long bones are caused due to excessive shrinkage of the muscles, which exert unduly great pull on the tendons and bones. When the body is completely burnt, bones from the neurocranium are commonly found as pieces up to 10 cm in size, but not facial skeleton. Peculiar, characteristically curved fractures . Fractures in the skull due to burns. Fractures are often seen in bones of extremities exposed to very high temperatures. Burnt bone has a grey-white colour, usually showing fine network of heat fractures on its cortical surface, which may crumble on handling.

Diffuse Axonal Injury CLINICAL FEATURES: Diffuse axonal injury (DAI) is a clinical condition, in which there is diffuse injury of the axons with immediate loss of consciousness and coma of more than six hours. In mild DAI, there is coma for 6 to 24 hours. In moderate DAI, there is coma for more than 24 hours, but there are no clinical signs of brain stem dysfunction. In severe DAI, there is coma of more than 24 hours with brain stem signs. It occurs due to vehicle accidents in about 90% of cases, and due to falls and assaults in about 10% of cases. Features of diffuse axonal injury are: (1) A focal lesion in the corpus callosum and other midline structures involving the parasagittal white matter, the interventricular septum and the wall of the third ventricle with some intraventricular haemorrhage. (2) A focal lesion in one or both dorsolateral sectors of the rostral brainstem. (3) Microscopic evidence of numerous axonal swellings and axonal bulbs. In fatal head injury greater or lesser axonal injury is ahnost always found. AUTOPSY: Autopsy may not show any change, but in some cases petechial haemorrhages may be found in the cortex, at the junction of the grey and white matter, in the roof of the fourth ventricle and under the pia mater of the upper segments of the cervical cord. Oedema, foci of myelin degeneration, etc., may be found. In mild DAI, some axons may be damaged. In severe DAI, there is shearing of axons in the white matter of the cerebral hemispheres, corpus callosum and upper brain stem, with focal haemorrhages in the corpus callosum and dorsolateral rostral brain stem. Microscopic examination does not show axonal injuries up to 12 hours after injury. After 12 hours, the axons first appear dilated, then club-shaped and finally appear as round balls known as "retraction balls", which indicates transected axons. The number of retraction balls begins to decrease 2 to 3 weeks after injury, and clusters of microglial cells appear, followed by astrocytosis and demyelinisation.

Factors Affecting Rate of Cooling of the dead body (1) The difference in temperature between the body and the medium: The temperature fall is rapid when the difference between body and air temperature is great. In India, during summer, the temperature of the environment may be higher than that of the body temperature, and as such the cooling is very slow. In tropical climates the heat loss is roughly 0.4°C to 0.6°C and in temperate countries l°C per hour. (2) The build of the cadaver: The rate of heat loss is proportional to the weight of the body to its surface area. Thus, children and old people cool more rapidly than adults. (3) The physique of the cadaver: Fat is wea bad conductor of heat. Fat bodies cool slowly and lean bodies rapidly. (4) The environment of the body: A body kept in a well-ventilated room will cool more rapidly than one in a closed room. Moist air is a better conductor of heat than dry air, so that cooling is more rapid in humid atmosphere than in dry atmosphere. Cooling in water is rapid because, water is a far better conductor of heat. Cooling in still water is about twice as fast as in air, and in flowing water, it is about three times as fast. Bodies cool more slowly in water containing sewage effluent or other putrefying organic material than in fresh water or sea water. (5) Covering on or around the body: The rate of cooling is slow when the body is clothed, as clothes are bad conductors of heat. A breadspread covering may at least halve the rate of cooling. Because of the above factors, an accurate formula cannot be devised to define rate of heat loss. The rectal temperature of an average-sized naked body reaches that of environment in about 15 to 20 hours. If the body is exposed to a source of heat for a few hour shortly after death, its temperature will rise. A body in zero weather may undergo freezing and become stony-hard from formation of ice in cavities and blood vessels. The ice inside the skull may expand and cause separation of sutures. Medicolegal Importance: Determination of temperature of the body is important only in cold and temperate climates, where more people die indoors. They are often useless in warm or tropical climate zones and outdoor deaths. In tropical zones, the postmortem fall in temperature may be minimal. It helps in the estimation of the time of death., which is not reliable. By: Dr Nayana For more notes join www.aim4pg.com/study-group

MOLECULAR DEATH: It means the death of cells and tissues individually, which takes place usually one to two hours after the stoppage of the vital functions. Molecular death occurs piecemeal. Individual cells will live on their residual oxygen for a variable time after the circulation has stopped, depending on the metabolic activity of the cell. The subsequent changes occur due to metabolic dysfunction and later from structural disintegration. Nervous tissues die rapidly, the vital centres of the brain in about five minutes, but the muscles live up to one to two hours. Mechanical excitability of skeletal muscle: (1) Tendon reaction or Zasko's phenomenon: Striking the lower third of the quadriceps femoris muscle about I 0 cm. above the patella with a reflex hammer causes an upward movement of the patella because of contraction of the whole muscle.This can be seen up to 1 to 2 hours after death. It seems to be a propogated excitation of muscle fibres. (2) Idiomuscular contraction or bulge: Striking at the biceps brachii muscle with the back of a knife causes a muscular bulge at the point of contact due to local contraction of the muscle. In the second phase lasting for 4 to 5 hours a strong and typically reversible idiomuscular pad develops. In the last phase, a weak idiomuscular pad develops between 8 to 12 hours, which may persist up to 24 hours

Bone length measurement Long bone lengths using osteometric board are measured as follows (I) Femur: Head to medial condyle. (2) Tibia: Lateral condyle to tip of medial malleolus. (3) Fibula: Tip of head to tip of lateral malleolus. (4) Radius: Medial margin of head to tip of styloid process. (5) Ulna: Top of head to tip of styloid process. (6) Humerus: Trochlea to the head. A useful rule of thumb is that the humerus is 20%, the tibia 22%, the femur 27%, and the spine 35%, of the individual's height in life. In the absence of long bones, adult stature can be calculated from the articular length of the five metacarpals.