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Medico-legal Autopsy
Introduction
Forensic pathology: Deals with the investigation of sudden, unexpected and/or violent deaths that includes determining the cause of death and the circumstances of how the death occurred.
Autopsy: Refers to the systematic examination of a dead person for medical, legal and/or scientific purposes.
Academic autopsy: Dissection carried by students of anatomy.
Pathological, hospital or clinical autopsy: Done by pathologists to diagnose the cause of death or to confirm a diagnosis.
Medico-legal or forensic autopsy: Type of scientific examination of a dead body carried out under the laws of the State for the protection of rights of citizens in cases of sudden, suspicious, obscure, unnatural, litigious or criminal deaths.
Virtopsy: A bloodless and minimally invasive procedure to examine a body for cause of death.
Psychological autopsy: An investigative procedure of reconstructing a person’s state of mind prior to death.
Purpose/Objectives of Autopsy
Identity of the deceased in case of decomposed, burnt, mutilated or an unidentified body.
Cause of death, whether natural or unnatural, and to interpret the significance and effect of the disease present in case of natural death.
Approximate time of death, mode of death, age of injuries, and place of death.
Manner of death, whether accidental, suicidal or homicidal.
Poison or weapon responsible for death in case of homicide.
Volitional activity possible after receiving the trauma, and survival time.
Extent of external and internal injuries present.
Whether the injury present is expected to cause death in ordinary course of nature.
Whether deceased received any treatment before death.
In case of homicide, whether:
One or more person(s) was/were involved.
Any trace evidence was left behind on the body that may help in identification of the assailant.
Any other offence was related with the death, e.g. strangulation along with rape.
More than one method or weapon was involved in the crime, e.g. firearm along with knife.
The body has been displaced from the original place of disposal.
The relative positions of victim and the assailant(s) can be deciphered.
In case of newborns, to determine the question of live birth and viability of the baby.
In case of mutilated or skeletal remains, to determine if they are human, and if human, whether they belong to one or more than one person, the probable cause of death and approximate time since death.
Procedure for Medico-legal Autopsies
In certain cases, such as murder, poisoning, traffic accidents, firearm injuries, and sexual offences, visiting the crime scene is worthwhile.
Crime is often ruled out in favour of accident, suicide, or natural causes.
The police or Magistrate must order the autopsy.
All government-employed registered medical practitioners (RMP) can perform the exam.
Two physicians do autopsies on women who die of burns or other suspicious causes within seven years of marriage.
For custodial, operating room, and second autopsy fatalities, a panel of physicians is formed.
To resolve disagreements, a board should have an odd number of members.
No unauthorized person should be present at the autopsy.
The medico-legal autopsy should be conducted in an authorized center.
Histopathological investigation is impossible before embalming the corpse.
When the corpse is putrefied, an on-site autopsy may be needed.
Even if the body is decomposed, autopsy should be done.
In such cases, forensic entomologists can estimate victim death and other useful information.
Autopsy should be done immediately after getting the demand.
A copy of the inquest or preliminary inquiry report, a dead-body challan with the deceased's name, age, sex, identity markings, religion, apparent cause of death, and any other important papers are included with the demand.
Before conducting the autopsy, the doctor should read the inquest report and requisition and sign them serially.
The inquest report may include incomplete, inaccurate, or erroneous history.
The autopsy should be done in daylight because colour changes like jaundice, bruises, and postmortem staining cannot be seen in artificial light.
If the body is received in the mortuary at night, it is preserved at 4°C after noting the date and exact time.
A police officer or any other authorized person and two relatives should identify the dead body in front of the autopsy surgeon.
Medico-legal autopsy does not require any consent from the relatives of the deceased.
Both positive and negative findings should be recorded.
Nothing should be erased, and all alterations should be initialled in the report.
It is absolutely essential to preserve the chain of evidence by identifying the body and maintaining absolute control of specimens removed at autopsy.
A list is made of all the articles removed from the body. All should be labelled, sealed, mentioned in the report and handed over to the police.
After completion of autopsy, the body is stitched, washed and restored to the best possible cosmetic appearance, and then handed over to the police constable/IO.
Instruments for Autopsy Examination
Scalpel and disposable blades of 22 size.
Toothed forceps: Teeth lend strength in gripping the skin and organs.
Rib shear: Small pruning shears and are used to cut through the ribs prior to lifting off the sternum.
Enterotome: Large scissors used for opening the intestines.
Scissors: used for opening hollow organs and trimming off tissues.
Bone cutter: This is used to cut the ribs and has curved blades.
Councilman rib shear/cutter: Small pruning shears used to cut through the ribs prior to lifting off the sternum.
Vibrating saw (Stryker saw): Instrument of choice for most autopsy surgeons for removing the skull cap.
Bone saw: The hand saw can be used to saw through the skull, but it’s very slow-going compared to the vibrating saw. Infections from aerosols being thrown up are other disadvantages.
Virchow skull breaker or chisel: After scoring the calvarium with the vibrating saw, the chisel is used to separate the top of the calvarium from the lower skull, thus exposing the brain and the meninges.
Hammer with hook: is used with the chisel to separate the calvarium from the lower skull.
Brain knife: Long knife used to smoothly cut solid organs into slices for examination.
Hagedorn’s needle: is used for sewing up the body after autopsy.
External Examination
The observation and documentation of various external characteristics of the decedent is the essence of the external examination.
Clothing: They are listed and their number, labels and laundry marks, design, stains, tears, loss of buttons, cuts, holes or blackening from firearm discharges with their dimensions should be noted.
Hair, fibers, paint chips, glass bits, flora, and insects are labeled and kept.
Jewelry may prove identity, pockets can include medications, and personal documents can reveal medical history.
To prevent confusing struggle signals, remove garments gently without ripping them.
If they cannot be removed whole, trim them along the garment seam away from bullet holes or injuries.
Following autopsy, wet garments should be air-dried, wrapped, sealed in paper bags, and sent to police.
The whole surface of the body should be carefully examined before and after washing from head to foot, and back and front, and the details noted.
Body length, weight, sex, race, dentition, general state, built, development and nourishment is noted.
Following should be noted in external examination:
Skin: General health, asymmetry, or muscle loss. Blood, dirt, vomit, excrement, corrosives, poisons, and gunpowder stains are recorded.
General description includes deformities, scalp hair, beard, scars, tattoo marks, moles, skin disease, circumcision, amputations and vermilion mark.
Signs of disease: Edema of legs, dropsy, surgical emphysema about the chest, skin disease, eruptions.
Time since death: Rectal temperature, rigor mortis, postmortem staining, putrefaction, maggots, stomach contents, etc. are required to estimate time since death.
Face: Cyanosis, petechial hemorrhages, pallor, protrusion or biting of the tongue, state of lips, gums, teeth, marks of corrosion or injuries inside the lips and cheeks.
Eyes: Condition of the eyelids, conjunctivae, softening of the eyeball, color of sclera, state and color of pupils, contact lenses, petechiae, opacity of the cornea, lens and artificial eyes .
Natural orifices, i.e. nose, mouth, ears, urethra, vagina and anus should be observed for any discharges, injuries and foreign body. Leakage of blood or CSF from ears, mouth or nostrils is noted.
Neck: Bruises, fingernail abrasions, ligature marks or any other abnormalities.
Thorax: Symmetry, general outline, and injuries if any.
Abdomen: Presence or absence of distension or retraction, striae gravidarum.
Back: Bedsores, spinal deformity, or injuries.
External genitalia: General development, edema, local infection, and position of testes.
Hands: Injuries, defense wounds, electric marks, and in clenched hands if anything is grasped.
Fingernails: Presence of tissue, blood, dust or other foreign matter may be indicative of struggle.
Limbs and other parts: Fracture and dislocation.
External Injuries
Documenting injuries by kind and anatomical location or numbering them without assuming a severity rating is the last step of external assessment.
The weapon, assault direction, and other crucial details may frequently be inferred from exterior data.
Each injury is characterized by its:
Type/nature of injury.
Size (length, breadth and depth).
Shape.
Site (in relation to two external anatomical landmarks).
Direction of application of the force.
Margins, edges and base.
Distance of the wound from the heel.
Time of infliction of the injury should be studied from inflammatory and color changes.
Vital reaction.
Foreign materials, e.g. hair, grass, fibers, etc.
Hair should be shaved to reveal injuries.
Before opening the corpse, deep wounds should not be examined.
Burns should be described by kind, location, body surface area, and severity.
Search for punctured wounds, lip frenulum bruises, and injection marks.
Body drawings done on paper are beneficial.
In skeletal diagrams, injuries should be shown.
Major injuries are now photographed. Markers with the autopsy number and a measuring scale should be added to confirm that the images match the case.
For identification and documentation, external examinations use photos.
Tattoos, bruises, trace materials, and patterned injuries are enhanced by infrared and UV photography.
Patterned injuries may be enhanced by high-contrast black-and-white photos or computer-directed picture augmentation.
Indications of radiological examination
Identification and dentistry
Mutilated/charred remains
Gunshot wounds
Air embolism
Sharp force wounds
Barotrauma
Explosives deaths
Child abuse
Decomposed body
Internal Examination
Examine the damaged cavity first. Routinely open and inspect the skull, thorax, and abdomen. Dissectors choose whether to access the skull or body cavities first.
In suspected head injury, the skull is opened first and then the thorax and the abdomen, but some autospy surgeons are of the view that it should be opened after blood has been drained out by opening the heart.
In suspected asphyxial deaths due to compression of neck, the skull and abdomen is opened first followed by dissection of the neck.
The draining out of blood from neck vessels via the skull provides a comparatively cleaner field for the study of neck structures.
In all other cases, the thorax and abdomen are opened first, and then the skull.
Skin Incisions
I-shaped incision: extending from the chin straight down to the symphysis pubis and avoiding the umbilicus (because the dense fibrous tissue is difficult to penetrate with a needle, when the body is stitched after autopsy).
Y-shaped incision: Straight line of Y corresponding to the xiphisternum to pubis incision and forks of Y runs down medially to the chest and extending towards the acromion process.
Some prefer to extend the upper incision in an arc around the inferior portion of the female breasts (inframammary incision), but there is a chance of fluids inadvertently leaking from the closed body after autopsy.
This technique is commonly used in the US.
Modified Y-shaped incision: An incision is made in midline from suprasternal notch to symphysis pubis.
The incision extends from suprasternal notch over the clavicle to its center on both sides and then passes upwards over the neck behind the ears (1 cm behind external auditory meatus).
It is used when a detailed study of neck organs is required, like in hanging or strangulation.
T-shaped or ‘bucket handle’ incision: The neck is opened with a transverse incision which runs from acromion to acromion process (bisacromial) along the line of clavicles, creating a trough that is located at the jugular bifurcation.
Then a single midline incision is made down the anterior body wall, avoiding the umbilicus, to pubis.
The resulting incision is called a calyx since it creates a cup-like structure.
This is sometimes called a ‘U-shaped’ incision.
Evisceration Methods
En masse: This method, described by Letulle, involves removing most of the internal organs in one full swoop.
It removes organs quickly but takes the longest to dissect.
It has the advantage of leaving all attachments intact.
Virchow’s method: This method of evisceration is simply removal of individual organs one by one with subsequent dissection of that isolated organ.
It is useful in assessing individual organ pathology, a quick and effective method, if the pathological interest is in a single organ.
En bloc removal: It is a compromise between the above two methods and most widely used in the UK.
Ghon developed this method, which is relatively quick, but preserves most of the important inter-organ relationships.
In situ dissection: This method, developed by Rokitansky, is rarely performed which involves dissecting the organs in situ with little actual evisceration being performed prior to dissection.
It may be the method of choice in patients with highly transmissible diseases.
The autopsy surgeon must use an organ-specific dissection approach to eviscerate.
Hollow structures, such as blood vessels and GI tract is cut opened in order to reveal the pathology present inside.
For solid organs, many parallel cuts, in a fashion similar to slicing a loaf of bread (‘bread-loafing’) is done.
Examination Proper
Abdomen and Pelvis
Stomach: Two ligatures are applied at the cardiac end of the esophagus and two ligatures below the pyloric end of the stomach.
The stomach is removed by cutting between the two ligatures at both ends and opening along the larger curvature.
The mucosal membrane is inspected for the presence of any stain, congestion, bleeding, desquamation, ulceration, sloughing, or perforation.
The stomach contents are observed in terms of amount, kind of material/food, stage of digestion, color, and fragrance.
Intestine: It is cut throughout its full length. Any harm or response caused by poison or the presence of a foreign substance, such as a bullet, is recorded.
In cases of mercuric chloride poisoning, ulcerative colitis-like lesions are seen.
Liver: It is removed and its weight, size, color, consistency and presence of any pathology or injury is noted.
An adult's liver weighs around 1300-1550 g.
Hepatomegaly is often caused by inflammatory or neoplastic processes, however fibrotic diseases such as cirrhosis result in a reduced organ.
Several transverse slices are taken from one side to the other for macroscopic evaluation of the liver.
The gallbladder is removed together with the liver. It is noticed whether there is any disease or stone development inside it.
Spleen: It is removed by cutting through its pedicle; its size, weight, consistency and condition of capsule, and rupture, injuries or disease is noted.
Before dissecting the spleen, the hilum should be checked for splenunculi.
The weight of a typical spleen is between 130 and 170 g.
It is sectioned along its long axis, and the characteristics of the parenchyma, follicles, and septa are documented.
Septicemia causes the spleen to become mushy and liquid, making slicing difficult.
Slicing is simple with a normal spleen, amyloid accumulation, or portal hypertension.
Pancreas: It is removed along with the stomach and duodenum. It is sliced by multiple sections at right angles to the long axis to expose the ductal system.
Kidneys: They are removed along with adrenal glands after tying the ureters along with the vessels at least 1 inch away from the hilum.
Texture, congestion, bleeding, and damage should be evaluated on the surface of the kidneys as well as the covering capsules.
An adult kidney weighs around 150 g.
Fine or coarse scars associated with capsular fibrosis may be seen in chronic renal parenchymal illness such as nephrosclerosis, ischemia, or infection.
The kidney is sectioned longitudinally into the hilum via the convex border. Calculi and inflammation in the pelvis are investigated.
Renal infarcts are pyramidal or wedge-shaped lesions with the base at the cortical surface and the tip pointing to the artery supply's medullary origin.
They begin as pale necrotic regions with hyperemic margins and proceed to yellow-gray lesions that eventually form depressed V-shaped gray-white furrows.
Urinary bladder: It is inspected on the spot. If the bladder contains urine, it is syringed out before opening to eliminate the possibility of contamination by blood or other debris.
Any pathology, bleeding, congestion, or damage to the bladder should be investigated. Both ureters should be opened longitudinally.
Female genitalia: The uterus and its appendages should be checked in situ before being removed en masse with the vagina by an external incision on the labia up to the symphysis pubis above and the anus below.
An incision is made along the pelvic brim and continues downhill to the pelvic outlet until it meets the vaginal incision.
The uterus is examined and its dimensions, weight, whether gravid, parous or nulliparous, or any pathology present is noted.
In the event of a gravid uterus, the state of the whole result of conception should be observed.
In situations of abortion or attempted abortion, the presence of any portion of the product of conception within the cavity, the color of the endometrial surface, erosion, any lesion, ulceration, or perforation of the vaginal canal, or the uterine wall is noticed.
A foreign body may be found within the uterine cavity.
The smell and type of the fluid contained within the uterine cavity are recorded.
Signs of tool usage may be seen in the cervix or os.
The vagina is inspected for damage, foreign bodies, hymen, mucous membrane, and rugae condition.
Any fluid in the vaginal cavity is aspirated and saved.
The existence of corpus luteum in the ovaries should be checked.
Fallopian tubes and ovaries have unique medico-legal relevance in situations of ectopic pregnancy fatalities caused by their rupture.
Prostate (in males): It is examined for enlargement or malignancy. In prostatitis, it is firm and in carcinoma, it is hard and granular.
Chest
The chest skin and muscles are dissected sideways and continued back to the midaxillary line, down to the costal edge, and up over the clavicles.
The ribs and sternum are inspected for fractures, and the chest is opened by using a cartilage knife to cut the costal cartilages close to the costochondral junctions and commencing at the upper border of the second cartilage.
The sternoclavicular joint is then disarticulated on either side by putting the knife tip into the semicircular joint.
Before the sternum is completely removed, the pleural cavity is checked.
Before removing thoracic organs, the atrium and ventricle are examined for air embolism, distension or collapse of the lungs, the chest cavity for fluid, hemorrhage, or pus, pleural adhesions, and traumas such as rib fracture.
Lungs
After tying the arteries and bronchioles, both lungs are separated from the mediastinal structures.
Pleuritis, petechial hemorrhages, damage, effusion, hemothorax, pneumothorax, or pyothorax are all noted.
An adult's normal lungs weigh 250-400 g each, but they may weigh more than 1 kg in situations of acute cardiac failure or widespread alveolar injury.
It is customary to cut open the airways from big to tiny, from medial to lateral, to include all lobes and segments opening along the branches as they are met.
The impression of the parenchymal look and texture is noticed, and apical illness such as ancient tuberculous cavities or fungal balls may also be seen.
The parenchyma is squeezed, and any pus or fluid that is expressed is recorded.
The remainder of the parenchyma is next examined by horizontally slicing through each lobe with a brain knife.
In situations of massive mass lesions, it is better to create wide horizontal slices across the whole lung rather than opening the airways and arteries (e.g. carcinoma).
Dissection of the vessels
Antemortem thrombus: firmly adheres to the lining endothelium, with a pale, granular and transversely ridged surface because of alternating layers of platelets and fibrin.
Postmortem thrombus: is weakly adherent to the lining endothelium, dark-red, glistening and friable
Black currant-jelly: When blood clots rapidly, a soft, lumpy, uniformly dark-red, rubbery and moist clot is produced.
Chicken-fat: When red cells sediment before blood coagulates, the red cells produce a clot similar to the first, but above this a pale or bright-yellow layer of serum and fibrin is seen.
Heart
The heart is maintained at the apex, raised, and isolated from the other thoracic organs by severing the inferior and superior vena cava, pulmonary arteries, and ascending aorta as far away from the heart as feasible.
The heart's size and weight are recorded.
The adult heart weighs between 250 and 300 g.
Overweight hearts are vulnerable to abrupt, fatal arrhythmias.
The heart may be dissected in a variety of ways.
The proper approach is chosen based on the patient's age and any detected abnormalities.
The heart's general anatomy must be assessed for any congenital defects.
The condition of the valves is observed, as well as the presence and degree of atheroma in the valves and the intima of the major vessels.
Any ischemic lesion is investigated.
The condition of the myocardium, chamber size, thickness of the right and left ventricle, endocardium (subendocardial bleeding in the left ventricle), valvular lesions, and aorta condition with reference to any aneurysm, atherosclerosis, or syphilitic aortitis (tree bark appearance) are all observed.
Examination of the Heart
Valvular heart disease is more frequent than coronary artery disease.
The myocardium is checked for fibrosis or evidence of a recent infarction.
When a myocardial infarction is more than 12 hours (h) old, it is readily identified.
If an infarct is found, sections from its core and peripheral zones may be used to determine the beginning of ischemia damage and any recent expansion.
The extramural coronary arteries are checked by making serial cross-sectional incisions approximately 3-5 mm apart to look for atherosclerotic constriction, with the usual location being 1 cm distant from the origin of the left coronary artery.
Microscopic inspection should begin with the narrowest segments and any regions harboring thrombi.
The anterior descending branch of the left coronary artery is severed at the front of the septum, followed by the circumflex branch on the opposite side of the mitral valve.
The right coronary artery is traced from the aorta to a cut at the pulmonary valve and then above the tricuspid valve.
The presence of acute coronary lesions, such as plaque rupture, plaque bleeding, or thrombus, is detected.
The degree of coronary artery atherosclerosis is classified based on the approximate percentage stenosis induced by the plaque.
Anything less than 50% is considered mild, 50-75% is considered moderate, and more than 75% is considered severe.
Another method to examine the heart is the inflow-outflow method or following the direction of blood flow.
The right atrium is opened first, then the tricuspid valve, and finally the pulmonic valve.
The left atrium is next opened, followed by the mitral and aortic valves.
The valves should be checked before being cut and the valve orifice measured while opening.
At this stage, special sections may be taken to analyze the heart's conduction (electrical) system.
Another lesser used method is the short axis or ventricular slicing method.
With the heart in the anatomical position, the first slice is made across the heart approximately 3 cm from the apex, separating it from the rest of the heart.
Additional full slices are then cut in parallel to this slice, 1 cm apart, until they reach below the atrioventricular valves.
The remainder is then investigated by making openings along the blood flow channel.
It is beneficial if ischemic myocardial illness is suspected since it clearly shows the spread of infarction.
The intramural or ‘sandwich’ technique can be used to cut through the thickness of the left ventricle.
The heart is placed open on the cutting board, with the endocardium downwards.
A knife is passed into the cut edge of the left ventricle and sliced right through the muscle, keeping equidistant between endocardium and epicardium.
The myocardium can then be opened out like a book, showing the interior with any infarcts or fibrotic plaques.
Examination of valve: The circumference of the valve is measured.
The circumference of mitral valve is 8–10.5 cm (mean 10 cm) and admits two fingers; tricuspid valve is 10–12.5 cm (12 cm) and admits three fingers; aortic valve is 6–8 cm (7.5 cm) and pulmonary valve is 7–9 cm (8.5 cm).
The decrease in circumference is suggestive of stenosis whereas increased circumference could be due to regurgitation or incompetent valves.
Ventricular hypertrophy: An estimate is made by measuring the thickness of the ventricular walls at a point about 1 cm below the atrioventricular valve.
The upper limits of normal are: left ventricle: 1.5 cm, right ventricle: 0.5 cm and atrial muscle: 0.2 cm.
Subendocardial or Sheehan’s Hemorrhages: These flame-shaped, confluent hemorrhages appear in one continuous sheet rather than patches in the left ventricle, on the left side of the interventricular septum, and on the opposing papillary muscles and adjacent columnae carnea.
These are seen in:
Severe loss of blood or shock
Intracranial damage, such as head injury, cerebral edema, surgical craniotomy or tumors
Death due to ectopic pregnancy, ruptured uterus, abortion, antepartum or postpartum hemorrhage
Poisoning, e.g. arsenic or oleander
Agonal thrombi: In case of a person dying slowly due to circulatory failure, a firm, stringy, tough, pale-yellow thrombus forms in the cavities, usually on the right side of the heart.
The pericardium is examined for presence of any pathology or injury.
The contents of the pericardial sac and quantity of fluid is noted.
Pericardial effusion, cardiac tamponade, subpericardial hemorrhage and constrictive pericarditis are looked for.
Neck
Before removing the thoracic organs, the neck structures are checked so that the tongue, larynx, trachea, and esophagus may be removed together with the lungs.
This aids in the inspection of the whole upper respiratory system in its entirety.
In the event of death caused by purported neck constriction, there may be fracture of the hyoid bone or thyroid cartilage with extravasation of blood into the tissues, as well as harm to the carotid arteries, sternomastoid muscles, or platysma.
The cervical vertebrae and the associated section of the spinal cord may be injured if the neck is compressed with hard objects.
The level and amount of additional mechanical injuries to the neck are carefully investigated to determine the kind of damage, as well as the organs or structures harmed, which result in death.
Skull and Brain
Procedure
A wooden block is put beneath the shoulders, extending the neck and securing the head with a headrest.
A coronal incision is created in the scalp that extends from one mastoid process slightly below the ear to the opposing mastoid process and continues across the vertex of the head.
The incision should reach the periosteum.
The scalp is reflected forward to the superciliary ridges and backward to a point near the occipital protuberance.
There is evidence of hematoma, petechial bleeding, edema, or fracture.
For cutting the skull, the temporal and masseter muscles are incised on both sides.
The saw-line is produced in a slightly V-shaped manner (angle of 120°) so that the skull cap may fit back into place when the body is rebuilt.
Remove the skull cap by sawing it just above the superciliary ridges in front, to the base of the mastoid process on either side, and just above the occipital protuberance behind.
Dura
The dura is inspected from the outside for extradural bleeding (weight and volume are recorded if present) and antemortem thrombus in the superior sagittal sinus.
It is sliced along the line of the detached skull cap and gently dragged from front to back while cutting falx cerebri, and subdural and subarachnoid hemorrhage are inspected.
The weight and amount of subdural bleeding, as well as its impact on the brain—flattening or asymmetry—are all observed.
Subdural bleeding may be cleansed with flowing water, whereas subarachnoid hemorrhage cannot.
Delivery of the Brain
Put four left-hand fingers between the frontal lobes and the skull.
Pull them backward, then sever the nerves and arteries as they emerge from the skull with your right hand.
Cut the tentorium at the petrous bone's superior edge.
Cut as far below the cervical cord, first cervical nerves, and vertebral arteries as feasible.
With the left hand, support the brain throughout.
Remove the brain, as well as the cerebellum and brainstem, which are held in place by the right hand.
Check for antemortem thrombi in the residual venous sinuses and the cerebral cavity.
Remove the pituitary gland by chiseling the posterior clinoid processes and incising the sella turcica diaphragm around its perimeter.
Remove the dura and look for any fractures at the base of the skull and the remainder of the cranial cavity.
Hold the skull cap up to the light to check for fractures.
Examine the mastoid for any accumulation of pus, hemorrhage, or fluid in the middle ear by removing a wedge-shaped part of the petrous temporal bone.
Examination of the Brain
The brain is weighed and then checked for edema, shrinkage, or herniation, as well as asymmetry or flattening of the convolutions on the top and lateral surfaces.
Arteriosclerosis, embolism, and aneurysms are all examined in the cerebral vessels (especially the circle of Willis).
Berry aneurysms (which range in size from a few millimeters to a few centimeters) are often seen at artery junctions, particularly those between the posterior cerebral arteries, the posterior connecting vessels, the middle cerebral arteries, and the anterior communicating arteries.
A thrombus or an atheroma may cause a cerebral infarction.
Most medico-legal autopsies examine the brain in its fresh condition; but, in certain situations, the autopsy surgeon may need the brain to be 'fixed' before further investigation.
Fixation is a critical step in examining the brain and spinal cord properly.
The best regular fixative is 10% formalin, and good fixing takes 2-3 weeks.
The addition of acetic acid to the fixative solution in fetuses and newborns enhances the specific gravity of the fixative and enables the brain to float in the solution.
It also makes the tissue tougher without changing its histological properties.
Dissection of the Brain
The coronal cutting technique is the most often used and dependable method of brain sectioning, whether the examination is performed fresh or after formalin fixation.
All sections, including the cerebrum, cerebellum, and brainstem, are serially sectioned. The cerebellum and brainstem must first be separated from the cerebrum. This is done as high as feasible, using a huge scalpel cutting the surface in a horizontal plane.
Using a scalpel, the brainstem is separated from the cerebellum at the cerebellar peduncles, as near to the brainstem as feasible.
Cerebrum
The cerebrum is then dissected at 1 cm intervals on a coronal plane.
If the brain is still fresh, it is cut from the frontal and superior surfaces.
The major goal with the fresh brain is to be as soon as possible, since the brain is so delicate that it collapses quickly.
The initial slice in a fixed brain is through the mammilary bodies (at the basal surface), which split the brain in half in the precise coronal plane.
After that, each half is cut 1 cm at a time, with the flat side facing down.
To prevent a sawing action and consequent imperfections on the cut surface, it should be done with a single sweep with a brain knife.
These slices should then be arranged in a straight line on a level surface.
Other planes that can be used for special cases:
Cutting the brain in the plane of CT-scans, for comparison with the radiology.
Single, midline sagittal section, particularly useful if a third or fourth ventricle lesion is expected.
Features to look for:
The cortical ribbon, white matter, basal ganglia, and lateral ventricle should be evaluated for any asymmetry or brain shift that would suggest a space-occupying lesion—abscess, massive hemorrhage, recent infarction, or either metastatic or original malignancies.
Old infarcts are cystic areas that do not cause a brain change.
Tiny localized lesions, such as those linked with hypertension and gray regions of demyelination (plaques) inside the white matter, may not induce any brain change.
A dilated lateral ventricle may imply atrophy.
Chronic drinkers often have cerebral cortex (gray matter) shrinkage.
Cerebral fat emboli that have totally clogged the brain's tiny capillaries may be apparent to the naked eye as punctate hemorrhages in the white matter.
Petechial hemorrhages in the white matter are a typical finding in anaphylactic shock deaths.
Edema in the white matter surrounding or deep to contusions, lacerations, or ischemic lesions is found in head injury.
If the brain is injured, consecutive sections parallel to the affected surfaces should be created until the whole depth of the wound is disclosed.
Cerebellum
The cerebellum is dissected on the horizontal plane with the two lobes being sliced in a ‘fan’ shape with the middle slice going through the dentate nucleus which gives best histological orientation of the structures.
Brainstem
The brainstem may be dissected at 5 mm intervals perpendicular to its axis and arranged on a flat board in sequence.
Any localized lesions, such as bleeding, softening, or cystic degeneration, indicating recent or ancient infarction, and primary or metastatic malignancies, must be recognized in the brainstem and cerebellum.
Dissection of head in infants: Rokitansky’s method or Beneke’s technique is used to open the skull in infants.
Spinal Cord
The spinal cord can be removed from an anterior or posterior approach and usually removed separately from the brain.
If there is no sign, the spinal cord does not need to be exposed.
The anterior approach is more challenging, but it has the benefit of not needing the corpse to be rotated (messy process with evisceration already completed) and enabling the nerve roots and dorsal ganglia to be dissected.
To prevent the mess, the posterior approach is both faster and simpler.
It also enables for the removal of the spinal cord and brain in one piece, however it does not allow for study of the nerve roots and basal ganglia.
Posterior Approach to the Spinal Cord
A large midline incision is created, and the skin, muscle, and soft tissues are fanned out 1 inch on each side of the spinal column, sidewise or laterally.
The vibrating saw is used to cut the posterior arch. This dissection might continue superiorly to the foramen magnum along the cervical vertebrae.
The spinal processes and the posterior laminae are eliminated.
The dura is sliced circumferentially after being opened longitudinally to the topmost section of the incision.
The nerves are severed, and the spinal cord is delivered by constant traction.
Description of an Organ
Size: Measuring tape is used. A tense capsule indicates enlargement and loose capsule shrinkage.
Shape: Note any deviation from normal.
Surface: Most organs have a delicate, smooth, glistening and transparent capsule of serosa. Any thickening, roughening, dullness or opacity is noted.
Consistency: The softness or firmness is appreciated by application of finger pressure.
Cohesion: It is the strength within the tissue that holds an organ together. It is judged by the resistance of the cut surface to tearing, pressure or pulling.
Cut surface: Note color and structural details.
Post-autopsy reconstruction: It plays a key role in the presentation of the autopsied body to the relatives.
The reconstruction of body should be of a high standard so that it will not leak, and can be viewed after autopsy without distressing the next of kin.
Removal of accumulated fluids: To avoid leaks, remaining fluids, tissues, and bowel contents (blood, ascitic or pleural fluid, serosanguineous fluids, or fecal matter) should be aspirated, removed, and dried after evisceration of organs from the thoracic, abdominal, and pelvic cavities.
This is to avoid any serosanguineous fluids from splashing or welling up while inserting the viscera back into the thoraco-abdominal cavity.
Wadding: After the cavities are dry, they are coated with enough wadding or cotton wool to absorb any leftover bodily fluids or fluids that may leak after the repair.
Viscera containment: When histology and toxicological samples have been acquired, all organs and viscera must be returned to the body.
They are put in the cavities on top of the wadding in biohazard bags or transparent plastic bags.
This will keep the body from leaking.
Any alien things, such as gloves, aprons, universal containers, blood tube sets, syringes, or needles, should, however, be disposed of in a separate trash bin.
Head: When the skull is opened, a triangle or square cut in the midline of the frontal bone incision may be used to reduce the possibility of skull cap sliding following restoration.
On each side of the squamous temporal bones, a second notch is formed.
This will guarantee that the skull cap is properly relocated and moves as little as possible.
A sufficient amount of wadding is put within the cavity to absorb any liquids.
The stripped dura and brain are returned to the cranial cavity in a plastic bag.
Suturing: might begin above (chin) or below (mons pubis), depending on the patient's desire.
To ensure safety, this suturing procedure is always started with a downward stroke.
Suturing methods: include continuous sutures, under-stitching, baseball sutures, mattress sutures, individual sutures, and interlocking sutures.
To seal lengthy incisions, continuous suture is widely utilized.
Understitching involves tying a knot at the end of the suture to hold the beginning and then suturing in such a manner that the skin is sewed from below, resulting in favorable aesthetic outcomes.
Sutures: must be strong enough to keep tissue in place while yet being flexible enough to be knotted.
Nylon should be used to stitch and seal bodily cavities.
Cotton, on the other hand, is extensively used for suturing in most countries due to its low cost.
Washing: Upon repair, the whole body must be cleansed of any lingering bodily fluids or stains.
Hot water should be avoided since it might cause skin injury and induce confusion during a second autopsy.
Disinfectant-containing detergents may be used in conjunction with water to help in the washing process.
Demonstration of Pneumothorax
Pneumothorax occurs when a leakage through the pleura allows air to enter the pleural cavity, and the communication rapidly closes. It can be demonstrated by three ways during autopsy:
The skin and subcutaneous tissues are reflected from the chest wall till the mid-axillary line, being careful not to open the pleural cavity.
Care should be taken not to puncture the intercostal soft tissue and penetrate the pleural space, as this releases air from an underlying pneumothorax.
Water is poured into the angle between subcutaneous tissue and the chest wall, and the intercostal tissues below the water line are pierced with a blade.
If pneumothorax is present, bubbles of air will be seen rising through the water.
Another method is possible before any incision is made.
This involves introducing a wide bore needle attached to a 50 ml syringe into the subcutaneous tissue over an intercostal space into the pleural space.
The plunger should be removed previously and the syringe filled with water.
The water is observed for the presence of any bubbles.
A similar procedure is then followed on the other side.
A third method involves postmortem chest X-ray, and assessment in a manner similar to detection of a pneumothorax in the living patient.
Demonstration of Air Embolus
To illustrate the pathophysiology of a venous air embolus, a plane chest X-ray may be performed prior to evisceration.
An ophthalmoscope should be used to look for intravascular bubbles in the retina.
To minimize the confusion of air introduction during evisceration, the big neck veins should be carefully exposed during dissection of the neck, but not opened before the heart is dissected in situ.
The abdomen is opened normally, and the contents are transferred to check the inferior vena cava for bubbles in the lumen visible through its clear wall.
There are three ways to show venous air embolus:
The sternum is removed by splitting the ribs and cutting through the sternum distal to the sternoclavicular joint, taking care not to rupture the pericardial sac.
Internal mammary vessels should be bandaged.
The anterior pericardial sac is opened, and the external epicardial veins are examined for intraluminal bubbles.
The pericardial space is filled with water.
The right atrium and ventricle are incised after being entirely submerged in water, and any air bubbles that escape are carefully examined.
Another approach involves putting a water-filled syringe (without the plunger) linked to a needle into the right ventricle and observing the syringe chamber for the presence of bubbles.
Pyrogallol assay: A syringe is loaded with a 2% pyrogallol solution mixed with sodium hydroxide.
The gas is then inhaled and shook from the right side of the heart.
If there is any air in the mixture, it will become brown.
The solution remains transparent in the absence of air (indicating gas production by bacteria).
Arterial air emboli are uncommon and mainly occur as a consequence of a severe lesion to the pulmonary veins or as a result of the injection of air during cardiopulmonary bypass.
Such emboli are connected with a smaller amount of air, making them more difficult to show.
Systemic emboli may be confirmed by evaluating the intracranial vessels of the meninges and circle of Willis, followed by an underwater examination after clamping the internal carotid and basilar arteries.
Collection of Samples
Blood: After death, the cellular barrier of mucous and serous membranes breaks down, allowing chemicals from the stomach and intestine to travel to organs in the thorax and abdomen, resulting in incorrect findings.
A syringe may be used to take 10-20 ml of blood from the femoral (best sample), jugular, or subclavian veins prior to autopsy.
Blood should never be drawn from the pleural or abdominal cavities because it may include stomach or intestinal contents, lymph, mucus, urine, pus, or serous fluid.
CSF: It can be extracted from the cisterna magna or from the lumbar region by inserting a long needle between the atlanto-occipital membrane.
After the brain has been removed, CSF can be aspirated directly from the lateral ventricles or the third ventricle.
Vitreous humour: After pulling the eyelid aside, a fine hypodermic needle (20 gauge) attached to a syringe is inserted through the outer canthus into the posterior chamber of the eye, followed by aspiration of 1-2 ml of crystal clear colourless fluid from each eye.
Water/saline is reintroduced through the needle to restore the tension in the globe for cosmetic reasons.
Lungs: In cases of solvent abuse ('glue sniffing') or death from gaseous or volatile substances, the lung is mobilised and the main bronchus is tightly tied off with a ligature.
The hilum is then divided, and the lung is immediately placed in a nylon bag, which is then sealed.
Plastic (polythene) bags are not suitable because they allow volatile substances to pass through.
Urine: It may be collected through suprapubic puncture or when the bladder is opened in a suitably sterile or non-sterile 'universal container' for microbiological or toxicological investigation.
Urine may be obtained prior to dissection using a catheter or an abdominal wall puncture.
Bone: About 200 g is collected. It is convenient to remove about 10–15 cm of the shaft of the femur.
Hair: A sufficient sample of head and pubic hair should be extracted by plucking together with the roots, rather than cutting, and stored in separate Medico-legal Autopsy 113 containers (0.5 g for DNA analysis, upto 10 g for analysis of heavy metals).
Maggots: They are immersed in boiling 100% alcohol or 10% hot formalin for a lengthy period of time, which kills them (to disclose the internal structure of the larvae).
If the moment of death is a problem, some larvae/maggots should be kept alive for an entomologist to examine.
Maggots in decaying corpses may suggest the presence of medications or poisons.
Nails: All the nails (fingers and/or toes) should be removed in their entirety and collected in separate envelopes.
Skin: If there is a needle puncture, the whole needle track and surrounding tissue should be removed.
Control specimens should be collected from the same region on the other side of the body and stored in a different container.
In firearms situations, a part of the skin surrounding the entry and exit wounds should be maintained.
Fibroblasts for tissue culture: Karyotyping, metabolic assays, enzyme assays and diagnostic ultrastructural studies can be performed on cultured fibroblasts.
Skin, fascia, lung, diaphragm, muscle and cartilage are useful for fibroblast cell cultures.
Tissue for metabolic studies and nucleic acid analysis: Liver, kidney, cardiac and skeletal muscle, and peripheral nerve obtained at autopsy may be used for biochemical studies in the diagnosis of inborn errors of metabolism.
The tissue should be frozen rapidly in liquid nitrogen or dry ice and stored at –70°C.
Preservation of Viscera
Viscera should be preserved in cases of:
Suspected death due to poisoning
Deceased was intoxicated or used to drugs
Cause of death could not be found after autopsy
Accidental death involving driver of a vehicle or machine operator
Death due to burns (if needed)
Advanced decomposition
Any case, if requested by the head.
Some practical points need to be considered:
The preferred specimens collected at postmortem will depend on the type of case/poison suspected.
Blood: It is the most useful sample because toxins present in it can be best linked to a physiological effect and can be used to assess the likelihood of recent poison/drug exposure.
Urine: It is the second most important specimen collected.
The disadvantages are: it is unavailable in half the cases poison may be metabolized so extensively that the parent compound may not detected, and concentration of most poisons are difficult to interpret.
Vitreous humor: As vitreous does not generate ethanol postmortem, it is the best specimen for alcohol intake confirmation in decaying corpses.
Stomach content: It is invaluable in cases of suspected poisoning—establish actual content of poison, determination of route of administration, high concentration of toxins, and analysis is uncomplicated by metabolism.
While spleen and kidneys are regularly maintained, liver is most essential due to its huge tissue supply, simplicity of sample collection, high toxin concentration, and extensive hepatic drug concentration database.
Bile: It has been collected historically, but its usefulness is limited.
It may be show the presence of number of drugs including morphine/heroin, benzodiazepine, cocaine, methadone, glutathione, many antibiotics and tranquillizers and heavy metals.
Brain, kidney and spleen: are used to determine and interpret the concentration of toxins.
Spleen: It is useful as a specimen for toxins, such as carbon monoxide (CO) and cyanide that binds to hemoglobin.
The viscera should be refrigerated at about 4°C, if not sent to the laboratory.
Preservation of Samples
The optimal samples are those that have not been preserved and are delivered to CFSL within a few hours. In practice, however, it is often delayed.
The specimens are stored at 4 degrees Celsius until analysis.
For long-term storage, a temperature of –10°C is required.
Some preservatives are employed so that putrefaction does not set in and makes chemical analysis difficult.
Viscera
Saturated solution of common salt: The most commonly used preservative for viscera. It is easily available, cheap and effective preservative
Rectified spirit: It is used in cases of suspected alkali or acid poisoning (except carbolic acid), only is used.
Blood
For toxicological analysis, it is preserved in sodium or potassium fluoride at the concentration of 10 mg/ml of blood and anticoagulant potassium oxalate, 30 mg/10 ml of blood.
Heparin and EDTA should not be used as anticoagulants.
If blood is required only for grouping, no preservative is necessary and small amount of blood is well preserved by soaking in a blotter.
In the event of suspected CO poisoning, a coating of 1-2 cm of liquid paraffin is applied immediately over the blood sample to prevent exposure to ambient oxygen.
To prevent exposure to ambient oxygen, paraffin is applied directly over the blood sample.
If solvent misuse and anesthetic death are suspected, the glass container should have a foil-lined cover (gas may infiltrate rubber) and be entirely filled to prevent gas from escaping in "dead" air space.
Hematological examinations, especially glycosylated hemoglobin in diabetics, need clean glass containers containing anticoagulant.
Urine
Persevered by adding small amount of phenyl mercuric nitrate or thymol.
Fluoride should be added to urine if alcohol, cyanide or cocaine is suspected in the sample.
Vitreous humor is preserved using sodium fluoride (10 mg/ml).
For bones, hair and nails, preservative is not required.
It has to be dried in normal temperature and sealed in plastic bag.
But, bone marrow is preserved in a test tube containing 4–5 ml of 5% albumin-normal saline solution and stored at 4°C.
Formalin is not employed as a preservative for chemical analysis because toxins, particularly non-volatile organic chemicals, are difficult to remove.
For preservation, utilize disposable, hard plastic (particularly polypropylene) or glass containers.
The patient's name, hospital number, sample type, collection location, preservative, date, and time should be on all samples. It should be given to the IO following receipt.
Most glycolysis inhibitors are sodium fluoride. It inhibits bacteria and enolase.
EDTA efficiently chelates blood calcium ions, preventing blood coagulation, leukocyte quantity and size, and erythrocyte stability.
Citrate, potassium oxalate, and lithium heparin are anticoagulants.
Samples for Laboratory Investigations
Histopathological examination: Sections of various internal organs (1.5 × 1.0 × 1.0 cm) in case of suspected abnormality are preserved in 10% formalin or 95% alcohol.
Bacteriological/serological examination: Blood should be kept in sterile container using sterile syringe from the right ventricle of the heart or from some large vessel, such as femoral vein or artery. It may also be used for biochemical examination.
Virological examination: A piece of tissue is collected and preserved in 50% sterile glycerin.
Enzymatic studies: Small pieces of tissues are collected into a thermos containing liquid nitrogen.
Smears: Vaginal/anal smears are needed in cases of alleged sexual assault.
In suspected malaria, smears from cerebral cortex, spleen and liver may be taken and examined for malarial parasite.
Obscure, Negative and Second Autopsy
Obscure autopsy: In about 20% of all postmortem examination cases, the cause of death may not be clear at the time of dissection of the body, and there are minimal or indeterminate findings or even no positive findings at all.
These are a source of confusion to any forensic pathologist.
Causes of obscure autopsy
Natural diseases: Epilepsy, paroxysmal fibrillation.
Concealed trauma: Concussion, blunt injury to the heart, reflex vagal inhibition.
Poisoning: Anesthetic overdose, narcotic, neurotoxic, cytotoxic or plant poisoning.
Biochemical disturbances: Uremia, diabetes.
Endocrinal disturbances: Adrenal insufficiency, thyrotoxicosis.
Miscellaneous: Allergy, drug idiosyncrasy
Negative autopsy: In about 2–5% of all postmortem examination cases, the cause of death remains unknown, even after all laboratory examinations including biochemical, microbiological, virological, microscopic and toxicological examination.
Reasons of negative autopsy
Inadequate history.
Inadequate external examination and internal examination.
Insufficient laboratory examinations.
Lack of toxicological analysis.
Lack of training of the doctor.
Second autopsy or re-postmortem examination: It is the autopsy conducted on an already autopsied body.
Indications of second autopsy
Relatives are not satisfied with the first autopsy
Cause of death cannot be opined in the first instance
Expert opinion wherein some question left unanswered or some issues unattended
Suspicion of doctor conducting the postmortem coming handin-glove with the accused
Involvement of the police in concealing the facts
Examination of Decomposed, Mutilated and Skeletonized Remains
Forensic anthropology: It is that branch of physical anthropology which for forensic purposes deals with identification of skeletonized remains known to be or suspected to be being human.
Mass disaster: Death of more than 12 victims in a single event, like fire, air crashes or floods.
The number of victims far exceeds the capacity of local death investigation system to handle.
Decomposed bodies: These show putrefactive changes in varying degree depending upon the time elapsed since death.
Hemorrhage and fractures usually indicate trauma.
Where feasible, preserve viscera for chemical investigation of probable poisoning.
Mutilated bodies: These are extensively disfigured, deprived of a limb or a part of the body, but the soft tissues, muscles and skin are still attached to the bones.
Fragmentary remains: These include only fragments of the body such as head, trunk or limb.
Exhumation
Exhumation: It is the lawful digging out of an already buried body from the grave for postmortem examination.
It is a situation where a previously-buried dead body is ‘dug up,’ ‘unearthed,’ or ‘disinterred’.
Reasons
Criminal Cases
Establishing the cause and manner of death in suspected homicide disguised as suicide.
Death as a result of criminal abortion and criminal negligence.
Retrieving some vital object which may throw light on the case, e.g. bullet from the dead body, if the person was killed by a firearm.
Civil cases: Identification of the deceased for accidental death claim, insurance, workmen’s compensation claim, liability for professional negligence, survivorship and inheritance claims, disputed identity, separation overseas, and burial of the wrong body inadvertently or by fraud.
Procedure
It should be begun in the morning and finished in daylight.
The corpse is unearthed by a medical officer, magistrate, and police officer.
Before accessing the grave, it should be definitely recognized from the burial ground, headstone, and gravemarker.
Soil from above, below, and two sides of the corpse or coffin should be maintained in separate glass jars with identifying marks.
Disinfectants and insecticides should not be applied to the body since they may interfere with toxin detection.
The doctor should observe the body's location and appearance in the grave or casket. Whether the face is up, to the side, arms outstretched, or lower limbs flexed, sketch the grave and corpse or skeleton.
The grave or casket should be photographed.
A board or plastic sheet should be lowered to the body's soil level if decomposition is slow.
The corpse is removed and submitted for postmortem examination with a demand and a preliminary inquiry report. Postmortem inspection is done at the morgue as usual.
Attempt to identify extremely putrefied corpses. Preserve viscera for chemical analysis. Examine the bones if the body is skeletal.