Human dissection in forensics

Human dissection plays an important role in the medical science, especially in identifying the cause of death of an individual. The results of this play an important role in forensic science. Today, with the help of latest technology, human dissection of body parts has become much simpler, yet very efficient.

Human dissection of head

A wooden block is placed under the shoulders so that the neck is extended and the head is fixed by a head rest, which should have a semicircular groove to hold the back of the neck.

A coronal incision is made in the scalp when starting the human dissection, which starts from the mastoid process just behind one ear, and is carried over the vertex of the scalp to the back of the opposite ear. The incision should penetrate to the periosteum. The scalp is reflected forwards to the superciliary ridges, and backwards to a point just below to the occipital protuberance. Any bruising of the deeper tissues of the scalp or injury to the bone should be noted.

The temporal and masseter muscles are cut on either side, for sawing the skull. The saw-line is made in slightly V-shaped direction, so that the skull cap will fit exactly back into the correct position.

The saw-line should go through the bones along a line extending horizontally on both sides, from about the center of the forehead to the base of the mastoid process, and from these latter points backwards, and upwards to a point a little above the external protuberance.

Thickness of the skull varies in different parts, being thinner where protected by thick muscles. The average thickness is 3 to 5 mm. Care should be taken to avoid sawing through the meninges and brain.

human dissection

human dissection

To avoid this, stop when saw meets little resistance. A chisel and hammer should not be used to loosen the skull completely. Heavy hammering may cause false fractures, or extend any existing fractures. This is the most difficult part of human dissection of head.

Skull cap is removed by gently inserting and twisting the chisel at various places through the cut. Fixation of dura to bone is much firmer in children, in whom it tends to dip into the sutures. The meninges are examined for congestion, disease, etc. In old persons, the meninges over the vertex are often white and thickened, with little calcified patches (arachnoid granulation).

A note should be made of extradural or subdural hemorrhage, which should be measured, and also of intracranial tension. If they are solid, express in terms of grams of weight, or area covered over the superior portion of the brain. Describe variation in thickness if the material is semi-liquid and cannot be easily collected.

The superior longitudinal sinus is opened along its length with a scalpel, and carefully examined for an antemortem thrombus. This is of medico legal importance in human dissection, as antemortem thrombus in this situation can lead to back-pressure in the bridging veins crossing the subdural space, and cause subdural hemorrhage.

The dura mater is grasped anteriorly with a forceps, and with a scissors or scalpel, the dura mater is divided from before backwards at the level of the skull division on both sides. The scalpel is now passed vertically downwards alongside the falx cerebri at its anterior end, and the knife turned medially to divide the falx. With the forceps, the dura and the falx are now pulled backwards, and the surface of the brain examined.

Head dissection in infants

Rokitansky’s method is autopsy human dissection technique for infants. The scalp flaps are reflected as in adult. The skull can be opened as described by Baar (1946). With a knife, incision is made into the anterior fontanelle at its posterior margin, about 5 mm. from the midline.

The point of the knife is pushed parallel to the inner aspect of the parietal bone for one to 2 mm. between dura and leptomeninges, and the incision is extended to the lateral angle.

The opposite side and both anterior margins are cut similarly. One blade of scissors is passed under the original incision and the parietal bone is cut longitudinally about 5 mm. parallel to the sagittal suture, up to lambdoid suture. The coronal suture is cut in a similar way.

The other side is cut similarly, and the two parietotemporal flaps are turned outward. Similarly, flaps of the two halves of the frontal squania are prepared and turned outward. Usually, a horizontal fronto-medial extension is required with the help of a bone forceps, which leaves only short bridge for outward reflection of the flaps. This leaves a medial strip about one cm. in width with the intact superior longitudinal sinus.

After reflecting the flaps, the vertex of the brain and the terminations of the pial veins into the superior longitudinal sinus are examined for hemorrhage. The hemispheres are gently pushed side ward and faix cerebri is examined. Haematoma may be found between the falx and the medial aspect of the hemispheres or between the two dural layers of the falx.

The superior longitudinal sinus is opened and examined for thrombi. The falx is separated at its antero-inferior insertion, and the brain is removed as in the case of an adult. The tentorium is examined for tears and for haematoma between its layers. The dural sinuses are opened and the dura is detached from the base and sides of the skull with a pair of forceps, or a part of the dura is held with a towel and is pulled. This head dissection method is much safer.

Human dissection of Brain

Cut the dura all along the line of cleavage of the skull and fold it back to mid line. Free the falx cerebri from the cribriform plate and pull dura and faix backwards. The brain is removed by inserting the four fingers of left hand between frontal lobes and skull, and drawing frontal lobes backwards and cutting the vessels and nerves at the base.

The tentorium is cut along the posterior border of the petrous bone. The brain is supported by the left hand. The knife is passed into occipital foramen and cervical cord, first cervical nerves and cerebral arteries cut as far below as possible.

The right hand grasps the cerebellum and the brain is removed from the cranial vault. If any intracranial hemorrhage is present, the blood should be collected and measured. The child’s brain attains mature size and weight at about six years of age.

The surface and base are examined for hemorrhage, injury or disease before proceeding with human dissection of brain. The condition of the cerebral vessels, especially the vessels in the circle of Willis is noted for the presence of arteriosclerosis, minute aneurysms, etc. In the fixed brain, cortical contusions and hemorrhages are much more distinct, but it becomes difficult to dissect out ruptured Berry aneurysms or small haemangiomas.

Ruptured Berry aneurysms may be more easily dissected under a flow of running water, by a careful blunt human dissection from the origin of the greater intracerebral vessels, around the circle of Willis, to the major branches of the circle. Berry aneurysms (size varies from few mm. to few cm.) are usually present at the junction of vessels especially at the junction of the posterior cerebral arteries, the posterior communicating vessels, the middle cerebral arteries and the anterior communicating arteries.

Note for cerebral infarction which may occur due to a thrombus or atheroma or due to raised intracranial pressure causing obstruction to venous outflow. Hemorrhagic infarction appears as a pinkish-purple discoloration of the cortex with stippled hemorrhages.

Fixation of Brain For complete examination in human dissection of brain, it is fixed in 10 percent formalin for one week. In fetuses and infants, acetic acid may be added to formalin which makes the tissues firmer. To facilitate penetration of formalin, the lateral fissures are opened with the fingers which tear open the  pia-arachnoid, and a long sagittal cut is made through the corpus callosum to allow formalin to pass into the ventricles.

The brain can also be perfused with fixative through the arterial stumps before further fixation by immersion. To keep the organ in its natural form, the brain is suspended upside down, supported by a string passed under the basal vessels and attaching the ends of the thread to the two sides of the jar. Gauze should not be put beneath or around the brain, as it imprints an ugly pattern. The weight of the brain is increased by about 8% due to fixation in fomalin.

While doing human dissection of brain, the brain is placed in its normal anatomical position, and with a long knife the two halves of the brain are separated by a single incision which passes through corpus callosum, and through the mid line of the mid-brain, pons and medulla. If the incision passes through the median plane, it will pass through the cavity of the septum lucidum and expose the internal surfaces of its two laminae which form part of the medial walls of the lateral ventricles on each side.

The incision passes through the third ventricle, the aqueduct of sylvius and the fourth ventricle. The lateral ventricles are opened by dissection of the anterior, posteror and inferior horns, and the ependymal lining examined. Turn the cerebellum over and cut straight down through the vermis to expose the fourth ventricle. To expose the dentate nucleus, cut obliquely through each hemisphere.

Whole of the stem is sectioned transversely at intervals of a few millimeters, to demonstrate hemorrhages or other abnormalities. The cerebral hemispheres are placed base down on a board, and serial sections made in the coronal plane, beginning at the frontal pole passing backwards to the occiput, at intervals of about one cm. The slices should be moved aside in sequence and placed on the cutting board so that they can be identified consecutively later.

Other method of human dissection of brain is to make a horizontal cut through the cerebrum, parallel to the cutting board at a level through the tips of the frontal lobes and temporal lobes to the occipital lobes. Inspect the choroid plexus and locate the interventricular foramen. The fornices and corpus callosum are cut and bent backwards. Examine the thalamus and caudate nucleus.

The third ventricle will now be exposed. Pass a probe through the aqueduct of Sylvius. Now expose the fourth ventricle by cutting along the vermis in the mid line with scalpel. This exposes the basal ganglia and lateral ventricles. Expose the third ventricles and trace the aqueduct.

The dura is stripped from the base of the skull with forceps to look for basal fractures. The bones of the skull must be tested for any signs of abnormal mobility. Subdural hemorrhage can be washed, whereas sub-arachnoid hemorrhage cannot be washed. This is important information in human dissection of brain.

If the skull is crushed or broken into pieces, replacement and fixation of the bone fragments may be carried out by using an electric drill and copper wire, for personal identification and determination of type of violence.

In generalized edema of the brain, flattening of the cerebral convolutions with obliteration of the sulci, and a herniation of the inner portions of the temporal poles through the tentorial hiatus, and of portions of the cerebellar lobe and cerebellar tonsils through the foramen magnum are found.

In true “coning” the cerebellar tonsils will be discolored or even necrotic. Gross changes are not present when oederna is present in minor degree. When it is of severe degree and widespread, the convolutions are flattened, lateral ventricles are reduced to mere slits, and the white matter appears glistening, smooth and shiny. The cerebral hemispheres are pressed hard against the dura in human dissection of brain.

The increased bulk of the hemispheres causes tentorial herniation and the uneus is pushed down the tentorial orifice. The brain may weigh up to 1750 g. Histologically, the white matter is vacuolated and in severe cases shows pools or lakes of pale staining fluid. In head injury, the edema is seen in the white matter around or deep to contusions, lacerations or ischemic lesions.

The middle ear can be examined by chiseling out wedge-shaped portion of petrous temporal bone. The mastoid is examined by nipping away the bone with a pair of bone forceps. The orbits can be examined by removing the orbital plates in the base of the skull.

The sphenoid and frontal sinuses are opened from the inside of the skull by a chisel. The pituitary is removed by chiselling the posterior clinoid process and incising the diaphragm of the sella turcica around its periphery. Abscess formation in or septic condition, etc., about the jaws and teeth should be looked for on completion of brain dissection.

Human dissection of heart

Here is the procedure to remove heart for forensic examination by forensic experts. It is held at the apex and lifted upwards and pulmonary vessels, superior and inferior vena cavae, and the ascending aorta are cut as far away as possible from the base of the heart. The human dissection of heart is examined externally for adhesion, pericarditis, Discoloration of an underlying infarct and for aneurysms.

The pulmonary arteries should be palpated before they are cut and looked for an embolus when they are incised. The pericardium is examined and incised with the tip of the scissors and the heart is exposed. Any blood or fluid in the pericardium is noted. The isolated heart is studied as follows. It is opened in the direction of the flow of blood (inflow-outflow method), with the enterotome.

For human dissection of heart, the right atrium is cut between the openings of superior and inferior vena cavae. A small secondary incision is made to open the auricular appendage to detect thrombi. In opening the right ventricle, the lateral margin of right ventricle faces the dissector, the atria being directed towards him. The enterotome introduced into the right atrium, cuts through the tricuspid orifice, and opens the right ventricle along the lateral margin.

The circumference of an intact valve of heart can be measured by inserting specially made graduated cones, marked at various levels with the circumference. The heart is held in the palm of the hand so that the pulmonary valve is horizontal and neither collapsed nor stretched. To demonstrate the competence of the pulmonary valve, a gentle stream of water is directed on to the valve.

After the blood is washed away in human dissection of heart, it can be observed how well the cusps come into apposition, and whether water leaks into the already opened ventricle. The competence of tricuspid and mitral valve cannot be satisfactorily tested postmortem. In opening the pulmonary valve, the heart is placed so that the apex is directed towards the examiner.

The enterotome is introduced into the right ventricle close to the apex, and the conus pulmonalis and pulmonary valve are cut about 15 mm. to the right of, and parallel to the interventricular septum in the anterior wall of the right ventricle. The interventricular septum is identified by the anterior descending branches of the coronary vessels crossing down the epicardium.

The incision should extend into the pulmonary trunks and the left pulmonary artery. Note whether the contents of the right ventricle and auricle are fluid blood, currant-jelly clot or chicken-fat clot. The left atrium is cut between the openings of the pulmonary veins. Then, the left atrium is cut along its lateral wall. This incision extends through the mitral orifice, and passes along lateral margin of the left ventricle up to the apex.

The next incision extends from the apex along the interventricular septum into the aorta, opening the aortic valve. The water competency of the aortic valve can be tested after cutting the aorta transversely. Both auricular appendages should be examined for the presence of thrombi.

While doing heart dissection, the heart should be weighed, after the blood clots in the cavities are removed, and measurements of the circumference of valves and of thickness of right and left ventricle should be taken. Chordae tendinae are attached to papillary muscles and cusps of valves.

The anatomy of coronary arteries varies considerably. Usually, there is a short main trunk of the left coronary artery, which soon bifurcates into the circumflex branch, and the anterior descending branch. The coronary arteries are examined by making serial cross-sections along the entire course of the major vessels about 2 to 3 mm. apart, using a scalpel.

This method demonstrates narrowing (percentage stenosis) of the vessel, and any antemortem thrombus in its lumen, without danger of dislodging it. In heart dissection, the coronaries should not be opened by passing a scissors through them from the ostia, as they have a crushing and cutting action and produce so much distortion that any thrombus is obscured, and also the thrombus may be pushed along with the point of the scissors.

The anterior descending branch of the left coronary artery is cut downwards along the front of the septum, then the circumflex branch on the opposite side of the mitral valve. The right coronary artery is followed from the aorta to the cut near the pulmonary valve, and then above the tricuspid valve.

The presence of acute coronary lesions, e.g. plaque rupture, plaque hemorrhage, or thrombus should be noted. The muscle of the right and left ventricles is incised in a plane parallel to epicardial and endocardial surfaces, which reveals infarction and fibrosis most clearly. In death due to ventricular fibrillation, heart is flabby.

SUB-ENDOCARDIAL HEMORRHAGES in human dissection of heart

The hemorrhages are seen in the left ventricle, on the left side of the interventricular septum and on the opposing papillary muscles and adjacent columnae carnae. The hemorrhages are flame- shaped, confluent and tend to occur in one continuous sheet rather than patches. When the bleeding is severe, it may raise the endocardium into a flat blister. The mechanism of production is obscure. They are nonspecific finding and are seen:

(1) after sudden severe hypotension due to severe loss of blood or from shock,

(2) after intracranial damage, such as head injury, cerebral edema, surgical craniotomy or tumours,

(3) death from ectopic pregnancy, ruptured uterus, antepartum or postpartum haemorrhage, abortion,

(4) various types of poisoning, especially arsenic.

Antemortem blood clots (thrombi) are dark red, firm but friable, dry, pale, granular, adherent to vessel wall and on section show alternate layers of platelets and fibrin (coralline platelet thrombus). Dark lines are composed of red cells and a network of fine white lines of fibrin.

Older thrombus is greyish-red and varies in color from place to place. When lung is sliced, emboli slightly project above the surface. The postmortem thrombus is dark red, glistening, soft, jelly-like and very friable. When pulled out of the vessels it forms cast of the branches. When the lung is sliced, clot does not pour out of cut small vessels.

AGONAL THROMBI in human dissection of heart

In case of a person dying slowly with circulatory failure, a firm, stringy, tough, pale-yellow thrombus forms in the cavities, usually on the right side of the heart. The process may begin in the atrial appendage, in the apex of the ventricle or in the angles of the ventricular surfaces of tricuspid valve. It extends and fills the right auricle and ventricle and spreads into the pulmonary artery and its branches like a tree-like cast. In the left ventricle, agonal thrombi are not so big.

POSTMORTEM CLOTS in human dissection of heart

Two types are seen:

(1) when blood clots rapidly, a soft, lumpy, uniformly dark-red, slippery, moist clot is produced (“black currant-jelly”).

(2) When red cells sediment before blood coagulates, the red cells produce a clot similar to the first type.

Above this, a pale or bright-yellow layer of serum and fibrin is seen (“chicken-fat”). The fibrin clot may be soft or jelly-like, but is elastic, when the amount of fibrin is greater. Usually, a mixture of the two types of clot is seen.

Postmortem clots are moist, smooth, shiny, rubbery, homogeneous, loosely or not at all attached to the underlying wall, and there are no fine white lines of fibrin (striae of Zahn). Postmortem fibrinous clots in heart are known as cardiac polyps.

Unclotted Blood in heart dissection

In sudden death, the clots are greatly reduced in amount. The blood is fluid in certain cases of septicaemia, in CO poisoning, in rapid death from asphyxia, with large doses of anticoagulants, in hypofibrinogenaemia due to amniotic fluid embolism, retained abortion or puerperal sepsis.

Human dissection of Organ

A description of the organ systems should be limited to a clear, concise, objective description of shape, color, and consistency and the presence or absence of any lesions other than those systematically described under trauma. The microscopic description may be limited to the positive findings. The pathologist should indicate those tissues he had examined and the number of sections he has taken in any one tissue.

(1) Size Measure by tape: In the liver, blunting of the inferior border points to enlargement, and sharpness to atrophy. A usually tense capsule is in favor of enlargement, and loose capsule with laxness. A straight course of superficial vessels as on heart shows increased size, while undue tortuosity means decrease.

(2) Shape: Note any departure from normal.

(3) Surface: Most organs have a delicate, smooth, glistening, transparent capsule of serosa. Look for any thickening, roughening, dullness or opacity.

(4) Consistency: The softness or firmness as measured by pressure of the finger.

(5) Cohesion: It is the strength within the tissue that holds it together. It is judged by the resistance of the cut surface to tearing, pressure or pulling. An organ with reduced cohesion is friable, while when it is increased, the tissue seems to be tough or leathery. If a small toothed forceps bites into a testis it should pull away threads composed of tubules.

(6) Cut surface: (A) Color: Every organ (except brain) is basically some shade of grey, but this is altered by the red contributed by its blood supply. Other colors can be added by jaundice or fatty infiltration (yellow), lipofuscin or haemosiderin (brown), malarial pigment (grey-brown). Anemia causes pallor, while congestion adds a blue tinge. (B) Structure: This is a factor of the particular organ, e.g., cortex and medulla in the kidney. In disease these may become indistinct or greatly exaggerated.

ORAL CAVITY in human dissection

Examine the tongue for any disease or ‘injuries, especially bite marks which are usually seen along the sides, and less commonly at the tip. A small hemorrhage is seen under intact mucosa in bite marks. Serial incisions should be made through the tongue for the presence of bruises. The pharynx, epiglottis and glottis should be examined, especially for a foreign object. The condition of the tonsils should be noted.

NECK STRUCTURES in human dissection

A large blunt-pointed scissors is used to cut open the esophagus from the posterior surface up to the cardiac end of the stomach. The lower end often shows postmortem erosion, due to the regurgitation of gastric juice through the relaxed cardiac sphincter. Note for the presence of any capsules, tablets, powders, etc. , which should be preserved. If the oesophagus is cut at the lower end, blood will drain from varices, which would then collapse and may be missed. When death occurs from rupture of oesophageal varices, the break should be demonstrated. A blunt-ended fine probe is helpful in cases where milking of the veins does not force a little blood through the tear. Injection of saline or coloured fluid into a varix is useful to find the leak from the tear.

The larynx, trachea and bronchi are examined by cutting them open from the posterior surface. The presence of blood, mucus, foreign bodies, vomited matter, tumors, inflammation, mucopus, etc., in them should be noted. The thyroid is removed and examined. Sections are made in both lateral lobes along their longest diameter. The parathyroids are examined. The carotid arteries must be examined for the presence of thrombosis particularly at the bifurcation near the skull. The hyoid bone, thyroid and cricoid cartilage are examined.

JAWS in human dissection

The masseter and temporalis muscles can be divided above their insertion into the mandible, to allow the jaw to become mobile. To remove the jaws, the upper jaw is excised by sawing along a horizontal line placed above the hard palate. The mandible is dis articulated.

LUNGS in human dissection

Place the lungs with the anterior surfaces uppermost and open the pulmonary artery and continue into the lung tissue as far as small scissors will allow one to go. Look for thrombi, emboli and atherosclerosis. Trace the course of pulmonary veins into the lung, looking for evidence of thrombosis. An antemortem embolus may sometimes be coiled, and when straightened out resembles a cast of the vessel from which the thrombus originated, usually in the leg. There may be side-branches and it does not fit the vessel in the lung. Massive pulmonary emboli completely block either the main trunk of the pulmonary artery or impact in one of the major pulmonary vessels, more commonly the right side.

To separate the lungs, the long-bladed knife is placed blunt-edge upwards under the hilum of each lung and turned around so that the sharp edge is upward. Then with a short sawing motion, the hilum is completely cut through. The Jung is held on the upper surface by the left hand (or by an interposed sponge) and the organ cut across from apex to base with the large brain knife, held parallel to the board. This produces an anteroposterior slice.

The lungs are examined for consolidation, edema, emphysema, atelectasis, congestion, Tardieu spots, emboli, tumour, infarction, etc. The smaller bronchi are examined for mucosal thickening, infection and blockage. The smaller pulmonary arteries are examined for thrombosis or embolism.

For fixation of lungs, a cannuila is held or tied into the bronchus and 10% formal-saline is perfused through a tube from a reservoir held one meter above the lung. The lung is then put in formalin solution.

AORTA in human dissection

The scissors is passed into the iliac vessels, and the whole length of the aorta is cut on its posterior surface around the arch, up to the aortic valve. Note for any chronic aortitis with plaque formation which obstructs the mouths of the coronary arteries.

ABDOMEN human dissection

For examining the abdominal organs, keep the organs on the board with the liver away from the operator and the anterior surface upwards.

STOMACH human dissection

The stomach is removed after applying double ligatures at each end, and is placed in a clean dish. It is opened along its greater curvature, from the cardiac to pyloric end. Note the size of pyloric ring with a finger, and open the duodenum along the anterior wall. The contents are examined for nature of any food which may he present and its state of digestion, smell, color, character and also for the presence of foreign or suspicious matter. The contents are washed out and mucous membrane is examined for the presence of congestion, hemorrhage, ulceration or other abnormal conditions.

The gastric contents are yellow or yellow-green in regurgitation of bile from the duodenum. In paralytic ileus, a foul-smelling, copious, thick fluid, dirty-green, brown or black is found. In gastrocolic fistula, faecal material may be found. In massive hemorrhage, the stomach is filled with large soft clots which may take the form of a cast of the gastric outline. Small haemorrhages are partially digested and have ‘coffee-ground” appearance. Blood may be swallowed from the lungs, oronasopharynx or esophagus.

INTESTINES human dissection

Examine the small and large intestine for serosa, diameter of the various portions, color, consistency of wall, adhesion, hernia or other abnormalities. The superior mesenteric vessels are examined for any disease, thrombi or emboli. Hold the upper cut end in the left hand and apply the sharp edge of knife against the attachment of the mesentery to the jejunum. Long, sweeping, to-and-fro movements will separate the intestine due to the mere weight of the knife. The inferior mesenteric vessels are examined and the transverse colon and pelvic mesocolon are separated from the mesentery. The small intestine is opened along the line of mesenteric attachment, and the large intestine along the anterior taenia. They are examined for congestion, inflammation, erosion, ulcers, perforation, etc. The contents are also examined.

LIVER human dissection

It is removed by itself or attached to the stomach and the duodenum when bile ducts are to be examined. Its weight, size, color, consistency and the presence of any pathologic process or injury is noted. It is cut into slices 2 cm. thick, which run in the long axis.

In chronic venous congestion, the cut-section has a granular (nutmeg) appearance. Amoebic abscesses are usually single, large and confined to the right lobe. Pyogenic abscesses are multiple. In fatty liver, the cut- section is greasy. In portal cirrhosis, the liver is studded with nodules, 1 to 3 mm. in diameter. In posthepatic cirrhosis, nodules of varying sizes, 4 to 10 mm. or more are seen. In biliary cirrhosis, the liver is granular and olive-green in color.

The anterior wall of the second part of the duodenum is opened and the ampulla of Vater is identified. Squeeze the gall bladder gently and note if bile enters the duodenum. The common bile duct is opened with a fine scissors. Look for tumors, calculi and strictures. The portal vein and hepatic artery are opened. The condition and nature of lymph nodes in the neighborhood are noted.

SPLEEN human dissection

The spleen is removed by cutting through its pedicle. Note size, weight, consistency, condition of capsule, rupture, injuries or disease. It is sectioned in its long axis, and the character of parenchyma, follicles and septa noted. Look for accessory spleens.

In congestive splenomegaly, the pulp is very soft and can be scraped easily. In portal hypertension, it is greatly enlarged and firm. It is also enlarged in malaria, Kala-Azar, portal vein thrombosis, leukaemia, reticulosis, schistosomiasis, etc.

PANCREAS human dissection

The pancreas is usually removed together with the stomach and duodenum. It is sliced by a series of cuts at right angles to the long axis, which gives the best exposure of the ductal system. The duct can be probed and opened by scissors in its full length before any cuts are made. In acute hemorrhagic pancreatitis, areas of fat necrosis will be seen as small, round, opaque areas around the pancreas and in the mesentery.

KIDNEYS human dissection

The abdominal aorta is opened along its anterior mid line. The renal artery ostia are examined for thrombi, emboli or atherosclerosis. Renal veins are also examined for thrombus. Note size and weight of kidney. The capsule is stripped with toothed forceps. The capsule strips with difficulty in chronic nephritis, hypertensive nephrosclerosis and pyelonephritis. In these conditions, the kidneys are reduced in size, and their surface is granular. Hold the kidney in the left hand between the thumb and fingers, the ureter passing between ring and middle fingers. The kidney is sectioned longitudinally through the convex border into the hilum so as to split in half and open the pelvis. The pelvis is examined for calculi and inflammation. The ureters are split by fine scissors.

ADRENALS human dissection

They are identified by their relationship to the upper pole of each kidney. If the right kidney is taken in the left hand and pulled forward, the adrenal will be projected forwards in the tissues between the upper pole and the undersurface of the liver, which tends to fall backwards when the kidney is pulled forward. The left adrenal lies much more medially in relation to the kidney, and can be found by pushing the medial border of the left kidney forwards, and cutting into the tissues between the kidney and spleen. The periadrenal fat is gripped with a forceps and cut, and adrenal removed. Cut the gland gently with a scalpel without applying undue pressure. Haemorrhage is seen in meningococcal septicaemia, bleeding disease, hypertension, birth trauma, pregnancy, etc.

BLADDER human dissection

It is opened from the fundus and incision extended into the urethra. The condition of the wall and amount and character of urine are noted. In acute cystitis, the mucosa is red, swollen and covered with fibrin and pus. In chronic cystitis, the mucosa is covered with much mucus and pus and may show ulcerations.

PROSTATE human dissection

It is examined for enlargement or malignancy. Vertical cross-section through the lateral and median lobes are made with knife. In prostatitis the organ is firm, and in carcinoma it is hard and granular.

TESTES human dissection

Incise the inguinal canal from the peritoneal aspect and pull out a loop of vas with finger. Free the vas to the internal inguinal ring. Push the testis up out of the scrotum with the right hand, and pull the vas with the left hand. The testis usually comes out without difficulty or damage. The testis and epididymis are held with the left hand and are cut longitudinally with knife. Note for the presence of any clotted blood inside the scrotum and around the testis. Normal seminal tubules can be lifted like thin long by toothless pointed forceps. In acute orchitis and epididymitis, the organ is swollen and firm and may show small abscesses. In chronic orchitis, the organ is firm, nodular and reduced in size.

FEMALE GENITALIA human dissection

The tubes, ovaries and uterus are freed from the pelvis and are removed. The anterior vaginal wall is cut from below upwards, exposing the cervix. The fornices are examined. The uterus is opened from the external os to the fundus. Two short incisions are made in the fundus from main longitudinal incision towards each cornu, to expose endometrium. The ovaries are sectioned longitudinally, and the tubes are cut across at intervals. If the uterus contains a fetus, its age should be determined.

VERTEBRAL COLUMN human dissection

The atlanto-occipital joint should be examined for any fracture-dislocation by moving the head on the spine. The cervical spine should also be examined. If there is excess mobility, look for hemorrhage on the anterior surface of the spinal ligaments and cut into the bodies of the vertebrae. The thoracic and lumbar spine should be examined by pushing the spine forwards with the hand under the body, which will show abnormal movement at the site of any fracture. The pelvis should be squeezed from side to side by pressure on each iliac crest. Mobility of the pelvis indicates fractures of the sacroiliac joints or of the pelvic bones. The thorax should be examined for recent or old fractures of the ribs.

SPINAL CORD human dissection

It is not examined routinely, unless there is an indication of disease or injury. The body is placed prone on the table, face downwards. A wooden block is placed under the chest, and the head is bent downwards. This stretches cervical spine. An incision is made on the back in mid line extending from the occipital protuberance to the lower end of sacrum and the muscles are dissected away from the top of the spinal column, noting their condition.

The atlanto-occipital joint capsules are incised and articular surfaces examined. The atlas is dis articulated. The laminae are sawed close to the transverse processes through the entire length of spine on each side of the spinous process, by means of an adjustable double blade saw, and are separated with the chisel. It is easier to cut through the arches of the atlas and the axis with a pair of bone shears. The lumbar end of the freed spinous processes are grasped with bone forceps and spinous processes lifted upwards in one piece.

The dura is slit open along the mid line with scissors and the presence of hemorrhage, inflammation, suppuration, infarction, degeneration, crushing or tumor is noted. The nerves are cut from below up as they pass through spinal foramina. The cord is separated at the foramen magnum. The cord is sectioned transversely and serially. The vertebral column is examined for fractures or dislocations. The empty spinal canal must be examined for disc protrusion, tumors, fractures, dislocations and vertebral collapse.

EXTREMITIES human dissection

The femoral vessels are examined by a longitudinal incision down the center of the upper anterior half of the thigh, starting below the inguinal ligament. They should be examined in continuation with iliac vessels. For examination of popliteal and calf veins, a vertical midline incision is given over the back of the knee joint and leg and skin flaps are reflected. The tendon of Achilles is divided. The calf muscles are then separated from the bones from the heel upward.

Transverse sections about two cm. apart are then made in the calf muscles. If thrombi are present, they protrude as firm, solid, tube- like masses. The major arteries of the calf pass between the tibia and fibula. For removal of the marrow from the femur, the incision for the femoral vessels can be employed. In the upper end of the shaft, a rectangle of cortex is cut out, using a rotary saw, and the marrow is scooped out.

All the organs and parts removed from the body should be returned to the dead body for the purpose of burial, except when they are required for further studies or to be produced as evidence in subsequent trial. If the organs are retained by the doctor for his department, he can be sued by any relative of the deceased.