Organ Dissection

The thoracic and abdominal viscera should be laid at a comfortable height, under good illumination, in a way that the tongue faces the doctor and the aorta faces upwards. The same sequence of examination should be carried out in all cases routinely.

Neck
Tongue is examined for any injury, congestion or disease. Slicing the tongue may reveal deep-seated hemorrhages occurring commonly in cases like hanging, choking and strangulations. In case of suspected choking, the glottis should be examined. Hyoid bone and thyroid cartilage should be palpated to check for fracture, usually present over the horns and cornua.

Esophagus is opened with blunt-end scissors to avoid artefact over the mucosa, until cardiac sphincter is reached. Any foreign object found must be recorded. Thyroid must be sliced and examined. Scissors are then introducted through larynx, into the trachea up to the carina. Any objects found here must be correlated with possible choking. Regurgitation following death is a common occurence and therefore presence of any material in the trachea should be correlated with findings in the bronchioles and lungs. Contusions if present in lumen of trachea must be recorded.

Examination of lungs
Any adhesions noted during removal of lungs must be corroborated with surface patches, emphysema and petechiae. Lungs are separated at hilum with the help of a brain knife. During this procedure, any visible embolism needs to be retrieved for histopathology. To demonstrate saddle embolus, some authors advice opening the pulmonary trunk and right ventricle before removing the lungs.

The lungs are weighed before sectioning. Both lungs are placed with the hilum facing the dissection table. Upper surface is held by the non-operating hand and the lung is cut along the sagittal plane from apex to base,  with a brain knife held parallel to the board. The cut surfaces can be opened like a book and examined for the presence of any tumor, mass, infarction, pneumonic changes, trauma, etc. Small bronchioles must be assessed for thickening and blockage. Small pulmonary vessels must be examined for embolus and thrombus.

Examination of heart and great vessels

In infants, thymus must be examined by slicing it. Scissors are used to cut the aorta, at the level of aortic arch. The inferior vena cava is opened from its lower end, at the liver.  The major vessels are examined for injury, disease and plaques. The pericardium is inspected externally for patches of adhesions, collection of fluid and blood tamponade and opened with scissors. The delivered heart is then inspected externally for pericarditis, adhesions, infarct or aneurysms.

The heart is placed so that the lower end faces the doctor.  The general size of the heart must be noted, but it is weighed only after all the clots are removed following completion of dissection. Valve patency is checked and inspected.

All three major coronary arteries are examined before opening the cardiac chambers. The ostia are examined for congenital variations (which are frequent) and for obstruction. The left anterior descending coronary artery is cut across from the epicardial surface, starting as close to the ostium as possible, as occlusion and severe stenosis can occur very near the origin. Serial cuts are then made at intervals of not more than 3 mm, first into the common trunk, then following the left circumflex
laterally until the vessel becomes too small to examine. The right coronary artery, is similarly examined by serial cut sections from as close to the ostium to the distal segment, until it becomes the posterior descending branch. During this process, the dominance of right versus left vessels should also noted. Difficulty or gritty feeling in making cut sections indicates calcification of vessel wall. 

Inflow outflow technique of dissection is the most convenient and widely used technique for dissection of heart chambers.  A blunt end scissors is passed through the opening for inferior vena cava, and a cut made extending to the right auricle. Right atrioventricular valve is examined for stricture or stenosis, by inserting the fingers into the valve opening. With the help of scissors, lateral wall of right atrium  and right ventricle is opened laterally to expose the chambers. The whole of the right side of heart is now open and displayed. It should be washed with water and endocardium and valves examined for any gross pathological changes.

A similar procedure is repeated on left side of the heart but the mitral valve is examined before dissection of the left venticle. The opening for pulmonary veins are cut open and fingers inserted into the mitral valve opening to note for stricture or stenosis. The left ventricle is cut open along the anterior interventricular groove upto the apex.  The aorta is cut open from left chamber in the direction of blood flow. The whole heart is now exposed and washed before being weighed. The endocardium and valves are then examined and the thickness of both ventricular walls measured. The myocardium is then given a ‘sandwich’ cut through the thickness of the left ventricle. Any area of discoloration or fibrosis in this wall must be sectioned and samples collected for histopathological analysis.

Examination of the abdominal organs
After dissection of the oesophagus, the stomach is ligated at its pyloric sphincter with twine and entire block is separated from intestines. It is then placed in a container to be weighed. The content of stomach, color and its odor must be recorded. Greater curvature is opened with scissors and contents allowed to pour into a container, which can later be discarded or collected for analysis.

Gall bladder is squeezed to test for patency of bile duct and bile can be collected for analysis of drugs (esp. opium derivatives). Adrenals are separated and examined. If the  kidneys are lifted against the weight of the liver, adrenals can be located between liver and kidneys. The pancreas lies under the stomach and should be cut longitudinally, from the curve of the duodenum to its tail, lying against the splenic hilum. The kidneys are exposed by incising their capsules. The kidneys can usually be peeled out of their capsules unless adherent. It is not common to open the whole length of the intestines during autopsy unless indicated.