THE METHOD OF MAKING POST-MORTEM EXAMINATIONS. 9 



It is important to remember the difference between the distribution 

 of the blood in the body during life and after death. During life the 

 blood is in constant motion and is distributed in a regular way in the 

 heart, capillaries, arteries, and veins. Inflammations and obstructions 

 to the circulation may disturb this natural distribution and produce con- 

 gestion of particular parts of the body. After death the blood ceases to 

 circulate ; it leaves the left cavities of the heart, the arteries and capil- 

 laries, and collects in the veins and the right cavities of the heart. Ac- 

 cording to the character of the disease which causes death, coagulation 

 of the blood takes place more or less extensively and at an earlier or 

 later period. The local congestions which existed during life often dis- 

 appear after death. On the other hand, local congestions are found after 

 death which did not exist during life. Thus, after death the scalp often 

 contains a large amount of venous blood. The veins of the pia mater 

 and the sinuses of the dura mater may be filled with blood. The mucous 

 membrane of the larynx and trachea may appear to be deeply congested. 

 The lungs are congested if the patient has been comatose for some hours 

 before death. All the tissues of the back and the membranes of the 

 spinal cord are often gorged with venous blood. The right auricle and 

 ventricle of the heart may contain fluid or clotted blood in considerable 

 quantity. 



THE HEAD. 



The scalp is divided by an incision across the vertex, from ear to ear. 

 The flaps are dissected forward and backward, taking up the temporal 

 muscles with the skin and leaving the pericranium attached to the bone. 

 The internal surface of the scalp and the pericranium are to be searched 

 for ecchymoses and inflammatory lesions. 



A circular incision is now made through the cranium with a saw. 

 The incision should, in front, pass through a point about three and one- 

 half inches above the bridge of the nose ; behind, through the occipital 

 protuberance. Care should be taken not to cut through the dura mater 

 with the saw. When the roof of the cranium is thus entirely loosened, 

 a stout hook is introduced under the upper edge of the calvarium, and 

 this is wrenched off with a jerk. 



Sometimes the dura mater is so firmly adherent to the calvarium that 

 the latter cannot be torn from it without injury to the brain. In this 

 case, and also if the dura inater should have been accidentally cut 

 through by the saw in making the circular incision, the dura mater may 

 be cut through at the level of the cranial incision, and the brain removed 

 with the calvarium and separated afterward. Or, which is better, in 

 addition to the circular incision, a longitudinal incision is made, from 

 front to back, about three-quarters of an inch to one side of the median 

 line of the skull, and a segment of bone removed. The knife blade may 

 now be inserted from the open side, and the dura cut away from the 

 skull-cap along the line of the longitudinal sinus, where the adhesions are 

 apt to be most firm. 



