The body has been taken to ABC hospital for a post-mortem,” is a common phrase we find in the media. But what actually happens during a post-mortem? Why is it necessary? Under what terms is it called for? Why should you care about a post-mortem? And, above all, how does it help in the field of health science?
Picture this: A man is found hanging on a rope in his house. All indications will be that he committed suicide, but when taken to a pathology laboratory and his brains, heart, lungs, pancreas and kidney removed and examined, it might reveal there was no asphyxiation and that the laceration around the neck are ‘suspicious’ or too inconclusive to point to a suicide by hanging.
The post-mortem would then show that the person actually died from another cause, before the body was hanged on a rope to mislead concerned persons into believing the deceased committed suicide.
That is just a fraction of the essence of post-mortem, also known as autopsy. A post-mortem is a highly specialised surgical procedure that consists of a thorough examination of a corpse to determine the cause and manner of death and to evaluate any disease or injury that may be present, according to the web site, www.howstuffworks.com.
There are two types of post-mortems; forensic and clinical.
The forensic autopsy or medical-legal autopsy is the kind you most often see on TV and in movies. According to Dr Eric Kiesel, a deputy chief medical examiner in Atlanta, US, “The forensic autopsy spends almost as much time on the external surfaces of the body as it does on the internal surfaces, ‘cause that’s where evidence is.” Forensic autopsies try to find answers to the cause of death as part of an overall police investigation.
Dr Kiesel, who was speaking to How Stuff Works, said clinical autopsy is usually performed in hospitals by pathologists or the attending physician to determine a cause of death for research and study purposes.
“They’re really interested in the disease processes that are going on, and they’re interested… in making that clinical-pathological correlation. A person came in with these symptoms, here’s the treatment they got and here are my findings. They try to put the whole package together to help inform people of what happened or may have happened.
Medscape, a multi-speciality health web site, says of greatest interest to the family, post-mortem examinations can confirm or disprove a clinical diagnosis.
This is especially important when the disease is hereditary or in some other way confers increased risk upon family members. Clinical diagnosis of the various types of dementias, for instance, is an imperfect art. There is significant overlap in the clinical symptoms seen with Alzheimer’s disease, Parkinson’s disease, and other dementing disorders.
Pathologists say in these cases, a post-mortem examination is extremely valuable in identifying the nature of the disease process and the degree of risk for family members. Confirmation of diagnosis can also benefit families by reassuring them that the patient’s medical care was appropriate and adequate.
“In some cases, post-mortem examination remains the only completely certain method of diagnosis. The contributions of autopsy to medicine go far beyond confirmation of a diagnosis. Post-mortem examination helps validate new clinical diagnostic technology and monitor the effectiveness of new drug therapies,” Medscape says.
Francois Xavier Hakizimana, a consultant forensic at Kacyiru Police Hospital, says post-mortem examinations often reveal undiagnosed medical conditions that may be the immediate cause of death.
This way, a post-mortem examination can help to ensure that the death certificate reflects the correct cause of death and all diseases present.
Dr Hakizimana said the examination is always carried on to prove the cause of death, doctors to know the manner of death, and mechanism of death like what happened to the person before death.
“A post-mortem examination is frequently performed in cases of sudden death, where a doctor is not able to write a death certificate, or when death is believed to result from unnatural case such as murder, especially when medical examiners are looking for signs of death or the murder method, such as bullet wounds and exit points, signs of strangulation, or traces of poison,” he said.
The examinations are performed under a legal authority medical examiner and do not require the consent of relatives of the deceased.
A pathologist studies the effects of diseases, medical treatments and injury on the human body. A forensic pathologist specialises in using these studies to establish a legally admissible manner of death in a court of law.
There are five legally defined manners of death: natural, accident, homicide, suicide, and undetermined.
For example, if the autopsy reveals a natural disease process such as leukemia or cancer, then the death would be considered natural, Dr Kiesel said.
The answers are not always that clear. The pathologist must consider all of the information. Severe head injuries that result in death with no evidence of assault could be hard to explain. But when that evidence is added to the police report that states the body was found next to an ice-covered, fallen ladder, the manner of death is an accident.
It would be easy to assume a gunshot wound is the result of a homicide. But an autopsy could reveal that the wound patterns, angle of bullet entry and gun powder residue indicate that the gun was fired while being held by the victim. The wounds are self-inflicted, so that would be ruled a suicide.
Usually, it is recommended that after death, relatives or persons close to the deceased call in authorities to handle the body. Incidents like suicide, for instance, mean tampering with the body could lead to loss of several clues, according to Dr Hakizimana.
He said people should report suspicious deaths early enough and wait for authorities to handle the body. This, he said, would help the investigations team to find more evidence that would help in ascertaining the cause of death.
“Post-mortem helps to demonstrate to the family that the care provided was appropriate, there by alleviating guilt among family members and offering re assurance regarding the quality of medical care,” Dr Hakizimana said.
How autopsy is carried out
During the examination, the pathologist uses a standard set of surgical instruments and has assistance of an anatomical pathology technologist.
A forensic autopsy may include obtaining biological specimens from the body for toxicological testing, including stomach contents. Toxicology tests may reveal the presence of one or more chemical ‘poisons’.
There are two parts to the physical examination of the body: the external and internal examination. Toxicology, biochemical tests often supplement these and assist the pathologists in assigning the cause or causes of death.
Dr Hakizimana says the extent of a post-mortem examination can vary from the examination of a single organ such as the heart or brain, to a very extensive examination. Examination of the chest, abdomen, and brain is probably considered by most pathologists as the standard technique of a post-mortem examination.
Autopsy procedure: External examination
The body is received in a body bag or evidence sheet. If the post-mortem is not performed immediately, the body will be refrigerated in the mortuary until the examination.
A new body bag is used for each body. This is to ensure that only evidence from that body is contained within the bag. Body bags are closed and sealed to prevent any contamination or evidence loss during transportation.
The body is moved in the bag to the examination suite. The person responsible for handling the body is often called a diener. The diener is a mortuary attendant who is responsible for moving and cleaning the body and, in some cases, assisting in the autopsy.
When the body is received in a body bag, the seals of the bag are broken and the body is photographed inside the bag. In a forensic autopsy, it is important at this stage for the medical examiner to note the clothing of the deceased and the position of the clothing. This is because once the clothing is removed for the examination, any evidence pertaining to the position of the clothing cannot be documented.
Evidence is collected off of the external surfaces of the body. Hair samples, fingernails, gunshot residue (if present), fibers, paint chips or any other foreign objects found on the surface of the body are collected and noted.
Autopsy procedure: Internal examination
The internal examination starts with a large, deep, Y-shaped incision that is made from shoulder to shoulder meeting at the breast bone and extends all the way down to the pubic bone. When a woman is being examined, the Y-incision is curved around the bottom of the breasts before meeting at the breast bone.
The next step is to peel back the skin, muscle and soft tissue using a scalpel. The chest flap is then pulled up over the face, exposing the ribcage and neck muscles.
Two cuts are made on each side of the ribcage, and then the ribcage is pulled from the skeleton after dissecting the tissue behind it with a scalpel.
With the organs exposed, a series of cuts are made that detach the larynx, esophagus, various arteries and ligaments. Next, the medical examiner severs the organs’ attachment to the spinal cord as well as the attachment to the bladder and rectum. The entire organ set can be pulled out in one piece and dissected for further investigation.
During this dissection, the various organs are examined and weighed and tissue samples are taken. These samples take the form of ‘slices’ that can be easily viewed under a microscope. Major blood vessels are also bisected and examined.
The examiner opens the stomach and examines and weighs the contents. This can sometimes be helpful in figuring out the time of death (more on time of death later).
The examiner will then remove the body block from the back and put it behind the neck like a pillow, raising the patient's head so that it's easier to remove the brain.
The examiner makes a cut with a scalpel from behind one ear, across the forehead, to the other ear and around. The cut is divided, and the scalp is pulled away from the skull in two flaps. The front flap goes over the patients face and the rear flap over the back of the neck.
The skull is cut with an electric saw to create a ‘cap’ that can be pried off, exposing the brain. When the cap is pulled off, the dura (the soft tissue membrane that covers the brain) remains attached to the bottom of the skull cap.
The brain is now exposed. The brain’s connection to the spinal cord and tentorium (a membrane that connects and covers the cerebellum and occipital lobes of the cerebrum) are severed, and the brain is easily lifted out of the skull for examination.