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THE AUTOPSY

 

 

 

If only an arm is found, a    forensic expert will mutipiply the length of the humerus by 5 to  estimate the height of the person they belonged to. These methods are used when a dismembered body is found.

 

Here we have information on the general aspects of an autopsy such as causes of death etc and information on recognition of dismembered bodies.

Forensic determinations go beyond those of patient-oriented medicine, as they involve legal as well as medical considerations: 
A. Cause of death
This is a specific medical diagnosis denoting a disease or injury (e.g., myocardial infarction, strangulation, gunshot wound). 
B. Mechanism of death
This term describes the altered physiology by which a disease or injury produces death (e.g., arrhythmia, hypoventilatory hypoxia, exsanguination). 
C. Manner of death
This determination deals with the legal implications superimposed on biological cause and mechanism of death

     

 


"Normal" postmortem changes
These are important to be familiar with, as they may otherwise mislead the examiner into thinking trauma or other foul play led to the victim's death.
 

A. Rigor mortis, familiar to any aficionado of horror films, begins earlier in small muscles and muscles exercised vigorously prior to death. An extreme example is "cadaveric spasm," a great literary/cinematic device, in which a person dying following extreme exertion "freezes" in place virtually in a photographic pose of the moment of death. I would imagine that this occurs a lot more often in movies than in reality. Rigor mortis passes as muscle decomposition begins and is usually gone in 36 hours. It can also be mechanically "broken" by stretching the rigid muscles by force. 

B. Livor mortis, or hypostasis, a purplish discoloration of the body and organ surfaces, results when blood settles to dependent parts of the body. It becomes visible between onehalf hour and two hours after death. Early on, the blood remains in the vessels, so the livor can be blanched by applying pressure to the affected part. Later, the blood hemolyzes, and the hemoglobin breakdown pigment leaches out into the extravascular interstitium. At this point, the livor cannot be blanched by pressure and is said to be "fixed." The period over which livor becomes fixed is so variable that whether it is fixed or not offers little information in trying to determine the time of death.
 
C. Desiccation occurs most prominently on the mucous membranes, which during life are kept moist (by blinking, lip licking, etc) and are not protective by water repellant keratin in cornified skin. The membranes may look "burned," and the conjunctiva may actually be black ("tache noire").
 
D. Putrefaction is the sequence of physicochemical events that begins with death and ends with dissolution of the nondurable parts of the body. It begins with a greenish discoloration of the skin and mucous membranes. The epidermis becomes detached from its basement membrane, and flaccid cutaneous bullae form. Overgrowth of bacteria (which normally seed the entire body via the bloodstream at or immediately before the time of death) cause gas production, resulting in gaseous distension of the body cavities, which may then rupture. The soft tissues may also puff up and appear swollen, also as a result of gas release. Finally, autolysis and bacterial lysis hydrolyze proteins and fats, to produce frank liquefaction of the soft tissues. The proteins get broken down into amino acids, which then are decarboxylated and become "biogenic amines" with such memorable and apt names as "putrescene" and "cadaverine." Other protein-derived products of putrefaction are amino acid residues with sulfhydryl (-SH) groups; these are also mighty rank. The sulfhydryl groups are often further cleaved off, then released as hydrogen sulfide, which also has the ability to put your olfactory neurons into overload. 

E. Alternatives to putrefaction include mummification, in which the body dries out faster than decomposition takes place, and adipocere formation, in which by some unknown mechanism the adipose tissues become chemically transformed into a waxy substance that acts as a preservative. As might be expected, mummification typically occurs in dry environments. Adipocere formation, which is much rarer, tends to occur in moist environments, such as caves. A good example of adipocere can be viewed at Philadelphia's Mutter Museum, where the "Soap Lady" is on exhibit.
 

 


Trauma
This is the cornerstone of forensic pathology. Terms used to describe traumatic lesions are somewhat more specific than analogous terms used in surgery and internal medicine. 

A. Laceration is a tearing injury due to friction or impact with a blunt object. The typical laceration has edges which are ragged3, bruised, and/or abraded. Generally, surgeons and ER physicians do not make a distinction between lacerations and incised wounds, calling them both "lacerations." 
B. Incised wound is a cutting injury due to slicing action of a bladelike object. The wound edges are smooth. Serrated blades produce the same smooth edges as do nonserrated blades. 
C. Puncture is a penetrating injury due to pointed object without a blade, such as an ice pick. 
D. Abrasion is a friction injury removing superficial layers of skin, allowing serum to exude and form a crust. Abrasions may not be visible on wet skin; therefore, an abrasion not apparent when a body is first examined may appear the next day, after the wet body has had a chance to dry out in the morgue refrigerator. 
E. Contusion is a bruise due to rupture or penetration of small-caliber blood vessel walls. Contusions may be seen on the surfaces of internal organs (such as the brain or heart) as well as the skin and mucous membranes.

Copyright (c) 1995, Edward O. Uthman.