LATE POSTMORTEM CHANGES/DECOMPOSITION
WILLIAM A. COX, M.D.
FORENSIC PATHOLOGIST/NEUROPATHOLOGIST
November 17, 2009
General Information
The process of postmortem decomposition can be divided into five stages: Fresh
(autolysis), putrefaction, black putrefaction, butyric fermentation and dry decay. The
first stage begins within minutes of death and last typically up to 36 to 72 hours before
the beginning of putrefaction. The length of this first stage, as is true of the entire
decomposition process, is primarily determined by environmental temperature. The
higher the temperature the faster the decomposition process proceeds through each of the
stages. The first stage of decomposition was discussed in the previous article on early
postmortem decomposition. This stage included rigor mortis, livor mortis and algor
mortis. The underlying process, which initiates the first stage, is autolysis.
Autolysis is the result of molecular changes occurring within the cell, which gives rise to
the death of the cell and its subsequent necrosis. This process gives rise to the release of
enzymes from the cells, such as the pancreas, and in the case of the stomach also
hydrochloric acid.
The pancreas, because of the richness of its enzyme content, provides for digestion of
food by secreting more than a liter of digestive juice/24 hours into the digestive tract.
Within the digestive juice are enzymes (e.g., amylase, lipase) and precursor enzymes
(e.g., trypsinogen), which are responsible for the breakdown of ingested food.
Unfortunately, these same enzymes are released from the exocrine cells of the pancreas
into itself, which gives rise to autodigestion (autolysis).
The stomach contains a variety of cells, which secrete enzymes and hydrochloric acid
that participates in digestion. One of the cells of the stomach are Chief cells, which
produce an enzyme pepsinogen. Another cell is the Parietal cell, which, in addition to
producing intrinsic factor needed for the intestinal absorption of vitamin B12, also
produces hydrochloric acid. Following death both pepsinogen and hydrochloric acid are
released from these cells, which gives rise to autodigestion of the gastric mucosa
(gastromalacia). If this process is severe enough it can cause perforation of the stomach,
typically in the region of the fundus. This same process can also involve the distal ⅓ pf
the esophagus due to relaxation of the lower esophageal sphincter following death. This
allows for the gastric contents containing the described enzymes and hydrochloric acid to
pass into the lumen of the distal esophagus-giving rise to autodigestion
(esophagomalacia) of its mucosa and on occasion perforation of its wall. Both
gastromalacia and esophagomalacia can give rise to stomach contents leaking into the
abdominal cavity and left pleural cavity respectfully. Both can occur within a few hours
of death. Although, gastromalacia and esophagomalacia are not common postmortem
features, they are seen most frequently in those who have sustained substantive
intracranial injuries or have developed terminal pyrexias. These complications have been
attributed to an imbalance in the activity of the autonomic nervous system, possibly as a
consequence of hypothalamic or brain stem injury.
When the cells of the body reach the end of the autolytic process, an anaerobic
environment is created one in which oxygen is no longer present. At this point the
body’s normal bacteria begin to break down the tissues further producing acids, gases,
and volatile organic compounds with their putrefactive effects.
Putrefaction
Putrefaction is the process by which tissue is destroyed primarily through bacterial
proliferation, which occurs soon after death. The bacteria most responsible are those
normally found in the respiratory tract and gastrointestinal tract. These bacteria include
anaerobic spore forming bacilli, coliform organisms, micrococci, diphtheroids and
proteus organisms. The growth of these anaerobic organisms is enhanced due to the
increase in hydrogen-ion concentration in the tissues as well as the immediate decrease in
oxygen concentration. Between the respiratory and gastrointestinal tracts, it is the latter,
which provides the majority of postmortem bacterial growth of which Clostridium
welchii is the principal agent. The principal factor, which influences this process, is
environmental temperature. Should the deceased have been pyretic prior to death that
will also have an effect on the rapidity of development of putrefaction. The optimal
temperature for the development of putrefaction is between 70 – 100 ˚F. Putrefaction is
retarded below a temperature of 50 ˚F and is hasten by temperature above 100 ˚F.
Putrefaction also occurs faster in those who are obese, have septicemia, congestive heart
failure or anasarca, have multiple layers of clothing, hot and humid environments, those
dying of cocaine intoxication and those who have sustained traumatic lacerations or
incised wounds to the body. Although, warm temperatures hasten putrefaction, very high
temperatures will actually delay putrefaction, primarily due to the drying effect on the
tissues.
Putrefaction will proceed at a slower rate in cooler temperatures, with freezing
suspending the process all-together, in those who are thin, in infants, those who are found
in water, those who die in a dry environment, whether cold or warm, those who are found
lying on a stone surface and in some cases in which the person has been buried.
In reference to those who have been buried, whether putrefaction is hasten or delayed
will be determined by the depth of burial, temperature of the soil, water table, the natural
drainage of the burial site and the quality of construction and water tightness of the
coffin. If the decedent is buried deep, in well drained soil, especially clay soil, whose
coffin is water tight, the process of putrefaction will be substantively delayed. If
however, the gravesite is shallow, the soil is moist with poor drainage or the water table
is high and the coffin is not water tight the rate of putrefaction will be hastened.
However, even without embalming a body buried in a sufficiently dry environment may
be well preserved for decades. It is generally agreed that an unembalmed adult buried
deep in well drained soil, with a water tight coffin, will be reduce to a skeleton in
approximately 10 years, whereas a child will become a skeleton in approximately 5 years.
There is a general axiom referred to as “Casper’s dictum” which provides an overall
perspective to the putrefaction process, “one week of putrefaction in air is equivalent to
two weeks in water, which is equivalent to 8 weeks buried in soil, given the same
environmental temperatures.”
The first evidence of putrefaction is the development of a greenish discoloration to the
skin usually in the lower right abdominal quadrant, although occasionally you may see it
develop simultaneously or initially in the peri-umbilical or left lower abdominal regions.
This is typically seen between 36 to 72 hours following death at a temperature of
approximately 70 ˚F. The green discoloration is due to the spread of bacteria from the
cecum, which lies close to the overlying peritoneal lining in the right lower abdominal
quadrant, into the soft tissues. It then spreads from the right lower abdominal quadrant to
the remaining abdominal wall followed by involvement of the flanks, chest, limbs and
face. The actual green color is due to the bacteria breaking down the hemoglobin of red
blood cells (R.B.C) along with the concomitant production of hydrogen sulfide, the net
effect of which is sulfhemoglobin. During this process the superficial veins of the skin
become visible in an arboressent pattern delineated by a purple-brown coloration. This
process is referred to as marblization, which is most commonly seen on the superior
aspect of the chest, shoulders, arms and lateral aspect of the trunk. On occasion you may
see marblization on the anterior-medial aspect of the thighs. This process is due to the
anaerobic bacteria spreading through the veins participating in the hemolysis of the
R.B.C., which leads to the staining pattern of marblization, the color being due to
hemolyzed R.B.C. reacting with hydrogen sulfide produced by the bacteria. The
hemolysis of the R.B.C. will also impart a red color to the endothelial lining of the
arteries as well as the endocardium. The time frame that marblization occurs in again is
very much temperature dependent. Typically in temperate climates, if the body is
exposed to air at temperatures between 64 and 68 ˚F, marblization may appear with in
thirty-six to forty-eight hours. It will develop much more rapidly in warmer
temperatures.
At this point the skin has taken on a slippery feel and is showing multiple vesicles to
frank blisters filled with serous fluid and putrid gases. These vesicles and blisters
culminate into skin slippage, with areas of the skin being easily removed from the body
with minimal contact. The skin slippage represents the superficial epidermis. The
underlying base has a shinny, moist, pink appearance, which if the body is located in a
warm dry environment takes on an orange-yellow parchment-like appearance. Along
with skin slippage the hair of the scalp, axillae and pubic region is easily removed with
minimal pressure.
The skin about the face, neck, upper chest and arms begins to change from a red-green to
gray-green, followed by brown-green to purple black color. Gradually this coloration
will involve the entire body, however, not necessarily with the same intensity. The entire
body will show putrefactive changes in about sixty to seventy-two hours. The change in
coloration from green to more of a brown to black hue represents the transition from the
early stage of putrefaction to the advanced stage, which is referred to as black
putrefaction.
Black Putrefaction
The abdomen at this point is bulging and tense due to putrid gas formation from primarily
coliform bacteria and Clostridium welchii both within the gastrointestinal tract and within
the abdominal cavity, organs and soft tissues of the chest and abdominal cavities. The
putrid gas formation with its concomitant increase in intra abdominal and gastrointestinal
luminal pressure leads to purging of putrid, blood-stained fluid from the nose, mouth,
vagina and rectum. This same putrid gas formation within the tissue leads to bloating of
the body (swelling) in general. The purple-black face swells which also includes
swelling of the eyelids and lips, which gives rise to the eyelids being tightly closed and
the lips taking on a “fish-mouth-like appearance.” The swollen tongue, often having a
purple-black color is seen protruding between the swollen lips. The teeth will often show
a red discoloration due to the diffusion of hemoglobin from the lysed R.B.C. into the
dentin canaliculi. The swelling of the face and neck can approach grotesqueness, which
along with the purple-black color can make identification impossible. The scrotum and
penis in the male and the labia majora and breast in the female also exhibit prominent
swelling. The gases, which are responsible for this bloating, are comprised of hydrogen
sulphide, methane, carbon dioxide, ammonia and hydrogen. These gases, along with the
produced mercaptans are responsible for the disagreeable odor these bodies produce.
Typically generalized bloating with purging, skull and hair slippage at a temperature of
70 ˚F occurs between 60 - 72 hours. In addition to the head and body hair becoming
loose at their roots and thus being easily removed by minimal pressure, the finger and
toenails will at some point become dislodged. Sometime the dislodged finger and
toenails will contain much of the epidermis (superficial layer of skin) of the hands and
feet, a process called ‘degloving.’ This process of ‘degloving’ occurs at a later time than
the loss of either scalp or body hair.
Just as putrefaction affects the external surface of the body so does it involve the internal
organs. The stomach and small and large bowel begin to dilate due to various gases
being produced by the bacteria within these structures. Both the serosal and mucosal
surfaces assume a brown-deep red to purple color. The normal rugal folds become flat.
The mucosa of the larynx, trachea and especially the bronchial tree take on a deep-red
color; the lumen of the bronchial tree often contains thin reddish-black fluid. The
endothelial lining of the major vessels as well as the endocardial surface of the heart has a
reddish hue due to hemolysis of R.B.C., thus releasing hemoglobin, which stains these
surfaces. On a rare occasion you may see white granules measuring approximately 1 mm
in diameter on the surface of the epicardium as well as the endocardium. These white
granules are referred to as ‘miliary plaques’ and are believed to be the result of a
degenerative process of the cardiac muscle. These ‘miliary plaques’ are rich in calcium.
The heart becomes soft and flabby, giving rise to dilatation of the cardiac chambers and
thinning of the chamber walls. They myocardium takes on a deep red-brown color.
Although, these postmortem decomposition changes make diagnosing antemortem
dilated cardiomyopathy virtually impossible, thrombi within the epicardial coronary
arteries can still be ascertained. Thus, it is important you dissect the coronary
vasculature.
The liver and kidneys assume a deep reddish-brown color with the parenchyma of both
organs losing consistency, most especially the liver. As the decomposition process
continues the liver shows a myriad of minute cysts, which develops into a honeycomb
pattern due to bacterial production of various gases. Bile within the gallbladder diffuses
through the degenerating wall staining the adjacent liver, transverse colon and duodenum
an olive green color. The adrenal glands quickly undergo autolysis, as does the pancreas.
Decomposition fluid, which has a dirty-red color, accumulates in the pleural and
abdominal cavities. The chest and abdominal wall panniculus as well as the perirenal,
omental and mesenteric fat becomes very slippery, giving rise to a translucent yellow
fluid, which also seeps into the body cavities. Organs such as the prostate and uterus
remain well preserved even up to a point where the body is partially skeletal zed. The
lungs take on a deep red-black color, losing their elasticity, becoming very friable. As
they degenerate they exude a dirty red fluid into the pleural cavities.
The brain takes on a gray-white color and a soft consistency, which contains multiple
cyst-like cavities throughout its deep white and gray matter. These cyst-like cavities are
referred to as ‘swiss-cheese artifact.’ As the decomposition process continues the brain
becomes putty-like and eventually liquefies. At some point the maggots will completely
consume the entire liquefied brain. However, epidural, subdural and subarachnoid
hemorrhage as well as intrparenchymal hemorrhage can often be identified up to the
semiliquid (putty-like) state. Neoplastic lesions involving the gray and/or white matter
lose their consistency quickly. However, meningiomas and sarcomatous lesions arising
from the meningies, because of their fibrous nature can be identified for a far longer
period of time.
As the decomposition process proceeds in the black putrefaction stage, both on the
external surface as well as within the body cavities, the thoracic and abdominal walls
eventually degenerate to the point the contents of the pleural and abdominal cavities are
exposed. This process reached this point in the black putrefaction stage not only as the
result of bacterial action but also as the result of insect activity, especially in the form of
maggots and predators. Before continuing with a general overview of insect and predator
activity and their contribution to decomposition I would like to discuss the final two
phases of the decomposition process, Butyric fermentation and Dry decay.
Butyric fermentation
The butyric fermentation phase typically begins around the 20th to 25th day following
death with the actual time being determined primarily by the environmental temperature.
During the black putrefaction stage the bloating begins to subside and the body begins to
flattened due to the breakdown of the tissues and the release of the fluid of decomposition
and gases as the thoracic and abdominal walls disintegrate as well as consumption by
insect and predator activity. In the butyric fermentations stage the body finishes
flattening out as the flesh and fluids of the body are consumed and or dry up. Remnants
of the more fibrous or muscular organs, such as the heart, prostate and uterus may still be
found. It is during this process that butyric acid is produced, which has a very distinct
“cheesy” smell. This “cheesy” smell attracts new organisms to the body. The maggots
and other insects that feed on soft tissue are unable to feed on a body that is drying out,
however, beetles and other insects with chewing mouth appendages are able to chew the
tougher drying out tissues of the body. Early in this stage most of the beetles seen are in
the larval stage. Hide Beetles from the family Trogidae and Carcass Beetles from the
family Dermestidae are among the last beetles and generally the most common beetles
seen during this stage. The Hide Beetles and the Carcass Beetles are found on the
tougher portions of the body such as bone and ligaments. This is not only due to their
chewing mouth appendages but also they are the only beetles that have an enzyme which
can break down proteins such as keratin. Although maggots cannot feed on these tough
tissues there is a fly that is attracted to the body due to the “cheesy” smell, which is called
the cheese fly from the family Piophilidae.
Dry decay
This is the final stage in the decomposition process. It typically begins between 25 and
50 days after death and can last up to a year, again depending on environmental
temperature. The only remnants of the body are dry skin, hair, and bones.
Mummification, which will be discussed later in this article, may be seen due to the
dehydration process in environments, which are typically of dry heat or low humidity.
Such mummified bodies can last for decades. The bones go through a process referred to
as diagenesis that changes the organic to inorganic constituent ration within the bones.
As the protein-mineral bond weakens, the organic protein begins to leach away, leaving
behind only the mineral composition. Unlike soft-tissue decomposition, which is
influenced mainly by temperature and oxygen levels; the process of bone breakdown is
more highly dependent on soil type and pH, along with the presence of groundwater.
However, temperature can be a contributing factor, as higher temperature leads the
protein in bones to break down more rapidly. If buried, remains decay faster in acidicbased soils rather than alkaline. Bones left in areas of high moisture content also decay at
a faster rate. The water leaches out skeletal minerals, which corrodes the bone, and leads
to bone disintegration.
Bacteria are also present, feeding on the hair and skin of the body, attracting many mites.
Certain tineid moths can also be found feeding on the remaining hair. Silphidae, a family
of carrion beetles, may still be present during this stage as well as those of the family
Nitidulidae. At this stage, these beetles they are not only feeding on the remnants of
dried skin and hair but also the larvae of other insects.
Decomposition and insects
If the process of putrefaction is occurring other than in the winter months and the body is
exposed to insects, they will also contribute to the breakdown of the tissues. This is
especially true of maggots which give rise to abundant perforations of the chest and
abdominal wall with leading to a breakdown of both with exposure of the internal organs.
Each stage of decomposition will have certain insects involved. This will be from flies
through to beetles and finally moths as indicated above. The blowflies are the first to
find the body and lay eggs. Then come the houseflies and flesh flies.
Blowflies are referred to as carrion flies, bluebottles, greenbottles, or cluster flies. They
are insects of the Order Diptera, family Calliphoridae. The female greenbottles (Lucilia
cuprina in the United States) is generally the first to colonize the body; the second is the
Hairy Maggot Blowfly, Chrysomya rufifacies. Other fly families generally present during
this stage are Sarcophagidae, Piophilidae, and Muscidae.
The females of the family Calliphoridae are attracted to carrion both for protein and egg
laying, laying from 150 to 200 eggs per patch. Hatching from an egg to the first larval
stage takes about 8 hours to 24 hours. Larvae have three stages of development (called
instars); each stage is separated by a molting event. The larvae have proteolytic enzymes,
which they use to breakdown proteins of the body they are feeding on. At a temperature
of 86 ˚F the black blowfly (Phormia regina) can go from egg to pupa in 6 to 11 days.
When the third stage is completed the pupa will leave the body and burrow into the
ground, emerging as an adult 7 to 14 days later. The rate at which blowflies grow and
develop is highly dependent on the environmental temperature and species. There are
some 1100 known species of blowflies.
The housefly (Musca domestica) is of the Order Diptera of the Brachycera suborder. It is
the most common of all flies found in homes. Each female fly can lay approximately 75
to 150 eggs in each batch. Within a day, the larvae (maggots) hatch from the eggs; they
live and feed in decaying organic material, such a dead bodies as well as garbage, feces,
open sores, and sputum. The larvae live about one week. At the end of their third instar,
the maggots seek a dry cool place where they transform into pupae. The adult flies then
emerge from the pupae.
In the life of an insect the pupal stage follows the larval stage and precedes adulthood
(imago). The pupal stage is found only in holometabolous insects, that is those insects
that undergo a complete metamorphosis, going through four life stages: embryo, larva,
pupa and adults (imago). It is during the pupal stage that the adult structures of the insect
are formed while the larval structures are broken down. Pupae are inactive, and usually
are not able to move.
The flesh flies are of the Order Diptera, family Sacrophagidae. Most breed in carrion,
fecal matter, or decaying organic material. A few of species can lay their eggs in open
sores. Their larvae (maggots) live for about 5 to 10 days, before descending into the soil
and maturing into adulthood. Adults live for 5 to 7 days.
In addition to the flies the beetles (Order Coleoptera) enter the picture, where they feed
on the maggots as well as the body itself. Beetles have no specific time that they make
their appearance. For example, Staphylinidae may arrive within a few hours after death
and remain active into the later stages of decomposition. The Silphidae (carrion beetles)
are found in the early stages of putrefaction remaining both as adults and immature forms
until the dry stage of decomposition, which depending of the environmental temperature
and moisture can be anywhere from 50 to 365 days after death. The skin beetles
(Dermestidae) typically arrive at the beginning of the dry stage of decomposition. These
bettles feed primarily on dried skin and remaining tissues both as adults and larvae. On
occasion you may see species of the checkered beetle (Cleridae), which feed on the
Dermestidae. Tineid moths and bacteria eventually eat the person’s hair, leaving nothing
but bones.
There are also other insects involved in the decomposition process that can have a
substantive influence on the rate of the decomposition process; these belong to the Orders
Hemiptera (true bugs) and Hymenoptera (ants, bees, and wasps). Ants can significantly
effect decomposition by feeding on the maggots, thus decreasing the rate of
decomposition. Wasps also feed on adult flies as well as their larvae. There are certain
families of the Order Hymenoptera, which are parasites of larvae and pupae of Diptera,
Coleoptera, and other insects, the actions of which retard the decomposition process.
True bugs also feed on maggots, thus decreasing their numbers and consequently
retarding decomposition.
Fundamental knowledge of entomology can provide invaluable insight into not only
when the deceased died but also where and if the body had been moved following death.
For example the time of year the deceased died can be determined because certain species
of insects are only active at certain times of the year. As an example the bluebottle flies,
Calliphora vician, is more abundant during the cooler parts of the year, whereas the
greenbottle fly, Phaenicia sericata dominates corpses during the warmest parts of the
summer. This determination can be made from insect remains or empty pupal cases of
adult flies; thus, depending upon the time of year you will see different grouping of
insects. The geographic origin can be determined because many insects are localized to
certain localities due to climatic conditions. A specific locality can also be determined
based on the fat that certain species of insects are found only in specific locations. As an
example, it is possible to determine whether the deceased had been moved from an urban
to rural environment following death based upon the fly species present on the body.
Altering of the decomposition process may suggest movement or storage of the remains.
The decomposition process can be altered if the body is wrapped or stored following
death such that it is not exposed to flies. Although the body will continue to decompose
due to bacterial action it will reach a point were if it is moved to another location the first
blowflies will not lay their eggs due to the stage of decomposition. Also certain species
of blowflies only lay their eggs in dark places (Calliphora, bluebottle flies), whereas
Lucilia, greenbottle flies, prefer to lay eggs in well-lit environments.
There is one species of fly that can be seen on buried bodies, called the Coffin Fly,
Megaselia scalaris. This fly has the ability to dig up to six feet underground to reach a
body and oviposit.
Maggots tend to congregate in traumatic areas, such as lacerations, incised wounds,
gunshot wounds, stab wounds, etc. Thus, the maggots in a traumatized area may actually
be of an older age than those in the non-traumatized area. This can be very helpful if
there is heavy maggot infestation in the genital area. Sampling those maggots with those
from other areas of the body may be of some help in determining the existence of trauma.
You need to be careful in your interpretation here due to the fact flies tend to lay their
eggs first in body orifices.
If you see heavy maggot infestation on one of the hands, this is suggestive of a traumatic
injury. Typically the hands become mummified during the decomposition process, hence
adult flies would not find them a suitable place to lay their eggs.
It is important to remember that under certain circumstances maggots can be found in
those who are still living. As an example, maggots can be found in decubitae (skin
ulcers) of those in nursing homes who are not properly looked after. Maggots can also be
found in the diapers of infants who are neglected.
Summation of decomposition
How long this process takes is dependent on the environmental temperature, location of
the body, time of year and whether insects and or predators have access to the body. If
the deceased dies in the summer months, most especially in the south, such as Texas, and
is located where insects and predators have ready access to the body, this entire process
can occur within days, often less than 2 weeks. If however, the death occurs in the fall
the process may take several months not becoming skeletalized until the following
spring. In the more temperate climates the process is much slower with skeletalized
remains including attached fragments of skin and tendonous tissue taking as long as 12 to
18 months. Skeletal remains without any evidence of attached tissue may take up to 3
years. What is important to remember the time frame in which a body undergoes
decomposition and ultimately becomes a skeleton is extremely variable.
There are two variants of the putrefaction process, adipocere and mummification.
Adipocere
Adipocere is a variant of the putrefaction process characterized by hydrolysis and
degeneration of unsaturated body fat (adipose tissue) into a yellowish-white, waxy
substance consisting of saturated fatty acids. In essence the hydrolysis and
hydrogenation of the bodies fat is a form of decomposition specific to the adipocytes (fat
cells) and their contained lipids.
Adipocytes are rich in glycerol molecules and are formed by triglycerols (or
triglycerides). When these cells are exposed to damp, warm, anaerobic environment,
which has undergone invasion by Clostridium welchii, the process of adipocere formation
will commence. Although it was once thought that adipocere required either damp
conditions or the immersion of the boy in water, it is now know that the water content of
the body may be sufficient in of itself to give rise to adipocere even in bodies buried in
well sealed coffins. In one study over half the occupants of dry vaults had some
adipocere. It was present in 63% of women and 45% of men.
For the process of adipocere formation to take place the invasion of the adipose tissue by
endogenous bacteria, of which Clostridium welchii is the principal organ is absolutely
essential. Clostridium produces and enzyme lecithinase, which breaks down the
triglycerides into saturated and unsaturated, free fatty acids, a process referred to as
hydrolysis. In the presence of enough water and enzymes, triglycerol hydrolysis will
proceed until all molecules are reduced to free fatty acids. Normally the nondecomposed body contains approximately 0.5% free fatty acid. However, with adipocere
formation the percentage of free fatty acid may reach as high as 70% or higher. The
unsaturated free fatty acids, such as palmitoleic and linoleic acids, react with hydrogen to
form hydroxystearic, hydroxypalmitic acids and other stearic compounds, a process know
as saponification, or turning into soap. This final product is referred to, as adipocere is
stable for long periods of time due to its substantive resistance to bacterial action. Also,
adipocere formation due to the increase acidity of the tissues as well as dehydration due
to the loss of water in hydrolysis inhibits the endogenous bacteria thus slowing down the
putrefaction process.
Adipocere typically develops in the subcutaneous tissues of the orbits, cheeks, breasts,
abdominal wall and buttocks first. There are also occasions where it will involve the
internal organs, most especially the liver. The time frame in which adipocere develops is
quite variable, with the foundation of the variability being based on the environmental
conditions, i.e., a warm, moist, anaerobic environment favoring adipocere formation.
Adipocere can be seen in as early as 2 weeks, though usually it requires 1 to 2 months to
be substantive and as long as 5 to 6 months for completion. In a closed vault it can
persist for centuries. In its early formation it gives rise to an ammonia-like odor, some
describing it as earthy. Later on in its development it has a rancid sweetness.
One of the points you need to keep in mind is if the body is exposed to insects, adipocere
formation may not occur due to the fact the putrefactive process will proceed at a much
faster rate due to the insect activity (i.e., maggots, etc.). Also predators feeding on the
body will also prevent adipocere formation.
Adipocere is often admixed with other forms of decomposition most notably
mummification or parts of the body will be skeletalized.
Mummification
Mummification is a modification of putrefaction due to dehydration and desiccation of
the tissues. It typically occurs within a dry environment (low humidity), one with high
temperatures and movement of air. However, there is a form of peripheral
mummification, which is seen quite commonly in the early stages of decomposition, in
which the trunk is beginning to show in early green coloration in the lower right
abdominal quadrant. Examination of the distal extremities, especially the fingers and
toes will show a black coloration with evidence of desiccation of the tissues and skin
assuming a leather-like appearance. This drying effect can also be seen involving the
skin of the scrotum in which it takes on a brown parchment-like appearance. These
changes are typically seen between 48 to 72 hours in those dying in temperate climates,
with a temperature of approximately 70 ˚F. The process we are interested in is one more
of central or diffuse mummification of the body.
The process of mummification typically occurs in a hot, dry environment, one with air
circulation, it can also occur in refrigerated or freezing-like conditions. This is primarily
due to the low humidity and the inhibition of bacterial action.
The process of mummification is rarely seen in adults with the exception of those who
die in geographical localities that are constantly hot and dry, such as in the southwestern
United States and the Sahara of North Africa. There are other microenvironments in
which it can occur such as a death in a vehicle, in which the windows are closed with the
death occurring in the winter. The cold temperatures would retard the endogenous
bacteria and do to the dryness of the air the body would have a shriveled-like appearance
covered with brown parchment-like skin, with the extremities being more severely
involved then the trunk.
There is an important point to remember and that is the skin shrinkage can actually
produce linear defects in the skin, which can mimic incised wounds or lacerations. These
are typically seen around the neck, groin and armpits.
The internal organs will also show evidence of mummification manifested by prominent
shriveling. They typically will have a black coloration and a leather-like consistency.
Mummification, although uncommon in adults, is quite common in newborn infants and
fetuses. This is due to the fact they have little if any endogenous bacteria within the
intestines, hence the usual decomposition process is markedly inhibited. Also, due to
their large surface area relative to their body mass dehydration occurs much faster and is
far more complete than in the adult.
The time required for complete mummification of the body is difficult to ascertain due to
the variability under the conditions it occurs as well as the lack of definitive knowledge
in knowing how long the body was exposed to these environmental conditions; clearly it
requires several weeks, especially in ideal conditions.
Postmortem changes in buried bodies
In general the decomposition process is slower when the body is buried, whether in or not
in a coffin, as compared to air or water. The degree of putrefaction of buried bodies is
determined by a number of factors: degree of decomposition before burial, environmental
temperature, whether insects or animals had access to the body before burial, lack of
oxygen, depth of the burial, type of soil and whether buried in a coffin or not.
If the body is buried before postmortem decomposition takes place, putrefaction if it
occurs, will do so at a much slower rate and may never reach the stage of black
putrefaction. This is especially true of a body buried deep in clay soil, but well above the
water table. Sandy soil will allow more oxygen and water to reach the body enhancing
decomposition. However, if it has good drainage, this feature may partially offset the
increase exposure to water.
If decomposition has already started before burial, it will continue after burial, the rate
being principally determined by environmental temperature, shallowness of the grave,
soil type and water table.
Lower environmental temperatures, as previously discussed, will in of itself retard
decomposition. If animals and insects, such as flies, do not have access to the body than
their enhancement of decomposition such as through maggot activity will not take place.
There is however an exception, the Coffin Fly, Megaselia scalaris, is one of the few fly
species seen on buried bodies because it has the ability to dig up to six feet underground
to reach a body and oviposit.
Although, the initiation of the decomposition process is due to endogenous bacteria
within the intestines, which are anaerobic, with Clostridium welchii being the principal
organism, aerobic bacteria also play a role. Lack of oxygen would thus decrease their
participation.
In regard to coffins, their ability to retard decomposition is determined by the quality and
types of materials used in their construction, whether they are water tight, and the water
table and or drainage of the soil. A coffin made of wood laminate or chipboard will
disintegrate rapidly when exposed to water. In contradistinction, a watertight metal
coffin will maintain the body in an excellent state of preservation, especially if they have
been embalmed well.
Postmortem changes in bodies buried in moist environments
As previously discussed, Casper’s law indicates a body will decompose twice as fast in
air than water and eight times faster than those who are buried. Casper’ law should be
interpreted in a general sense. In essence, what it is trying to indicate is that bodies in
water will decompose at a slower rate due primarily to the lower environmental
temperature as well as denying insects and animal predators access to the body. Having
said that, bodies that have been in the water, even for a brief period of time, may show
the effects of fish, crab, and shrimp activity. These effects are typically noted on the
eyelids, lips, tip of the nose and earlobes. Also, any exposed skin may show evidence
their activity.
The type of water the body is immersed in also makes a difference. Bodies immersed in
seawater decompose at a slower rate than those in fresh water; this is due to the salinity
of seawater, which retards bacterial growth. If the body is immersed in stagnant water,
the decomposition process will proceed at a rapid rate due to the high bacterial content.
Whether a body is found on the surface of the water or found below the surface is
dependent on the salinity of the water, fat content of the body, temperature of the water,
and whether putrefaction has occurred with gas formation.
Bodies found in seawater will not uncommonly be found on the surface. In fresh water
bodies will usually sink towards the bottom, resurfacing, due to gas formation within the
body due to putrefaction. In general, it is the temperature of the water, which determines
how fast a body resurfaces. In the warmth of a temperate zone summer, a body may rise
to the surface within two to three days in a lake or pond. If a body sinks in seawater
under the same conditions it may take two to three weeks to resurface. However, if the
water is cold the body may not resurface for weeks to months. If the water is very cold,
near freezing, it may never resurface.
Another factor that effects how soon a body will resurface is its habitus; obese bodies
tend to rise sooner than lean ones.
Bodies that resurface are usually found floating face down due to the fact of the relative
density of the head as compared to the rest of the body and also that it does not develop
early gas formation that occurs in the abdomen and thorax.
Other forms of decomposition can also be seen in bodies found in water. Mummification
can be found in those parts of the body not immersed and exposed to the air. Adipocere
can also be found in immersed bodies, especially those immersed in warm water.
Adipocere usually requires immersion in water for several months, although it can form
in a matter of weeks in warm water. This is primarily due to warm waters less oxygen
content as compared to cold water and its enhancement of bacterial growth. Fungi can
also be found in bodies immersed in water or found in a moist environment.
On occasion bodies can be found in a unique wet environment referred to as a bog. A
bog is a wetland that is formed through the accumulation of acidic ground water and
deposits of dead plant material, typically mosses. The water in a bog has a brown color
due to the dissolved peat tannins. This coloration is imparted to the immersed bodies.
Due to the bogs natural anaerobic environment and the presence of tannic acids they
serve as an excellent medium for preservation of organic materials including human
remains. It is not uncommon for bogs to preserve bodies with the internal organs, skin
and hair all intact for thousands of years.
Maceration
Maceration is the aseptic autolysis of a fetus, which has died in utero and remained
within the closed amniotic sac. Intrauterine maceration must be distinguished from
decomposition due to the fact that in most instances decomposition is indicative of a live
birth whereas maceration indicates stillborn.
The changes of maceration occur quickly in an intrauterine death, with skin slippage,
which is due to separation of the epidermis from the underlying dermis, occurring as
early as 6 hours of death and most definitely within 12 hours. With slippage of the
epidermis from the dermis, the dermis takes on a red color. If the fetus is retained in
utero for 7 to 10 days the red color changes to a purple to brown hue. After several
weeks in utero the deceased fetus will take on a yellow-gray color.
Typically within 2 to 3 days of death in utero the fetus will lose firmness of its tissues,
which manifest by a generalized softness on palpation. This is due to autolysis of its
tissues. At the 7 to 10 day mark the skin has a slimy-like feel. The limbs are very loose,
which in some cases will easily separate from the trunk. The prominent over-lapping of
the bones of the calvarium gives the skull a misshapen appearance. The fetus will often
have a rancid odor but there will be no gas formation.
The organs most severely affected by autolysis in macerated stillbirths are usually those
in the abdominal cavity, i.e., the pancreas, liver, spleen and adrenal glands. It is the
presence of abundant protolytic enzymes in the pancreas and liver which gives rise to
their rapid autolysis. The other organ, which undergoes rapid autolysis, is the brain,
which is primarily due to its high water content. However, even if the brain is in a semiliquid state, the cerebral hemispheres will retain their normal convolutional pattern; hence
the gyration formation may aid you in the determination of gestational age. Another
factor to keep in mind when determining gestational age is that autolysis of the
connective tissue may allow for stretching of the fetus, thus increasing the crown-rump
and crown-heel lengths. However, the foot and hand lengths are typically minimally
altered. Also, the overlapping of the cranial vault bones, although making head
circumference measurements difficult, if done carefully, and used in conjunction with
cerebral cortical gyral formation and foot and or hand lengths, may give you a reasonably
accurate gestational age.
In rare instances, typically in multiple pregnancies, one of the fetuses will die. Their
death is followed by a progressive loss of fluid from the tissues and organs, which leads
to shrinkage and compaction. This ultimately culminates in the fetus becoming flattened
due to mechanical compression in the womb, assuming the appearance of parchment-like
paper. The process is referred to as “fetus papyraceus.” There are also rare cases in
which an extrauterine pregnancy is retained within the mother’s abdomen for years, with
the fetus becoming calcified (Lithopedion).
There are occasions, however, in which the putrefaction process will override the
maceration process. As an example, should the amniotic membranes rupture, but the
deceased fetus is retained in the uterus for any length of time, it will be exposed to the
endogenous bacteria in the cervix and vagina, thus giving rise to decomposition. Also,
should the intact amniotic membranes become involved with chorioamnionitis, the fetus
will be exposed to the causative bacteria, which in turn would give rise to decomposition.
The reason this is of great importance is any degree of decomposition will make it
virtually impossible to determine, whether a live birth took place.