The word tanatología comes from the Greek: tanatos : death and logo : treaty and is the part of the legal medicine that studies the modifications of the human organism as of the same moment to have produced the death. (1)

Within same we can to find different branches as tanato-I diagnose (it determines biological signs that they allow to affirm the death state), tanato-semiología (it studies the phenomena of deathly pale transformation, immediate and moved away, in relation to the moment of happened the death), tanato-conservation, tanato-legislation and others. (1)

The primary target of this work is to study the crono-tanato-diagnosis (CTD) that includes the set of observations and techniques that allows to indicate two moments between which, WITH GREATER PROBABILITY, the death has taken place. And rebound the fact that he is not exact since except for the direct observation of the fact, at the present moment methods do not exist that, isolated or altogether, allows to determine with certainty the exact moment of the death. The times can be influenced by own factors of the corpse or other people's to him. (7)

For the criminology they are the three questions that consider: CAUSE of the death and circumstances in which one took place, DATA of the death and PLACE in which the death took place. The CTD can answer two of them: the data and the place (this last one, thanks to the indispensable contribution of the forense entomología - to see ahead but -). (2)

Its importance is that from the determination of the data of the death: (7)

• The police investigations can be centered
• An alibi can be accepted or be discarded (argument of culpability of a person) to be in another place at the moment of a crime.
• Consequences economic, relative to testaments and some commercial relations are derived.
• It can affect the legal recognition of a posthumous paternity.

The first step to carry out before a body is I diagnose accurate of the death since we can find the apparent death in which the vital functions of circulation and breathing are in their minimum expression, imperceptible by the current methods giving the sensation of which the person this dead; and the real death that is the total losses and definitive of the circulation and the breathing.

Some of the methods to determine if the death is real are: test of the pulse, disappearance of the noises cardiac, tie of the finger, reaction to the pain, temperature, etc. (6)

The procedures to apply in the cronotanatodiagnóstico depend on the type of corpse:

1. Recent corpse

In the recent corpse there is no evident rotting.

• Evolution of deathly pale phenomena

The deathly pale phenomena can be immediate , that is to say, the extinction of the vital functions of the nervous, cardiovascular and respiratory system; consecutive , constituted by processes and physical, chemical and biological modifications and transformativos that the deathly pale rotting includes, produced by bacterial action that destroys the corpse gradually. (5)

• Dehydration: (1)

Loss of I eliminate that by evaporation it undergoes the corpse and that is translated in losses of weight and cutaneous modifications, mucous and ocular.

The corpse loses weight in the following and approximate proportion (Dupont): in new born, 8 grams by kilo per day and in adults, 8-10 grams by kilo per day.

The cutaneous modifications are by the apergaminamiento of the skin and escroto; the mucous by the drying of the lips, glande and vulva and, finally, the eyeglasses, by the sign of Stenon Louis (opacity in cheats on it that hs begins 12. after the death) and the one of Sommer or it stains esclerotical black (stains irregular Black who must to the oxidation of the hemoglobina of the coroideos glasses and to the dehydration; it is located soon in the external angles of the previous segment of the eye and in the internal ones. Ta begins from the 5 hour post mortem if the eyelids are open)

The dehydration can study according to the diminution of the tension of the ocular globe (hs takes 15). , the enturbamiento of the cornea (45 minutes with open eyes and 24 hs. with the closed eyes), and the esclerótica spot (hs delays 6. in appearing with open eyes and 5 hs. when they are closed).

1.1.2. Cooling: (1)

It represents the reduction of the corporal temperature until balancing with the one of the atmosphere. One has been to logically establish a relation approximated between deathly pale corporal temperature and probable time of death, within the average numbers that it admits this possibility. Several forms exist but but used they are those of Bouchat and Glaister.

Formula of Bouchat: during the first hours of happened the death there is a diminution of 0.8 to 1 degree per hour. During following the twelve hours, the diminution is from 0.3 to 0.5 degree per hour. The corpse equals room temperature 24 hs. after the death.

Formula of Glaister: Rectal Tº normal average - deathly pale rectal Tº

1,5

The deathly pale temperature is influenced by external factors (room temperature, body outdoors or submerged or within a room, humidity) or by own factors of the individual: age (the children and the old ones cool off more express), type of affection (the caquectizantes cool more express than the sudden ones, presence of previous hemorrhages or fever to the death), degree of nutrition (the amount of fat is directly proportional at the speed of cooling) and degree of clothes (the naked one cools off more express).

Based on this it is important to measure the cavitaria temperature of the corpse (for example, rectal) and of the corporal surface in different parts and planes at the moment from the rise and the room of form autopsies so to be able to have an own notion with no need to guide by you formulate determined to us by other people. Serious interesting to make nomograma according to the collected data. (7)

1.1.3. Deathly pale rigidity: (1)

Post is consequence of the coagulation mortem of the miosina with the consequent hardening of muscular fibers, are these smooth ones or fluted. As result appears the “attitude of envaramiento” of the corpse, constituted by the discreet flexion of the arms on the forearms; of the legs on the thighs and the thumb below the remaining fingers.

The rigidity follows a descendent march (cefalo-of great volume) throughout muscles of the body: it begins by the maseteros and it finishes in the feet.

The time of appearance is variable according to the law of Niderkorn:

• Precocious Rigidity: before 3 hours.

• Normal Rigidity: between 3 and 6 hours.

• Delayed Rigidity: between 6 and 9 hours.

• Very delayed Rigidity: after 9 hours.

Factors exist that influence the time of appearance of the rigidity:

• F. Accelerating: heat (the rigidity lasts little), cold (the rigidity lasts much), childhood (the rigidity lasts very little), oldness and previous agony.

• F. Delaying: clothes, clothes of bed, adultez, sudden death or do violence to.

In agreement with the rule of Brouardel the rigidity disappears when the deathly pale rotting and in he himself order in which begins it appeared (direction cefalo-of great volume). In new born and nursing one settles immediately after the death and it disappears very quickly.

1.1.4. Deathly pale Espasmo: (1)

Post is the maintenance mortem of a certain corporal or vital position as resulting from a sudden death (of encephalic or cardiac etiología) natural or does violence to.

The difference between deathly pale rigidity and espasmo is in the fact that in the first case muscular relaxation to the death exists previous, whereas in second mortem without intermediate stage exists a transition of the state of vital muscular contraction to post.

Later the rigidity is superposed espasmo and, finally, both disappear when the rotting settles.

1.1.5. Livideces deathly pale: (1,5)

They are cutaneous spots of violáceo color (lívido) that appear in the zones but declivities product of the vasodilatación by encharcamiento of the blood by coagulation absence. The livideces indicate to the position of the body when taking place the death and they are moved according to the changes in the position of the subject without life. This last phenomenon is called transposition of the livideces and single it can happen within the first 12-15 hours of happened the death and never after the 24 hours of the same one.

The time which they take in appearing the deathly pale livideces is variable: from almost immediately after the decease to 4 or 5 hours later. From the moment in which they are pronounced are increasing slowly and losing speed to reaching their Maxima intensity between 12-15 hours and do not take place beyond the 30 hours.

It is possible to clarify that the livideces can not appear due to a severe external hemorrhage or vary in their coloration due to poisoning. For example, they are but clear when carbon monoxide exists in the blood. (3)

1.1.6. Deathly pale Hipostasia: (1)

It is the accumulation of the blood in the parts declivities of the vísceras in regard to the force of the gravity. Hipostasias visceral is to the organs as the livideces are it to the skin. They seat mainly in encéfalo, the lungs and the kidneys.

1.2. Dependent data of the organic weave survival (7)

Table 1: Reaction of different organic weaves, in time after the death

Reaction of different organic weaves	Time (hs)
Reaction of the pupil to the light	4
Reaction of the pupil to the instilación of drops of atropine	4
Reaction of the pupil to the instilación of drops of eserina	2
Electrical Excitabilidad of the musculatura	6
Mobility of epitelio respiratory	24
Mobility of the espermios	36
Excitabilidad of the glands sudoríparas	6

1.3. Dependent data of the halting of the vital processes (7)

Study of the gastric content: it serves to determine if the ingested foods can be identified but its utility for the CTD is relative since the time of digestion and permanence of foods in the stomach is variable. So that this data is useful is due to have a study of how it is I journey gastric of the person at issue, which is almost impossible. Its main function is for comparing if the found thing in the search agrees with which they affirm the witnesses (if there are them).

• Study of the intestinal content: similar to the previous item.

• State of vejiga: similar to the previous item. In addition it serves mainly to determine tinkles in search of drugs (specially marijuana) and other metabolitos.

• Length of the hair and face hair: but it is guessed right in the people who shaved the day of the death because if the data does not become necessary of the length of the previous hair to the death.

• State of the yellow body

1.4. Tanatoquímicos data (7)

One is collected data of the study of different markers, in samples different from the blood:

• Cefalorraquídeo Liquido

• Endolinfa

• Pericárdico Liquido

• Sinovial Liquido

• Vitreous Humor

The most trustworthy data are obtained from markers in this last one, specially the potassium, since vitreous humor is a practically isolated fluid of all the putrefactivos phenomena and the potassium is the main intracellular ion, which increases to their concentration when increasing the rate of autolisis. The determination of the potassium concentration is made with an electrode specific ion and a regression curve is obtained whose equation is: interval post mortem = 3.38 xs [K +] - 10,66. (4)

Vitreous humor is also useful for the study of drugs (cocaine, heroin, etc.), alcohol and values of glucemia to determine cases of hipo and hiperglucemia like death cause.

2. Nonrecent corpse

The nonrecent corpse is that in which the rotting is already manifest in its three first stage.

2.1. Rotting (1,5)

The rotting is the moment in that the complex chemical structures of the organism are simplified and this constituted by exogenous and endogenous factors. First they include the temperature and environment where one is the body and the seconds to the intestinal parasites and originating bacteria and ptomaínas of the proteinic rotting. The diffusion takes place by vicinity throughout the blood vessels and lymphatic constituting the call “vascular network of the rotting”.

The decomposition is very precocious in delayed summer and in winter (as long as the corpse is outdoors and not in a calefaccionada room since this I complete serious similar to the summer). The most fragile organ to the rotting is the brain and the most resistant heart, the uterus and the prostate.

We can distinguish four phases: (1,2)

a. Chromatic: Constituted by the appearance of the “green spot of the abdomen” in the region to cecoapendicular (it moats right ilíaca) as of the 24 hours after the decease. It is consequence of I hydrogenate sulfurated produced by the intestinal rotting. Also hs begins to see itself after the first 24-48. the venous framework of dark green color (that in the alive individual can be appraised of red color wine) by the transformation of the hemoglobina. Nevertheless, it is possible to clarify that in the violent deaths the rotting begins in early form in the places where the body presents/displays wounded and that in patients who undergo problems in torácicos organs (infarcts, asphyxias) the green spot begins in that zone.

b. Enfisematosa: Cutaneous gaseous vesicle presence that when breaking itself takes to the loosening of epidermis (36-72 hs. post mortem), voluminous distension of the abdomen, escroto, vulva, the lips (24-48 hs.). The blood by the same pressure of gases is displaced of the deep planes the superficial ones, giving rise to the call “posthumous circulation” (Brouardel).

The gastric content can flow back by the mouth and lees by the anal region. By an analogous mechanism the uterus or the rectum can prolapsar and can happen that a fetus stopped in the vaginal channel, after the death of the mother can totally be expelled. This last event is bad call “childbirth post mortem” since the word childbirth implies an active mechanism, an essentially vital dynamism; in this case one is a corpse therefore there is no vitality and single there is expulsion by the force of gases formed in the abdominal cavity. The correct thing would be then to speak of “expulsion post mortem”

c. Colicuativa: There is a liquification of weaves transforming itself these into a putrilaginoso magma making disappear the habitual form.

d. Reductivo: Constituted by a series of phenomena that determine the transformation or disappearance of the soft and bony parts throughout the time and according to phenomena that depends on the corpse and of the atmosphere in which one is buried (table 2). (1,3)

Table 2: Phenomena that can happen in the reductivo period of the rotting

Phenomenon		Characteristics
That they conserve the corpse	Momificación	• Product of the concomitancia of the fast drying of the corpse and the absence or suspension of the phenomena of deathly pale rotting. • Approximate Time of production: 6 months to 1 year of produced the death, or more according to the cases. • The optimal conditions so that it happens east phenomenon are in atmospheres of high temperatures, dry and ventilated. • In this process the histológicas structures are respected allowing to carry out retrospective diagnoses of different pathologies.
Petrifaction or calcification	• Resulta from the infiltration of part or all the human organism of calcáreas salts. • Can be primitive (fetuses retained in the uterine cavity that transform themselves into “litopedios” - of the Greek: litos , stone and pedos , boy) or secondary, in a corpse of minor or adult. • Approximate Time of production: it has not been possible to establish, but it requires many years.
That they destroy the corpse	Adipociria	• Greasy Transformation of the corpse. Chemically it is a soap of calcium, potassium or magnesium that form by autolisis to expenses of the fatty weave and organic proteins. And others give rise to glycerin and fatty acids. These last ones are combined with salts of calcium, potassium or magnesium having determined an insoluble soap. • Evoluciona towards the calcification if the accumulation of calcáreas salts intensifies or towards the coliquification if the humidity predominates acclimates. • Approximate Time of production: 3 months to 1 year from the death. • The optimal atmosphere so that it happens is the humid lands and/or the suspended waters.
Corificación	It is an incomplete form of adipociria. • According to Scythe Volta, own of corpses buried in coffins of zinc or lead constituting a phenomenon different from first. • Approximate Time of production: just as adipociria.

	Colicuación	• Transformation eliminates putrefactiva of all the deathly pale soft parts. • Approximate Time of production: it does not exist. He is generally precocious in relation to the time of the death. • The optimal conditions are given by the inhumación in earth and a fragile coffin that let arrive liquid or neighboring humidity.
Decalcification	• Beginning of the pulverization. • Ocurre when, to the missing salary all the soft parts by the rotting, the bones are losing their fragile and papiráceos calcium salts slowly and becoming in the open. • Approximate Time of production: it has not been possible to even establish with relative exactitude. Generally in a period that oscillates between the year and the five years of happened the death.
Pulverization	• Final Transformation of the human organism. • Approximate Time of production: 15, 20 or more years. • The optimal conditions are given by the inhumación in earth directly; that is to say, without surrounding coffin or without inhumación, in outdoors left corpses.

2.2. Deathly pale fauna (1,2)

Set of insects that follow one another to chronological regularity in a human corpse, from the moment at which the death takes place until the complete destruction of the soft parts.

First swelling of insects arrive at the body attracted by the scent of gases given off in the process of the degradation of the immediate principles (glúcidos, lipids and proteins) and other gases like ammonia, sulfuric acid, free nitrogen and carbonic anhydride.

The different artrópodos that arrive at a corpse can be classified in:

• Species necrófagas: They are fed on the body. It includes to dípteros (Calliphoridae and Sarcophagidae) and coleopters (Silphidae and Dermestidae).

• Species parasitic pregivers and of necrófagos: It includes coleopters like Silphidae, Staphylinidae and Histeridae, dipteros (Calliphondae and Stratiomydae) and parasitic himenópteros of the larvae and pupas of dípteros.

• Omnívoras Species: Wasps, ants and other coleopters that feed so much on the body as of the artrópodos associate.

• Accidental Species: They use the body like an extension of his normal habitat (spiders, centipede, acaruses which they are fed on the mould and the fungi that grows in the body).

Two forms exist to determine the time passed from the death leaning in the forense entomología: a) to use the age and rate of development of the larvae; b) to use the succession of insects in the decomposition of the body. Both methods can be used separately or jointly.

According to the successive progression of the artrópodos that reach the corpse we can make picture 1. (2)

Picture 1: Succession of artrópodos from the moment of the death (time in days)

It is possible that in certain cases the data given by the entomólogo does not agree with the data provided by the forense doctor who has practiced the autopsy. This can happen or because the insects have not colonized the corpse in the first days (places difficult, houses perfectly closed, etc.) or in the cases of abandonment and bad treatments in old children and in which they exist wounded and injuries that are colonized by the insects before taking place the death.

The steps to follow according to Catts & Haskell in “Entomology and death: to manual procedural” they are:

• Determinar the phase or physical state of decomposition in which is the body.

• Realizar an exhaustive study of the insects that are on the corpse as well as of the gathered ones underneath him to discard the possibility that it has been transferred of place. If some suspicion is had an additional examination as much of the rest as of the near areas would be necessary.

• Clasificar the specimens gathered as much of the rest as of the scene of the crime of the possible most exact way. To conserve a part of the immature stages and to raise the other until the adult stage for its correct identification.

• In outdoors found corpses, is essential to collect data like the temperature, rainfall, cloudiness, etc. in addition to factors like the vegetation, hoisted, unevennesses of the land, etc. For the scenes in the interior it is equally necessary to write down temperature, existence of automatic heating engineers, position of the corpse with respect to the doors and windows, as well as any other detail that can give information us of how and when the insects have arrived at the corpse.

• During the autopsy is important to take note from the exact location of the artrópodos in the body, the cause and the way of the death. Also it is important to write down if antemortem of some type of drugs or toxic products exists evidence of the administration since these substances could alter to the rate of development and the patterns of insects that have fed themselves on the rest.

The first insects that colonize the body are the dípteros (to see picture 1) like for example those of the family Calliphoridae and Sarcophagidae. The females deposit eggs in the natural orifices of the corpse, that is to say, eyes, nose and mouth; and in the possible wounds that could have the body. It is possible to clarify that the Sarcophagidae family does not place eggs but larvae.

The egg stage usually lasts between 24 and 72 hours depending on the species. The dissection and the analysis of the state of embryonic development of the egg are useful to specify the data of ovoposición still more, reason why it becomes necessary to know the characteristics own eggs of each species.

The number of eggs depends on the nutricional state of the female and of its corporal size, an inverse relation between the size of the egg exists and I number of eggs by package.

Another zone of putting is the place of contact of the body with the substrate because in that zone it is where the corporal fluids are accumulated.

The eggs normally eclosionan all simultaneously. Soon the larvae introduce themselves underneath the subcutaneous cellular weave, they liquefy it with the aid of bacteria and enzymes and are fed by suction. When the larvae finalize their growth go to you fold them of the body or the clothes and they are transformed into pupa. These you complete transformations not only depend on the species, but also on the outer conditions, the cause of the death and the type of feeding. It is important to indicate that the callifóridos ones are buried to make the pupación and prefer to make their own orifices.

She is very strange which in a body without life there is not a presence, although vague, of the passage of the callifóridos ones. Commonly their larvae are depredated by sarcophagidas those of, but this does not explain the lack of pupas empty, adult deads, etc. that could be found.

With the appearance of butyric acid in the corpse they appear the first lepidópteros coleopters and (approximately to the month of the death). Their eggs eclosionan according to the temperature between 3 and 12 days after the putting and present/display a vital cycle of 4 to 6 weeks. They are fed mainly on the fat in decomposition and remainders of the previous squares.

When it appears the caseica fermentation of the protein rest the flies appear, whose vital cycle is of about 30 days. Also we can find in this stage of the decomposition to other groups of dípteros and coleopters.

The following process in happening is the ammoniac fermentation, in that they appear the last types of flies that usually live in nests of birds, madrigueras of small mammals, etc.

They have happened already but of 6 months and in the stage of disappearance of the rest presents become the masses of microscopic acaruses. When these go away, the practically dry corpse this and makes their appearance coleopters that are going to feed themselves on the faneras.

When the corpses been have submerged in water the fauna that we found is different (Table 3). (2)

Table 3: Hydric deathly pale fauna per periods

It is not necessary to let consider that in entomología which insects exist pregivers (ants, wasps, etc.) that they capture and they destroy the larvae of dípteros being able to take to confusions or erroneous interpretations.

3. Bibliography

• Bonnet, P. (1978). Legal medicine lessons . (3ª ed.) Buenos Aires. Argentina: . Editorial Lopez Booksellers.