May 30, 2023
The study of death and dying from a variety of reasons including medical, physical, psychological, spiritual, ethical, and more, is known as Thanatology.
Thanatology is used by experts from a wide range of professions, from doctors and coroners to hospice workers and grief counselors, to inform their work. Additionally, there are Thanatology experts who concentrate on a particular component of the dying process or work directly with those who are confronting their own death or the death of a loved one.
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In this there is complete and irreversible stoppage of any of Bishop’s tripod of life components which includes
Or there is a loss of any one function and it leads to death or the Doctor declares the individual dead.
It Occurs within 1-2 hours after somatic death.
It Depends on the dysfunction i.e., may be respiratory, circulatory, or brain function.
Asphyxia, syncope, and coma are examples of Bichat’s mode of death.
Stopping of only one component of Bichat’s tripod of life (respiration, circulation, or brain function) results in death. It is an example of somatic death.
In this, signs of life are reduced to a minimal level and resuscitation leads to survival. Causes of suspended animation are:
Signs of death may be immediate, early, or late.
Early signs include:
Immediate signs include
Late signs include:
The Retinal blood vessels appear segmented or fragmented. It is seen within a few minutes to one hour after death. It can be seen using an ophthalmoscope. It is the earliest eye sign and it is used to determine time since death (TSD). Before the Kervokian sign, corneal reflexes are lost, and the pupil is dilated.
The "Kevorkian sign" is the fragmentation or trucking of blood vessels and it is a crucial ophthalmoscopic finding. Within a few minutes of death, the Kevorkian sign appears and lasts for around an hour.
Normal intraocular pressure is 20mmHg.Two hours after death, intraocular pressure drops to 0 mmHg. It is also used to determine time since death.
After death, if the eyelids are open and dust is present in the atmosphere, it will get deposited in sclera resulting in formation of 2 brownish triangular shaped opacities on either side of the cornea which is known as Tache Noire Sclerotique. It occurs after 3-6 hours of post-mortem and is used to determine time since death.
Normally the cornea is transparent but after 1 hour of death the cornea becomes Hazy. Whereas opacity of cornea occurs after 6 hours.
It is the most important medium in the eye which resists putrefaction. There are no chemical changes in vitreous humor after putrefaction.It is the best medium for estimating time since death, as it is enclosed within the eyeball so bacteria cannot have access to it easily.
So, even in an advanced decomposed body, this medium is very helpful. Best parameter is vitreous potassium levels. There is Linear increase in K+ and hypoxanthine. It has linear correlation with time since death. Two formulas used for finding time since death are Sturner's Formula and Madea's Formula.
It is seen within 15 minutes after death. In this the body core temperature (BCT) decreases. Thanatometer is a chemical thermometer used to measure BCT in post-mortem. It may be 25-30 cm. It can measure temperatures between 0-50°C. Ideal site for recording temperature is the rectum (rectal temperature is almost equal to BCT).
Other sites include the inferior surface of the liver, external auditory meatus, nasal spaces, and the lower end of the esophagus. Graph illustrating the relationship between temperature and time post-mortem produces a sigmoid curve or inverted S-shape curve.
Algor mortis Occurs in 3 phases
Rate of fall of temperature is 0.4°C – 0.7°C / hr that is, in summer it is 0.4° C / hr and in winter it is 0.7° C / hr. Average fall of temperature is 0.5 C/hr. By knowing the rate of fall, we can calculate time since death.
Normally, the body becomes cold within 15 mins after death [Algor mortis]· But, if the body remains warm for 1-2 hrs even after death, it is known as Post-mortem caloricity. Whenever there is increased body core temperature at the time of death, post mortem caloricity is seen.
Increased body core temperature at death is seen in conditions with increased Muscle contraction that is Tetanus, Strychnos Nux vomica poisoning exercises etc. Defective thermoregulation in the body is associated with Heat stroke, Pontine hemorrhage [have pyrexia, paralysis, pinpoint pupils] and Septicemia.
It is Also known as post-mortem lividity, hypostasis, livor mortis, vibices, or suggillation. This stain is Present in dependent parts of the body i.e., areas that do not touch the ground but face towards the ground.
Gravitational forces cause the pooling of blood in capillaries and venules so there is accumulation of deoxyhemoglobin blood in the skin causes a bluish-purple appearance there is Skin discoloration of rete mucosum of the dermis.
This stain is absent in pressure parts of the body. It begins shortly after death, that is after 30 minutes. And it is visible for 2 hours after death. Maximum visibility is for 6-12 hours and fixation occurs after 7-8 hours.
Secondary lividity occurs when changing the position of the body before 7-8 hours leading to post-mortem staining in other areas of the body, it persists till decomposition. Decomposition changes the skin color to green.
Post-mortem staining in different positions
It helps to determine time since death and determine the position of the body at the time of death and also Determine the cause of death (COD).
It is also known as cadaveric rigidity / Cadaveric stiffening . It gives muscle status after the death of a person. The decrease in ATP causes stiffening of the muscle. Rigor mortis is generalized, that is it is seen in both voluntary & involuntary muscles but it is first seen in involuntary muscles.
3 stages muscles undergo after death include:
Primary flaccidity occurs during somatic death. Rigor mortis occurs during cellular death. Mechanism of rigor mortis is ATP depletion. Actin-myosin separation takes place in primary flaccidity. Lack of actin-myosin separation causes rigor mortis.
Secondary flaccidity occurs when decomposition starts in this Actin and myosin filaments are broken down leading to separation. When rigor mortis starts, ATP decreases to 85% of the normal content. At maximum rigor mortis, ATP decreases to 15-30% of the normal content.
It begins 1-2 hours after death. It is seen in all muscles whether voluntary or involuntary. 1st muscle affected is the myocardium. 1st external muscle affected is the upper eyelid muscle i.e., orbicularis oculi.Sequence in which external muscles are affected:
Eyelid muscles → Neck → Lower jaw → Muscles of face → Muscles of chest → Upper limbs → Abdomen → Lower limbs → Fingers and toes
Rigor mortis disappears in the same order that it appears. It will disappear first from the upper eyelid and last from the fingers and toes.
In fetuses of less than 7 months of age, rigor mortis is absent because the Actin and myosin filaments have not developed. Rigor mortis' appearance is according to seasons. In summer, it is seen in 18-36 hours whereas In winter, it is seen after 24-48 hours.
In this Muscle mass is thin with decreased ATP storage it is seen in Diseases such as cholera, TB, cancer, cachexia, and typhoid. In this there is Early onset of rigor mortis with short duration.
In Cases such as cut throat injury or firearm injury leads to appearance of rigor mortis in violent death. It has Early onset rigor mortis with short duration.
There is Increased ATP storage and it has Late onset of rigor mortis.
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It is Also known as boxing attitude or pugilistic attitude or fencing attitude. It occurs when Surrounding external temperature is ≥ 65°C. Mechanism involves the coagulation of muscle protein. Normal rigor mortis is not seen. Heat stiffening Persists till decomposition occurs.
It occurs when Surrounding external temperature is ≤ -5°C. Mechanism involves freezing of the body fluid and hardening of the subcutaneous tissue.In warm temperature, cold stiffening disappears. In this Normal rigor is present.
Occurs due to intense accumulation of gas. It is Seen with decomposition. During decomposition, there is excess gas production · These gasses get accumulated in the body, resulting in stiffness of the body.
It is Also known as cataleptic rigidity or instantaneous rigor. Mechanism involves ATP depletion. Muscles remain contracted for lifetime and remain rigid and stiff after death. It Occurs immediately after death. Primary relaxation is absent whereas Secondary relaxation is present. It is An exclusively ante-mortem event.
Causes of cadaveric spasm:
|Cadaveric spasm||Rigor mortis|
|Time||Immediately after death.||1-2 hours after death.|
|Muscles||Mainly involves voluntary muscles.|
Generally, it involves a short group of muscles e.g. hand muscles.
|Involves both voluntary and involuntary muscles.|
|Electronic stimuli||Response present.||Response absent.|
|Importance||Describes the manner of death.||Determines TSD.|
In these changes the body gets decomposed. Decomposition occurs by Two mechanisms: autolysis and putrefaction.
It is a process in which Body enzymes cause cell lysis. Examples of autolytic changes:
Aseptic autolysis involves the mummification of the fetus in intrauterine death.
It is Stimulated by bacterial activity. Most common bacteria involved is Clostridium welchii or Clostridium perfringens. Most common enzyme involved is lytic lecithinase.
Putrefaction occurs in Three stages of change:
1st internal/overall change of putrefaction is reddish-brown discoloration of aortic intima. 1st external change is green discoloration of the right iliac fossa.
Bacteria forms hydrogen sulphide. Cecum located beneath the right iliac fossa has maximum bacterial activity. Skin lies superficial to the cecum. Sulphur combines with hemoglobin to form a green color compound. In summer, discoloration starts in 12-18 hours. In winter, discoloration starts in 1-2 days.
In this there is Discoloration of prominent superficial veins to green-brown color which Corresponds to the vascular channel.
Mechanism: Clostridium welchii bacteria form hydrogen sulfide gas in the superficial veins with the formation of green, brown sulphahemoglobin.it Starts in 24 hours and is Prominent in 36-48 hours. It helps in determining TSD. It is Seen in the chest, shoulder, abdomen, and thigh.
Predominant gas produced in decomposition is H2S.This gas gets accumulated in the body resulting in stiffening known as gas stiffening · Gas in skin at dermo – epidermal Junction results in Blister Formation
It takes 5-10 days. Loosening of hair/ nails, occur in 3-5 days and kin around the hands & legs peel off i.e Degloving/Destocking pattern is seen in 5-10 days
Body emits light after death. Causes of post mortem luminescence are:
It is about rate of putrefaction in different medium · Rate of putrefaction is compared b/w 3 imp medium. This Formula was proposed by Taylor. It Shows the relationship between the rate of decomposition in air, water and soil (earth).
If decomposition in the air takes 1 week, it will take 2 weeks in water and 8 weeks in soil. Air has the fastest rate of decomposition.
Also known as Grave wax/ Saponification . The Fat in the body gets converted into fatty acids; and combines with Calcium in the body & forms insoluble wax like substances i.e (SOAP) adipocere.
When an adipocere is formed, it is preserved for a longer time. It is Hydrolysis and hydrogenation of fat. Factors required for conversion are Warm, moist climate, Clostridium welchii (lecithinase), Intrinsic lipases (lipases within the body). The predominant fatty acid is Palmitic acid. Acidic medium Inhibits the multiplication of bacteria (Further putrefaction is inhibited),Hence the body is preserved, Smell of adipocere is Ammoniacal.
Appearance of adipocere :
Fresh adipocere - greasy and it Looks like rancid butter
Old adipocere- dry,hard, yellow and brittle
Time required for adipocere formation is 3 days to 3 months and it is Absent in fetuses of less than 7 months.
It helps to Describe the climate at time of death and Determination of Time since death and helps in Preservation of the dead body for easy identification.
When the body is exposed to dry / hot climate, drying & dehydration of the body occurs resulting in mummification, in this the Body size is shrunken , There is loss of weight that is more than 70% weight is lost. It has No specific smell / Odourless. It takes 3 months – 12 months to occur. Mummification is also seen in intrauterine death of fetus, when there is intact membranes & deficient blood supply. Arsenic & Antimony favor mummification. It is an Important feature of intrauterine death.
Artificial method of preserving the body by injecting anti septic's & preservatives ·
Exhumation is lawful digging of the body · Ideal Time for embalming is less than 6 hrs after death (Very effective)
Ethanol is not a part of embalming fluid.
Protein (mainly, albumin).
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