This document summarizes post-mortem changes that can help estimate time of death. It describes immediate changes that occur within 30 minutes of death, early changes within 36 hours such as algor mortis (body cooling), rigor mortis (muscle stiffening), and livor mortis (post-mortem lividity). Late changes after 36 hours include decomposition stages of bloating, decay, and skeletonization. Specific changes in the skin, eyes, and potassium levels in vitreous humor are also noted.

1. Time since death
Post mortem changes
Anup Tiwari
Roll no 22

2. Post-mortem Changes
 The changes which occur after death that are helpful in estimation of the
approximate time
 of death can be classified into :
 Immediate changes (Few minutes after death to maximum 30 minutes)
 a) Insensibility and loss of voluntary power
 b) Cessation of respiration
 c) Cessation of circulation

3.  Early changes (1-36 hours.)
 a) Changes in the skin
 b) Changes in the eye
 c) Cooling of the body (Algor mortis)
 d) Postmortem lividity (Livor mortis)
 e) Changes in the muscles (Rigor mortis, RM)
 Late changes (>36 hours)
 a) Decomposition (combination of autolysis and putrefaction)
 b) Modifications of putrefaction (adipocere, mummification)

4. Changes in skin
 Skin becomes ashy-white, pale and loses elasticity,
 within a few minutes of death.
 Lips are dry, brownish and hard due to drying

5. Changes in the eye
 Tache noire - If the eyelids remain open after death, desiccation of
 sclera occurs giving rise to somewhat triangular shaped discolored
 areas [simply Tache noire (black spots)]. These are yellowish in color
 in the beginning, but as dust settles in, they become dark red or later
 even black.
 Loss of intraocular tensionIntraocular pressure (IOP) falls rapidly after death. It
becomes
 zero in 4–8 h from 10–20mmHg (Average–15mm )during
 life. Due to this, The eyeballs look sunken in the orbit.

6.  Rising potassium level in vitreous humour:
 After death, the cells around the vitreous chamber breakdown
 and release their fluid in the vitreous, due to this the
 concentration of ions slowly increases.
 Increasing concentration of ions in vitreous chamber provide a
 remarkable data of time since death and medical history.
 If a body finding in underground water, in this case the
 environmental conditions make difficulties to determine the time
 of death, but examination of potassium level give estimate time
 since death.

7. Rigor mortis
 The stiffening of muscle after Death
 Without oxygen in the blood—
 Calcium accumulates in the muscles
 Muscles stiffen
 Starts in the eyelids and expands throughout and lastly the
 lower limbs.
 After about 15 hours—
 Muscle fibers begin to dissolve
 Softening begins

8.  Time of appearance: (Rule of twelve)
 • Starts in 3 to 6 hours
 • Takes 12 hours to complete
 • Stays for another 12 hours
 • Passes off in the next 12 hours.

9. Livor mortis
 Lividity begins about 2 hours after death.
 Discoloration becomes permanent after 8 hours
 Ambient temperature affects the speed of decomposition.
 Cooler temp – occurs slower
 Warmer temp – occurs faster
 Lividity can determine the position of the body during the first eight
 hours.

10.  The normal colour of livor mortis changes from red to purple as
 oxygen gradually dissociates from the hemoglobin of red blood cells.
 This produces deoxyhemoglobin that is purple in colour and therefore
 postmortem lividity normally looks purplish.

11. Algor mortis
 Body heat falls after death
 Average rate of fall -
 (a) during summers -0.75°F/h (b) during winters -1.5°F/h. Heat loss is affected by the ambient
temperature( environmental
 temperature)
 Corpse temperature is measured by a thermometer inserted into
 the liver or rectum.
 Time of death is expressed as a range of time
 Temperature is measured by using a chemical thermometer graduated from 1 to 50 degrees
centigrade, inserted 10 cm into the rectum.

12. Stages of decomposition
 A. Within 2 days. : Initial Decay (Fresh)
 Cell autolysis begins.
 Green and purplish staining occurs from blood
 decomposition.
 Skin takes on a marbled appearance.
 Face becomes discolored.

13.  B. After 4 days : Putrefaction (Bloating)
 Skin blisters.
 Abdomen swells with carbon dioxide (released by
 bacteria living in the intestines).
 Lecithinase is major bacterial enzyme responsible
 for putrefaction.

14.  Within 6-10 days : Decay stage - Black
 Putrefaction (Butyric Fermentation)
 Corpse continues to bloat with CO2 as
 bacteria continue to feed on tissues
 Eventually, gas causes chest and
 abdominal cavities to burst and collapse.
 Fluids begin to leak from body openings as
 cell membranes rupture
 Eyeballs and other tissues liquify
 Skin Sloughs off
 Very strong odor

15.  D. Within 10-25 days : Post decay Stage- Butyric
 Fermentation
 Corpse is beginning to dry out
 Most of flesh is gone
 E. >25-50 days : Dry Decay (Skeletonization)
 Corpse is almost dry
 Further decay is slow due to lack of moisture

17. Stomach and intestinal contents

18. Thank you