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1. Changes after Death Contd. Dr. Md. Iqbal Bahar Chowdhury Associate Professor SMAMC

2. Objectives After this class you will be able to know about- Muscle changes after death Rigor mortis Cadaveric spasm D/D of rigor mortis

3. Muscle Changes Primary relaxation or flaccidity : D ue to lack of control of higher centers to the muscles Rigor mortis /Cadaveric rigidity/Death stiffening Secondary flaccidity : The rigidity disappears with the molecular death of the muscles, thus the body gets flaccid again Cadaveric Spasm

4. Rigor mortis/ Cadaveric rigidity/Death stiffening The phase of primary relaxation of muscles continue for an hour or more after death. After this period, the muscles of the body gradually become stiff or rigid . This rigidity of muscles after death indicates molecular death of concerned muscle.

5. Definition Rigor mortis is a condition characterized by stiffening & shortening of the muscle due to chemical changes in their myofibrils which follow the period of primary relaxation after death of an individual.

6. Mechanism Energy(ATP) needed for separation of actin & myosin filaments. But after death ATP is progressively & irreversibly destroyed & no re-synthesis of ATP.

7. Mechanism When ATP fall to critical level(85% of normal) overlapping portion of actin & myosin combine as rigid link of actinomyosin & causes hardness & rigidity of muscle when fall to 15% rigidity is maximum.

8. Order of appearance & disappearance( Nysten’s rule) Starts appearing in small muscles of the eye lids & cardiac muscle. Eyelids -> back of neck & lower jaw -> front of neck -> face -> Chest, abdomen, upper extremities -> lower extremities -> fingers & toes. Disappear in same manner

9. Duration of Rigor mortis Rigor mortis in general sets on within 1-2 hours after death, 12 hours to develop completely from head to foot, persist for 12 hours & passes off in about another 12 hours However when rigor mortis sets early then it passes off early & vice versa

10. Contd. Muscle site Time interval after death Eye lids 3-4 hours Face 4-5 hours Neck & Trunk 5-7 hours Upper extremities 7-9 hours Legs 9-11 hours Finger & toes 11-12 hours

11. Testing rigor mortis Opening of eyes Depressing the jaw Gently bending the neck Bending the various joints of the body

12. Factors affecting rigor mortis Age: I n healthy adult person its onset is slow & last longer, rapid in children & old . Physique of subject : Comes early & passed of early in thinly build subject , Temperature : Comes early & passed of early in high temp .

13. Contd. Nature of death: In exhaustive disease, wasting disease, convulsion precedes death rigor mortis appears & passed off early. In HCN & strychnine poisoning rigors appears early & passed off late. Death due to asphyxia, hanging, CO poisoning, severe hemorrhage rigor comes late.

14. Conditions where Rigor mortis doesn’t occur Heat stiffening Dying from Septicaemia Foetus less than 7 month of intrauterine age

15. Medico legal importance Sign of death Time since death can be estimated Indicate molecular death of muscle involved Cadaveric spasm, heat/cold/gas stiffening may confused with it.

16. Cadaveric spasm / cataleptic rigidity / Instantaneous rigor It is a condition in a dead body in which muscle of the body which were in a state of strong contraction immediately before death, continues to be so contracted at the moment of death & after death, without passing through the stage of primary relaxation.

17. Mechanism The mechanism is possibly neurogenic , but no scientifically satisfactory explanation R elated to individuals who are at high levels of emotional or physical stress immediately before death. Many reports relate to i ) battlefield casualties , ii)individuals recovered from rivers with weeds or twigs grasped firmly in their hand, iii)finger of a suicidal shooting found tightly gripping the trigger.

18. Condition/ predisposing factors Sudden death Excitement(soldier in battle field) Fear Severe pain Cerebral hemorrhage Injury to nervous system Firearm wound of head Convulsing poisons e.g. strychnine

19. Medico legal importance Ante-mortem phenomenon in origin Reflects the last act at the time of death Cause & nature of death can be guessed Weapon in firmly grasped of victims hand indicates suicide . Button or hair of assailant in firmly grasped of victims hand indicates assault .

20. Cont.… It passes in to normal rigor mortis without any interruption Disappears when rigor disappears

21. Differences Rigor mortis V Cadaveric spasm Onset Muscle involvement Primary flaccidity Mechanism Muscle reaction Predisposing factors Molecular death Medico-legal importance

22. Secondary Relaxation (breakdown of rigor mortis) By the action of alkaline liquids produced by putrefaction By excess of acid production during rigor mortis Enzymes are developed in dead muscle which dissolve myosin by a process of auto digestion .

23. Heat stiffening If death occurs due to 2 nd or 3 rd degree of burn injuries or dead body is subjected to exposure to more than 65 O C then there will be coagulation of the muscle protein , & body will be stiff with contraction of the muscles. Flexor muscle take upper hand, give rise to pugilistic/boxer’s/fencing attitude.

24. Cold stiffening Stiffening occurs due to – ( i ) freezing of the body fluids at tissue level, synovial fluid . (ii) due to hardening of the subcutaneous fatty tissue . Body temp will be below 0 O C, There will be cracking sound or crepitation, if the joints are manipulated.

25. Gas stiffening This is due to accumulation of putrefying gases in the tissues that cause false rigidity.

26. Summary Muscle changes after death Rigor mortis Cadaveric spasm D/D of rigor mortis