Rigor mortis ppt

Rigor mortis is a measure to determine time till death. It is a stage of dead body after death.

1. RIGOR MORTIS Presented By: Ajay Sharma

2. 1. Introduction 2. Primary relaxation or flaccidity 3. Rigor mortis 4. Factors affecting rigor mortis 5. Medico-legal importance of rigor mortis 6. Conditions simulating rigor mortis 7. Secondary relaxation or flaccidity 8. Case study 9. Conclusion References

3. Primary Relaxation or Flaccidity Death is only somatic. All the muscles are begin to relax soon after death. Joints become flexible and all muscles lose their tension. Contact flattening of body. Muscles may respond to mechanical, electrical or chemical stimuli. Pupils react to atropine or physostigmine , but not to light. Peristalsis may occur in intestine with cilia movement of intestinal cells. After death, as long ATP presents, muscles are relaxed. ATP is produced by anaerobic  glycolysis . This stage lasts from 3 ─ 6 hours, but the average is 2 ─ 3 hours.

4. STRUCTURE OF SKELTAL MUSCLE

5. Fig. 1: Stages in Actin and Myosin cross cross bridge formation and breaking

6. Appearance of rigor mortis indicates death of individual cells. After death the ATP is progressively and irreversibly destroyed. There is no resynthesis of ATP. Calcium ions to flood the contractile units of the muscle fibres ( sarcomeres ) because of membrane disruption and lack of ATP. Increased calcium level in the sarcomeres causes muscle contraction. Rigor mortis or Cadaveric rigidity

7. Fig.2: Binding of actin and myosin filaments Fig.3: Diagrammatic representation of muscle contraction

8. Order of Appearance and Disappearance of Rigor Rigor mortis first appears in the involuntary muscles, and then in the voluntary muscles ( Nysten’s rule). In the heart it appears, within an hour after death and may stay for 10–12 hours. In the voluntary muscles rigor mortis follows a definite course. The disappearance of rigor follows the same fashion as its appearance. According to Shapiro─ Rigor mortis most likely to develop simultaneously in all the muscles.

9. Fig.4: Showing order of appearance and disappearance of Rigor

10. Development of rigor is concerned with muscles only. Development of Rigor If force is applied when rigor is fully developed, stiffness is broken up permanently and the rigid muscles may show postmortem ruptures.

11. Features of Rigor mortis It may affect the eyes unequally, making the pupils unequal. Contracted, stiff, left ventricle may be mistaken for left ventricular hypertrophy. Rigor in the muscle of scrotum, may be responsible for postmortem expulsion of semen. It c auses goose-skin or pimpling appearance of the skin with the erection of cutaneous hairs (cutis anserina ) . It may cause expulsion of the foetus . Muscle relaxation immediately after death with opening of the eyes and mouth and subsequent fixation in rigor mortis, changes face expression.

12. Testing of Rigor Rigor is tested by trying to lift the eyelids. Depressing the jaw. Gently bending the neck. Try flexing/extending various joints of the body. Note the degree (absent, minimal, moderate, advanced or complete) and distribution (patchy/complete).

13. Time of Onset and Duration Generalized categorization of Appearance and Disappearance of Rigor Mortis

14. Rule of 12: It is generally considered that it takes about 12 hours after death to develop rigor mortis, remains for another 12 hours and takes about 12 hours to pass-off. This is also called as March of rigor. Fig. March of Rigor

15. Adult, Child or Old Natural, Disease or Poisoning Healthy, Robust, at Rest or Weak and Exhausted Cold or Hot No effect of brain

16. Medico-Legal Importance It is the sign of death. It helps in estimating time since death to some extent. It indicates the position of the body at the time of death to some extent. It helps in determining whether a still-born child is alive in uterus up to the initiation of birth process and died during the process of delivery. It is also developed in paralyzed limb. It shows whether body is disturbed from its original position or not.

17. Conditions Simulating Rigor Mortis 1) Heat Stiffening It is seen in deaths from burning, high voltage electric shock and from falling into hot liquid. Heat causes stiffening of the muscles, because the tissue proteins are denatured and coagulated as in cooking. Muscles are contracted, desiccated or even carbonized on the surface. The body assumes an attitude commonly called ‘pugilistic attitude’ (Boxer’s attitude) with lower limbs and arm flexed and hands clinched. (Fig.5) This heat stiffening cannot be broken down by extending the limbs as in rigor mortis. Stiffening remains until the muscles and ligaments get soften due to decomposition. In such state, rigor mortis do not occur.

18. Fig.5: Heat stiffening of body showing pugilistic attitude

19. 2. Cold Stiffening When a body is exposed to freezing temperatures, the tissues become frozen and stiff. Freezing of the body fluids and solidification of subcutaneous fat simulating rigor. When the joints are forcibly flexed, ice breaks in the synovial fluid with a sudden sharp sound. If the body is placed in warm atmosphere, the stiffness disappears and after a time, the normal rigor mortis occurs rapidly and passes off quickly. Hardening of the subcutaneous fat, particularly in infants, may render the skin-folds rigid and may be mistaken for ligature marks.

20. 3 . Cadaveric Spasm or Instantaneous Rigor Cadaveric spasm is a well-recognized but quite rare phenomenon. Primary flaccidity does not occur in case of cadaveric spasm, and the muscles undergo stiffening at the moment of death. This is usually limited to a group of voluntary muscles. Adrenocortical exhaustion, which interferes with the resynthesis of ATP, may be the possible cause of cadaveric spasm. It is usually associated with the violent deaths occurring under circumstances of intense emotions. No other condition simulates cadaveric spasm and it cannot be produced by any method after death. It passes without interruption into normal rigor mortis .

21. The obvious circumstances of cadaveric spasm may be: It may be encountered in cases of drowning (fig.6). Death from violent disturbance of nervous system . Strychnine, cyanide poisoning. In suicidal deaths (fig.7). In certain cases of homicides. In certain cases of accidents such as mountain fatalities. Fig.7: Victim of suicide Fig.6: In case of drowning.

22. Medico Legal Importance of Cadaveric Spasm Presence of cadaveric spasm indicates that person was alive at the time of instantaneous rigor. It indicates ante-mortem nature of drowning. In case of suicide, when some weapon is found clenched tightly in the hand of the deceased is a strong presumptive evidence of suicide. If the deceased dies due to assault, some part of clothing of his assailant or some hair may be firmly grasped in the hands. Cadaveric spasm helps in indicating the mode of death i.e., whether suicide or homicide or accidental.

23. Differences Between Rigor Mortis And Cadaveric Spasm FEATURES RIGOR MORTIS CADAVERIC SPASM Time of onset 1-2 hours after death Immediate Mechanism Due to depletion of ATP Not clearly known Muscles involved All muscles (both voluntary and involuntary) are involved gradually. Usually restricted to single group of voluntary muscles. Muscle stiffening Comparatively moderate Comparatively strong Predisposing factor None Sudden death, excitement, fear, emotional disturbance, etc. Molecular death Occurs Does not occur Electrical stimuli Muscles do not respond Muscles respond Medico-legal importance Helps to know time since death, position of body Indicates mode of death (whether suicide/ homicide/ accidental)

24. This sort of stiffening occurs in dead bodies showing signs of decomposition. Gases evolving during putrefactive processes also stiffen the body, due to accumulation of gases in tissues. Usually, this poses no problem in distinguishing from true rigor. 4. Gas stiffening

25. ( 3)` Secondary Relaxation or Flaccidity Rigor mortis disappears, and the muscles become soft and flaccid. Muscles do not respond to a mechanical or electrical stimulus. This is due to myosin being dissolved by the excessive production of acid during the stage of rigor mortis. It may caused by the action of the alkaline liquids produced by putrefaction. Enzymes are developed in dead muscle which dissolve myosin by a process of auto-digestion. The signs of decomposition start appearing on the body. The body becomes totally relaxed and flaccid and can be put in any position or posture.

26. Case Study July, 2011. Dead body of an unknown female aged about 25 years was brought for medico legal autopsy with an unknown history, but with the suspicion of a murder. Autopsy was carried out after 3 h from the time of finding the dead body in an isolated place at the suburbs of Bangalore, India. The body was found in an unusual position at about 7 am, when the temperatures at that place ranged between 21°C ─ 27°C in the past 6 hrs. During autopsy, the dead body was found with well established rigor mortis all over the body. A horizontal ligature mark was seen completely encircling the neck. Autopsy findings were consistent with a death due to ligature strangulation.

27. Photograph from Right side of body Photograph from Left side of body

28. The autopsy confirms that there was no decomposition, and the stiffness seen in the unusual position, is due to rigor mortis. The victim's dead body was disposed off, after positioning in an unusual way, prior to the onset of the rigor mortis. Such an unusual positioning of the dead body is not possible at the flat surface, where the dead body was found disposed off. It shows that the dead body has originated from a different place. Many factors affect the onset or progress of rigor mortis, after considering the usual possibilities, the dead body must have reached the place of disposal, from 2 to 6 hours after the death. To conclude, the clues from the ‘rigor mortis in an unusual position’ are revealing a homicidal offence and an attempt to hide the evidence. The investigations in this case had not proceeded further because the victim was unidentified.

29. CONCLUSION Following death, muscles of the body pass through three phases, i.e. primary flaccidity, rigor mortis and secondary flaccidity . The importance of these changes is related primarily to their sequential nature that can be utilized to estimate the time since death. Estimation of postmortem interval may be extremely helpful in the screening procedure in some cases. Rigor mortis helps in determining position and conditions of body at the time of death and manner of death. It may be confused with cadaveric spasm, heat stiffening and cold stiffening.

30. REFERENCES Bardale , R. 2011. Principles of Forensic Medicine and Toxicology . First Edition. Jaypee Brothers Medical Publishers (P) Ltd. New Delhi. PP-147-151. D’Souza , D.H., Harish,S ., Rajesh, M. and Kiran , J. 2011. Rigor Mortis in an unusual position: Forensic considerations. International Journal of Applied and basic Medical Resarch . 1(2): 120-122. Modi , J.P. 2006. A Textbook of Medical Jurisprudence and Toxicology . Twenty third Edition. Lexis Nexis Butterworths India Ltd. New Delhi. PP- 431-435. Reddy, K. S. and Murty O. P. 2014. The Essentials Of Forensic Medicine And Toxicology . Thirty third Edition. Jaypee Brothers Medical Publishers (P) Ltd. New Delhi. PP-160-164. Sharma, R.K. 2011. Concise Textbook of Forensic Medicine & Toxicology. Third Edition. Global Education Consultants, Noida , Uttar Pradesh. PP-47-48. Vij , K. 2011. Textbook of Forensic Medicine and Toxicology . Fifth Edition. Reed Elsevier India Private Limited, New Delhi. PP-84-88. https://en.wikipedia.org/wiki/Rigor_mortis (visited on 5/2/19)