Forensic Lectures 1, 2, 3 (Death) PDF

LECTUREs (1,2,3) Diagnosis of death & pm changes  Irreversible stop of brain and brain stem functions  Irreversible stop of circulation and respiration with loss of consciousness ① Stop of vital process such as : respiration ① Death of tissue that depend on the ability of and circulation...

LECTUREs (1,2,3) Diagnosis of death & pm changes  Irreversible stop of brain and brain stem functions  Irreversible stop of circulation and respiration with loss of consciousness ① Stop of vital process such as : respiration ① Death of tissue that depend on the ability of and circulation tissue for function without blood supply ② Unconscious (nerve tissue 5-7 m muscle 3h ) ③ Unable to communicate with the ② Occurs after somatic death environment ③ Occurs when all cells stop respiration and ④ Unable to appreciate sensory stimuli metabolism ⑤ Unable to initiate any voluntary movement ④ Manifested by post mortem changes  Changes which occur in the body after death resulting from cessation of vital functions. ❶ Post Mortem Cooling. ❸ Rigor Mortis. ❷ Post Mortem Hypostasis. ❹ Putrefaction.  Gradual decrease of dead body temperature until it comes in equilibrium with environmental temperature.  After death, there is paralysis of heat regulating centre with stop of heat production (no oxidation or metabolism) while heat loss continues via ① Conduction (absorption of heat by object in contact with the body) ② Convection (movement of air). ③ Radiation. ④ Evaporation. ① Mass/surface area. ② Body temperature at the time of death. ③ Posture of the body: extended or curved into a fetal position. ④ Clothing ⑤ Obesity: because fat is a good insulator. ⑥ Emaciation: lack of muscle bulk allows a body to cool faster. ⑦ Environmental factors: temperature, winds, rain, humidity  The average rate of heat loss is 1-1.5 C/h  The best site for temperature measurement is Rectum.  Anus and rectum should be examined under adequate light with taking swabs if required before thermometer insertion.  Small electronic temperature probes are available to be introduced in other orifices (nose, ear) but unlikely to register the same temperature as the deep rectum. ① Rough estimation of post mortem interval  In order to use body temperature as an indicator of the time of death, we must assume that the body temperature was 3737°C at the time of death and the rate of cooling is regular ② Differentiate between primary and secondary flaccidity. ‫الركود الريم‬  Discoloration of the most dependent parts of the body including skin and organs due to accumulation of blood under the influence of gravity after death.  Postmortem lividity = livor mortis.  Hypostasis is absent in areas of pressure that prevents Capillary filling, as in areas of: ① Contact flattening: flattening of convex parts of body on pressure due to loss of muscle tone and skin elasticity. ② Pressure by bands and elastic under-cloth.  If body position is changed before coagulation of the body i.e. before 8 hours → a new area of hypostasis will developed.  If body position is changed after coagulation of the body i.e. after 8 hours → no significant change.  It starts immediately after death  It starts to appear within 1/2 to 2 hours after death as mottled patches  It gradually intensifies in colour and reaches its maximum intensity after 6 to 8 hours and becomes fixed.  N.B.: Hypostasis is reported sometimes to occur shortly before death as in congestive heart failure  During first 6 to 8 hours blood remains fluid then clotting takes place so: ① If position is changed within 2 hours:  Hypostasis appears at the new dependent site. ② If position is changed between 2 and 8 hours:  Hypostasis appears in two sites. ③ If position changed after 8 hours:  There is no change of the site of hypostasis. BLUISH RED  Natural death DEEP BLUE  Asphyxia (reduced hemoglobin)  Red asphyxia or red death: carbon monoxide, cyanide, RED and death from cold  Methemoglobinemia (toxicity by nitrite, nitrate, BROWN sulfonamide) PALE  Death due to hemorrhage  Hypostasis in head and neck → drowning.  Hypostasis in feet and hands → hanging. RAPID ONSET AND MARKED EXTENT DELAYED ONSET AND LIMITED EXTENT Death due to congestive heart Death due to severe hemorrhage failure and anemia  ‫التخشب الريم‬  Progressive muscular stiffening and shortening (rigidity) affecting both voluntary and involuntary muscles including cardiac muscles, blood vessels, iris and erector pilae muscles of the skin  Occurring after primary flaccidity and followed by secondary flaccidity.  Depletion of adenosine triphosphate (ATP) after death.  ATP is required to cause separation of the actin-myosin cross-bridges during relaxation of muscle. When oxygen is no longer present, the body may continue to produce ATP via anaerobic glycolysis.  When body's glycogen is depleted, the ATP concentration diminishes, and the body enters rigor mortis because it is unable to break those bridges  It starts in face between 1 - 4 hours and in limbs between 4 - 6 hours after death, and completes in 12 hours.  Then followed by secondary flaccidity 24 to 36 hours after death because of enzymatic breakdown of actin and myosin binding sites.  Rigor mortis first appears in smaller muscles e.g. jaw and eyelids due to quicker depletion of ATP relative to larger muscles in trunk and limbs. 1) Temperature:  In high temperature: rapid in onset with short duration.  In low temperature: delayed onset with prolonged duration 2) Age:  In old age & infant: rapid onset with short duration.  In adult athletes: delayed onset with prolonged duration. 3) Muscular activity before death:  Death due to convulsion:  Rapid onset with short duration (ATP is depleted by muscle contraction). 4) Muscular built:  Slow in athletes and muscular adults (due to much ATP)  Rapid in infants and senile persons. ① It is a sure sign of death. ② It can give information about the position of body at time of death. ③ It help to estimate the time passed since death.  Body feels warm and flaccid: dead less than 3 hours.  Body feels warm and stiff: dead 3–8 hours.  Body feels cold and stiff: dead 8–36 hours.  Body feels cold and flaccid: dead more than 36 hours ❶  Shortening and stiffness of the muscles due to exposure to intense heat due to coagulation of muscles protein as in burn. ❷  Tissues become frozen and stiff simulating rigor mortis due to postmortem exposure to freezing temperature.  The body takes the position in which it was lying.  It occurs due to freezing of body fluids.  When the body is transferred to warm place, cold stiffness rapidly disappears and rigor mortis starts rapidly with shorter duration ❸  State of strong contraction of one group of the voluntary muscle occurring immediately before death (at the moment of the death) without passing to the stage of primary flaccidity. ① Record the last act of the body before death ② Indicate death associated with severe emotional tension  Suicides: cadaver firmly grasps the weapon  Homicide: victim firmly grasp hair, button, and piece of clothes of assailant during struggle  Accidental: hand of drowned cadaver firmly grasp the aquatic weeds, mud or sand. ③ Indicate the cause of death as in drowning.  After death.  At moment of death.  Gradual  Sudden  Preceded by Iry flaccidity  Not preceded by 1ry flaccidity  Occur in all cases of death due to  In some cases with severe decrease ATP. nervous tension.  Both voluntary and involuntary  Voluntary muscles only. muscles.  The usual end stage of decomposition and resolution of the soft tissue of body from the organic to the inorganic states after death. ❶ Autolysis:  Due to action of certain enzyme already present in the tissue cells causing liquefaction of the body tissues. ❷ Bacterial Effect:  Action of certain bacteria both aerobic and anaerobic.  The first external sign is greenish discoloration of skin over right iliac fossa opposite to caecum 2-4 days after death due to formation of sulfhemoglobin by the commensal intestinal bacteria that invade the tissues after death.  Marbling (arborization): bacteria extend through blood vessels decomposing haemoglobin which, when present in the superficial vessels → linear branching patterns of brown discoloration of the skin  Swelling and distension due to accumulation of putrefactive gases starts at the abdomen then extent over the body (face, external genetalia).  Putrefactive blisters are formed and when burst the skin sloughs off  Separation of skin of hands and feet  Loosening of hairs and nails.  The increased internal pressure causes the eyes and tongue to protrude  Froth at mouth and nostrils: offensive, coarse, dark, and bloody  Generally, within a week body cavities burst and tissues liquefy  By six months, all soft tissues disappear & nothing is left except bones attached by ligament  Then, ligaments disappear and bones only are left.  More rapidly at 37 °C: suitable for breakdown of tissues and multiplication of organisms.  Retarded < 10 °C (inhibition of bacteria) & > 40 °C (dried body fluid).  Necessary for putrefaction as it help rapid multiplication of organism  Air accelerates putrefaction: as most putrefactive organisms are aerobic.  Blood is a good medium for putrefactive bacteria so putrefaction in liver gravid uterus prostate non gravid uterus.  Putrefaction is more rapid in deaths from infective diseases or congestive heart failure  Putrefaction is retarded in death due to dehydration or arsenic poisoning ①  Post mortem changes replacing putrefaction in hot dry climates e.g desert  Slow drying of body fluid by evaporation.  Tissues become dark and hard ① Personal identification ② Time pass since death ③ Place of death ④ Cause of death  ②  Post mortem change replacing putrefaction in dead body submersed under water  Hydrogenation of oleic acid to stearic acid  Yellowish white, greasy wax like body, soft with rancid smell ① Personal identification ② Time pass since death ③ Place of death ④ Cause of death ③  Aseptic autolytic changes in dead fetus inside uterus and remain at least 5 days  Brown red discoloration.  Rancid smell.  Peeling of skin  Blisters formation  Post mortem  Ante mortem  Has no swelling  Has swelling  Has defined margins  Has ill defined margins  The cut surface shows that the blood is lying  The cut surface shows that blood is lying within the blood vessels and oozes from inside tissue them  Show one color  May show different color  Microscopic examination shows no vital  Microscopic examination shows vital activity reaction ① What are early signs of Death? ② What are late signs of Death?  Changes which occur in the body after death resulting from cessation of vital functions. ❶ Post Mortem Cooling. ❸ Rigor Mortis. ❷ Post Mortem Hypostasis. ❹ Putrefaction. ③ What is Postmortem Cooling?  Rate?  Factors Affecting?  Medicolegal Importance? ④ What is Postmortem hypostasis ?  Definition?  Description?  Medicolegal Importance? ⑤ Please mention the position of the victim at death? ⑥ Please mention the cause of death? ⑦ What is cadaveric spasm? ⑧ What are the conditions replacing putrefaction? ① Hypostasis become fixed through : a. 0-1 hour b. 2-3 hours c.-4-5 hours d.-6-8 hours ② Post mortem cooling is rapid in obese person: a-True b-False ③ Which of the following indicates rigor mortis? A. Discoloration of the skin of the most dependent part of the dead body B. Progressive muscular stiffening and shortening after death C. Transformation of organic matter of dead body to inorganic matter D. Gradual reduction of the body temperature after death ④ If the position of a body is changed 4 hours after death, where does hypostasis appear? a. No hypostasis will be observed b. Hypostasis appears at the most dependent site according to original position only c. Hypostasis appears at the most dependent site according to new position only d. Hypostasis appears at the most dependent sites according to both positions ⑤ What is the first site where greenish discolouration of putrefaction appears? a. Over the right iliac fossa b. Over genitalia c. Over chest d. Over the back ⑥ A 23 years old man was found dead , his body shows cherry-red hypostasis. What is the likely cause of death? A) Carbon monoxide poisoning B) Asphyxia C) Blood loss D) Poisoning by nitrites ⑦ Dead body with offensive odor and green discoloration on the abdomen. Which post-mortem stage is this body in? A) Rigor mortis B) Putrefaction C) Hypostasis D) Adipocere formation ⑧ A forensic pathologist observes fixed hypostasis on a body. What does this indicate about the time since death? A) Less than 2 hours B) 2-4 hours C) More than 12 hours D) 5-6 hours ⑨ Rigor mortis is : A) Progressive stiffening of muscles after death B) Cooling of the body after death C) Discoloration of the skin due to blood settling D) Decomposition of body tissues ⑩ Average rate of cooling after death in a temperate environment? A) 1-1.5°C per hour B) 2-3°C per hour C) 0.5°C per hour D) 3-4°C per hour ⑪ Which of the following causes brown hypostasis? A) Death due to cold B) Asphyxia C) Poisoning by nitrites D) Drowning ⑫ What condition simulates rigor mortis but is caused by freezing temperatures? A) Cadaveric spasm B) Cold stiffness C) Heat stiffness D) Putrefaction ① Mention 2 M.L.I of hypostasis? ② Mention 3 conditions replacing putrefaction?