1. بسم الله الرحمن الرحيم

2. ASPHYXIA

3. Definition:  Conditions in which the supply of oxygen to the blood and tissues has been reduced below the normal working level by any interference with respiration.  Asphyxia is used as being equal to “lack of oxygen” or “hypoxia”,

4. Gordon’s classification: AAAAnoxia is classified into 4 types: I) Anoxic anoxia: This means defective oxygenation of blood in the lung and due to: 1- Absence of oxygen. 2- Obstruction to respiratory passage 3- Obstruction to respiratory movements 4- Depression of respiratory centre

5. II) Anemic anoxia  O2 carrying capacity of the blood: hemorrhage and CO poisoning III) Stagnant anoxia: Inefficient circulation through the tissues, as in: Shock and heart failure Inefficient circulation through the tissues, as in: Shock and heart failure IV) Histotoxic anoxia: Inability of the tissues to utilize oxygen delivered to them, cyanide poison

6. Stages of asphyxia 1- Stage of dyspnea: Cyanosis, rapid deep breathing with acting extraordinary muscles of respiration. Rapid pulse and high blood pressure. 2- Stage of convulsions: Cyanosis becomes deeper. Breathing becomes difficult and spasmodic. Congestion and edema of lungs and other organs. Petechial hemorrhages in skin, lungs, heart and brain. Convulsions occur.

7. 3- Stage of apnea (respiratory paralysis): UUUUnconsciousness occurs. Breathing becomes  s s s shallow,  i i i infrequent and ggggasping, tttthen apnea occurs.  P P P Pulse becomes weak and BP is reduced.

8. External Postmortem (PM) picture 1- Petechial hemorrhages:   Sites of formation:   Mechanism of formation 2- Postmortem hypostasis is well- developed and dark in color 3- Cyanosis 4- Rigor mortis is rapid 5- Putrefaction is rapid.

10. Internal Postmortem (PM) picture PPPPetechial hemorrhages under the pleura and pericardium and in the internal organs. Congestion and edema of the viscera ( except the spleen). TTTThe blood is dark in color and more fluidly. TTTThe right heart and great veins are engorged with blood.

12. Violent Asphyxial Deaths 1- Hanging 2- Ligature strangulation 3- Manual strangulation (Throttling) 4- Smothering: 5- Choking 6- Traumatic asphyxia (Crush asphyxia)

13. 1- Hanging  It is Asphyxial death caused by suspension of the body by a ligature around the neck, the constricting force being the weight of the body. A) It may be either complete or partial: B) It may be either typical or atypical:

14. Mechanism of death:  Cerebral anoxia  Cerebral congestion. 3.Asphyxia: 4.Reflex vagal inhibition

15. Externally:  The neck is stretched.  The face is pale or bluish.  The rest of the body is cyanosed.  Saliva may be seen dripping from the mouth (It is a vital sign and is present only in hanging but not in postmortem suspension). (It is a vital sign and is present only in hanging but not in postmortem suspension).

16. Ligature mark: SSSShape: It is a depression at the site of the ligature SSSSituation: Transverse and complete (if running noose). TTTThe pattern of the ligature: Is imprinted on the neck as a pressure abrasion.

21. Internally:  Fracture of the hyoid bone  Petechial hemorrhage and ecchymosis of the subcutaneous tissue under the ligature, but never in postmortem suspension. Is it hanging or PM suspension?

22. Is it suicidal, homicidal, or accidental hanging? Suicidal: (most common):  Circumstantial evidence (history of failure).  Absence of signs of struggle.  Presence of signs of previous suicidal attempts.  Suicidal note

23. 2- Ligature strangulation  A violent Asphyxial death caused by constricting the neck by a ligature.  Mechanism of death:  Asphyxia: from compression of air passage  Cerebral congestion or apoplexy:  Reflex vagal inhibition  Cerebral anoxia:  Combination of any of the above

24. Autopsy appearances:  Externally:  The face is either pale or bluish and congested. The rest of the body is cyanosed.  The tongue may be protruded, swollen and bitten.  Bleeding from ears and nose may be seen.

25. Ligature mark:  Shape: as in hanging.  Situation: At the level of thyroid cartilage or below.  Symmetrical  Transverse and  complete (this is the usual).

26. Ligature mark:  A postmortem swelling of the neck associated with exaggeration of  skin folds or any  clothes worn around the neck may produce depressed marks. All these look like ligature mark. Neck dissection can differentiate

28. Suicide, homicide, or accident:  Newborns strangled by the umbilical cord.  Children plying with ropes  Adults strangled by the neck tie caught in moving machinery.

29. Methods commonly used for homicidal strangulation: MMMMugging: by compressing the victim's neck against the forearm. GGGGarroting: attacking the victim from behind and grasping his throat or throwing a ligature over the neck and tightening it quickly. BBBBansdola: compressing the neck between 2 sticks TTTThrottling: by compressing the victim's neck by the hand.

30. : Differences between hanging and strangulation : Circumstantial Circumstantial Rope marks Rope marks Signs of resistance Signs of resistance Starched neck Starched neck

31. 3- Manual strangulation (Throttling) caused by constricting the neck by the hand. caused by constricting the neck by the hand. Mechanism of death: Autopsy appearances: Autopsy appearances: When death occurs as a result of vagal inhibition, Asphyxial signs will be absent. Externally: Externally: Injuries on the neck: Injuries on the neck: Abrasions (caused by finger nails). Abrasions (caused by finger nails). Contusions (caused by finger pads). Contusions (caused by finger pads). Both are found on the front and sides of the neck Both are found on the front and sides of the neck

32. Suicide, homicide, or accident: Suicide: A case was recorded and it was due to cadaveric spasm. Suicide: A case was recorded and it was due to cadaveric spasm. Homicide: (most common) Homicide: (most common) Circumstantial evidence. Circumstantial evidence. Presence of signs of struggle. Presence of signs of struggle. Evidence of drink or drugs, or the victim is young or weak. Evidence of drink or drugs, or the victim is young or weak.

36. 4- Smothering:  Caused by mechanical occlusion of the air passages from outside (i.e. the mouth and nostril) by hand or by any object.  PM picture  Asphyxial signs will be present except in case of plastic bag suffocation.  Abrasions and contusions on the skin of the face around mouth and nose (Absent if a soft material, such as a pillow, is used).

37. Suicidal, homicidal, or accidental: SSSSuicide BBBBy hand is impossible. (Tying a plastic bag over the head is rare). Accident: (most common) IIn children playing with plastic bags. AAn alcoholic adult who rolls over (during sleep) and his face in the pillow.

38. 5- Choking  Caused by mechanical occlusion of the air passage from inside. Mechanism of death: Asphyxia: due to either complete occlusion of air passage, or partial occlusion that is completed by spasm, edema and mucus secretion.

39. Accidental: (most common) May arise from: IIIInhalation of irritant fumes. IIIImpaction of foreign material, such as food or denture. IIIInhalation of dust and sand in falling of houses. IIIInhalation of vomit or blood during operations. FFFFalling back of the tongue epileptic fit. CCCCafé coronary:

43. 6- Traumatic asphyxia (Crush asphyxia) RRRResulting from trauma to the chest or pressure on the chest and abdomen which prevent respiratory movements  * * * *Penetrating trauma e.g. stab injury  pneumothorax  lung collapse ****Non-penetrating trauma e.g. run-over car accident  fracture of ribs  restriction of respiratory movements from the severe pain occurring during respiration.

44. Pressure on the chest and abdomen due to:  Burial in earth following house collapse.  Crushing by a crowd, as in case of a fire.

46. 7- Drowning (Immersion):

47. It is a form of violent asphyxia in which death results from submersion of mouth and nostrils of a living person under water  Classification (types) of drowning: 1- Typical (wet) drowning: 2- Dry drowning. 3- Secondary drowning (Near- drowning).

48. Physiopathological changes:  In fresh water  hypervolemia  hypoxia and potassium excess.  In salt water  pulmonary edema  hypovolemia and circulatory shock.

49. Dry drowning: Water in the larynx  laryngeal spasm  asphyxia Near-drowning (2 nd drowning syndrome):

50. glistening pleural surface of a lung

51. PM picture of drowning: TTTThese are signs of asphyxia unless death occurred from 1- shock, 2- syncope, 3- concussion.

52. External appearances 1.Signs of immersion: These are found in any body found dead in water (whatever the cause of death).  Coolness of the body.  Goose-skin the skin is wrinkled.  Washerwoman-skin: the skin is sodden.  Peeling of the epidermis in the form of gloves and stockings.  Hypostasis

53. 2- Sure external signs: A-Froth: (Fine – White – Odorless _ increase) B-Cadaveric spasm of the hands on weeds, mud, sand, etc.

55. Internal appearances  Voluminous lungs with indentation marks of ribs on their lateral surfaces.  Respiratory passages contain froth (having the same characters of that found externally at the mouth and nostrils),  foreign material ( weeds, mud, sand,.).

56. A normal pink aerated appearance with minimal anthracotic pigmentation,

57. Diffuse alveolar damage in which the lung is diffusely firm and rubbery

58. Diatoms: TTTThese are microscopic, unicellular algae, found in fresh as well as salt water. WWWWhen a live person is drowned in water, they penetrate his alveolar membrane and pass with the circulation to distant organs. BBBBut when a dead body is thrown into water, the absence of beating heart prevents circulation of diatoms to distant organs.

60. some of the plant material in the water was aspirated into a bronchus.

61. The medico-legal (ML) importance of diatoms: 1111- Sure signs of drowning, 2222- Could still be identified in putrefied bodies, 3333- Could give an evidence of the site of drowning (fresh or salt water species).

62. How to know that death was due to drowning: 1-Froth at mouth and nostrils: fine, white, abundant. 2.Cadaveric spasm on weeds, mud or sand. 3.Lungs: voluminous, edematous with indentation marks of the ribs. 4.Froth in the air passages. 5. Diatoms in the tissues.

63. In putrefied bodies:  Only diatoms could be identified