ASPHYXIA

1. ASPHYXIA • It is a condition that if oxygen supply to the blood and tissues is reduced because of interference with respiration,it is also called Anoxia\Anoxaemia\Hypoxia.

2. Causes of asphyxia • Obstruction to the air passages due to hanging,strangulation or throttling. • Causes of external respiratory orifices,as in smothering. • Occlusion of the air passages within as in drowning or laryngeal spasm. • Pressure on the chest,as in traumatic asphyxia

3. Inhalation of irrespirable gases like carbon monoxide. • Spasm of the respiratory muscles,as in strychnine poisoning. • Paralysis of the respiratory center,as by narcotics and anesthetics. • Obstruction to the upper respiratory passage in cases of angioneurotic oedema.

4. Features of asphyxia • Cyanosis,capillary dilatation,capillary stasis,rise of capillary pressure. • Increased capillary permeability,Tardieu’sspots and relaxation of sphincters.

5. Asphyxia Reduction in o2 tension Deficient oxygenation in lungs • Capillary dilatation • Reduced pulmonary flow • Capillary stasis • Diminished venous return to heart Capillary engorgement • Stasis of blood in organs

6. Mechanical asphyxial deaths or Violent asphyxial deaths • Hanging • Strangulation • Suffocation • drowning

7. Hanging • Hanging is a form of asphyxial death which is caused by the suspension of the body by ligature which encircles the neck,the constricting force being the weight of the body.

8. Types • Complete hanging. • Partial hanging. • Typical hanging. • Atypical hanging.

9. Complete hanging • When feet do not touch the ground and the weight of the body acts as a constricting force. Partial hanging • When the weight of the head and not the whole body acts as a constricting force is known as partial hanging.

10. Typical hanging • The ligature is situated in the midline above the thyroid cartilage and runs symmetrically upwards on both sides of the neck to the occipital region. Atypical hanging • Any variation of this standard position.

12. Ligature • Not particular,like ropes,chains,wire,leather straps,belts,scarf,dhoti,sarees etc. • Its important to match the ligature with the ligature mark and see if its strong enough to bear the weight and jerk of the body. • Cut the ligature away from the knot.

13. Symptoms • So rapid that they are rarely observed. • Flashes of lights before the eyes,ringing in the ears. • Unconsciousness and death. • The individual can do nothing to help himself even if it were possible. • Respiration stops before the heart which may continue for 10-15min.

14. Causes of death Asphyxia Ligature forces the tongue up and occludes air,15kg tension occludes the trachea. Cerebral congestion Obstruction of jugular veins by compression with 2kg wt tension.

15. Cerebral anoxia • Carotid artery occludes with 4-5kgs tension and vertebral artery with 20kgs tension. • Reflex vagal inhibition. • Fracture dislocation of cervical spine t the level of 2,3,and 4 vertebrae. • Combination of any of the above.

16. Postmortem appearance External appearance. Internal appearance. External appearance -Above the ligature. -Beneath the ligature. -Below the ligature.

17. Above the ligature mark • Tilt of the head. • Protrusion of tongue. • Dribbling of saliva. • Le Facia Sympathique. • Tardieu spots. • Congestion of the face. • Petecheal haemorrhages. • Middle ear haemorrhages.

18. Beneath the ligature • Fixed or running noose. • Position of the knot. • Course of the ligature. • Width and multiplicity. • Point of suspension. • Slipping of ligature. • Weight of the body.

19. Below the ligature • Postmortem lividity (Glove and Stocking) • Relaxation of sphincters. • Injury to legs.(partial hanging)

20. Internal appearance • Haemorrhages in the neck. • Dry,white and glistening. • Rupture of platysma and sternomastoid. • Transverse tear in the intima of carotid artery. • Fracture of hyoid,cricoid and thyroid cartilages. • Congestion of organs. • Petechial haemorrhages.

21. Diagnosis • Ligature mark around the neck. • Presence of abrasions,echymosis and redness around the ligature mark. • Trickling saliva from the mouth. • Echymosis of larynx and trachea. • Rupture of intima of carotids. • Signs of asphyxia.

22. Medico-Legal Aspects • Was the death due to hanging? • Whether hanging was suicidal,homicidal or accidental? • Typical oblique,non-continuous,high up ligature mark. • Abrasions and echymosis above and below the ligature mark. • Extravasation-tear of the intima of the carotids. • Saliva and signs of asphyxia.

23. Suicidal • Usually full suspension. • Ligature tied to beam,hook,fan,tree etc. • Suspension without any platform is unusual in suicide. • Occasional nail mark-may be self inflicted while trying to free him\herself. • Suicidal note.

25. Homicidal • Extremely rare,except in case of lynching. • Difficult,unless the victim is unconscious by injury or by drugs. • Marks of violence may be seen on the body.

28. Postmortem hanging\Suspension • Person murdered and the dead body suspended to simulate suicide. • Usually the rope is tied first to the neck and then around the beam\hook where beam shows evidence of rope being pulled from below upwards. • Ligature mark may be produced if the body is suspended within 2hrs after death.

29. Judicial hanging • Drop of 5-7meters. • Fracture dislocation at cervical 2-3 or 3-4. • Transection of spinal cord. • Tear of intima of carotid artery. • Injury to pons and medulla

30. Strangulation • It’s a form of asphyxial death caused by the constriction of neck by ligature or by any means without suspending the body. • By ligature. • Manual strangulation Or • Throttling.

31. Causes of death • Asphyxia • Anoxia • Congestion • Vagal inhibition • Combination of any of the above

32. Autopsy finding • Externally-usually those of asphyxia. Ligature mark • Well defined,slightly depressed at any level on the neck-usually at the level of thyroid cartilage or below. • Encircles the neck transversely-more prominently at the front than the sides. • It may be interrupted by clothing or victims finger or ornaments. • May be oblique if the victim is sitting and assailant is standing.

33. Fold marks on neck • Seen in infants and children with short neck. • Tight collar may produce a mark similar. • Examination of ligature-for blood,fragments of epidermis,hair or other substances. • Sign of struggle.

34. Internal • Laceration of muscles. • Hyoid bone fracture usually not seen. • Fracture thyroid is more common. • Fracture of cricoid is rare,but if pressure is used may be seen. • Organs are congested.

35. Medico-Legal aspects Suicide • Its rare but possible.cord may be used and twisted with a stick. • Congestion is very prominent because of slow obstruction.

36. Homicide • Common form of murder-associated with sexual offences. • Infanticide-by strangulation with umbilical cord. • Evidence of struggle,surprise attack,under intoxication,weak personality.

37. Common methods of Homicidal strangulation Throttling • Compression of neck by hands. • Bruises produced by tips of fingers. • More force is used than is necessary. • Marks of thumb on one side and fingers on other side. • Pressure of nails produce cresentic marks with or without incision,concavities follow anatomical shape of the nail margin and nails with straight border give unpredictable results. • Hyoid bone fracture and bruising can be seen with careful neck dissection.

38. Bansdola • Practiced in north India. • Bamboo or sticks are used. Garrotting • Victim is attacked from behind without warning,ligature thrown round the neck and tightened. Mugging • Strangulation by holding the neck in the bend of the elbow/knee.

39. Accidental strangulation • Children may get entangled during play. • Infants are strangled in their cots,when the neck is caught in sidebars. • Alcoholics,epileptics and insane persons are susceptible for accidental strangulation.

40. Suffocation • It’s a form of asphyxia caused by mechanical obstruction to air passage due to causes other than constriction of the neck. Smothering • It’s a form of asphyxia caused by closure of external respiratory passage either by hand or other means,or introduction of foreign materials like cloth or paper etc.

41. Medico-Legal importance Suicide • Not possible by hands. • Possible by means of tying polythene bag over the head/burring the face in mattress. • Creating suffocation in the closed and non-ventilated rooms. Homicidal • Possible when victim is incapacitated by drugs/alcohol,can be smothered.

42. Accidental • Infants/children by weight of clothes etc. • While playing with plastic bags. • In adults-plastic bags for auto erotic exercise as partial anoxia enhances sexual sensation. • Mothers-during breast feeding. Postmortem findings. • Asphyxial signs. • Abrasions & bruises around the lips and cheeks. • Injuries on inner side of lips.

43. Gagging • It results from closure of mouth by a cloth or similar material causing obstruction to the larynx or force the base of the tongue against the fauces. Overlying • Compression of chest to prevent breathing. • Mother infants. • Forceful pressure over the chest.

44. Burking • Method of homicidal smothering. • Practiced by “Burk” and “Hare” Chocking • Caused by obstruction within air passage. • Usually accidental. • From diseases-Diphtheria,laryngeal spasm,infection etc.

45. Hyoid bone fracture • Inward fracture. • Antero-posterior fracture. • Avulsion fracture.

46. Inward fracture • Seen in throttling-main force is an inward compression on the hyoid bone. • Fingers squeeze the greater horns towards each other,due to which the bone may be fractured and post fragments displaced inwards.

47. Antero-posterior compression fracture • In case of hanging,the hyoid bone is forced directly backwards due to which,the divergence of greater horns is increased which may fracture with outward displacement of the posterior small fragments. • Ligature strangulation,run over accidents.

48. Avulsion fracture • Very rare and is due to over activity of neck muscles without direct action or injury to hyoid bone. Incidence- • Hanging 15-20% above 40yrs age. • Very common in throttling.

49. Diagnosis of throttling • Cutaneous bruising and abrasions. • Extensive bruising with/without rupture of neck muscles. • Engorgement at/above the constriction. • Fracture of larynx,thyroid cartilage and hyoid bone. • Cricoid I almost exclusively fractured in case of throttling. • Asphyxial signs.

50. Chocking • Obstruction within the air passages. • Accidental inhalation of food when the victim is laughing or crying. • Vomited material may be inhaled by a person under the influence of drink or anesthetic drug. • Large food bolus,piece of meet seeds or fish,teeth(loose),marbles in children. • From diseases-diphtheria,laryngeal edema,bronchial growths.Hemorrhages.