Strangulation (Hanging)

Prepared by Muhammad Ariff Bin Mahdzub4th year (MBBS) Widad College University

Method of suicidal-Strangulation-suffocation-Road & railway injury-electrocusion

strangulation

• Strangulation is a form of asphyxia• characterized by closure of the blood vessels

and air passages of the neck due to external pressure on the neck.

Hanging (suicidal)

• In hanging, asphyxia happen due to compression /constriction of the neck by a noose or other constricting band tightened with weight of the body.

• In hanging, the cause of death is cerebral hypoxia secondary to compression and, thereby, occlusion of the vessels supplying blood to the brain.

Amount of pressure needed

The amount of pressure necessary to compress • the jugular veins is 4.4 lb (2kg) • the carotid arteries, 11 lb(5kg) • the vertebral arteries, 66 lb (33kg) • Compression of the trachea requires 33 lb

(15kg)(DiMaio2001)

Type Of Hanging

• There may be either complete or incomplete suspension of the body

autopsy

• the face is pale and the tongue is protruding

• Absence of petechiae in most hangings is because there is complete obstruction of the arterial system, so there is no pooling of blood in the head, no increased pressure, and, therefore, no petechiae

Material used

• Most common are ropes, electrical cords, and belts. In jails and prisons, convicts typically tear sheets into strips as well as using T-shirts, undershorts, trousers, or even socks.

• Usually, to prevent a change of mind, the victim ties his hands together.

Figure 8.14Hanging with point of suspension on (A) side of neck and (B) frontof neck

• The most common point of suspension is the side of the neck,

• followed by the back and the front. (Figure 8.14)

Point of suspension

• At the time of suspension, the noose typically slips above the larynx, catching under the chin (Figure 8.15)

Figure 8.15Furrow from noose slanting upward toward point of suspension.

The Furrow

• Present on the neck will be a furrow. This furrow generally does not completely encircle the neck,but rather slants upward toward the knot, fading out at the point of suspension (the knot) (Figure 8.16). Figure 8.16

(A) Noose mark with pale yellow base and congested rim.

• To clarify of the furrow, depend on the material used. A rope will give deep, well-demarcated, distinct furrow, often with a mirror-image impression of the twist of the rope on the skin

• If the ligature is a soft material, the groove might be poorly defined, pale, and devoid of bruises and abrasions(Figure 8.16a).

Figure 8.16(A) Noose mark with pale yellow base and congested rim. (B) Broadpale furrow due to soft noose.

• In hangings, blood will pool in the dependent areas of the body, usually the forearms, hands, and lower legs, secondary to gravity.

• This is caused by hydrostatic rupture of vessels

Suffocation

Suffocation

• Major Form in Asphyxia• Def: Suffocation is a general term used to

indicate death due to lack of oxygen, either from lack of the gas in the breathable environment or from obstruction of the external air passages.

• Asphyxia = lack of oxygen in respired air causing hypoxaemia and hypercapnia

Smothering

• Asphyxia by smothering is caused by the mechanical obstruction or blocking of the external airways, (nose and mouth)

• Deaths such as these are usually either homicide or suicide,

Suicidal smothering

• suicide eg head covered in plastic bag• Mechanism: hood of impervious substance,

usually polythene or other plastic, is placed over the head down to neck level. • The plastic is usually in the form of an open-

ended bag, either transparent or a ‘supermarket’ shopping bag

(DiMaio2001)

• Figure 4.7 Plastic bag suicide, with an open bag placed loosely over the head.

• Figure 8.l• (A) Suicide of elderly

female who secured plastic bag over head withtie around neck.

Cont.

• Figure 14.6 Plastic bag suicide. The bag is sometimes tied around the neck,

Classic signs of asphyxia

-petechial haemorrhage, -cyanosis, congestion, -swelling soft tissue (oedema)

• Petechiae are caused by an acute rise in venous pressure causing overdistension and rupture of thin walled peripheral venules,

• especially in lax tissues(eyelid), & unsupported serous membranes (pleura and epicardium)

Cont.

• Petechiae of the epicardium or pleural surfaces of the lung were sometimes present, but these are so nonspecific

• Petechiae of the face, sclerae, and conjunctivae were virtually always absent.

-Knight F.

• Cynosis: The colour of blood depends on quantity of oxyhaemoglobin

• When oxygen is lacking (cyanosis), normal pink colour of well-oxygenated skin may change to purple/ blue

• The Congestion & oedema is due to reduce venous return, result of rapid transudation thru capillary and venule walls,

-Knight F.

Road & railway injury (suicidal)

Pattern of injury ofvehicle occupants

• The pathology of all these is no different from accidents elsewhere (Knight f. p293)

• The type of vehicle (theory) makes little difference to the mechanism of injury

• In crashes, Heavy goods vehicles naturally suffer less than light vehicle because of their far greater mass and strength

-Knight F.

Cause of death

• gross musculoskeletal or organ damage, • severe haemorrhage, • blockage of air passages from blood, or• traumatic asphyxia from fixation of the chest

caused by crushing from some part of a vehicle.

-Knight F.

railway injury (suicidal)

• The common railway fatality is the suicide who lays himself in front of an approaching train.

• The Ix for alcohol and other drugs must be made, as suicides often employ multiple methods to ensure self-destruction.

• Sometimes the injuries complicated by high-voltage electrical lesions, as the typical traction voltage of an electric railway is in excess of 600 volts.

• Decapitation is the most common injury • Other obvious features are the local tissue

destruction, usually with grease, rust or other dirt soiling of the damaged area

• Figure 9.27 Amputation of the right arm and bruising of the face and chest in a pedestrian struck by a passing locomotive

• Figure 9.28 Extensive disintegration of the body that has been run over by a train.

ELECTROCUTION (suicidal)

ELECTROCUTION

• most deaths from electricity are from cardiac arrhythmias, usually ventricular fibrillation ending in arrest

• second (and far less common) mode of death is respiratory arrest, in which the passage of current through the thorax causes the intercostal muscles and diaphragm to go into spasm, or become paralysed

CUTANEOUS ELECTRICAL MARK

• occurrence of an areola of blanched skin at the periphery

• When voltage is in the multi-kilovolt range, sparking may occur over many centimetres. This can give multiple burn lesions giving rise to a ‘crocodile-skin’ effect

CHARACTERISTICS

• Charring and more extensive peeling and blistering of skin may occur, with deep muscle damage and cooking of the tissues when the current has flowed for an appreciable time

INTERNAL APPEARANCES

• gross findings in the internal organs may be absent and even histological changes are a matter of controversy

• usual mode of death is cardiac arrhythmia leading to ventricular fibrillation and arrest – little to no evidence during autopsy (epicardial petechiae may occur, but these are too non-specific to be of any use)

reference

Asphaxia, Chapter 8; Dimaio Forensic Pathology 2001, P246

Electrocusion Chapter 16; Dimaio Forensic Pathology 2001, P425

Self Inflict Injury, Chapter 7; Knight Forensic Pathology, P229