Intermediate Change-POSTMORTEM LIVIDITY

Synonyms - Postmortem Hypostasis
- Postmortem Staining
- Livor Mortis
It is a bluish or reddish- purple discolouration due to capillo-venous distention with blood, at the undersurface of skin of the dependant parts of the body, due to settling of the blood due to the pull of the gravity, when circulation to keep the blood in motion ceases.
Formation - when the body is left undisturbed without change of its position, the staining starts appearing in small patches at the dependant parts of the body, by the end of the first hour after death.

Fixation - After complete formation of the postmortem staining, if the body is still undisturbed for a period of another 5 to 6 hrs, then the staining over the area gets fixed.

Ø Fixation of postmortem staining is not due to intravascular coagulation of the settled blood. Very little coagulation of blood is seen in the small veins and capillaries. This is due to liquefaction of the postmortem clots in the smaller vessels and capillaries due to the action of fibrinolysin, liberated from the vascular endothelium at the time of death as a part of the death reaction. So there is free oozing of blood from the margins of the incision.
Ø Lividity also occurs at the dependant parts of all internal organs.
Ø The staining becomes discoloured, once decomposition starts in the body.
Ø It is an intravascular phenomenon hence there is no extravasation of blood in the area.
Ø Due to excessive loss of blood (Antemortem or Postmortem) lividity may absent.
Ø

Medico legal importance of Livor Mortis

a) It is a sign of death
b) Time passed after death can be roughly assessed
c) It indicates the posture of the body and the consequent cause of death.
· eg:- in hanging lividity appears in Lower limbs, lower part of upper limbs and in neck above the ligature.
d) From the colour of the Lividity cause of death can be predicted
· In death due to HCN poisoning the colour of the postmortem staining is Cherry red.
· In KCN and NaCN the colour is brownish.
· In Aniline or CO2 poisoning – deep blue
· In CO poisoning – pinkish
· In Phosphorous poisoning – dark brown

e) Postmortem staining, particularly when patchy and small in the early phase of its formation, may be confused with bruise.

Intermediate Change-Cooling of the dead body(ALGOR MORTIS)

· After death there is no heat generation, due to loss of all physical, chemical and metabolic functions of the body and there is constant loss of the body heat until it comes to the level of the environmental temperature, as the regulating centre is inactive.
· The rate of cooling depends mainly on the temperature difference between the surrounding and the body (but Newton’s law of cooling is not applicable)
· The body heat is lost by way of conduction, Convection & Radiation.
· After death the surface (Outer Core) temperature falls rather rapidly for some time. But during this period, the loss of heat from the depth (inner core) of the body is rather negligible. This is due to the thickness of the skin and the subcutaneous tissue which are good insulators of heat.
· Site of the body used to record inner core temperature is rectum- 4 inches above anus
· for the first 2 to 3 hrs, no loss of heat or fall of the inner core temperature occurs. Then there is sharp fall of the temperature for about 9 to 12 hrs.After this period the rate of fall again diminishes and the rate tends to zero when the body attains the temperature of the surroundings.

Time
Temp
Factors influencing the cooling of dead body
Ø Atmospheric temperature-
Ø Media of disposal of the dead body- Optimum cooling is earliest in the water media and latest in buried dead bodies. The ratio of rates of fall of the body temperature in water:air:grave::4:2:1
Ø Body built- A thinly built body loses heat rapidly.
Ø Age- Rate of loss of the body heat is comparatively more in cases of infants, young children due to greater surface area compared to volume.
Ø Sex- Female bodies retain heat for a comparatively longer period( due to the distribution subcutaneous fat in excess compared to male)
Ø Clothings/coverings of the body- A body well covered with cloth retains the heat for a longer period.
Ø Posture of the body- body with outstretched limbs losses heat rapidly(due to greater surface area)
Ø POSTMORTEM CALORICITY- condition in which the temperature of the body is raised for the first 2hrs after death. This occurs
· when death is preceded by severe convulsion- Tetanus, strychnine poisoning etc
· if death occurs due to infectious diseases or septicaemia, bacterimia etc (heat produced due to excessive bacterial activity)
· when the heat regulation has been disturbed before death e.g.Sunstroke, some nervous disorders etc.
· Postmortem glycogenolysis – produces up to 140 calories which can increase the body temperature at an instant time by 3.6º F or about 2º C. This is a compulsory phenomenon which occurs in all the dead bodies soon after death.
Medico legal Importance of Algor Mortis
Ø Cooling of the body is a sign of death
Ø from the cooling of the body, time of death can be roughly estimated.
Normal body temp.(98.4º F)- Rectal Temp
Time passed after death in hours = --------------------------------------------------------
Rate of temperature fall per hour

Average rate in temperate region -1.5º F
in tropical region - 0.6 - 0.75º F
Ø Early cooling of the body delays the processes of Rigor Mortis and decomposition

EARLY CHANGES

A) Facial Pallor
After death due to stoppage of circulation, blood drains from capillaries & small vessels to big ones, so face appears pale and bloodless.
Exception- where there is obstruction of venous return due to compression over the neck or below. The face is congested and cyanosed.
eg:-strangulation
B) Loss of Elasticity of the Skin
· Occur due to loss of tonicity of the skin muscles including those of the face
· Ironing of the facial creases
· The face looks younger
C) Primary relaxation or flaccidity of the muscles
· after death muscles loose their tonicity & become flaccid
· Joints are loose and the chest wall flattens
· muscular tissues are still alive during this stage & still respond to electrical stimuli
D) Contact Flattening and Pallor
· During the stage of primary relaxation of muscles the areas which remain in contact with the ground become flat.
· blood from vessels of these areas are pressed out
· During the stage of Rigor mortis the areas continue to be flat
· Medico legal importance- from the contact flattening, the position of the body in which it stayed for some time after death can be understood.
E) Changes in the Eye
· The Corneal and Pupillary reflexes are lost
· The pupils dilate moderately after death
· The eyelids usually close due to loss of tonicity of the muscles of the eyelids
· Haziness of the Cornea-(1) When the eyes are open, then within about 15 minutes the cornea become hazy due to drying/dessication & deposition of dust and debris over them.(2) The cornea becomes permanently hazy after about 10-12 hours of death, due to decomposition
· Occular tension falls rapidly after death and within about half an hour it becomes zero
· Taches Noien scleroitiques –when the eyes remain open, within 2-3 hrs, the exposed white parts of the eyeballs become yellowish and within 2-3 days, the areas become brown. Each discoloured area is triangular in shape with the base on the limbus, the apex at the lateral or medial canthus and the two other sides of the triangle are formed by the margins of the upper and lower eyelids(4 such areas are formed)The retinal veins appear segmented within 10-15 seconds after death.

POSTMORTEM CHANGES (Changes after death)

• I. Immediate changes
  a) Stoppage of function of Nervous System
  b) Stoppage of respiration
  c) Stoppage of Circulation
• II. Early changes
  a) Facial Pallor
  b) Loss of elasticity of the skin
  c) Primary relaxation of the muscles
  d) Contact flattening & Pallor
  e) Changes in the eye
• III. Intermediate Changes
  a) Cooling of the body
  b) Postmortem Lividity
  c) Rigor Mortis
• IV. Late changes
  a) Putrefaction
  b) Adepocere formation
  c) Mummification

IMMEDIATE CHANGES
1) Stoppage of function of Nervous System
Ø Loss of sensory functions
Ø Loss of motor function
Ø Loss of reflexes
Ø Loss of tonicity of the muscles

2) Stoppage of respiration
Total stoppage of respiration can be established by the following tests
1. Inspection
2. Palpation
3. Auscultation
4. Feather Test
If a downy feather or a few cotton fibres are held in front of nose, then, if respiration continuing, it will rhythmically move with inspiration and expiration.
5. Mirror Test
The reflecting surface of a mirror is held in front of the nose & mouth the person. If respiration is continuing then the mirror will partly become hazy due to condensation of the moisture of the expired air.
6. Winslow’s Test
A small bowl with water is placed over the chest of the subject with arrangement of some light rays falling on the surface of the water. Slightest movement of the chest wall will disturb the plain of the surface of the water, which can be well marked from the rays of light reflected from the surface of water.

3) Stoppage of Circulation
can be established by the following tests
1. Palpation
§ Radial pulse
§ Brachial pulse
§ Femoral Pulse
§ Carotid pulse

2. Auscultation of heart

3. Diaphanous or Transillumination test
§ The outstretched hand is held against some bright light rays in dark room, if circulation continuing hand will appear pinkish & translucent, if circulation has ceased then the hand will appear yellowish and opaque.
4. Magnus Test
§ A ligature is applied on a finger sufficiently tightly to compress the superficial veins but not the arteries, if circulation is continuing then, after a while the part of finger distal to the ligature will appear swollen & bluish due to venous obstruction.
5. Icard’s Test
§ 1ml of 20% alkaline fluorescein solution is injected in the dermis, if circulation has not stopped the area of yellowish discolouration spreads locally.
6. Pressure Test
§ In a living subject if pressure is applied on the nail of a finger then, it becomes pale but soon becomes red on release of the pressure. In case of cessation of circulation it takes much more time to return to its normal colour.
7. Cut Test
§ If circulation is continuing then, there is active bleeding from a small superficial cut.
8. Heat Test
§ a small area of the skin is brought in contact with some hot (say 100ºC) object.
§ If circulation is continuing then, at the site of contact there will be blister formation surrounded by red ring, if the period of contact is very short then, there may not be any blister formation, but there will be redness over the area of contact.
§ If circulation has stopped then the above changes will not happen. Instead, the area of contact will become dry, firm without any redness.
9. ECG Test