Forensic Medicine Practical

1. BLOOD STAIN ANALYSIS

2. 3 THINGS TO DETERMINE REGARDING BLOOD STAINS ARE;
1. The nature of stain
2. if stain is of human/Animal
3. Blood Group of the blood”.

3. THE METHODS USED TO DETECT THESE ARE A FOLLOWS
 1. Physical Examination
 2. Chemical Examination
 3. Spectroscopy

4. PHYSICAL EXAMINATION;
1. Clothing
2. Size, Shape and Direction
3. Character
4. Age of Stain
5. Condition of body

5. 1. BLOOD STAIN ON CLOTHS

6. Supine Position ------- Back Side
Standing Postion ----- Vertically Downward
Perfused Blood Stain--- Major Bleeding
Undergarments-- Vitims’s Blood and also indicates genital Injury

7. SIZE, SHAPE AND DIRECTION (ON SURFACE)
1. Size and Shape
Indicates height and direction of blood fallen.
When a blood falls on a surface from a height (not more than a few centimeters)--- Circular Shape
With increase in height the circle of blood shows projections.
The Number of Projections directly proportional to height

8. ATERIAL VS VENOUS BLOOD
Arterial
Spurting/Splashing
May Produce
Exclamation Mark
Sharp end shows
direction of spurt
The more oblique,the
more elongated
Venous
In a form of oozing or
continuous Stream

9. LIVING VS DEATH
1. Living
Can be peeled off on drying (due to presence of fibrin)
2. Death
Blood breaks up into a powder on drying

10. VICTIM VS ASSAILANTS
 Blood contains Finger or Foot prints:
 Presence of some diseases in blood such as leukemia / filariasis can be helpful in identifying victim or
assailant
 Traces of blood found underneath fingers, nails of victims---- result of struggling
 & in the case of assailant-- possible case of throttling

11. MALE VS FEMALE
Female -> BARR Bodies
(dense X Chromosome, inactive in the presence of another X Chromosome).
Reagent = Orcine
Male -> Presence of atleast 50 Y chromosomes in WBC
Reagent = Quinacrine ( Y chromosome become Fluorescent)

12. BLOOD VS FRUIT/VEGETABLE STAIN
Ammonia --- Turns vegetable or fruit stains into green,
No change with blood color
Alkaline Solution of Aminophthalic Acid hydrazide mixed with hydrogen peroxide and sprayed on suspected area,
the area luminescent, if the stain is due to blood

13. CHEMICAL DETECTION OF BLOOD
1. Benzidine Test
Two Reagents
10% Benzidine and Hydrogen Peroxide
2. Phenolphthalein Test (kastle Meyer Test):
1-2g of phenolphthalein
+
20-25g of Hydrogen Peroxide
+
15g of Zinc Powder

14. SPECTROSCOPIC EXAMINATION OF BLOOD
 LIGHT consists of different color wavelength spectrum
 Eg = Prism
 When this spectrum passes from a blood different colors
are absorbed.
The absorbed colors appears as dark bands and the full band is
Is known as absorption band
In the case of oxyhemaglobin, two dark absorption bands will be seen between D and E
lines in the yellow green region.