Examination of hair, forensic medicine,fmt, forensic science

1. Examination of Hair
Dr. Chandra Prakash Singh
JR 2

2. • Hair is a filamentous biomaterial, that grows
from follicles found in the dermis.
• Hair often refers to two distinct structures:
1)The hair follicle
2)The shaft

3. • Hair grows from the papilla
• Point of generation is made up of dead,
cornified cells.
It consists of
• Shaft that projects above the skin
• Root that is imbedded in the skin

4. • A cross section of the hair shaft may be
divided roughly into three zones.
The cuticle
(several layers of flat, thin cells laid out
overlapping one another as roof shingles,
The cortex
(keratin bundles in cell structures that remain
roughly rod-like)
The medulla
(area at the fiber's center.)

6. • Hair is composed keratin, rope-like intermediate
filaments.
• Hair growth begins inside the hair follicle.
• The hair that is visible is the hair shaft is
considered "dead".
• Other structures of the hair follicle include the
1)Oil producing sebaceous gland
2)The erector pili muscles,

7. • All natural hair colours are the result of two
types of hair pigment.
1)Eumelanin -dark-blond, brown, and black
hair
2) pheomelanin - red hair.
Blond hair is the result of having little
pigmentation in the hair strand.
Gray hair occurs when melanin decreases or
disappears

8. • In humans, hair undergoes cyclical phases
Growth (anagen),
Transition (catagen),
Resting (telogen),
Anagen phase lasts about 1,000 days.
Telogen phase, follicle are dormant and hairs fall
out- 100 days.
10 and 18% of all the hairs are in the telogen phase;
2% are in the catagen phase.
80 and 90% are actively growing.
There is no pattern to determine which hairs on the
head are in any phase at a given time

9. Hair Cuticle
• The cuticle is a translucent outer layer of the
hair shaft consisting of scales that cover the
shaft.
• Cuticular scales always point from the
proximal or root end of the hair to the distal
or tip end of the hair.

10. Medulla
• The medulla is a central core of cells that may
be present in the hair.
• The medulla, in human hairs, less than one-
third the overall diameter of the hair shaft.
• The medulla in animal hairs is normally
Continuous and structured and Greater than
one-third the overall diameter

12. • Human Hair :- Different Sites
• Scalp
• Pubic
• Vulvar
• Chest
• Beard
• Axiliary
• Eyebrow
• Eyelash
• Nose
• Limb
• Buttocks

13. LOCATION OF HAIR EVIDENCE
• Scene of occurrence.
• On the body and clothes of victim.
• On the body and clothes of suspect.
• On the weapon of offence.
• The vehicle.
• The routes.

14. FORENSIC EXAMINATION OF HAIR
• Whether the material is hair or not?
• Is the hair of human or animal origin?
• What is the site of origin ?
• To which sex it belongs?
• What is the age of the individual to whom the
hair belongs?
• Whether the hair was pulled out forcibly or
naturally?
• To which race it belongs?
• Is it possible to individualize hair or not

15. • Whether the material is hair or not?
Physical test
Burning test
Microscopic test
Chemical test
2. Is the hair of human or animal origin?
On the basis of scales patterns of cuticle.
On the basis of medullary ratio.
On the basis of color and pigmentation.
3. What is the site of origin?
Can be determined on the basis of structural analysis. r

17. • . 4. To which sex it belongs?
• Can be determined by the presence of barr
bodies.
• 5. What is the age of individual to whom the hair
belongs?
• Through microscopic examination but not
definitively.
• 6. Whether the hair is pulled out forcibly or
naturally?
• By examining the root bulb.

19. Sampling Of Hair
• Spread the exhibit on a clean white surface under
proper illumination.
• With hand magnifier, carefully locate any loose hair
and collect.
• Hair can be collected by forceps or transferred to
adhesive tape.
• Samples collected should be packed in cellophane or
paper folders with proper labeling on them.
• Root bulb and follicle of hair should be carefully
preserved for determination of sex , serological and
DNA Examination.

20. Examination of Hair
• 1) Temporary mount
• 2) Scale casting
• A)Cellulose acetate Method
• B) Polarised coated Method
• 3) Permanent Mount
• 4) Cross sectioning
• 5)Micrometry

21. Temporary Mount
• Make a temporary mount of the hair sample
on a clean slide with the distilled Water or
glycerin. Cover with cover slip.
• Observe morphological characteristics under
microscope.

22. Scale Casting
• Cellulose Acetate method-
• On a clean microscopic slide, place a thin layer
of cellulose acetate paste with low viscosity.
• With fine forceps, place hair on to the
cellulose acetate paste and press with another
clean slide.
• Allow it to dry for 2-5 min.
• Observe scales of hair under microscope.

23. • B)Polaroid Coated Method-
• Place the hair on a clean microscope slide, securing the
ends with cellophane tape.
• Using a Polaroid film coater, make 2 or 3 passes along
the length of the hair.
• Allow the coating to dry for 23 hours.
• After removing the cellophane tape, gently peel the
hair from the slide.
• With a sharp scalpel, slice away the excess coating
protruding above the flat surface of the scale cast.
• Observe the scale impressions microscopically.

24. Permanent Mount
• Place hair on slide in a drop of xylene and add
permanent mounting medium.
• Place a cover slip on the hair allowing the
medium.
• Label the slide appropriately and allow it to
dry for 48 hours

25. Cross Sectioning
• Clean hair in solution of ether and ethanol in
ratio 1:1
• Bundle the samples and dip in a block of molten
wax and allow to cool.
• Cross sections can be taken either with a sharp
blade or with a microtone to a thickness of 5-10
microns.
• Place sections on a clean slide and dissolve wax
with a drop of xylene.
• Prepare permanent mount of the sections and
examine under the microscope

26. Micrometry
With the help of micrometer measure following
distances & calculate different indices:
Maximum diameter of the shaft.
Number of scales per unit length.
Diameter of hair in microns / scale count.
Maximum diameter of hair medulla / Maximum
diameter of hair shaft.
Minimum diameter of shaft / Maximum
diameter of the shaft x 100

27. Report Writing

28. THANK YOU