- Fingerprints.

-friction skin (i.e. palms and soles) have a

impressions due to presence of ridges & grooves .

- These impressions made by dermal papillae in the dermis.

- Finger prints appear in the 4th month intrauterine life.

-Sweat glands open through minute openings on the

summits of the ridges. The sweat contains fat.

- When the skin is applied to a glistening

non-absorbable surface an impression is left behind.


Principles of fingerprint identification :

-fingerprint patterns are unique

(1 in 64 billion chance of 2 prints being identical).

-FBI has over 100 million records, no two of which are alike.

-Fingerprint pattern of an individual remains

unchanged throughout life.

-Reversible atrophy occurs in certain diseases

(coeliac disease, dermatitis).

- Some people have some skin diseases which

prevent normal formation

of fingerprints (may be genetically ).

-Permanent impairment occurs in leprosy and after

exposure to radiation.

-Attempts to mutilate fingerprints are sometimes made.

- If only the epidermis is destroyed there is no

alteration in ridge pattern.

-If dermis is destroyed additional points of

identification are created.

Types:

1-Arches.

2-Loops.

3-Whorls .

4-composite: of more than one type.

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poroscopy

Def: study of the pores of the sweat glands which

present at the ridges of the prints.

Position of the pores requires higher resolution scanner.

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N.B: There are artificial finger prints which

used by criminals for misleading.

see you,

Dr Ibrahim