BASICS OF FINGERPRINTS

Objectives

• Dermatoglyphics

• Dactyloscopy / Study of Fingerprints

• Types of prints

• Characteristics of fingerprints

• Development of fingerprint (during birth)

Dermatoglyphics

• Dermatoglyphics is the study of the epidermal ridge patterns of the skin of the fingers, palms, toes and soles.

• Dermatoglyphics is derived from two Greek words (‘Derma’ means skin and ‘Glyphe’ means carve).

• Ridges – the raised portion of skin found on the fingers, palms, toes and sole of feet.

• The ridge configuration present on the palm is called Palmar Dermatoglyphics.

• The ridge configuration present on the fingers is called Finger Dermatoglyphics.

Dactyloscopy / Study of Fingerprints

• Scientific study of fingerprints is known as Dactyloscopy.

• Unique – Epidermal ridges are very highly variable in all individuals. This characteristic even in small regions of palm, finger or sole are not duplicated either in another region or in different persons.

• Permanent throughout life.

• Classifiable – These ridge patterns are easily classifiable and can be compared easily with simple techniques whether using a hand lens or software.

• Probability – Probability of having same fingerprints is 1 in 64 billion, which is extremely low and calculation is based on minutia and ridge characteristics.

Types of Prints

Chance Prints

Chance fingerprints are those prints which are found at the scene of crime. Scene of crime prints are of three types:

1. Visible Prints

Fingerprints which are visible to the naked eye are called visible prints.

2. Plastic Prints

Plastic prints are formed when the fingers or palm come in contact with a plastic body or a surface such as soap, butter, wax, etc.

3. Latent Prints

Latent prints are such impressions that are not readily visible to the naked eye and they need to be developed by physical and chemical methods.

Characteristics of Fingerprints

A fingerprint consists of:

• Pattern area

• Type lines

• Delta

• Core

1. Pattern Area

It is the area that contains the pattern area like loop, whorl, however it is indefinable in arches.

2. Type Lines

These lines may be defined as two innermost ridges, which start parallel, diverge and surround the pattern area.

Not usually continuous and often found broken.

3. Delta / Tri-radius

Delta or Tri-radius is formed when:

• A ridge bifurcates and the two arms of bifurcating ridge diverge, or

• Two adjacent ridges running side by side diverge causing an interspace within which the pattern lies.

Important Points

• The delta is the point from which ridge counting is started in loop pattern.

• The loop pattern possesses a single delta.

• Whorl pattern possesses two deltas.

• Arches do not have delta formation.

4. Core

• Core is the central point of the pattern.

• The core is placed upon the innermost sufficient recurve, which is absent in arches.

Loop Pattern

• They may consist of stable or even or uneven number of ridges not joined together, which are called rods.

Whorl Pattern

• The center of first ring, elliptical or circular, is taken as the core point.

Spiral Pattern

• The point from which the spiral begins to revolve is taken as the core point.

Importance

• The core is considered very important because it is the landmark for ridge counting by connection of tri-radius in a straight line.

Basics of Fingerprints -Dermatoglyphics, Dactyloscopy, types and Characteristics