A fingerprint is a sway left by the friction ridges of a person’s being. The study of fingerprint impressions is known as Dactyloscopy.
Fingerprints are the commonly used human characteristics for identification of an individual. Though every fingerprint is unique, yet it shares some common characteristics that make fingerprint classification possible.
The fingerprint patterns are determined by the arrangements of the ridges formed by the distal phalanges of the finger. The fingerprint patterns categorized into different types based on the shapes, lengths, joining and turnings.
The common terms that are used in fingerprint patterns are:
TYPE LINE: In fingerprint patterns, the outermost line of the encloses pattern area, delta, core. These are well defined as the two innermost ridges starting parallel or run parallel to each other then diverge and tend to cover the pattern area.
PATTERN AREA: is a part of fingerprint that includes core, delta, ridges that are responsible for classifying fingerprints.
DELTA: is formed when the ridge bifurcates or the two adjacent side ridges joins that covers the pattern area.
CORE: the central most of the pattern.
There are 4 major types of fingerprint patterns
- 1. ARCH: the ridges run from one side of the print to another side forming an arch like formation.
There is no recurving of the ridges
The pattern accounts for approximately 5% of recorded fingerprint.
It is of two types:
- Plain arch (A):This is the simple of all fingerprint patterns. The ridges run from left side to other side with a small rise at the center like a hill or hump.
- Tented arch(T): In this ridges entering from left side making an upright thrust at the center flowing towards the right side of the pattern.
- 2.LOOP: A loop is formed when one or more ridges entering from the same side recurving, existing form the same side.
A loop always has a core and a delta. 60-65 % of population have loop pattern.
Based on the side where the ridge recurve they are of two types:
- Radial loop: The loop where the ridges start from radial bone or thumb side of the hand and recurving around the core and exiting to the same side of the hand.
- Ulnar loop: The loop where the ridges start from ulnar loop or little finger of the hand and recurving around the core and exiting to the same side of the hand.
- 3.WHORL: Almost 30-35 % populations have whorl pattern. Whorl is having one core and 2 deltas. It is simple to identify.
Plain whorl posses a type line and at least two deltas.
It has at least one ridge forming complete trip may be in the form of spiral, oval, circle.
- 4.COMPOSITE: the composites are combinations of all the above mentioned patterns.
- CENTRAL POCKET LOOP: the central pocket loop is a combination of a loop and a whorl. In this pattern majority of the ridges forming a loop but at the center one or more ridges within the pattern are forming an whorl or pocket like structure.
- LATERAL POCKET LOOP:
- This is often basically a double loop pattern in which two loops are formed either by overlapping or surrounding one another and both the loops after terminating exiting from the same side of the delta.
- TWIN LOOP: This is often also a double loop pattern. The pattern is made by either overlapping or surrounding one another and both the loops after terminating exiting from the both sides of the delta. one loop exiting from left side and one from right side.
- ACCIDENTAL: A pattern, which does not fall under the above types, are called accidental. It is a combination of any two different patterns except one of the pattern is plain arch. Such patterns must consist 2or more than 2 deltas.