Fingerprints

Intro to Forensic Chemistry

Three primary categories of fingerprints

Loop

Whorl

Arch

Loop Patterns

60% of all cases

Dominate fingerprint classification

Whorl Patterns

35% of all cases

Arch Patterns

5% of all cases

emerge as the least common fingerprint pattern

Types of Loops

Radial

Ulnar

Radial Loops

point toward the thumb

commonly gracing the left hand

Plain radial loops

showcase smooth, flowing ridges

Tented radial loops

display distinctive spike-like centers

Ulnar loops

flowing toward the little finger

dominate the right hand

Plain ulnar loops

create gentle, continuous flows

Tented ulnar loops

feature dramatic central peaks

Types of Whorls

Plain

Central Packet Loop

Double Loop

Accidental

Plain Whorl

The most common type features complete circular circuits. An imaginary line between deltas crosses the pattern’s heart. The plain whorl fingerprint is found in approximately 20% to 30% of population samples.

Central Pocket Whorl

A tighter formation where delta-connecting lines avoid the central pocket. The central pocket whorl fingerprint is less common but still significant in fingerprint classification.

Double Loop Whorl

Two loops dance together, creating distinctive S-shaped patterns.

Accidental Whorl

Nature’s wild card, combining various pattern elements into unique formations. The accidental whorl fingerprint is the rarest type of whorl pattern.

Types of Arches

Plain

Tented

Plain Arches

Ridges enter from one side, rise gracefully in the center, then exit the opposite side. These patterns frequently grace middle and ring fingers

Plain Arches Shape

Smooth, wave-like ridge flow

Clean lines without dramatic peaks

No deltas or cores

Tented Arches

Tented arches rise dramatically from their centers

Tented Arches Shape

Sharp central spikes

Bold upward thrusts

Common presence on index and middle fingers