Forensic Science: Fingerprint Analysis and Ridgeology

Vocabulary flashcards covering latent print collection techniques, principles of fingerprints, minutiae and ridge characteristics, and primary fingerprint pattern classifications.

Latent Prints

Impressions left by friction ridge skin on surfaces such as tool handles, glass, or doors.

Black Powder

A fine dusting powder applied with a brush to reveal latent fingerprints before lifting them with clear tape.

Camel Hair

The most common animal hair traditionally used to manufacture fingerprint dusting brushes.

Fiberglass

A synthetic material commonly used to construct modern fingerprint dusting brushes.

Cyanoacrylate Fuming Method

A latent print development procedure, commonly referred to as the super glue method, used to reveal prints on a variety of objects.

Magnetic Powder

A specialized powder used to reveal latent prints that performs best on shiny surfaces, plastic baggies, or plastic containers.

Fluorescent Powder

A dusting powder utilized in conjunction with UV lights to visualize latent fingerprints on dark or multi-colored surfaces.

Ninhydrin

A chemical reagent that reacts with amino acids in fingerprints to produce a blue or purple color, primarily used on porous surfaces like paper and cardboard.

Ridgeology

The study of the uniqueness of friction ridge structures and their forensic application for personal identification.

Minutiae Points

Specific locations where individual friction ridges begin, end, or divide, establishing the uniqueness of a fingerprint.

Points of Similarity

Identical minutiae points found between two different fingerprint impressions, also termed points of identification.

AFIS

The Automated Fingerprint Identification System; a computerized database used to read, classify, match, and store fingerprint records for criminal justice agencies.

Ridge Characteristics

The various minutiae formations used as points of identification during fingerprint comparison, such as bifurcations, crossovers, and islands.

Bifurcation

A ridge characteristic or minutia point where a single friction ridge branches or forks into two separate ridges.

Ridge Ending

A minutia point where an individual friction ridge abruptly stops or terminates.

Island

A short, isolated friction ridge segment that stands independently between other ridges.

Delta

A triangular ridge pattern formed where friction ridges diverge at the entrance of loop and whorl patterns.

Core

The central focal area or inner-most turning point of a loop or whorl pattern.

Crossover

A short ridge structure that links two adjacent, roughly parallel friction ridges.

Dactyloscopy

The scientific discipline and study of fingerprint identification.

Dactylograms

The technical forensic term used to describe fingerprints.

First Principle of Fingerprints

The principle stating that a fingerprint is an individual characteristic; no two individuals have been found with the exact same fingerprint pattern.

Second Principle of Fingerprints

The principle stating that a fingerprint pattern remains unchanged for the life of an individual, though changes may result from permanent scars or skin diseases.

Third Principle of Fingerprints

The principle stating that fingerprints have general characteristic ridge patterns that allow them to be systematically identified and classified.

Arches

The simplest fingerprint class, representing approximately $5\%$ of individuals, formed by ridges entering on one side and exiting on the other without deltas.

Plain Arch

An arch subcategory where friction ridges enter on one side and flow out the opposite side without forming any sharp spikes or deltas.

Tented Arch

An arch subcategory similar to a plain arch, but characterized by a distinct central spike or tent-like thrust.

Loops

A fingerprint pattern class found in approximately $60\%$ of people, featuring at least one delta and one or more ridges entering and exiting on the same side.

Radial Loop

A loop pattern where the ridges open toward the radius bone, which aligns with the thumb side of the hand.

Ulnar Loop

A loop pattern where the ridges open toward the ulna bone, which aligns with the little finger side of the hand.

Whorls

A fingerprint pattern class found in roughly $35\%$ of people, characterized by at least one ridge making a complete circuit and possessing at least two deltas.

Plain Whorl

A whorl pattern in which an imaginary line drawn between the two deltas touches or crosses at least one of the circular or spiraling ridges.

Central Pocket Whorl

A whorl pattern in which an imaginary line drawn between the two deltas does not touch or intersect any of the circular center ridges.

Double Loop Whorl

A whorl pattern formed by two separate and distinct loop formations combined into a single fingerprint.

Accidental Whorl

A complex whorl pattern that contains two or more distinct patterns (excluding plain arches), has more than two deltas, or fails to meet any other standard category definition.