Chapter 6: Fingerprints

Vocabulary flashcards covering the historical origins, fundamental principles, classification patterns, computer databases, ACE-V methodology, print types, and development techniques for friction ridge evidence.

Bertillonage

An anthropometric identification system devised by Alphonse Bertillon that involved taking 11 precise body measurements, photographs, and individual descriptions.

Will West and William West Case

A 1903 case at Leavenworth Penitentiary where Bertillonage measurements failed to differentiate two look-alike inmates, proving the necessity and superiority of fingerprint identification.

Henry Faulds

A Scottish physician who was the first person to publish that fingerprints could be utilized for personal identification.

Francis Galton

Author who published the classic textbook Finger Prints in 1892, prompting the British government to adopt fingerprinting.

Juan Vucetich

The doctor who devised a fingerprint classification system that is still widely used in most Spanish-speaking countries.

Sir Edward Henry

The creator of the fingerprint classification system implemented across most English-speaking countries.

Identification Division of the FBI

Established in 1924 to serve as a national clearinghouse and repository for fingerprint records across the United States.

Minutiae

Individual ridge characteristics in a fingerprint, such as bifurcations and ridge endings, that establish uniqueness during comparison.

Dermal Papillae

The layer of cells between the dermis and epidermis that dictates the shape and pattern of friction ridges on the skin.

Loop

A fingerprint pattern class (accounting for $60\text{--}65\%$ of prints) characterized by one or more ridges entering from one side, curving, and exiting on the same side.

Ulnar Loop

A loop pattern that opens and exits toward the little finger side of the hand.

Radial Loop

A loop pattern that opens and exits toward the thumb side of the hand.

Type Lines

Two diverging friction ridges that enclose the pattern area of loops and whorls.

Delta

The ridge point located directly in front of or at the point of divergence of two type lines.

Core

The approximate center region of a loop or whorl pattern.

Arch

The rarest fingerprint pattern class (accounting for approximately $5\%$ of prints) where ridges enter one side and exit the other without type lines, cores, or deltas.

Plain Arch

An arch pattern where friction ridges enter from one side, rise gently to a rounded center peak, and flow out the opposite side.

Tented Arch

An arch pattern that forms a sharp, pronounced central peak.

Plain Whorl

A whorl pattern positioned between two deltas where an imaginary line drawn between the deltas touches at least one continuous ridge surrounding the core.

Central Pocket Loop

A whorl pattern containing at least one continuous ridge where an imaginary line drawn between its two deltas does not touch the central pattern core.

Double Loop

A pattern formed by two separate loop structures swirling around each other.

Accidental Whorl

A complex fingerprint pattern combining two or more distinct patterns (excluding plain arches) or failing to fit standard pattern classifications.

Primary Classification

A numerical fraction derived from the Henry system based on assigning point values to whorl patterns across ten fingers: $\frac{\text{Even Fingers} + 1}{\text{Odd Fingers} + 1}$.

AFIS

Automated Fingerprint Identification System; a computerized database that digitizes prints to search spatial relationships between ridge endings and bifurcations.

ACE-V Method

A systematic four-step forensic protocol for friction ridge examination consisting of Analysis, Comparison, Evaluation, and Verification.

Level 1 Features

General friction ridge flow and pattern type (loops, arches, whorls), used during analysis but insufficient alone for individual identification.

Level 2 Features

Individual minutiae structures such as line-units, line-fragments, ridge endings, bifurcations, eyes, and hooks that allow individual identification.

Level 3 Features

Dimensional details of friction ridges including sweat pore locations, line shapes, incipient ridges, creases, warts, and scars.

Patent Print

A visible friction ridge impression left when a finger transfers visible material such as blood, paint, dye, or ink onto a surface.

Plastic Print

A visible 3D friction ridge impression pressed into a soft substrate with memory, such as clay, putty, or drying paint.

Latent Print

An invisible print formed by body sweat and oils deposited on a surface, requiring physical or chemical processing to be visualized.

Cyanoacrylate Fuming

A development method for non-porous surfaces where heated Super Glue vapors ($98\%$ to $99\%$ cyanoacrylate ester) polymerize on latent print deposits to form a durable white impression.

Ninhydrin

A chemical reagent used on porous items (like paper) that reacts with amino acids in latent print residue to yield a purple-blue compound known as Ruhemann's purple.

Physical Developer

A silver nitrate-based liquid reagent that reacts with water-insoluble lipids and fatty acids in latent prints, useful on wet porous items but required to be performed last.