Dactyloscopy and Fingerprint Identification

The scientific examination and identification of fingerprints, particularly friction ridge patterns on the fingers.

The scientific study of epidermal ridge patterns on the fingers, palms, toes, and soles.

Dermal structures help support the interface between the dermis and epidermis and contribute to the formation and maintenance of friction ridge skin.

The outer layer of the skin, consisting primarily of stratified squamous epithelial tissue.

The connective tissue layer beneath the epidermis containing blood vessels, nerves, glands, and supporting structures.

To improve grip and tactile sensitivity on the fingers, palms, toes, and soles.

During fetal development, with major ridge pattern formation occurring approximately between the tenth and twenty-fourth gestational weeks.

Friction ridge arrangements generally remain stable throughout life unless sufficiently deep injury or disease alters the underlying structures.

Friction ridge arrangements exhibit extensive variation, supporting comparisons based on the overall configuration of ridge detail.

Yes. Identical twins ordinarily share the same nuclear DNA profile but develop distinguishable friction ridge patterns.

The portion of a fingerprint containing the pattern's characteristic ridge flow and features used in classification.

A designated point or area near the center of a fingerprint pattern used as a reference for classification.

A designated reference point at or near the divergence of ridge flows that form a triangular region.

None.

One.

Two, although some complex patterns may show additional delta-like formations.

Arches, loops, and whorls.

Plain arch and tented arch.

Ridges generally enter from one side, rise gently near the center, and exit on the opposite side without forming a true loop.

An arch pattern showing a pronounced upthrust, sharp angle, or other characteristic ridge formation.

Ulnar loop and radial loop.

A loop whose opening or ridge flow is directed toward the little-finger or ulna side of the hand.

A loop whose opening or ridge flow is directed toward the thumb or radius side of the hand.

Plain whorl, central pocket loop whorl, double loop whorl, and accidental whorl.

A whorl with at least one ridge forming a complete circuit and satisfying the applicable imaginary-line test.

A classification test involving a line drawn between the two deltas to distinguish certain whorl subtypes.

A whorl containing a recurve or circuit in which the imaginary line between the deltas does not touch or cross a qualifying recurving ridge within the inner pattern area.

A whorl pattern containing two distinct loop formations with separate shoulders and two deltas.

A pattern combining characteristics of different pattern types or otherwise meeting the conventional criteria for accidental whorl classification.

Counting the ridges crossed or touched by an imaginary line from the delta to the core, excluding the delta and core themselves.

Following a selected ridge from one delta toward the other to determine the pattern's tracing designation.

Inner, meeting, and outer.

A systematic method of organizing ten-print fingerprint records using pattern types and numerical or symbolic classifications.

Sir Edward Richard Henry, building on work by earlier fingerprint researchers and collaborators.

A fraction based on assigned numerical values for whorl patterns appearing in specified finger positions.

The five finger pairs are assigned values of 16, 8, 4, 2, and 1, respectively.

Even-numbered fingers: 2, 4, 6, 8, and 10.

Odd-numbered fingers: 1, 3, 5, 7, and 9.

To prevent either part of the primary classification fraction from being zero.

1/1.

32/32.

32.

32.

Right thumb through right little finger as positions 1–5, followed by left thumb through left little finger as positions 6–10.

The right thumb and right index finger occupy positions 1 and 2, and each qualifying whorl contributes a value of 16 to its respective denominator or numerator.

17/1, because position 2 contributes 16 to the numerator and 1 is added to both parts.

1/17, because position 1 contributes 16 to the denominator and 1 is added to both parts.

9/9, because positions 3 and 4 each carry a value of 8, with 1 added to both parts.

26/1, because their numerator values are 16, 8, and 1, totaling 25, plus 1.

A loop, subject to confirmation that the required loop characteristics are present.