Forensic Analysis of Fingerprints, Hair, and Skin Layers

Arch pattern

A fingerprint pattern where ridges enter from one side of the finger and flow out the other side, usually forming a slight wave or 'hill' in the center.

Loop pattern

The most common pattern; ridges enter from one side, curve around (recurve), and exit on the same side they entered.

Whorl pattern

Fingerprint ridges that form a circular or spiral pattern, resembling a whirlpool or bullseye.

Bifurcation

A common 'minutiae' point where a single ridge splits or forks into two separate ridges.

Cheiloscopy

The forensic study of lip prints as a means of identification.

Pinnascopy

The forensic study of ear prints for identification.

Epidermis

The outermost, protective layer of the skin that we see and touch.

Dermis

The thick layer of 'true skin' beneath the epidermis containing blood vessels, nerves, and sweat glands.

Hypodermis

Also known as the subcutaneous layer; it is the deepest layer of the skin, mostly made of fat and connective tissue.

Sebaceous glands

Glands in the skin that secrete sebum (oil) to lubricate the skin and hair; this oil is often left behind in fingerprints.

Latent fingerprints

Invisible prints left on a surface by the transfer of body oils or sweat; they require chemicals or powders to be seen.

Patent fingerprints

Visible prints left when a finger touches a liquid like blood, ink, or paint and transfers it onto a surface.

Ninhydrin

A chemical reagent used to develop latent fingerprints on porous surfaces (like paper) by reacting with amino acids to turn them purple.

Cyanoacrylate

Commonly known as 'Super Glue'; its fumes react with moisture and oils in a latent print to create a hard, white permanent record.

Furrows

The 'valleys' or low points between the raised ridges on the skin of the fingers.

Ridges

The raised lines on the surface of the skin that create the fingerprint pattern.

Natural fibers

Fibers derived entirely from animal or plant sources (e.g., wool, cotton, silk).

Synthetic fibers

Man-made fibers produced from chemicals or polymers (e.g., nylon, polyester, acrylic).

Anagen phase

The active growth phase of hair where the root is firmly attached to the follicle.

Catagen phase

The transition stage where hair growth slows down and the follicle begins to break down.

Telogen phase

The final 'resting' phase where hair naturally falls out of the follicle.

Keratin

A tough, fibrous protein that is the main structural component of hair, nails, and the outer layer of skin.

Cortex

The middle layer of the hair shaft that contains the pigment (color) and gives hair its strength.

Medulla

The central core or innermost canal of a hair shaft, which can be solid, broken, or absent.

Melanin

The natural pigment granules found in the cortex that give hair its specific color.