Parts of the Fingerpad
Apocrine Glands |
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A type of sweat gland found predominantly in the underarm and genital regions. Not often considered when analysing fingerprint impressions as they are not found on the palmar surface.
Basal Layer |
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This is the innermost layer of the epidermis and is responsible for the production of new skin cells. As the new skin cells form, they push the older cells closer to the surface where they can be shed as dead skin.
Dermal Papillae |
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Peg-like adjoining structures linking the dermis and the epidermis.
Dermis |
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The thick, foundation layer of the skin below the epidermis composed of fibrous tissue and nerve cells.
Eccrine Glands |
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These are present all over the body but only these glands are present in volar skin. Pores along the fingerprint ridges secrete eccrine sweat; this sweat is the main component of the fingerprints that are left behind on contacted surfaces.
Epidermis |
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The thin, external layer of the skin with a thickness of 15–20 layers of cells. Of these, there are five primary layers of epidermis: stratum basale (also known as basal layer or stratum germinativum), spinous layer, granular layer, stratum lucidum, and stratum corneum. Cells are constantly generated at the stratum basale and migrate to the stratum corneum where they are sloughed off as dead skin cells. This process takes approximately one month.
Friction Ridge (Fingerprint Ridge) |
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A raised texture on the palmar and plantar surfaces of primates that enhances their ability to grip objects.
Palmar Surface |
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The palmar surface refers to the underside of the hand, including fingers. This surface contains only eccrine glands and not sebaceous glands.
Plantar Surface |
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The plantar surface refers to the soles of the feet. This surface contains only eccrine glands and not sebaceous glands.
Pore |
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A small orifice at the surface of the skin, through which gases, liquids, and small particles can pass. Characteristics of the pore that are measured include shape, size, and density.
Ridge Unit |
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The smallest functional unit of a fingerprint ridge. Several of these fuse together to form a continuous ridge.. A single ridge unit consists of one pore and one sweat gland.
Sebaceous glands |
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Small, oil-producing glands present in the skin that are associated with hair follicle presence and secrete an oily material called sebum. Sebaceous glands are not present on the plantar and palmar surfaces, but since hands can touch different regions of the body, sebum can be picked up and deposited along with eccrine sweat as a component of a fingerprint matrix.
Sweat gland |
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Responsible of secreting aqueous material with ions, electrolytes, etc. These differ from sebaceous glands that secrete sebum.
Volar skin |
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The textured skin located on the palmar and plantar surfaces of primates. This skin provides a biological advantage to allow for the ability to hold onto things and have traction.
Describes the transfer of oils or lipids from a finger onto a surface resulting in the replication of the friction ridge pattern seen on the fingertip, including the minutiae.
The palmar surface refers to the underside of the hand, including fingers. This surface contains only eccrine glands and not sebaceous glands.
The thin, external layer of the skin with a thickness of 15–20 layers of cells. Of these, there are five primary layers of epidermis: stratum basale (also known as basal layer or stratum germinativum), spinous layer, granular layer, stratum lucidum, and stratum corneum. Cells are constantly generated at the stratum basale and migrate to the stratum corneum where they are sloughed off as dead skin cells. This process takes approximately one month.
The thick, foundation layer of the skin below the epidermis composed of fibrous tissue and nerve cells.
The textured skin located on the palmar and plantar surfaces of primates. This skin provides a biological advantage to allow for the ability to hold onto things and have traction.
A small orifice at the surface of the skin, through which gases, liquids, and small particles can pass. Characteristics of the pore that are measured include shape, size, and density.
Friction ridge pattern that is found on the fingertips' skin.
This sweat is the main component of fingerprints that are left behind on surfaces from contact, and consists of amino acids, proteins, ions, electrolytes, and water.
This layer is the most internal layer of the epidermis and is responsible for the production of new skin cells. As the new skin cells form they push the older ones closer to the surface and once at the surface can be shed as dead skin.
Present all over the body but are the only glands present in volar skin. Sweat pores along the fingerprint ridges secrete eccrine sweat from these glands.
Small oil-producing glands present in the skin that are associated with hair follicle presence and release/produce oily material called sebum. Sebaceous glands are not present on the plantar and palmar surfaces but since the hands touch different regions of the body, they pick up sebum and deposit it, along with eccrine sweat, as components of fingerprints.
An uninterrupted friction ridge that continues until there is a ridge ending.
The plantar surface refers to the soles of the feet. This surface contains only eccrine glands and not sebaceous glands.
The chemical composition of a fingerprint impression. Often assumed to be a natural eccrine sweat or sebaceous sweat impression, but can also commonly be blood. Often there are contaminants such as hand lotion, dirt, or food residue, or job-specific contaminants such as paint, engine oil, etc.
An atom or molecule with a positive or negative electric charge due to a loss or gain of one or more electrons.
The ionized or ionizable components of cells, blood, or other organic matter (i.e., sodium, potassium, chloride).
