Skin, Hair, and Nails Anatomy and Assessment

This flashcard set covers the essential vocabulary, anatomical structures, developmental changes, and diagnostic visual descriptors for the skin, hair, and nails as presented in the Chapter 13 lecture notes.

Epidermis

The outer highly differentiated layer of the skin, consisting of an inner basal cell layer and an outer horny cell layer.

Basal cell layer

The part of the epidermis that forms new skin cells.

Horny cell layer

The outer layer of the epidermis consisting of dead keratinized cells.

Dermis

The inner supportive layer of the skin made of connective tissue (collagen) and elastic tissue.

Subcutaneous layer

A layer of adipose tissue beneath the dermis that stores fat for energy, provides cushioning, and aids in mobility.

Melanin

A brown pigment that is one of three sources of skin color and provides protection against skin cancer.

Carotene

A yellow-orange pigment that contributes to skin color.

Vellus hair

One of the two types of hair; fine, faint hair that covers most of the body.

Terminal hair

The darker, thicker hair that grows on the scalp, eyebrows, and, after puberty, on the axillae, pubic area, and face in males.

Sebum

A lipid substance secreted through hair follicles by sebaceous glands to lubricate the skin and form an emulsion.

Eccrine glands

Sweat glands that produce a clear saline secretion known as sweat.

Apocrine glands

Sweat glands that produce a thick, milky secretion and open into hair follicles; their secretions increase during adolescence.

Lanugo

The fine downy hair found on a newborn infant.

Vernix caseosa

A thick, cheesy substance present on the skin of a newborn.

Senile purpura

Discoloration in the aging adult caused by increasing capillary fragility.

Keloids

A benign excess of scar tissue that grows beyond the boundaries of the original injury.

Wood’s light

A filtered ultraviolet (UV) light used for special skin assessment procedures.

Pallor

A widespread color change where the skin appears pale.

Erythema

A widespread color change where the skin appears red.

Cyanosis

A widespread color change where the skin appears blue.

Jaundice

A widespread color change where the skin appears yellow.

Diaphoresis

Profuse perspiration or moisture on the skin.

Edema

Fluid accumulation in the interstitial space.

Mobility and turgor

Assessments used to determine skin elasticity; mobility is the skin’s ease of rising, and turgor is its ability to return to place promptly when released.

Profile sign

An assessment of the index finger profile to note the angle of the nail base; the normal angle is about $160^{\circ}$.

Capillary refill

The process of depressing the nail edge to blanch it and noting the return of color; a normal return is $< 3$ seconds.

ABCDEF rule

A tool for skin self-examination: Asymmetry, Border irregularity, Color variations, Diameter greater than $6\,mm$, Elevation or Evolution, and Funny looking.

Macule

A primary skin lesion consisting solely of a color change; it is flat, circumscribed, and less than $1\,cm$.

Papule

A primary skin lesion felt as a superficial thickening of the epidermis, less than $1\,cm$.

Patch

Macules that are larger than $1\,cm$.

Plaque

A skin lesion formed by papules coalescing to create a surface elevation wider than $1\,cm$.

Nodule

A solid, elevated, hard or soft lesion greater than $1\,cm$ that may extend deeper into the dermis than a papule.

Wheal

A superficial, raised, transient, and erythematous lesion that is irregular in shape due to edema.

Urticaria

Also known as hives; a condition where wheals coalesce to form an extensive pruritic reaction.

Vesicle

An elevated cavity containing fluid, up to $1\,cm$ in size; also known as a blister.

Cyst

An encapsulated fluid-filled cavity.

Bulla

A lesion larger than $1\,cm$ in diameter; it is usually single-chambered, superficial in the dermis, and ruptures easily.

Pustule

An elevated and circumscribed cavity containing pus.

Crust

A secondary skin lesion consisting of thickened, dried-out exudate left when vesicles or pustules burst or dry up.

Scale

Compact flakes of desiccated skin from the shedding of dead excess keratin cells.

Fissure

A secondary skin lesion appearing as a linear crack with abrupt edges extending into the dermis.

Erosion

A scooped-out but shallow depression in the skin that does not extend into the dermis.

Ulcer

A deeper depression extending into the dermis with an irregular shape; it may bleed and leaves a scar.

Excoriation

A self-inflicted abrasion that is superficial and often results from scratching.

Lichenification

Thickened skin with tightly packed sets of papules resulting from prolonged, intense scratching.

Stage I Pressure Injury

A pressure injury characterized by non-blanchable erythema of intact skin.

Petechiae

Tiny, round, discrete punctate hemorrhages measuring $1$ to $3\,mm$ caused by bleeding from superficial capillaries.

Ecchymosis

A purplish patch resulting from extravasation of blood into the skin, greater than $3\,mm$ in diameter.