CNA Exam Preparation · Mobility and Skin Integrity

Skin Care and Pressure Injury Prevention

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In 30 seconds
Why this matters
The college version
Eli explains
Worked example
Key takeaway
Study tools

In 30 seconds

The skin is the body's largest organ and its first barrier against injury and infection, but it thins, dries, and frays with age, so older residents bruise and tear easily. A — sometimes called a pressure ulcer or bedsore — is damage to the skin and underlying tissue caused by unrelieved pressure, usually over a . The CNA prevents these injuries by keeping skin clean and dry, turning residents at least every 2 hours, using , , applying barrier creams as directed, and reporting every skin change to the nurse at once.

Why this matters

Skin care is a clear example of the delegation boundary. Observing the skin, providing routine skin care, turning, and applying barrier creams as directed are CNA tasks. Staging a pressure injury, diagnosing its cause, or choosing a treatment are outside CNA scope and belong to the licensed nurse. Prevention is dignity-centered care: keeping a resident clean, dry, and comfortable protects both their skin and their sense of worth, and it spares the resident the pain and complications of a wound. State registry rules, NNAAP/Prometric/Credentia materials, facility policies, nurse delegation, care plans, and scope-of-practice rules vary by jurisdiction and must be followed; this material is educational exam preparation only.

The college version

1. Skin Anatomy and Aging

The skin has layers: the outer (the protective surface) and the inner (which holds strength, blood vessels, nerves, and glands). Below the skin lies fatty tissue over muscle and bone. With aging, the epidermis and dermis thin, oil and sweat glands produce less, and the fatty cushion shrinks, so skin becomes drier, thinner, less elastic, and easier to bruise, tear, or break down. Because blood flow also decreases, older skin heals more slowly. The CNA protects fragile skin with gentle handling, mild cleansers, moisturizers as directed, and careful positioning — pulling or rubbing fragile skin causes tears.

2. Pressure Injury Risk Factors

A pressure injury (also called a pressure ulcer, decubitus ulcer, or bedsore) is localized damage to skin and underlying tissue, usually over a bony prominence, caused by pressure or by pressure combined with . The main risk factors are:

: residents who cannot move on their own cannot shift pressure off a spot, so blood flow is reduced and tissue begins to break down.
: urine, stool, sweat, or wound drainage softens (macerates) the skin, making it break down faster.
: skin rubbing against sheets or another surface rubs off the top layer.
Shear: skin and the surface beneath move in opposite directions while deeper tissue stays put (as when a resident slides down in bed), stretching and tearing the tissue inside.
: without enough protein, calories, and fluid, the skin cannot repair itself.

These factors often combine, which is why prevention addresses all of them together rather than one at a time.

3. Common Sites and Interventions

Pressure injuries form where bone is close to the surface — the bony prominences. The most common sites are the (tailbone), heels, hips, elbows, and the back of the head, along with the ears and ankles. The interventions the CNA performs and helps carry out are:

Floating the heels: keeping the heels off the bed surface (with a pillow under the calves or a heel-offloading device) so the heels bear no pressure.
Barrier creams: applying moisture-barrier ointment as directed to protect the skin from urine and stool.
Dry, wrinkle-free linens: keeping the bed smooth and dry, because wrinkles and dampness cause friction and moisture damage.
Frequent turning: repositioning at least every 2 hours (or more often per the care plan) to relieve pressure.

The CNA also observes the skin at every position change and reports redness, blisters, open areas, warmth, swelling, or a change in skin color to the nurse immediately.

How it works

Pressure on a bony prominence squeezes the tiny blood vessels, reducing blood flow to the skin and tissue.
When pressure lasts too long, the tissue does not get oxygen and nutrients, and it begins to break down.
Moisture, friction, shear, and poor nutrition make that breakdown happen faster.
The CNA interrupts the chain: turning every 2 hours shifts pressure, dry wrinkle-free linens prevent friction and moisture, floating the heels removes heel pressure, and barrier cream shields skin from urine and stool.
At every care episode, the CNA looks at the skin and reports any change — especially non-blanchable redness — to the nurse.
The nurse assesses and stages any injury; the CNA continues prevention and carries out the care plan.

Common confusions

Do not confuse	With	Difference
Friction	Shear	Friction rubs off the top layer of skin; shear slides skin and deeper tissue in opposite directions
Blanchable redness	Non-blanchable redness	Blanchable redness turns white when pressed; non-blanchable does not and is a warning sign
Moisture	Friction	Moisture softens skin; friction rubs it away
Pressure injury	Skin tear or bruise	A pressure injury is from unrelieved pressure over a bony area; tears and bruises are from trauma
Sacrum	Coccyx	The sacrum is the broad bone at the base of the spine; the coccyx is the small tailbone below it

Memory aids

"MIFFS breaks skin: Moisture, Immobility, poor Food (nutrition), Friction, Shear." Those are the five conditions that let a pressure injury start. To keep the two "F" terms straight, remember that friction rubs the top layer off, while shear slides skin and tissue in opposite directions beneath the surface.

Quick review

Topic Recap

The skin is a living barrier that thins and slows with age, so older residents need gentle, consistent skin care. A pressure injury is damage from unrelieved pressure over a bony prominence, made worse by immobility, moisture, friction, shear, and poor nutrition. The CNA prevents injury by turning residents at least every 2 hours, floating the heels, using dry wrinkle-free linens, applying barrier creams as directed, and checking the skin at every opportunity — reporting any change, especially non-blanchable redness, to the nurse immediately.

Knowledge Check

A resident who lies on the back most of the day is at highest risk for a pressure injury over which two areas?
Which risk factor describes skin sliding one way while the deeper tissue stays in place?
What does "floating the heels" mean, and why is it done?
During skin checks, the CNA finds redness over the sacrum that does not turn white when pressed. What should the aide do?
Which of the following is NOT a pressure-injury risk factor: immobility, moisture, frequent turning, or poor nutrition?

Answers and Rationales

The sacrum and the heels. Why: these bony prominences bear the most pressure in a supine (back-lying) resident.
Shear. Why: shear stretches tissue when skin and deeper layers move in opposite directions; friction only rubs the surface.
Keeping the heels off the bed surface, usually with a pillow under the calves or a heel device. Why: it removes pressure from the heels entirely so no pressure injury can form there.
Report it to the nurse immediately and document what was seen. Why: non-blanchable redness can be the first visible sign of a pressure injury and needs a nurse's assessment.
Frequent turning. Why: turning is a prevention measure, not a risk factor — the risk factors are immobility, moisture, friction, shear, and poor nutrition.

Eli explains

The same idea, in plain words

Explain it like I’m 10

Think of the skin like the protective cover on a sofa cushion. A thick new cover is strong and smooth; an old cover is thin, cracked, and tears easily. Under the cover, the cushion's stuffing is delicate — if something heavy presses on one spot too long, the stuffing crushes and will not bounce back. Skin is the "cover," and the muscle and fatty tissue underneath are the "stuffing." Aging makes the cover thin and fragile, and unrelieved pressure crushes the stuffing beneath it.

This comparison stops being exact at one key point: a sofa cover does not heal, grow, or feel pain, and it is not kept healthy by blood flow, moisture, and nutrition. Real skin is alive — it needs circulation and nutrients, and it repairs itself when conditions are right. That is why pressure-injury care is really about prevention and early detection, not just covering damage after it happens.

Simple Example

An immobile resident lies on the back most of the day. The back of the heels, the sacrum, and the elbows press into the mattress. Without turning, blood flow to those spots slows and the skin can begin to break down. The CNA floats the heels (keeps them off the bed with a pillow under the calves or a heel device), turns the resident every 2 hours, and checks the skin at every turn.

Worked example

A resident who is incontinent and moves little in bed is at high risk. During routine care, the CNA checks the skin each time — especially the sacrum, heels, hips, and elbows. The aide notices a red area over the sacrum and, when pressing lightly with a finger, the area does not turn white (does not blanch). This is a red flag: non-blanchable redness can be the first visible sign of a pressure injury and must be reported to the nurse at once. The CNA documents exactly what was seen — where the redness is, its size and color, and whether the area blanches — and reports it the same shift, then continues the prevention measures already in the care plan (turning, dry linens, floating heels, barrier cream as directed).

The CNA does not stage, grade, or diagnose a pressure injury, and does not decide on treatment. Staging and treatment decisions belong to the licensed nurse or provider. The aide's responsibility is to observe, document, report, and prevent — and to get help early, because a small red area caught on day one is far easier to manage than a deep wound weeks later. If a resident is losing weight, eating poorly, or becoming more incontinent, those changes are also reported, since they raise pressure-injury risk.

Key takeaways

High yield: Turn residents who cannot move themselves at least every 2 hours.
High yield: Non-blanchable redness (redness that does not turn white when pressed) must be reported to the nurse immediately.
High yield: The most common pressure-injury sites are the sacrum and heels.
Pressure injury = damage from unrelieved pressure, usually over a bony prominence.
Aging makes skin thinner, drier, and slower to heal — handle it gently.
The five risk factors are immobility, moisture, friction, shear, and poor nutrition.
Friction rubs the surface; shear slides skin and deeper tissue in opposite directions.
Float the heels, apply barrier cream as directed, and keep linens dry and wrinkle-free.
The CNA observes, documents, and reports skin changes; the nurse stages and treats.
Report weight loss, poor intake, and increasing incontinence as added pressure-injury risk.

Keep learning

Ready to build on this? Continue to the next lesson.

Study tools & related lessonsYou’ll learn to · Key vocabulary · Related

You’ll learn to

Describe the basic structure of the skin and explain how aging makes skin thinner, drier, and more fragile.
Explain the risk factors for pressure injury — immobility, moisture, friction, shear, and poor nutrition — as cause-and-effect.
Identify the bony prominences most at risk and the interventions that protect them: floating the heels, barrier creams, dry wrinkle-free linens, and frequent turning.
Distinguish what a CNA observes, documents, and reports about skin from what requires a nurse's assessment.

Key vocabulary

Epidermis: The outer, protective layer of the skin
Dermis: The inner layer holding blood vessels, nerves, and strength
Aging skin: Skin that becomes thinner, drier, and less elastic over time
Pressure injury: Damage to skin and underlying tissue from unrelieved pressure
Immobility: Inability to move or reposition oneself
Moisture: Urine, stool, sweat, or drainage on the skin
Friction: Skin rubbing against a surface
Shear: Skin and deeper tissue sliding in opposite directions
Poor nutrition: Too little protein, calories, or fluid
Bony prominence: A place where bone is close to the skin's surface
Sacrum: The tailbone area at the base of the spine
Heel: The back of the foot
Elbow: The bony point of the arm
Hip: The side of the upper thigh/hip bone
Back of the head (occiput): The bony back of the skull
Floating the heels: Keeping the heels off the bed surface
Barrier cream: Ointment that shields skin from urine and stool
Wrinkle-free linens: Smooth, dry sheets without folds
Frequent turning: Repositioning at least every 2 hours
Non-blanchable redness: Redness that does not turn white when pressed

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