Which part of the body is most likely to be affected by pressure ulcers?

According to the National Pressure Injury Advisory Panel (NPIAP), the sacrum and heels are among the most common sites for pressure injury development. This guide explores which part of the body is most likely to be affected by pressure ulcers and what can be done to prevent them.

Quick Summary

The parts of the body most susceptible to pressure ulcers are bony areas like the tailbone (sacrum), hips, heels, and ankles, especially in individuals with limited mobility. These pressure points are vulnerable because they lack sufficient cushioning from muscle or fat, making them prone to compromised blood flow when pressed against a surface for prolonged periods.

Key Points

• Bony Areas Most Vulnerable: Pressure ulcers are most likely to affect areas with prominent bones and minimal padding, such as the tailbone (sacrum), hips, heels, and ankles.

• Immobility is the Main Culprit: Limited movement or immobility is the primary risk factor, as it prevents natural weight shifting that protects skin from constant pressure.

• Different Locations for Different Positions: The specific high-risk areas depend on a person's position; the tailbone and heels are common for bedridden individuals, while the buttocks are most vulnerable for wheelchair users.

• Prevention is Key: Effective prevention strategies include frequent repositioning, using specialized support surfaces, maintaining proper nutrition, and keeping skin clean and dry.

• Early Detection is Crucial: Regular, daily skin inspections are vital for identifying the first signs of a pressure ulcer, such as persistent redness or discoloration, before it progresses.

• Understand Risk Factors: Factors like poor nutrition, incontinence, and conditions that affect sensory perception can increase an individual's susceptibility to developing pressure ulcers.

Understanding the Anatomy of a Pressure Ulcer

Pressure ulcers, also known as bedsores or pressure injuries, are localized injuries to the skin and underlying tissue, usually over a bony prominence, that result from sustained pressure. This constant pressure can reduce or completely cut off blood flow to the tissue. Without the oxygen and nutrients supplied by blood, the tissue can die, leading to the formation of an ulcer. While they can occur anywhere on the body, some areas are at a much higher risk due to their anatomical structure.

The Bony Truth: High-Risk Areas for Pressure Ulcers

Pressure ulcers almost always develop over bony prominences, where the bone is close to the surface of the skin and there is minimal muscle or fat to act as a cushion. The most vulnerable areas vary depending on a person's position, whether they are in a wheelchair or bedridden.

For those confined to a bed:

• Sacrum and Coccyx (Tailbone): The tailbone area is one of the most frequent sites for pressure ulcers, particularly in individuals who spend long periods on their back.
• Heels and Ankles: For people lying on their backs, the heels and ankles are at high risk, especially if their feet are not properly supported. The bony parts of the ankle, the malleoli, are particularly susceptible when a person is lying on their side.
• Hips (Greater Trochanter): When lying on one's side, the greater trochanter, or the prominent part of the hip bone, bears significant weight and is a common site for pressure injury.
• Shoulder Blades (Scapula): The shoulder blades can develop ulcers in people lying on their back.
• Back of the Head (Occiput): The back of the head is at risk, especially in those who are paralyzed or unable to move their head.
• Elbows: In a person who is constantly on their back, the elbows can become a high-pressure point.

For those who use a wheelchair:

• Ischial Tuberosities (Buttocks): The sitting bones are highly prone to pressure ulcers from prolonged sitting.
• Tailbone (Sacrum): The tailbone can also experience significant pressure when a person is in a slouched position.
• Back of Arms and Legs: Where the arms and legs rest against the chair can lead to friction and pressure ulcers.

Factors that Increase Risk

Several factors can exacerbate the risk of developing pressure ulcers on these vulnerable areas. Understanding these elements is key to effective prevention.

Immobility

Limited ability to change position is the single most significant risk factor. Whether due to poor health, paralysis, or unconsciousness, immobility prevents the natural shifts in weight that protect tissue from sustained pressure.

Sensory Perception

Individuals with conditions that cause a lack of sensation, such as spinal cord injuries, cannot feel the discomfort or pain that would otherwise signal the need to change position.

Moisture and Incontinence

Prolonged exposure to moisture, such as from sweat, urine, or stool, can make the skin more fragile and susceptible to breakdown. This often complicates the situation in the tailbone and buttocks areas.

Nutrition and Hydration

Poor nutrition and dehydration weaken the body's tissues, making them more fragile and less able to heal. Inadequate intake of protein, calories, vitamins, and minerals significantly increases risk.

Friction and Shear

• Friction: Occurs when skin rubs against a rough surface, such as clothing or bed linens. This can damage the top layers of the skin, making it more vulnerable to pressure.
• Shear: Happens when a person slides down in a bed or chair. This causes the skin to remain in place while the underlying tissue stretches and tears, damaging blood vessels and causing tissue death.

Preventative Strategies for Caregivers and Seniors

Preventing pressure ulcers is far more effective and less costly than treating them. Implementing a multi-faceted prevention plan is crucial for individuals at high risk.

Mobility and Positioning

• Frequent Repositioning: Individuals in bed should be turned or repositioned at least every two hours. Those in a wheelchair should shift their weight every 15 minutes if possible.
• Use Proper Devices: Special mattresses, cushions, and pillows can help redistribute pressure more evenly across the body. Never use donut-shaped cushions, as they can restrict blood flow.
• Proper Lifting Techniques: Use a draw sheet to lift, not drag, a person during repositioning to minimize friction and shear forces.

Skin Care

• Daily Skin Inspection: A daily skin check is critical for early detection. Pay close attention to bony areas, looking for persistent redness, warmth, or discoloration. For individuals with darker skin tones, look for changes in skin temperature, consistency, or pain.
• Keep Skin Clean and Dry: Clean skin promptly after episodes of incontinence. Use a pH-balanced cleanser and a protective barrier cream.
• Manage Moisture: Address any sources of excessive moisture, such as sweat or incontinence, with absorbent pads and regular checks.

Nutrition

• Ensure Adequate Nutrition: A balanced diet rich in protein, vitamins, and minerals is essential for healthy skin. Work with a doctor or dietitian to ensure nutritional needs are met.
• Promote Hydration: Encourage consistent fluid intake to support overall skin integrity and health.

Comparison of Support Surfaces

Support surfaces are critical tools in pressure ulcer prevention and management. Different types offer various benefits and drawbacks.

Support Surface	Advantages	Disadvantages
Foam Mattress Overlay	Inexpensive; lightweight; offers some pressure redistribution.	Can retain heat and moisture; limited pressure relief for high-risk patients.
Gel-Filled Cushions/Pads	Molds to the body; provides effective pressure redistribution.	Heavy; can be costly; may lose effectiveness if not properly maintained.
Air Mattress (Low-Air-Loss)	Actively redistributes pressure; good moisture control; adjustable.	Higher initial cost; requires power and regular maintenance; can be noisy.
Air-Fluidized Bed	Provides the lowest interface pressure; reduces friction and shear.	Very expensive; requires power; noisy; difficult for transfers.

Conclusion

While any part of the body can develop a pressure ulcer, the bony prominences are most vulnerable due to the constant pressure and limited cushioning. The sacrum, heels, and hips are particularly high-risk areas for bedridden individuals, while the sitting bones are a key concern for wheelchair users. However, with vigilant skin inspection, frequent repositioning, proper nutrition, and the use of appropriate support surfaces, many pressure ulcers are preventable. Proactive care is the best defense in promoting healthy aging and maintaining skin integrity.

For more detailed information and clinical guidelines on pressure ulcer prevention and management, visit the National Pressure Injury Advisory Panel website. https://npiap.com/

Frequently Asked Questions

What is the very first sign of a pressure ulcer?

The earliest sign is typically a persistent area of skin redness over a bony area that does not turn white (blanch) when pressed. For individuals with darker skin tones, the area may appear purplish or bluish and feel warmer or cooler to the touch.

Can a pressure ulcer develop quickly?

Yes, a pressure ulcer can develop in as little as two to three hours of sustained pressure, especially in high-risk individuals. The rate of development is highly dependent on factors such as pressure intensity, duration, and the individual's overall health.

Why are bony areas so susceptible to pressure ulcers?

Bony areas have less protective fat and muscle, meaning the blood vessels get compressed more easily when an individual is lying or sitting down for long periods. This cuts off blood flow, leading to tissue damage.

How often should a bedridden person be repositioned to prevent pressure ulcers?

According to standard best practices, a bedridden person should be turned or repositioned at least every two hours. This helps to redistribute pressure and restore blood flow to vulnerable areas.

What is the difference between a friction injury and a shear injury?

Friction occurs when skin rubs against a surface, damaging the top layers. Shear happens when underlying tissue and blood vessels are stretched and torn due to a combination of gravity and resistance, like sliding down in a bed.

What role does nutrition play in pressure ulcers?

Proper nutrition is critical. Adequate intake of protein, calories, vitamins, and minerals helps maintain healthy skin and supports wound healing. Malnutrition can significantly increase the risk and hinder recovery.

Can I use a donut-shaped cushion to prevent a pressure ulcer?

No, donut-shaped cushions should be avoided. While they seem helpful, they can actually increase pressure on the surrounding tissue by compressing it against the ring's edges, potentially worsening the risk.