The lateral position in nursing is when a patient lies on their side, either left or right, with supportive pillows or padding placed strategically to maintain body alignment and protect vulnerable areas. It is one of the most commonly used positions in patient care, serving purposes that range from preventing pressure injuries to improving airway drainage. You’ll also see it called the lateral decubitus position or the lateral recumbent position.
How the Lateral Position Looks
In a standard lateral position, the patient lies on one side with both hips and knees slightly bent. The top leg is placed in front of the bottom leg with the hip and knee flexed, which creates a wider triangular base of support and keeps the patient stable. This staggered leg placement is what prevents the patient from rolling forward or backward.
Proper alignment requires several support points. A pillow goes under the head and neck to keep the spine neutral. A second pillow is placed between the legs, running from the groin to the foot, to prevent the upper leg from pulling the hip out of alignment and pressing bone against bone at the knees. A folded “tuck-back” pillow is wedged slightly under the patient’s back to help maintain the position without constant effort. In surgical settings, additional supports like gel rolls or bean bags may be placed along both the front and back of the body, and a pad is often positioned under the chest wall to take pressure off the lower arm and protect the nerves and blood vessels in the armpit area.
Why Nurses Use It
The lateral position serves several clinical purposes. Its most frequent everyday use is relieving pressure on the sacrum (tailbone) and heels, the two areas most vulnerable to skin breakdown in patients who spend long periods on their backs or in a semi-reclined Fowler’s position. Shifting a patient onto their side redistributes body weight to different tissue and gives those high-risk areas time to recover blood flow.
In surgery, the lateral position provides access to structures that are difficult to reach when a patient is lying flat. Hip procedures, including posterior approaches for joint replacement and access to the femoral head and the back wall of the hip socket, commonly use lateral decubitus positioning. Thoracic and kidney surgeries also rely on it to expose the operative side while the patient lies with that side facing up.
The 30-Degree Rule
Not all side-lying angles are equal. The National Pressure Injury Advisory Panel recommends positioning patients at a 30-degree lateral tilt rather than a full 90-degree side-lying position. At 30 degrees, most bony landmarks stay free of direct pressure, and the patient’s weight is distributed across the fleshy part of the buttock rather than concentrated on the greater trochanter (the bony point of the hip). A full 90-degree side-lying position loads almost all the body’s weight onto the hip and shoulder, which is exactly the kind of concentrated pressure that causes tissue damage.
To achieve the 30-degree angle, a folded pillow or foam wedge is placed behind the patient’s back. The patient looks as though they are leaning back slightly rather than lying directly on their side. Feet should also be positioned to protect the ankle bones, and placing the top leg slightly forward (rather than stacking it directly on the bottom leg) further reduces pressure on the hip.
Pressure Points to Watch
Even with proper technique, the lateral position generates the highest peak pressures on bony prominences of any standard bed position. Research measuring surface pressure across different positions found that the trochanteric region (outer hip) bears the greatest load in lateral lying. Other vulnerable sites include the ear on the downside, the shoulder, the outer knee, and the lateral malleolus (the bony bump on the outside of the ankle). Each of these areas needs padding or offloading to prevent injury, especially in patients with poor circulation, limited sensation, or thin skin.
How Often to Reposition
Repositioning frequency depends on the patient’s risk level. NICE guidelines recommend turning at-risk adults at least every six hours, and high-risk adults at least every four hours. Children at risk should be repositioned at least every four hours, with more frequent turns for those at higher risk. These are minimum intervals. Patients with existing pressure injuries, very thin body composition, or conditions affecting blood flow often need more frequent position changes, and nursing judgment plays a role in adjusting the schedule.
Lateral Position vs. Sims’ Position
The Sims’ position is closely related but distinct. Where the standard lateral position keeps the patient squarely on their side, Sims’ is a halfway point between side-lying and lying face down. The lower arm is positioned behind the patient’s body, and the upper arm is flexed at the shoulder and elbow. The upper leg is bent more sharply at both the hip and knee than the lower leg, tilting the patient partially forward onto their chest.
Sims’ position is particularly useful for unconscious patients because the forward tilt allows saliva and fluids to drain from the mouth, reducing aspiration risk. It is also the standard position for administering enemas and for examinations of the perineal area. Pregnant individuals often find Sims’ position comfortable for sleeping because it keeps pressure off the large blood vessels that run along the spine. Both positions relieve sacral pressure, but Sims’ provides the added benefit of airway protection in patients who cannot manage their own secretions.
Effects on Breathing and Lung Function
In an awake patient, the lateral position preserves normal lung function quite well. Gravity pulls more blood flow to the lower (dependent) lung, roughly a 10% shift compared to being upright. Ventilation also shifts to the dependent lung because the diaphragm on that side sits higher in the chest and contracts more efficiently. The result is that the lower lung gets both more air and more blood, keeping the two well matched.
This balance changes under general anesthesia. Anesthesia reduces muscle tone in the diaphragm, causing a 15 to 20 percent drop in the lungs’ resting air volume. The dependent lung, now compressed by the weight of the body and the organs above it, becomes stiffer and harder to inflate. The upper lung, freed from that compression, becomes the easier one to ventilate. Blood flow, however, still favors the lower lung. This mismatch means the upper lung gets air but not much blood, while the lower lung gets blood but not enough air. Anesthesia teams manage this actively during surgery, but for nurses caring for sedated or ventilated patients, understanding this shift helps explain why positioning protocols matter and why the “good lung down” principle is sometimes applied for patients with one-sided lung disease.