Using an arm sling correctly means positioning your elbow at a 90-degree angle, supporting your wrist fully inside the fabric, and adjusting the strap so your shoulder muscles can relax completely. Getting these basics right prevents the secondary problems that make slings miserable: neck pain, hand swelling, and nerve compression.
Putting On an Arm Sling
Start by sliding your injured hand into the sling’s pouch. Pull the fabric up so your elbow fits snugly into the far corner of the pouch. Your elbow should be bent at 90 degrees, forming a right angle. If your elbow doesn’t reach the corner, the sling is too large and won’t provide proper support.
Next, take the shoulder strap and route it behind your neck to the opposite shoulder, then thread it through the ring or buckle at the top of the sling. Pull it until the sling holds your arm at that 90-degree bend without you needing to tense any muscles. Secure the strap’s Velcro back onto itself. If your sling has a waist strap, thread it through the side ring and fasten it snugly around your torso. This prevents the sling from swinging away from your body when you move.
The strap should run behind the shoulder on your injured side, not directly over your neck vertebrae. When it’s properly tightened, you should be able to completely relax your shoulder, neck, and back muscles while the sling does all the work of holding your arm up.
Wrist and Hand Position
One of the most common sling mistakes is letting the wrist hang past the edge of the fabric. When your wrist dangles unsupported, it compresses the ulnar nerve, the nerve that runs along the outside of your forearm and controls sensation in your ring and pinky fingers. Over hours and days, this can cause tingling, numbness, or pain that has nothing to do with your original injury.
Your wrist should rest fully inside the sling with a slight upward tilt of about 10 to 20 degrees. Your palm should face your body. Your fingertips should remain visible and exposed so you (or someone helping you) can check their color and warmth, which are signs of healthy circulation. The base of the sling fabric should sit at the base of your little finger.
Types of Slings and When They’re Used
Not all slings serve the same purpose, and the type you’re given depends on where and how you’re injured.
- Broad arm sling: The most common type. It supports injuries to the upper arm, wrist, or forearm, and is also used for rib fractures. Your hand sits slightly higher than your elbow when it’s applied correctly.
- High arm sling: Holds the hand and forearm in a raised position, with fingertips touching the opposite shoulder. This is used when swelling needs to be controlled or when there’s a wound that’s actively bleeding in the hand or forearm. Elevation helps with both.
- Poly sling: A sturdier option used for collarbone fractures or fractures near the elbow joint, where more rigid support is needed.
If you’ve had shoulder surgery, you may receive an abduction sling, which holds the arm slightly away from the body with a foam wedge. The general principles of fit still apply: 90-degree elbow bend, wrist supported, strap adjusted so muscles can relax.
Avoiding Neck Pain
Neck soreness is the most common complaint from sling wearers, and it’s almost always a fit issue. If your neck hurts, the strap is probably too tight, pulling your head forward or digging into the muscles at the base of your skull. Loosen the Velcro straps at either end incrementally until the tension eases. You want the strap snug enough that your arm stays in position, but not so tight that you feel pressure on your neck when you stand upright.
If the strap itself is thin or unpadded, folding a soft cloth or small towel around the section that crosses your neck can reduce friction and distribute the weight more evenly. Some slings come with removable padding for this purpose. Position the padded section so it sits on the fleshy part of your shoulder rather than directly over the spine.
Signs Your Sling Doesn’t Fit Right
Check your fingers several times a day while wearing a sling. Tingling, numbness, or weakness in your hand or arm means something is being compressed, either by the sling itself or by swelling beneath it. If your fingers turn cold, pale, or bluish, circulation is being restricted. These changes need prompt medical attention, especially if loosening the sling doesn’t resolve them quickly.
Other red flags: your hand swelling significantly more than the first day or two, pain that worsens rather than improves with the sling on, or the sling sliding out of position repeatedly no matter how you adjust it. A sling that keeps shifting usually means the shoulder strap is routed incorrectly or the pouch is the wrong size.
How Long You’ll Wear It
Sling duration varies widely depending on the injury. For conservatively managed upper arm fractures, most treatment plans call for two to four weeks of immobilization, though some injuries require up to six weeks. Surgical repairs, particularly of the rotator cuff, often require sling use for four to six weeks, sometimes longer. Your timeline will depend on how quickly you’re healing and when your doctor clears you to begin movement exercises.
Wearing a sling longer than necessary carries its own risks. Prolonged immobilization can lead to stiffness, muscle weakening, and a condition called frozen shoulder, where the joint capsule tightens and range of motion becomes severely limited. Follow your prescribed timeline closely, and don’t extend sling use on your own out of caution.
Sleeping With a Sling
Sleep is where most people struggle. The best position for the first few weeks is slightly reclined rather than flat. A recliner works well. If you don’t have one, stack pillows behind your back so your torso is elevated at a gentle angle, which reduces swelling and takes pressure off the shoulder.
If you sleep on your back, place a small pillow or rolled towel under the injured arm for extra support. Line pillows along both sides of your body to prevent rolling over in your sleep. If you sleep on your uninjured side, hug a large body pillow or stack of pillows against your chest and rest your injured arm on top. Then place pillows along your back as a barrier so you don’t accidentally roll onto the surgical shoulder during the night.
Keep the sling on while sleeping unless your doctor specifically says otherwise. Most post-surgical instructions call for continuous sling use, including during sleep, for the first several weeks.
Keeping the Sling Clean
Slings sit against skin for weeks and get sweaty, especially in warmer weather. Most fabric slings can be hand-washed in cool water (around 30°C) with a mild detergent. Before washing, press all the Velcro tabs firmly closed so they don’t snag the fabric or stick to other items. Rinse thoroughly, skip the fabric softener and bleach, and don’t wring the sling out. Instead, squeeze gently or press it with a dry towel to remove excess water, then lay it flat or hang it in a well-ventilated area to dry.
While the sling dries, you’ll need to keep your arm supported. Some people buy a second sling for this reason. Wearing a thin cotton sleeve or T-shirt under the sling can also reduce direct skin contact and cut down on how often the sling needs washing.