You can make an effective arm sling from any large piece of fabric, folded into a triangle and tied behind the neck. The whole process takes under two minutes once you have your materials. Whether you’re using a proper triangular bandage from a first aid kit or improvising with a pillowcase, the technique is straightforward.
What You Need
The ideal material is a piece of cloth about 5 feet (1.5 meters) wide at the base and at least 3 feet (1 meter) long on the sides. Cut it into a triangle, or take a large square piece of fabric and fold it diagonally to form one. A pillowcase cut to about 40 inches square works well. For a child, scale the dimensions down so the fabric matches their arm length from elbow to fingertips with a few inches to spare.
If you don’t have scissors or a large cloth, skip ahead to the improvised options below.
Step-by-Step: Triangular Bandage Sling
Have the injured person sit or stand as comfortably as possible. Bend the injured arm at the elbow so it forms a right angle (an “L” shape), with the hand resting across the stomach or chest.
Lay the triangular bandage flat against the person’s chest with the long edge running vertically. Position the top point of the triangle at the elbow of the injured arm, and place the wrist midway along the triangle’s bottom edge. One tail of the triangle should hang down toward the opposite hip, and the other should drape over the shoulder on the injured side.
Now bring the lower tail up and over the shoulder on the uninjured side, so both tails meet behind or to the side of the neck. Tie them together with a square knot (right over left, then left over right) positioned to the side of the neck rather than directly over the spine. Tuck a small pad of cloth or gauze under the knot to prevent it from digging into the skin.
At the elbow, fold the excess fabric neatly around the point and secure it with a safety pin or tuck it in. This keeps the elbow enclosed and prevents the arm from slipping out the back.
Getting the Position Right
Correct positioning matters more than the knot or the fabric you use. Three things to check once the sling is on:
- Hand higher than elbow. The hand should sit slightly above elbow level. This reduces swelling in the fingers and hand by helping fluid drain back toward the body.
- Elbow at 90 degrees. The forearm should be roughly level, forming that “L” shape. If the arm droops or the elbow hangs too low, the sling needs to be shortened by retying the knot higher.
- Fingers visible and free. Leave the fingers exposed so you can monitor circulation. They should stay warm, their normal color, and the person should be able to wiggle them without severe pain.
How to Check Circulation
A sling that’s too tight or positioned poorly can restrict blood flow. After you tie it, press firmly on one of the person’s fingernails for a couple of seconds until the nail turns white, then release. Color should return within 2 to 3 seconds. If it takes longer, the sling is likely too tight or the arm is positioned too low.
Ask the person if they feel any numbness, tingling, or pins and needles in their fingers. Check again every 15 to 30 minutes, especially in the first hour. If sensation decreases or the fingers look pale, blue, or swollen, loosen the sling and reposition the arm slightly higher.
Improvised Sling Options
You won’t always have a triangular bandage handy. Several everyday items work as substitutes.
A button-up shirt or jacket can serve as a sling without any cutting. Pin the hem of the shirt up to the chest area to cradle the forearm, or tuck the hand inside the shirt between two buttons. For someone wearing a zip-up hoodie, partially zipping it over the injured arm holds it snugly against the body.
A belt, scarf, necktie, or strip of torn fabric works for a collar-and-cuff sling. This is a simpler approach recommended for suspected collarbone fractures or elbow injuries where a full triangular sling puts too much pressure on the injury site. Loop the material around the wrist, bring both ends up behind the neck, and tie them. The forearm hangs supported but the elbow isn’t enclosed, so there’s less compression on a fractured collarbone. Strips of a bedsheet or even a pants leg can work in a pinch.
Collar and Cuff vs. Broad Arm Sling
A broad arm sling (the standard triangular bandage method above) supports the full forearm and distributes weight across the shoulder. It’s the go-to option for wrist injuries, forearm fractures, and general arm immobilization.
A collar and cuff sling supports only the wrist, letting the arm hang with gravity. This is preferable for collarbone injuries because it avoids pressing fabric across the collarbone, and for certain elbow injuries where enclosing the joint in fabric would increase pain. If you’re unsure which type to use, the broad arm sling is the safer default for most situations.
A high sling, where the hand is elevated well above elbow level with the fingertips near the opposite shoulder, is used for hand or finger injuries where maximum elevation is needed to control swelling.
Fitting a Sling for a Child
The same technique works for children, but sizing and security need more attention. Use a smaller triangle that matches the child’s arm length. When the sling is on, check that the arm sits at a 90-degree angle and the hand rests slightly above the elbow.
Children tend to move more and loosen their slings. Place the padded area of the sling around the back of the neck and make sure the fabric is snug, not hanging loose, so the arm doesn’t slide around. If the child has a cast, tie the sling so it holds the cast securely, with one knot above and one below the cast edge. Retie as needed throughout the day since fabric stretches with activity.
Common Mistakes to Avoid
Tying the knot directly on the back of the neck is the most frequent error. The cervical spine has very little padding, and a hard knot pressing into it for hours causes significant neck pain. Always position the knot to the side, over the muscle between the neck and shoulder, and cushion it.
Letting the hand hang below the elbow is another common problem. It feels natural but promotes swelling in the fingers. If the person’s hand looks puffy after 20 minutes, the sling needs to be repositioned higher.
Wearing the sling too loosely gives a false sense of security. The arm shifts with movement, which can worsen a fracture or increase pain. The fabric should be snug enough that the arm stays still when the person walks.
Poor posture while wearing a sling compounds discomfort. The weight of the arm pulling on one shoulder encourages slumping, which strains the neck, upper back, and the uninjured shoulder. Sitting and standing upright, with shoulders back, reduces this strain considerably. Gentle neck stretches, like slowly tilting the ear toward each shoulder, help prevent the stiffness that builds up after wearing a sling for several days. Keep the skin under the armpit dry to avoid irritation from moisture trapped against the body.