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General information, not medical advice. This page describes what a triangular bandage is and how first-aid organisations describe its use as a sling. It does not give application steps, and it does not diagnose or treat an injury; for the injury itself, ask a clinician or emergency service.
A triangular bandage is a large triangle of cloth. Used as a sling, it supports an injured arm so the person can rest it. Two sling types are common in UK first-aid guidance: the arm sling and the elevation sling.
What is a triangular bandage?
A triangular bandage is a large triangle of cloth that can be folded for use as a sling, a covering for the head, or a wrap to hold other items in place. See what a bandage is for how it compares with adhesive and roller bandages, and the first aid kit contents checklist for where a triangular bandage appears in a stocked kit. Elastic bandages are a separate product from a triangular bandage.
What you need
- One triangular bandage.
- Optionally, a safety pin; St John Ambulance lists it as one of two ways to secure the bandage edge at the elbow, the other being to twist and tuck the fabric.
Arm sling and elevation sling compared
| Point | Arm sling | Elevation sling |
|---|---|---|
| Arm position | Forearm raised or horizontal | Forearm and hand raised, fingertips touching the opposite shoulder |
| Described by St John Ambulance as supporting | An injured upper arm, forearm or wrist | The forearm and hand |
| Fastening | Ends tied with a reef knot | Ends tied with a reef knot |
Source for the table: St John Ambulance arm sling and elevation sling pages, checked 2026-10-30.
How to apply a triangular bandage
This page deliberately gives no step-by-step application instructions. Applying a sling to an injured person is a first-aid act, best learned from a recognised first-aid course; St John Ambulance publishes illustrated guidance on its arm sling and elevation sling pages. For how a sling differs from a splint, see what a splint is; for sling types sold or used in care settings, see types of slings.
The knot
University Hospitals Sussex NHS Foundation Trust says the ends of a sling are always tied with a reef knot, because it lies flat, will not slip and is easy to untie (leaflet last reviewed 14 February 2023, checked 2026-10-30).
When to get professional help
A sling supports an arm; it does not treat what is wrong with it. If you are unsure about an injury, ask a clinician or contact your local emergency or urgent-care service.
FAQ
How do you apply a triangular bandage?
The method depends on whether an arm sling or an elevation sling is needed, and is best learned on a first-aid course. St John Ambulance publishes guidance for both on the pages linked above.
What is a triangular bandage?
It is a large triangle of cloth that can be folded for use as a sling, a head covering or a wrap that holds other items in place.
What is the difference between an arm sling and an elevation sling?
An arm sling holds the forearm raised or horizontal. An elevation sling holds the forearm and hand raised with the fingertips touching the opposite shoulder (St John Ambulance, checked 2026-10-30).
What knot is used?
A reef knot (University Hospitals Sussex NHS Foundation Trust, checked 2026-10-30).
Sources
- St John Ambulance, How to make an arm sling, clinically reviewed 28 April 2025, checked 2026-10-30.
- St John Ambulance, How to make an elevation sling, reviewed 28 April 2025, checked 2026-10-30.
- University Hospitals Sussex NHS Foundation Trust, Slings and bandages, last reviewed 14 February 2023, checked 2026-10-30.
Both organisations are UK-based; this page makes no claim about rules or training standards in any other country.
