Splinting
Part of First Aid
A splint does one job — hold broken bones still so they can heal in the right position. Done well, it turns a crippling injury into a full recovery. Done poorly, it causes more damage than the break itself.
The Purpose of a Splint
A splint immobilizes a fractured bone to achieve three goals:
- Prevent further damage. Broken bone ends are sharp. Every time the fracture site moves, those edges can cut into muscle, blood vessels, and nerves. A good splint eliminates that motion
- Reduce pain. Most fracture pain comes from bone ends grinding against each other and against damaged soft tissue. Immobilization drops pain levels dramatically
- Allow healing. Bone knits itself back together through a process called callus formation. This requires the broken ends to remain in stable contact for weeks. Movement at the fracture site delays or prevents healing
The Cardinal Rule: Joint Above, Joint Below
Every splint must immobilize the joint above the fracture AND the joint below the fracture. This is the single most important principle of splinting.
Why: Joints allow movement. If you only immobilize the bone itself, the joints above and below still permit rotation and bending forces to reach the fracture site.
Examples:
- Forearm fracture (radius or ulna): splint must include the wrist AND the elbow
- Lower leg fracture (tibia): splint must include the ankle AND the knee
- Upper arm fracture (humerus): splint must include the elbow AND the shoulder (achieved with sling + body binding)
- Finger fracture: splint must include the fingertip AND extend past the knuckle
Splinting Materials
Almost anything rigid can serve as a splint. What matters is that it is:
- Stiff enough to prevent movement at the fracture site
- Long enough to span from the joint above to the joint below
- Padded where it contacts the body to prevent pressure sores
| Material | Best For | Notes |
|---|---|---|
| Straight sticks/branches | Arm and leg fractures | Most universally available; choose 3-5 cm diameter |
| Bark slabs | Forearm, lower leg | Moldable when fresh, stiffens as it dries |
| Boards/planks | Any long bone | Scavenged from buildings, furniture, pallets |
| Rolled newspaper/magazine | Forearm, wrist, ankle | Surprisingly rigid when rolled tightly |
| Cardboard | Arm, wrist, ankle | Fold into multiple layers for rigidity |
| SAM splint (if scavenged) | Any bone | Moldable aluminum with foam padding — the gold standard |
| Trekking poles/umbrella | Leg fractures | Already the right shape and length |
| Pillow or blanket | Ankle, foot, wrist | Wrap around the injury and secure — a “soft splint” |
| The body itself | Fingers, legs | Buddy-tape a broken finger to its neighbor; bind a broken leg to the uninjured leg |
Step-by-Step Splinting
Preparation
- Assess the injury. Identify the fracture location. Check circulation below the injury (pulse, sensation, movement in fingers/toes). Refer to Bone and Joint for assessment techniques
- Gather materials. You need: two rigid supports, padding (cloth, moss, clothing), ties (cloth strips, cordage, belts, tape)
- Cut or tear ties to length before you begin. You will need 4-6 ties depending on the length of the splint. Pre-cutting prevents fumbling while the patient is in pain
- Explain what you are doing. A patient who understands the process tenses less and cooperates more
Application
Step 1 — Place padding along the entire length of each splint where it will contact skin. Unpadded rigid material causes pressure sores within hours and can compress nerves.
Step 2 — Position the splints on opposite sides of the limb (typically one on top, one underneath, or one on each side). Do NOT place a splint directly over the fracture site — position them alongside it.
Step 3 — While an assistant gently supports the limb (preventing any movement at the fracture), slide the splints into position.
Step 4 — Secure with ties. Start with a tie ABOVE the fracture, then one BELOW the fracture, then work outward toward the joints. This sequence stabilizes the most critical area first.
Step 5 — Tie firmly enough that the splint does not shift, but not so tight that it compresses blood vessels. You should be able to slide a finger between the tie and the skin.
Warning
NEVER tie directly over the fracture site. The pressure causes extreme pain and can displace bone fragments.
Step 6 — Recheck circulation after splinting. Compare fingers/toes on the injured side to the uninjured side. If circulation is worse after splinting, loosen the ties immediately.
Step 7 — Elevate the splinted limb above heart level if possible. This reduces swelling.
Specific Splinting Techniques by Location
Forearm (Radius/Ulna)
- Two splints: one on the palm side, one on the back of the forearm
- Extend from mid-upper-arm (above elbow) to beyond the fingertips
- Pad the palm with a rolled cloth for the patient to grip (maintains functional position)
- Secure the elbow at roughly 90 degrees
- Support with a sling after splinting
Upper Arm (Humerus)
- Place a padded splint along the outer arm from shoulder to elbow
- Bend the elbow to 90 degrees and place the forearm in a sling
- Bind the upper arm to the torso with a broad wrap (swath) — the chest wall acts as the second splint
Lower Leg (Tibia/Fibula)
- Two splints: one on the inner side, one on the outer side of the leg
- Extend from mid-thigh (above knee) to beyond the foot
- Pad heavily at the ankle bones — these are pressure-sensitive bony prominences
- Secure the ankle at 90 degrees (neutral position) to prevent foot drop during healing
- The patient will need a stretcher or crutches — see First Aid for improvised options
Ankle/Foot
- A pillow splint works well: wrap a pillow or folded blanket around the foot and ankle, secure with ties
- Alternatively, use a figure-eight wrap with padded board splints on each side
- Maintain 90-degree ankle position
Fingers
- Buddy-tape the broken finger to an adjacent uninjured finger using cloth strips or tape
- Place a small pad between the fingers to prevent skin maceration (moisture damage)
- For severely displaced finger fractures, use a small stick or tongue depressor as a dorsal splint, padded and taped in place
Collarbone (Clavicle)
- Cannot be splinted directly — the collarbone sits under the skin with no good anchor points
- Use a sling to support the arm on the injured side
- Add a swath (broad wrap around the arm and torso) to prevent the arm from swinging outward
- These fractures generally heal well with simple immobilization
Common Splinting Mistakes
| Mistake | Consequence | Prevention |
|---|---|---|
| Splint too short | Does not immobilize joints above and below; fracture still moves | Measure before applying — span from joint to joint |
| No padding | Pressure sores, nerve compression, pain | Always pad between rigid material and skin |
| Tied too tight | Cuts off circulation, causes tissue death | Check that a finger slides under each tie; recheck circulation after |
| Tied over fracture site | Extreme pain, bone displacement | Tie above and below, never directly over the break |
| Not rechecking circulation | Swelling increases after splinting, ties that were fine initially become too tight | Check every 30 minutes for the first 2 hours, then every few hours |
| Removing the splint to “check” the fracture | Displaces healing bone, restarts pain cycle | Leave the splint in place; check circulation at fingers/toes instead |
| Splinting in an unnatural position | Joint contracture, poor healing alignment | Splint joints in functional position (elbow 90 degrees, wrist neutral, ankle 90 degrees) |
When to Resplint
Remove and reapply a splint only when necessary:
- Circulation is compromised and loosening ties is not sufficient
- The splint has broken or shifted and no longer immobilizes the fracture
- You need to check or treat the wound under the splint (open fractures)
- Swelling has decreased significantly and the splint is now too loose to provide support
When resplinting, have an assistant maintain manual stabilization of the fracture while you work. Never leave the fracture unsupported during the transition.
Key Takeaways
- Every splint must immobilize the joint above AND the joint below the fracture — no exceptions
- Padding between the splint and skin prevents pressure sores and nerve damage
- Check circulation (pulse, sensation, movement) after every splint application and every 30 minutes for the first 2 hours
- Never tie directly over the fracture site
- Almost anything rigid and long enough can serve as a splint — sticks, boards, bark, rolled magazines, trekking poles, or even the patient’s own body