How to Splint a Broken Arm With Cardboard

To immobilize a broken arm, make sure to immobilize the fracture site as well as the joints above and below the fracture.

Cardboard splints work very well for splinting broken arms in the field.


Items You'll Need

Items for splinting a broken arm
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To adequately splint a broken arm, you will need a cardboard splint, towels for padding, bandage scissors, roller gauze, and tape. Other items can be used to immobilize the broken arm. Anything that secures the broken arm and immobilizes it will work.


Assess the Break

Assessing a broken arm
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Determine the location of the broken bone and assess the arm to make sure victim can still move fingers, feel touch, and has circulation to his or her hand.

Assess the broken arm by feeling the area of the broken bone. Deformity, crepitus (a grinding feeling under the skin), or discoloration may be present in the area of the fracture. In most cases, the victim will just feel pain and tenderness near the injury.

Assess the victim's circulation, sensation, and motion in the hand.

  • Ask the victim to identify which finger is being touched.
  • Ask the victim to move fingers.
  • Feel the victim's fingers to see if they are as warm as the hand on the unbroken arm.

Cut the Splint to the Correct Size

Cutting a cardboard splint
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If the cardboard is too long, cut it to size. In this case, cuts are made to help shape the splint.


Shape the Splint to the Arm

Folding a cardboard splint
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Shape the splint to fit the broken arm by folding the splint to wrap around the arm.


Bend the Splint to Fit Around the Elbow

Bend the splint up around the elbow
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After the splint is cut, bend the splint up to fit around the elbow.


Fold the Remaining Flaps to Finish

Folding a cardboard splint
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Finish the splint by folding the remaining flaps around and tape them in place.


Pad the Splint

Padding a splint with towels
Rod Brouhard

Pad the splint with towels or other padding before placing it on the broken arm.


Position the Arm in the Splint

Fit broken arm into padded splint
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Correctly position the broken arm into the padded splint. Make sure fit is snug, but not tight.


Maintain Position of Function

Roller gauze in hand maintains correct position
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Put something in the victim's hand (like a roll of gauze) to maintain the position of function. The position of function is achieved when the fingers are slightly curled.​


Fill the Voids

Additional padding fills voids around broken arm
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Fill all voids (spaces) between the broken arm and the splint with additional padding. The rule: avoid the voids.


Secure the Splint Around the Arm

Use tape or gauze to secure the splint in place
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Secure the splint around the broken arm with tape or roller gauze.

Wrap the splint snugly around the broken arm. The splint should support the broken arm on all sides and immobilize the arm above and below the broken bone. In this example, the broken arm is immobilized from the elbow to the wrist.


Check Arm for Movement

A top view of the splint
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Once the splint is attached, the broken arm should be securely immobilized and should not be able to move.


Reassess Functionality

Check function of the hand after splinting the broken arm
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After the broken arm is secured in the splint, reassess the hand to determine if function and circulation are still intact. Recheck circulation, sensation, and motion.


Reduce Swelling With Ice

A cold pack reduces swelling
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Place ice or a cold pack on the injury to reduce swelling. For chemical cold packs, follow the manufacturer's directions. Never place ice directly on skin.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Honsik K, Boyd A, Rubin AL. Sideline splinting, bracing, and casting of extremity injuries. Current Sports Medicine Reports. 2003 May 1;2(3):147-54. doi:10.1007/s11932-003-0048-8

  2. American Academy of Orthopaedic Surgeons. Emergency Care and Transportation of the Sick and Injured. United States: Jones & Bartlett Learning, LLC.

  3. National Ski Patrol, N. S. Outdoor Emergency Care: a Patroller's Guide to Medical Care with Navigate 2 Advantage Access. United States: Jones & Bartlett Learning, LLC.

  4. American Academy of Orthopedic Surgeons: Ortho Info. Adult forearm fractures.

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.