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How To Apply a Long Arm Splint


Miranda Lewis

, MD, University of Washington

Reviewed/Revised Jul 2021 | Modified Sep 2022
Topic Resources

Long arm splints are devices applied for elbow and proximal forearm injuries in order to limit flexion and extension of the elbow.

Long arm splints are used for certain injuries requiring immobilization of the elbow. They limit flexion and extension of the elbow but are not adequate to prevent supination or pronation of the forearm.


  • Distal humerus fracture

  • Olecranon fracture

  • Proximal radius and ulna fractures

  • Elbow dislocation (after reduction)


Absolute contraindications

Relative contraindications

  • None



  • Stockinette (enough to cover the area from mid-humerus to the metacarpals)

  • Roll padding (eg, cotton roll) 7.5-cm (3-inch) width

  • Plaster or fiberglass splinting material, 7.5- to 10-cm (3- to 4-inch) width—wide enough to cover the posterior surface of the humerus and long enough to extend from mid-humerus along the ulnar surface of the forearm to the metacarpals

  • Strong scissors and/or shears

  • Elastic bandage, usually 10-cm (4-inch) width

  • Lukewarm water and bucket or other container

  • Nonsterile gloves


  • The patient should be positioned so that the operator has appropriate access to the patient's affected arm.

  • The elbow should be maintained flexed at 90°.

  • The forearm should be supinated with the palm facing the patient.

  • The wrist should be maintained in slight extension at 10 to 20°.

  • Unless there is an injury requiring additional immobilization, the splint should allow unrestricted motion of the MCP joint and thumb.

Step-by-Step Description of Procedure

  • Wear nonsterile gloves.

  • Apply stockinette, covering the area from the proximal third of the humerus to the metacarpals.

  • Make a hole in the stockinette to allow for protrusion of the thumb. Smooth the stockinette to ensure there are no folds in the material.

  • Wrap the padding from the MCP joint to the proximal third of the humerus slightly beyond the area to be covered by the splint material; overlap each turn by half the width of the padding and periodically tear the wrapping across its width to decrease the risk of tissue compression.

  • Place additional short strips of cotton padding over the olecranon to prevent pressure over the bony prominence. Avoid excessive bulk in the antecubital fossa.

  • Smooth the padding as necessary to avoid protrusions and lumps. Tear away any excess padding to prevent areas of localized pressure on the skin.

  • Lay out a length of splint material matching the distance from the MCP joint to the posterior humerus along the ulnar surface of the forearm—it should be just shorter than the area covered by the padding.

  • Unroll additional splint material, folding it back and forth along the first length until there are 8 to 10 layers (when using single-layer rolls).

  • Alternatively, if using ready-made splint material, cut a single piece to the above length.

  • Immerse the splinting material in lukewarm water.

  • Squeeze excess water from the splinting material (do not wring out plaster).

  • Apply the splint material to the posterior humerus and continue past the elbow and along the ulnar surface of the forearm and finish at the metacarpals.

  • Fold the extra stockinette and cotton padding over to cover all the edges of the splinting material.

  • Wrap the elastic wrap over the splinting material distally to proximally and overlap each revolution by half the width of the elastic wrap.

  • Smooth out the splinting material using your palms rather than your fingertips to conform to the contour of the arm to fill in the interstices in the material.

  • Maintain the elbow at 90° flexion and the wrist in neutral position with the palm facing the patient until the splinting material hardens.

  • Check the distal neurovascular status (eg, capillary refill, distal sensation, finger flexion and extension).

How To Apply a Long Arm Splint


  • Advise the patient to keep the splint dry.

  • Arrange or recommend appropriate follow-up.

  • Provide a sling to support the arm.

  • Instruct the patient to watch for complications such as worsening pain, paresthesias/numbness, and color change to the fingers.

  • Instruct the patient to seek further care if pain cannot be controlled with oral drugs at home.

Warnings and Common Errors

  • Be sure not to let the elbow joint relax while the splint hardens so that the 90° flexion angle is lost.

  • Ensure padding and elastic wraps are not applied too tightly.

  • Excessive padding may allow for movement and loss of reduction over time as swelling resolves.

  • Additional padding may be needed over bony prominences, particularly the olecranon and ulnar styloid.

  • Avoid excessive padding in flexural creases such as the antecubital fossa.

  • Avoid irregular contours and potential pressure spots by using the palms of your hands rather than the fingertips to smooth out the splinting material.

  • Make sure the stockinette and padding material are smoothed out so there are no pressure points before applying the splint material.

Tips and Tricks

  • Warm water makes plaster set more quickly, so if you are unfamiliar with applying splints use cooler water to increase your working time.

  • The top and bottom edges of the splint may poke the skin, so roll them over slightly.

  • Because this splint is lengthy, consider recruiting an assistant to help support the plaster material as it is being applied. Alternatively, if no assistant is available, a few short lengths of cotton padding can be loosely applied circumferentially around the proximal and distal aspect of the splint to help hold the wet plaster in place as you apply the elastic wrap.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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