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How To Apply an Ulnar Gutter Splint


Miranda Lewis

, MD, University of Washington

Reviewed/Revised Jul 2021 | Modified Sep 2022
Topic Resources

Ulnar gutter splints are devices applied to immobilize fractures of the 4th and 5th metacarpal.

Ulnar gutter splints are applied along the ulnar side of the forearm and hand to immobilize the 4th and 5th digits and prevent shortening of collateral ligaments during immobilization.


  • 4th or 5th metacarpal fractures

  • Angulated or unstable proximal and middle 4th and 5th phalanx fractures

Fractures with significant angulation and/or rotation may require reduction prior to splinting.


  • None



  • Stockinette (enough to cover the area from the metacarpal phalangeal joints to the mid-forearm)

  • Roll padding (eg, cotton roll) 5 cm (2 inch) width

  • Plaster or fiberglass splinting material 7.5 cm (4 inch) width

  • Elastic bandage 5 cm (2 inch) width

  • Strong scissors and/or shears

  • 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 hand.

  • Maintain the metacarpophalangeal (MCP) joints of the 4th and 5th finger at 70 to 90° flexion, the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints in slight flexion

  • Extend the wrist to 10 to 20°.

Step-by-Step Description of Procedure

  • Wear nonsterile gloves.

  • Apply stockinette, covering the area from the mid-forearm to the metacarpals.

  • Insert padding between the 4th and 5th fingers to prevent skin maceration and then wrap padding around both the fingers.

  • Continue wrapping the padding from the MCP joint to the mid-forearm 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.

  • Smooth the padding as necessary. Tear any areas of excess padding to prevent areas of increased pressure on the skin.

  • Lay out a length of splint material matching the distance from the DIP joints of the 4th and 5th fingers to the mid-forearm 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 along the ulnar side of the 5th finger, wrist, and forearm and fold it in a U-shape around the dorsal and volar surfaces of the 4th and 5th fingers, hand, and wrist.

  • Fold the extra stockinette and cotton padding over 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 arms to fill in the interstices in the material.

  • Maintain the MCP joints of the 4th and 5th finger at 70 to 90° flexion, the PIP and DIP joints in slight flexion, and the wrist in neutral position until the splinting material hardens.

  • Do not immobilize the thumb, index finger, or middle finger in the splint.

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

How To Apply an Ulnar Gutter Splint


  • Advise the patient to keep the splint dry.

  • Arrange or recommend appropriate follow-up.

  • 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

Tips and Tricks

  • For larger patients, 3-inch cotton padding can be used for the forearm portion of the wrap.

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

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