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Long Arm Posterior Splint

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Other Names

Illustration of the plaster slab in the posterior long arm splint[1]
Step-by-step instructions for the posterior long arm splint[3]
Prefabricated posterior long arm splint[4]
  • Posterior Long Arm Splint
  • Above Elbow Back Slab
  • Long Arm Posterior Splint


  • This page refers to the posterior long arm splint
  • Note that it does not completely eliminate supination/pronation




  • Absolute contraindications
    • None
  • Relative contraindications
    • Open fractures
    • Injuries with neurovascular compromise




  • Measure splint materials using unaffected arm
    • Splint extends from palmer crease up to mid-proximal humerus (about 3 inches below axilla)
    • Use 8-10 layers for the upper extremity


  • See: General Splinting Technique
  • Positioning
    • Elbow is flexed at 90°
    • Forearm is supinated or neutral
    • Wrist maintained in slight extension at 10 to 20°.
    • Unless needed, motion at MCP joints and thumb should be unrestricted
  • Stockinette
    • Apply stockinette
    • Should extend 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.
  • Cast padding
    • 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
    • Place cotton padding over the olecranon to prevent pressure over this bony prominence
    • Avoid excessive bulk in the antecubital fossa
  • Splint application
    • Splinting material should be laid out ahead of time
    • It should be just shorter than the area covered by the padding.
    • 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
    • Continue past the elbow and along the ulnar surface of the forearm and finish at the metacarpals.
  • Elastic wrap
    • 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
    • Overlap each revolution by half the width of the elastic wrap.
    • Smooth out the splinting material using your palms rather than your fingertips
    • Maintain appropriate level of compression until splinting material hardens
  • Check the distal neurovascular status
  • Place the patient in a shoulder sling to support shoulder

Pearls and Pitfalls

  • Alternative patient positioning
    • Appropriate only for certain stable fractures
    • This splint can be applied with the patient prone
    • The injured arm is hanging off stretcher with elbow at 90°
  • Be sure to apply extra padding on the olecranon process


  • Try to elevate extremity for the first few days to prevent more swelling
  • Advise patient to keep cast or splint clean and dry
  • Do not insert objects into splint/ cast
  • Monitor for complications (worsening pain, paresthesia/ numbness, color changes)
  • Seek further care if unable to control pain at home


  • Plaster burn/ thermal injury
  • Pressure sores
    • The epicondyles and olecranon process are particularly vulnerable.
  • Nerve palsy
    • Use extra padding to protect the subaxillary area.
    • The ulnar nerve is vulnerable to compression at the posterior lateral epicondyle
    • The radial nerve is vulnerable at the anterior medial epicondyle.
  • Vascular compromise
    • The axillary/brachial artery is vulnerable to compression from bone fragments, swelling, or splinting.
  • Splint dermatitis
  • Permanent joint stiffness

See Also


  1. Gluck, Matthew J., et al. "Comparative strength of elbow splint designs: a new splint design as a stronger alternative to posterior splints." Journal of Shoulder and Elbow Surgery 28.4 (2019): e125-e130.
  2. Hodax, Jonathan D., Adam EM Eltorai, and Alan H. Daniels, eds. The Orthopedic Consult Survival Guide. No. 25571. Springer International Publishing, 2017.
  3. mage courtesy of NHS "Practical Guide to Casting", https://heeoe.hee.nhs.uk/sites/default/files/practical_guide_to_casting_0.pdf
  4. Image courtesy of ncmedical, "https://www.ncmedical.com/wp-content/uploads/2011/07/Long-Arm-Precut-Splint_11.pdf"
Created by:
Jesse Fodero on 10 July 2019 18:47:47
Last edited:
25 June 2023 16:10:12