Place the extremity in a neutral position
Use an elastic or crepe bandage to wrap the entire affected extremity (distal to proximal)
Wrap very firmly, with the same<unk>  used to splint a sprain, but not so much as to obstruct distal pulses.
Continue to wrap the extremity to a rigid splint (ie. dowel) to immobilize.
Extricate the patient
Pressure immobilization dressing
Posterior ankle splint
Stirrup splint
Vacuum splint
Sling and swathe splint
Long leg posterior splint
Hair tourniquet
Ulnar gutter splint