It is called a swath or binder.
A splint and sling are what immobilize the extremity.
Swathe
Swathe
Swathe
Cloth or improvised swathes of fabric. SABC-Swathe
Cloth or improvised swathes of fabric. SABC-Swathe
Cloth or improvised swathes of fabric. SABC-Swathe
Cloth or improvised swathes of fabric. SABC-Swathe
Cloth or improvised swathes of fabric. SABC-Swathe
Cloth or improvised swathes of fabric. SABC-Swathe
Swathe
Swathe