A splint assembly for use with an individual's limb including an assembleable and rigid member positioned in surrounding fashion about an intermediate joint associated with the limb. A pair of support subassemblies secure about a location of the individual's limb contiguous to the joint, an extending edge of each support subassembly securing to a perimeter extending edge of the rigid member. Upper and lower wraparound support subassemblies secure to first and second perimeter extending edges associated with the rigid member, each further including a generally grid and web-shaped foam template with a hardened plastic backing being configured to match the configuration of the foam template. Edge extending straps provided for each of the hardened plastic backings overlap and engage opposite extending edge locations of each wraparound support subassembly.