The inventory icon for the Severed Hand exists in the files; it appears to be a recycled image for the same item from Frictional Games's Penumbra: Black Plague. The only evidence of its purpose is a cut puzzle involving combining two hand items to make a "gauntlet", which may have been used to unlock a door somehow. This was either a test or never made it very far beyond the basic concept, and the item icon itself was likely just a placeholder.
