Apparatus for protecting a user from impacts to the head. The apparatus includes a shell configured to receive a human head and a plurality of structures attached to the outer surface of the shell. Each structure includes an outer cell that absorbs direct impacts. Each structure is independently coupled to the shell with a respective assembly. The structures move independently of one another and are restricted to sliding tangentially along the outer surface of the shell. The assemblies each include a biasing mechanism that absorbs tangential impacts to the structure and returns the respective structure to its rest position. Thus, a user is protected from the concussive effects of a head-on impact and the rotational acceleration injuries of a tangential impact.