Facial nerve paralysis. Facial nerve paralysis most commonly causes a unilateral, but sometimes bilateral, paralysis of the muscles responsible for facial expression. Patients often present unable to move the lip or blink and with a droopy ear and severe ptyalism.
The Fourth World is an extension of the Three-World Model, used variably to refer to. Sub-populations socially excluded from global society; Hunter-gatherer, nomadic, pastoral, and some subsistence farming peoples living beyond the modern industrial norm.
Fourth generation warfare (4GW) is a concept defined by William S. Lind and expanded by Thomas X. Hammes, used to describe the decentralized nature of modern warfare. The simplest definition includes any war in which one of the major participants is not a state but rather a violent ideological network.