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.
The Fourth Crusade is considered to be one of the more prominent oppressive acts in the Great Schism between the Eastern Orthodox Church and Roman Catholic Church, and a key turning point in the decline of the Byzantine Empire and Christianity in the Near East.