Two different unusual cases of acute sciatic neuropathy are described. They appeared to have been caused by complications from a procedure performed on a patient in the lithotomy position, and an uncertain etiology associated with either a previous femur fracture or a recent blunt trauma to the buttock. Comprehensive histories of weakness, with radiographic or electrophysiological studies, or even exploratory surgery are important in order to understand the etiologies of the sciatic neuropathies.