Femoral mononeuropathy induced by the lithotomy position: a report of 5 cases with a review of literature.

We report 5 young women who developed femoral mononeuropathy (FMN) after placement in the lithotomy position. Three had uncomplicated vaginal deliveries and 2 underwent exploratory laparoscopies. EMG was performed on 3 patients. The lesions were localized to the inguinal ligament and probably demyelinating, accounting for their excellent prognosis. On reviewing the literature, however, we believe that lithotomy position can cause FMN, not only by nerve compression at the inguinal ligament, but also by stretching of the nerve by excessive hip abduction and external rotation.