Perilymph fistulas caused by myringotomy.

Two cases of rupture of the round window membrane verified by operation are presented. Both cases arose in connection with myringotomy and were presumably caused by a violent force acting directly on the tympanic membrane and the ossicles. This would result in a strong movement of the stapes and an acute change in the perilymph pressure, thereby causing an indirect injury to the round window. Symptoms and treatment are briefly discussed.