Dural defects of the temporal bone.

Cerebrospinal fluid leakage (otorrhea or otorhinorrhea) from the temporal bone is the end result of rupture of the arachnoid membrane or herniation of the brain through a defect in the protective dura mater and calvarium. The rupture may be small, admitting only a herniation of arachnoid (meningocele), or be large enough to accommodate brain tissue (encephalocele). Flow of cerebrospinal fluid through either type of fistula may be a trickle or profuse, chronic or intermittent, and usually ceases temporarily for a few weeks following an attack of meningitis. The etiology, anatomy, signs and symptoms, and various methods of treatment for cerebrospinal fluid otorrhea and otorhinorrhea are discussed.