Current status of muscle biopsy in facial paralysis.

The six abnormalities found in pathologic muscle biopsies are described and discussed. Those changes which are indicative of nerve denervation or muscle regeneration are tabulated. Muscle biopsy, as it related to facial paralysis, must still be considered, for the most part, an experimental tool. In certain puzzling situations, eg, neonatal facial paralysis, it can be of value as an adjunct to nerve excitability and electromyographic tests.