Observations on the innervation of human extraocular muscles.

The innervation of human extraocular muscles (EOM) was studied using a comprehensive histological and histochemical approach. In contrast to previous concepts, we have demonstrated that the coarse felderstrucktur muscle fibers are singly innervated by en plaque endings and that the fine and granular fibrillenstruktur fibers are multiply innervated by en grappe endings. Each of the fine and granular fibers is innervated by a single thin axon that travels along the fiber and sends collaterals to the en grappe endings. These findings may provide a new basis for the correlation of morphological and physiological properties of EOM.