ABSTRACT

The horizontal recti are the largest eye muscles with cross-sectional areas of about twice that of the oblique muscles. M. Hines observed that some of the fibers in rabbit eye muscle appeared to terminate abruptly, but R. D. Lockhart and W. Brandt and S. Cooper and P. M. Daniel favored the concept of tapering fibers that run the whole length of the muscle. Most of the electrophysiological studies of eye muscle have been made using cats or rabbits, and fibers have been divided into two basic groups: fast and slow contracting. A number of subcategories have subsequently been made based on the internal structure of the fibers and where they are placed within the two main cellular zones of eye muscle, the orbital region and global region. Eye fibers are adapted for a steady type of contraction. For a detailed description of the structure and function of extraocular muscle fibers, see D. J. Chiarandini and J. Davidowitz.