peripheral afferent fibers were grouped into two major classes : thick ( mean diameter 1.7 micron ) radial fibers projecting in a primarily radial fashion from the spiral ganglion and terminating on single inner hair cells and thin ( mean diameter 0.5 micron ) outer spiral fibers that spiral basalward in the organ of corti to terminate on outer hair cells , usually in one row .
C0018497
inner hair cells
C0029207
spiral