THE PATHWAY OF SYMPATHETIC NERVES TO THE CILIARY MUSCLES IN THE EYE

Abstract

Sympathetic fibers to the eye, stimulation of which causes the ant. face of the lens to flatten, emerge from the spinal cord in the ventral roots mainly of the 1st 2 thoracic nerves in the cat, dog, and monkey. In the monkey, the 8th cervical and the 3rd thoracic ventral roots also contain these sympathetic fibers to the ciliary muscle. In the cat and rabbit, these fibers synapse in the superior cervical ganglion and postganglionic fibers reach the eye via the 2 long ciliary nerves. Whether the short ciliary nerves contain such fibers has not yet been demonstrated. These fibers to the ciliary muscle follow a pathway nearly identical with that for pupillo-dilator fibers.