Oculomotor parasympathetic pathway to the accessory ciliary ganglion bypassing the main ciliary ganglion by way of the trigeminal nerve.

When an HRP or WGA-HRP solution was injected into the rostral midbrain including the oculomotor visceral nuclei, densely distributed HRP/WGA-HRP-positive granules were observed around the ganglion neurons in the accessory ciliary ganglion (ACG) and ectopic neurons in the communicating branch from the long ciliary nerve to the ACG. The same injections labeled fibers within the communicating branch as well as the fibers between the ACG and the main ciliary ganglion (CG). These findings indicate that some oculomotor parasympathetic preganglionic fibers reach the ACG bypassing the CG by way of the trigeminal nerve.