It is fairly generally accepted that, in man, the main nervous supply of the lacrimal gland is of parasympathetic origin and that it emerges from the bulbar region together with the seventh cranial nerve. Leaving the facial nerve at the level of the geniculate ganglion, the secretory fibers join the great superficial petrosal and the vidian nerve to reach the sphenopalatine ganglion. From the ganglion they travel with the sphenopalatine nerves to the maxillary nerve. They reach the gland by way of the zygomatic and zygomaticotemporal nerve, which communicates with the lacrimal nerve.
It is believed that, whereas all other nerve fibers pass through the sphenopalatine ganglion uninterrupted, the secretory fibers destined for the lacrimal gland synapse in the ganglion. This assumption, which seems to be based on histological work of L. R. Müller (1924), fits well into our general concept of the building-scheme of the parasympathetic nervous system whose
de HAAS EBH. Lacrimal Gland Response to Parasympathicomimetics After Parasympathetic Denervation. AMA Arch Ophthalmol. 1960;64(1):34-43. doi:10.1001/archopht.1960.01840010036002