1.NounA sympathetic nerve that originates in the carotid plexus, passes through the cartilage of the Eustachian tube, joins with the greater petrosal nerve at the entrance of the pterygoid canal to form the Vidian nerve, and as part of this nerve passes through the pterygopalatine ganglion without forming synapses to be distributed to the mucous membranes of the nasal cavity and palate.