The vidian nerve is formed from the greater/large superficial petrosal nerve of CN V (sympathetics) and the deep petrosal branch (parasympathetics). (There's also an ascending sphenoid branch from the otic ganglion).
The vidian canal transmits the nerve from the foramen lacerum to its exit at the pterygopalatine fossa.
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| Tracing the vidian canal superior to inferior. It originates at the pterygopalatine fossa (arrow) and proceeds through the skull base (circle). The branch point in the third image represents the take-off of the GSPN into the middle ear through the "hiatus" of the greater "superficial" petrosal nerve (longer left branch). The smaller branch represents the deep petrosal nerve joining the GSPN with its post synaptic carotid nerve fibers. |
Three variations of the vidian canal have been described with varying degrees of bony coverage (below).
Incidentally, The term vidian is derived from an anatomist, "Vidus."