NOT a relation of sphenoid sinus:
Structures related to sphenoid sinus are foramen rotundum (maxillary nerve), optic canal (optic nerve and ophthalmic artery), vidian canal (with nerve), internal carotid artery.
 Mandibular nerve is not related to sphenoid sinus.
Optic nerve
Mandibular nerve
Maxillary nerve
Vidian nerve