<prompt> CSF Rhinorrhea occurs dtRoof of orbitFrontal sinusCribriform plate of ethmoid boneSphenoid bone  <response>: Commonest area of causing CSF Rhinorrhea cribriform plate of ethmoid bone as it is extremely thin.Other possible areas of causing CSF Rhinorrhea Frontal sinus Posterior wall or of the anterior cranial fossa.Difference between CSF Rhinorrhea allergic or vasomotor rhinitis CSF contains glucose which can be demonstrated by chemical tests.CSF when collected into a test tube and allowed to stand, it remains clear in contradistinction to nasal discharge that leaves a sediment because of mucus and other proteins.Nasal discharge stiffens the handkerchief and CSF dries soft in it.Treatment: Prophylactic antibiotics X-ray If more than 2 wks then correct it surgically. 