cribriform fossa coronoid ventricle anterior Eustachian mastoid scalae meatus posterior urogenital medial concavity tympani sphenoidal urethra zygomatic sphenopalatine arytenoid petrotympanic squama sulcus fasciculus oblongata lacrimal ends cavity sinus clinoid otitis diaphragm aponeurosis perilymph malleus fissure infratemporal glottis ethmoidal basilar