Vertical crest of bone in the internal acoustic meatus is:

(a) Bill's bar(Ref. Shambaugh, 6th ed., page 42)Ponticulus is a ridge which runs from the oval window to the sinus tympani forming its superior extent.Cog is a bony projection from the roof of middle ear, i.e. tegmen tympani to the processus cochleariformis, serving as an approximate landmark for the facial nerve.Falciform crest divides the internal acoustic meatus into a superior and inferior part.