Enlarged View of the Right External Acoustic Meatus. The spine of Henle, located along the posterosuperior margin of the external canal, is positioned superficial to the deep site of the lateral semicircular canal and the junction of the tympanic and mastoid segments of the facial nerve. The mastoid antrum is positioned deep to the superficial depressed area, called the suprameatal triangle, located above and behind the spine of Henle. The medial wall of the tympanic cavity is the site of the promontory, which overlies the basal turn of the cochlea and the oval and round windows. The footplate of the stapes sits in the oval window. The round window is separated from the cochlea by a thin membrane. (Image courtesy of AL Rhoton, Jr.)