Anatomical illustration of a section of the cranium and face showing the Meatus Externus (a), the Membrana Tympani (b), and Eustachian Tube (c). The anterior part of the Meatus Externus is opened from the beginning of the Tragus to the Membrana Tympani, which lies at the bottom, and separates it from the Tympanum. The anterior part of the Eustachian Tube is opened, and a probe lies in it, and passes from its orifice in the upper and lateral part of the Pharynx into the Tympanum, which is left unopened. The head of the probe serves to mark the aperture of the right nostril in the Pharynx.
