21. Clearance of keratin can be disrupted by tympanic membrane retraction so that keratin accumulates within the retraction pocket. 22. If there is less inflammation, the cholesteatoma may present the appearance of'semolina'discharging from a defect in the tympanic membrane . 23. The apex of the cone is at the most depressed part of the tympanic membrane , known as the umbo. 24. Pakicetids could hear under water, using enhanced bone conduction, rather than depending on tympanic membranes like most land mammals. 25. In 1855 Rinne described the combined conductive process of the tympanic membrane and the ossicles of the middle ear. 26. As the nerve travels between the brain and the tongue, it passes right under the eardrum, the tympanic membrane . 27. Shining light on the tympanic membrane causes a cone-shaped reflection of light to appear in the anterior inferior quadrant. 28. Tympanic membrane retraction is fairly common and has been observed in one quarter of a population of British school children.29. When a tympanic membrane is concave does it remain so or does it self-correct over time or require medical intervention? 30. Attempts have been made to categorise the extent of tympanic membrane retraction though the validity of these classifications is limited.
