THE AMERICAN MEDICAL JOURNAL SAINT LOUIS. LIBRAI EDITED BY GEO. C. PITZER, M. D., Professor of the Theory and Practice of Medicine in the American Medical College, St. Louis : as a Food, a Medicine, a Poison, and as a Luxury." VOL. XIII., 1885. ST. LOUIS, MO.: Commercial Printing Company, 200 and 202 S. Fourth Street, cor. Elm. 1885. 409. LIBRARY AMERICAN MEDICAL JOURNAL. VOL. XIII. JANUARY, 1885. ORIGINAL COMMUNICATIONS. No. J. ART. I. The Membrana Tympani.-By O. A. PALMER, M. D. The tympanic membrane (see Fig. 1) is at the inner extremity of the auditory canal, and is inclined forward, downward and inward in adults, but in children it is more slanting, so that during infantile life it is difficult to see it. It is oval in form, its vertical diameter being about five lines and its transverse four lines. It is depressed inwards, causing its external surface to present a concav Fig. 1. A. Auditory Canal. B. Membrana Tympani. ity, at the apex of which is seen the handle of the malleus. It is composed of an external dermic layer that has no glands or hairs, a middle fibrous and internal mucous layer. The fibrous has an external and internal layer. Between these two layers is the long handle of the malleus and the short process. The long process moves in a groove, like an enarthrodial |