A guide to the study of ear disease / by P. Mcbride.

  • McBride, P. (Peter), 1854-1946.
Date:
[1884]
Catalogue details

Licence: Public Domain Mark

Credit: A guide to the study of ear disease / by P. Mcbride. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

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    and called incisurse Santorinianse. Just where these occur, the meatus is bounded by the parotid gland, so that it is possible for a parotid abscess to open into the external auditory canal. The cartilaginous is united to the osseous portion by means of connective tissue. This is fortunate; for while the axis of the former runs from without inwards and upwards, that of the latter is directed downwards and forwards. It therefore follows that traction of the auricle—and with it the outer portion of the meatus— upwards and backwards will convert the canal into a straight tube, and so enable the surgeon to inspect its deeper portions, including the drum membrane. The osseous or inner portion of the meatus presents few anatomical features of practical interest. Its anterior and inferior walls bulge more or less into the lumen of the tube, and in some individuals this is so marked, that it is well-nigh impossible to inspect the whole surface of the membrana tympani. Further inwards this convexity is succeeded by a concavity, which, with the membrane, forms a space (sinus of the external auditory canal) in which small and heavy foreign bodies may become lodged. The most important relations of the external meatus are as follows :— (1.) Anteriorly and inferiorly lie the parotid gland, and the temporo-maxillary articulation. (2.) Superiorly the osseous meatus is separated from the dura mater by a double layer of bone with inter- vening air spaces. Sometimes, however, only a single very thin plate exists. (3.) Posteriorly are the mastoid cells with an inter- vening lamella of compact bone. The lining membrane of the external auditory canal consists of true skin, which in the cartilaginous portion