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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    mucous membrane derives its nerves from the tym- panic plexus, and the stylo-mastoid artery famishes the blood supply. The Eustachian tube is a canal composed partly of bone and partly of cartilage and fibrous tissue, and unites the cavity of the tympanum with the pharynx. The osseous portion is about half an inch long, begin- ning in the anterior wall of the tympanum, and ex- tending downwards and forwards. The cartilaginous portion is about an inch in length, and extends from the osseous part, to which it is firmly attached, to the pharynx, where it ends in a trumpet-shaped opening almost on a level with the inferior meatus of the nose. This portion of the tube is formed by cartilage internally, superiorly, and to some extent externally, the remainder being membranous. This arrangement results from the fact that the cartilage is hook-shaped on transverse section. The whole tube is lined by mucous membrane, which is ciliated, and glands are found in considerable numbers towards the pharynx. There are three muscles which act especially upon the Eustachian tube :— (1.) The dilator tubae or tensor palati mollis arises among other parts from the tip of the free edge of the cartilage of the tube, and passing round the hamular process of the sphenoid goes to the soft palate. Whenever this muscle contracts it pulls the cartilaginous lip outwards, and so causes the tube to gape. (2.) The levator palati lies below the tube, and by its contractions pushes up the floor, so tending to widen its calibre. (3.) The salpingo pharyngeus is a delicate muscular band which connects the posterior wall of the carti- laginous part of the tube to the pharynx. Its