Observations on the physiology of the larynx / by John Wyllie, M.D.

  • Wyllie, John.
Date:
1866
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the physiology of the larynx / by John Wyllie, M.D. Source: Wellcome Collection.

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

    14/30 (page 12)
    A laryngoscopic examination fully confirms the view which I have just stated. The following phenomena may then be ob- served :— 1^^, When the glottis is simply closed^ and no effort is made either to take in breath or to expire, the false cords are separated by a very narrow interval through which the edges of the true vocal ligaments may be seen in close apposition. Idj When an effort is made to inspire^ the superior cords meet in the middle line so as to leave only a very small triangular opening posteriorly, through which there still may be caught a glimmering of the pale surface of the true ligaments. 3(f, When expiration is attempted, the false cords are immediately coaptated throughout their whole length, and if the effort made be powerful the parts above are observed to arch or curve outwards without allowing the air to escape (Czermak). This swelling out of the mucous membrane at the upper part of the larynx can be due to nothing but the inflation of the ventricles of Morgagni beneath. The physiology of these ventricles and of the superior ligaments of the larynx is thus after all so beautifully simple as to render it very surprising that their action was not long since recognised. Formerly, the difficulty no doubt lay in the impossibility of display- ing the parts in the living body. Even before the days of the laryngoscope, however, I find, on looking over the various treatises on the larynx, that among the numerous conjectures regarding their use, one shrewd guess has been made, which very nearly approaches the whole truth. In Mayo's Physiology there occurs the following passage Mr Willis has very ingeniously conjectured that the closure of the glottis takes place through the inflation of the ven- tricles from below, when the ligaments have been approximated and an expiration has been attempted. An objection, he continues, was suggested to me by Mr Wheatstone, which of itself appears fatal to Mr Willis's hypothesis;—we can close the larynx as well during inspiration as during expiration.^ I have not yet dis- covered this suggestion in Mr Willis's own writings, but it is evident that he has never thought of the true cords as preventing the entrance of air, otherwise Mayo's criticism would not have been offered. The characters of that peculiar brassy cough which exists so often in cases of aneurism of the aorta where the recurrent laryngeal nerve is involved, may, I think, be explained in the following manner. Each normal act of coughing may be divided into two stages. 1*^, The complete closure of the glottis, false and true cords to- gether, so as to enable the air to be compressed within the chest and trachea; its escape being prevented by the false cords and ventricles of Morgagni as just explained. 2dj The sudden and complete opening of the glottis, allowing at once the explosive ^ Mayo's Physiology, p. 381.