Diseases of the larynx / by Dr. J. Gottstein ... trans. and added to by P. M'Bride.

  • Gottstein, Jacob, 1832-1895.
Date:
[1883]
Catalogue details

Licence: Public Domain Mark

Credit: Diseases of the larynx / by Dr. J. Gottstein ... trans. and added to by P. M'Bride. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    fixes the whole larynx, or, more especially, one of the two larger car- tilages (thyroid or cricoid). The first of these three mnscles, the sterno-thyroid, contains a number of long fibres, which are attached to the posterior part of the thyroid cartilage behind its articulation with the cricoid, thus making it possible for it to raise the anterior part of this cartilage, and so to produce relaxation of the vocal cords. The posterior crico-arytenoid muscles or abductors act as enlargers of the glottis, and on their proper fulfilment of this function human life is often dependent. They arise on either side from the inferior half of the posterior surface of the plate of the cricoid, and, their fibres converging, run obliquely upwards and outwards, to be inserted into the posterior and lateral margin of the processus muscularis of the arytenoid ; through their contraction, the cartilage is fixed inwards and backwards, rotated round its long axis, and thus the vocal process is turned outwards and the glottis opened. A small external portion of this muscle, which runs more or less perpendicularly, may draw the arytenoid outwards and downwards. As antagonists of the last-named muscle, that is, as closers of the glottis (adductors), several muscles act, but more especially the lateral crico-arytenoid, which, arising from the upper margin of the side of the cricoid, passes backwards and upwards, and is inserted into the lateral surface of the muscular process; as it draws the arytenoid outwards and downwards, and thus rotates the point of the vocal process inwards, it closes the glottis, and more especially its ligamentous portion. The action of this muscle is aided and increased by (1) the transverse muscle (musculus transversus), which is stretched horizontally between the two lateral margins of the aiwtenoids, and by its contraction so approximates the two cartilages that their inner surfaces, and more especially the posterior inferior parts of these which principally compose the cartilaginous portion of the vocal cords, are in apposition. (2) The thyro-arytenoid (the vocal muscle proper), which passes backwards from the lower half of the inner surface of the thyroid, near its receding angle, in two portions, which are described by some anatomists as separate muscles (externus and interims), to be inserted into the Lateral margin of the arytenoid. While the fibres which run from before back- wards approximate the points of insertion of the vocal cord, the tension of the latter necessary for the production of various notes is regulated by the amount of their contraction ; ;it the same time, the voca] cords are approximated to one another, and thus, in other words, the muscle gives to the vocal cord as a whole both the position necessary for phona tion and the proper amount of tension. A tew fibres of the outer portion of this muscle Bpread outwards towards the ventricular hands, and by this means these may he approximated The Crico-thyroid muscle acts to a certain extent as an antagonist to