The Animal Kingdom (Volume 2); Considered Anatomically, Physically, and Philosophically (Paperback)

This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1844. Not illustrated. Excerpt: ... CHAPTER II. THE LARYNX AND THE EPIGLOTTIS. 353. Heister. "The larynx is the thick upper part or head of the trachea. It contains an aperture leading to the lungs, termed the glottis, which is nearly elliptical, and furnished with cartilages and muscles, by means of which it is dilated or straightened, so as to produce the wonderful variations of the voice in speaking and singing. The larynx is principally composed of cartilages, which are five in number. The first is the thyroid or scutiform cartilage: it is a kind of quadrangle, and is placed in the anterior part of the neck, where it forms the prominence commonly called the pomum Adami. The thyroid is the largest of the five cartilages. The second is the cricoid or annular cartilage: this may be considered as the base of the rest, occupying the lowest situation: the trachea is adherent to it inferiorly. The third and fourth are the two arytaenoid cartilages; these form a kind of basin, of a singular figure: they are connected by peculiar articulations on each side, to the posterior and superior parts of the cricoid cartilage, to enable the glottis the more readily to be constricted and dilated. The fifth is the epiglottis; this is often of the shape of a leaf of ivy, and is joined to the superior and anterior part of the thyroid cartilage, over which it stands erect immediately behind the root of the tongue: and it is connected thereto by its middle ligament, but by its two lateral ligaments to the cornua of the os hyoides, and by its two posterior ligaments to the arytaenoid cartilages. The epiglottis in the act of deglutition covers the glottis in the manner of a moveable bridge, and prevents anything from falling into it. The membrane which invests the larynx is very sensitive, and perforated with a great n...