910 THE LARYNX. 



the cricoid cartilage, above with the cornicula, and in front, by means of 

 fibres contained within the true and false vocal cords, with the thyroid 

 cartilage. 



The crico-arytenoid articulations are surrounded by a series of thin capsu- 

 lar fibres, which, together with a loose synovial membrane, serve to connect 

 the convex elliptical articular surfaces on the upper border of the cricoid 

 cartilage with the concave articular depressions on the bases of the arytenoid 

 cartilages. There is, moreover, a strong posterior crico-arytenoid ligament 

 on each side, arising from the cricoid, and inserted into the inner and back 

 part of the base of the arytenoid cartilage. 



The summits of the arytenoid cartilages and the cornicula laryngis have 

 usually a fibrous and synovial capsule to connect them, but it is frequently 

 indistinct. 



The superior thyro-arytenoid ligaments consist of a few slight fibrous fasci- 

 culi, contained within the folds of mucous membrane forming the false vocal 

 cords hereafter to be described, and are fixed in front to the depression 

 between the alae of the thyroid cartilage, somewhat above its middle, and 

 close to the attachment of the epiglottis : behind, they are connected to the 

 tubercles on the rough anterior surface of the aryteuoid cartilages. They are 

 continuous above with scattered fibrous bundles contained in the aryteno- 

 epiglottidean folds. 



The inferior thyro-arytenoid ligaments, placed within the lips of the 

 glottis, and forming the true vocal cords, are two bands of elastic tissue 

 which are attached in front to about the middle of the depression between 

 the alse of the thyroid cartilage, below the superior cords ; and are inserted 

 behind into the elongated anterior processes of the base of the arytenoid car- 

 tilages. These bands are of considerable strength, and consist of closely- 

 arranged parallel fibres. They are continuous below with the thin lateral 

 portions of the crico- thyroid membrane. 



Interior of the larynx. The cavity of the larynx is divided into an 

 upper and a lower compartment by the comparatively narrow aperture of 

 the glottis, or rima glottidis, the margins of which constitute in their two 

 anterior thirds the lower or true vocal cords ; and the whole laryngeal 

 cavity, viewed in transverse section, thus presents the appearance of an 

 hour-glass, or of two funnels meeting together by their narrower ends. 

 The upper compartment communicates with the pharynx by the superior 

 aperture of the larynx, and contains immediately above the rima glottidis 

 the ventricles and the upper or false vocal cords. The lower compartment 

 passes inferiorly into the tube of the windpipe without any marked con- 

 striction or limitation between them (Fig. 638). 



The superior aperture of the larynx, by which it communicates with the 

 pharynx, is a triangular opening, wide in front and narrow behind, the 

 lateral margins of which slope obliquely downwards and backwards. It is 

 bounded in front by the epiglottis, behind by the summits of the arytenoid 

 cartilages and cornicula laryngis with the angular border of mucous mem- 

 brane crossing the median space between them, and on the sides by two 

 folds of mucous membrane named the aryteno-epiglottidean folds, which, 

 enclosing a few ligamentous and muscular fibres, pass forwards from the 

 tips of the arytenoid cartilages and cornicula to the lateral margins of the 

 epiglottis (Fig. 637). 



In studying the form of the laryngeal cavity and its apertures, it is 

 proper to become acquainted with the appearances which they present on 

 examination during life by means of the laryngoscope, and with the relations 



