THE LARYNX. 959 



The ligament connecting the epiglottis with the hyoid bone is the hyo-epiglottic. 

 In addition to this extrinsic ligament, the epiglottis is connected to the tongue by 

 the three glosso-epiglottidean folds of mucous membrane, which may also be con- 

 sidered as extrinsic ligaments of the epiglottis. 



The hyo-epiglottic ligament is an elastic band, which extends from the anterior 

 surface of the epiglottis, near its apex, to the upper border of the body of the 

 hyoid bone. 



The ligaments connecting the thyroid cartilage to the cricoid are also three in 

 number the crico-thyroid membrane, and the capsular ligaments. 



The crico-thyroid membrane is composed mainly of yellow elastic tissue. It con- 

 sists of three parts, a central, triangular portion and two lateral portions. The 

 central part is thick and strong, narrow above and broadening out below. It con- 

 nects together the contiguous margins of the thyroid and cricoid cartilages. * It is 

 convex, concealed on each side by the Crico-thyroid muscle, but subcutaneous in 

 the middle line ; it is crossed horizontally by a small anastomotic arterial arch, 

 formed by the junction of the two crico-thyroid arteries. The lateral portions are 

 thinner and lie close under the mucous membrane of the larynx. They extend from 

 the superior border of the cricoid cartilage to the inferior margin of the true vocal 

 cords, with which they are continuous. 



The lateral portions are lined internally by mucous membrane, and covered by 

 the lateral Crico-arytenoid and Thyro-arytenoid muscles. 



A capsular ligament encloses the articulation of the inferior cornu of the 

 thyroid with the cricoid cartilage on each side. The articulation is lined by 

 synovial membrane. 



The ligaments connecting the arytenoid cartilages to the cricoid are two capsu- 

 lar ligaments and two posterior crico-arytenoid ligaments. The capsular ligaments 

 are thin and loose capsules attached to the margin of the articular surfaces ; they 

 are lined internally by synovial membrane. The posterior crico-arytenoid liga- 

 ments extend from the cricoid to the inner and back part of the base of the aryte- 

 noid cartilage. 



The ligament connecting the epiglottis with the thyroid cartilage is the thyro- 

 epiglottic. 



The thyro-epiglottic ligament is a long, slender, elastic cord which connects 

 the apex of the epiglottis with the receding angle of the thyroid cartilage, 

 immediately beneath the median notch, above the attachment of the vocal cords. 



The crico-tracheal ligament connects the cricoid cartilage with the first ring of 

 the trachea. It resembles the fibrous membrane which connects the cartilaginous 

 rings of the trachea to each other. 



Interior of the Larynx. The cavity of the larynx extends from its superior 

 aperture to the lower border of the cricoid cartilage. It is divided into two parts 

 by the projection inward of the true vocal cords, between which is a narrow triangu- 

 lar fissure or chink, the rima glottidis. The portion of the cavity of the larynx 

 above the true vocal cords, sometimes called the vestibule, is broad and triangular 

 in shape, and corresponds to the interval between the alse of the thyroid cartilage ; 

 it contains the false vocal cords, and between these and the true vocal cords are 

 the ventricles of the larynx. The portion below the true vocal cords widens out, 

 and is at first of an elliptical and lower down of a circular form, and is continuous 

 with the tube of the trachea. 



The superior aperture of the larynx (Fig. 529) is a triangular or cordiform 

 opening, wide in front, narrow behind, and sloping obliquely downward and back- 

 ward. It is bounded, in front, by the epiglottis ; behind, by the apices of the 

 arytenoid cartilages and the cornicula laryngis ; and laterally, by a fold of mucous 

 membrane, enclosing ligamentous and muscular fibres, stretched between the sides 

 of the epiglottis and the apices of the arytenoid cartilages: these are the aryteno- 

 epiglottidean folds, on the margins of which the cuneiform cartilages form more or 

 less distinct whitish prominences. 



The rima glottidis is the elongated fissure or chink between the inferior or true 



