THE LARYNX. 1817 



cartilaginous stroma is full of pits, or even perforations, containing glands. The 

 mucous membrane is attached to it very closely, so that in dissecting the cartilage it 

 is difificult to determine its true outline. 



The Ligaments of the Epiglottis. — The thyro-epiglottic ligament is an elastic 

 band continuing the stalk of the epiglottis into the angle of the thyroid, just below 

 the notch. Owing to the ill-defined structure of the epiglottis, it is often hard to say 

 what is ligament and what is stalk. The glosso-epiglottic ligaments, one median and 

 two lateral, are three folds of mucous membrane with more or less elastic tissue within 

 them, extending from the front of the epiglottis to the tongue, with which they have 

 been more particularly described (page 1575). The hyo-epiglottic ligame?it^ is de- 

 scribed as a bundle of elastic tissue extending between the middle of the anterior 

 surface of the epiglottis and the upper border of the hyoid. Such a structure may 

 be artificially dissected ; but the important point is the presence of a mass of very 

 dense areolar tissue, probably largely elastic, and with fat in its meshes, which forms 

 a firm pad between the front of the epiglottis below the line of reflection of the 

 mucous membrane and the thyro-hyoid membrane which is attached to the upper 

 border of the hyoid. This mass gives support to the epiglottis, and probably may 

 be made to press it backward when the hyoid is carried 

 in that direction. It is continuous with the septum of the Fig. 1543- 



tongue. 



The Movements of the Epiglottis. — The old idea that 

 the epiglottis turns over backward like a lid to close the ,^ ^ ^^ 

 larynx in swallowing is disproved. That it could ever be IB^.v. ,v,,.~t_l Depressions 

 so bent is unlikely. In swallowing it is carried bodily ^1^^^^^'' ,''/ for glands 

 backward, while the approximated aryepiglottic folds and 

 tubercles of Santorini are drawn upward, thereby closing 

 the laryngeal aperture. While there are muscular fibres 

 in the aryepiglottic fold, they are scanty and irregular 

 and hardly capable of exercising any great influence on 

 the shape of the epiglottis. . 



The cornicula laryngis, or cartilages of Santo- » 1 



ri7ii, are a pair of small horn-like structures of elastic car- Epiglottic cartilage from behind, 

 tilage on the apices of the arytenoids (Fig. 1542). As 



their sheath is continuous with the perichondrium of the latter, they are not very 

 easily isolated. They are 4 or 5 mm. long, curve backward and inward, and are 

 attached by their fibres to the arytenoids. 



The cuneiform cartilages (of IVrisderg) are two very slender rods of elastic 

 cartilage situated a little in front of the corniculae laryngis in the aryepiglottic folds 

 (Fig. 1545)- They are some 5 mm. or more long and i mm. thick. While the 

 swellings which they seem to produce in the folds are constant, the same cannot be 

 said of the cartilages. They are often difficult to isolate. 



Minute nodules of elastic cartilage are occasionally found in certain parts of the 

 larynx. The posterior sesamoid cartilages are on the lateral sides of the joints be- 

 tween the arytenoids and the corniculae. The anterior sesamoid, which may be double, 

 is at the anterior origin of the true vocal cords. An occasional interarytenoid has 

 been described under the mucous membrane of the pharynx between those cartilages. 

 It is regarded as representing a precricoid cartilage. 



The elastic sheath of the larynx is a layer of areolar tissue, rich in elastic 

 fibres, which lines the inside of the larynx, and is prolonged from it into the folds 

 of mucous membrane to be presently described. The superior and inferior thyro- 

 arytenoid ligaments in the false and true vocal cords respectively are thickenings oi 

 this layer. 



The superior thyro-arytenoid ligaments (ligamenta ventricularia), one on 

 each side, extend between the angle of the thyroid above its middle (the point of 

 origin will be described accurately with the vocal cords) and the tiibercle on the bor- 

 der of the fovea of the arytenoid. They are in no sense ligaments, but at most 

 slight thickenings of the elastic tissue in the folds of the mucous membrane forming 

 the false vocal cords, and can be demonstrated only by an artificial dissection. 



^ Dieulafe : La membrane glosso-hyoidienne, Bibliographic Anatomique, tome xi., 1901. 



