532 MUCOUS MEMBRANE OF THE LARYNX. 



bly minister to the function of deglutition, rather than to 

 that of voice, appear wholly from under the influence of 

 the will, and act in that spasmodic or convulsive motion 

 by which the food is hurried over the glottis, and precipi- 

 tated into the oesophagus." 



MUCOUS MEMBRANE OF THE LARYNX AND GLANDS. 



The mucous membrane of the larynx is a continuation of 

 that lining the mouth, nose, and pharynx. It is of a pink- 

 ish color, smooth and soft, and proceeds from the base of 

 the tongue to the anterior surface of the epiglottis, in three 

 folds, the middle one being the frcenum. From this it 

 passes round upon the posterior surface of the epiglottis, 

 where it adheres pretty strongly ; from this it is reflected 

 backward to the arytenoid cartilages, constituting the ary- 

 teno-epiglottic folds, or, according to some, the superior or 

 false vocal ligaments. Here it becomes continuous with 

 the mucous membrane of the pharynx, and covers the pos- 

 terior surface of the larynx. From the upper ligaments it 

 descends within the larynx, to the inferior or true chordae 

 vocales, lining the intervening space, called the ventricle 

 of Morgagni, and also an offset from this ventricle, termed 

 the sacculus laryngis. It adheres to both these cavities 

 loosely. Upon the inferior vocal chords it is very thin and 

 adheres strongly, is traced downward, lining every de- 

 pression and eminence, and is continuous with that found 

 in the trachea, bronchial tubes, and air-cells of the lungs. 



This membrane is perforated by a multitude of foramina, 

 the orifices of mucous ducts. Sixty or seventy are said to 

 belong to the sacculus laryngis. Its epithelium is found to 

 be of the columnar form and ciliated. The cilife direct 

 the secretion upward, and, according to Henle, are found 

 extending higher up in front than upon the sides or be- 

 hind. In front they reach to the posterior surface of the 

 epiglottis, and upon the sides as high as the superior 

 ligaments, beyond which the epithelium takes the lami- 

 nated form of the pharynx and mouth. The upper portion 

 of this membrane has great sensibility. 



