THE VISCERA. 229 



4. Thyreo-arytcenoidei, two thin, longish processes of the last muscle. Situ- 

 ation : between thyroid cartilage and mucous membrane of the internal surface 

 of the Larynx, chiefly in the fold of the vocal cords. Or. : the angle (in- 

 ferior two thirds) of the thyroid cartilage. Ins. : the anterior angle of the ex- 

 ternal border of the arytcenoid cartilages. Use : to draw the cartil. arytcenoid. 

 forwards, and shorten the rima glottidis ; extending at the same time the vocal 

 cords. 



5. jlrytcenoideus, short, thick, rhomboidal, lying in the concave posterior sur- 

 faces of the arytcenoid cartilages, and in the space which divides them ; con- 

 sists of a deep transverse layer, that is, aryt. transversus, and two crossing each 

 other obliquely, arytcenoidei obliqui. The inferior border touches the cricoid 

 cartilage ; upon the superior lie glands, and a fold of mucous membrane 

 which separates the introitus laryng. from the Pharynx. Points of attach- 

 ment: the external angle and the posterior concave surface of cartt. ary- 

 tcenoidece. Use : to approximate the arytcenoid cartilages, and thus contract the 

 posterior part of the rima glottidis. 



6. Reflector epiglottidis (Theile) ; in the fold of mucous membrane from the 

 lateral borders of the epiglottis to the cartill. arytcenoid. and Santorini of either 

 side. Or.: from three places. 1. Posterior portion from the external angle of 

 cartil. aryteenoid. of the other side, crosses obliquely. 2. Central portion, from 

 the attachment of the superior vocal cords to the arytcRnoid cartilages. 3. 

 Anterior portion, from the internal surface of the thyroid cart. Ins. : lateral 

 border of the epiglottis. Use : bends the epiglottis backwards, closing (and 

 contracting) the entrance to the larynx. 



c. The mucous membrane of the larynx, a continuation of that of the 

 mouth and nose, passes from the root of the tongue upon the anterior surface 

 of the Epiglottis, as it forms three folds (ligg. glosso-epiglottica), then covers the 

 posterior surface and passes from its borders upon the cartil. arytcenoid., and 

 from these upon the posterior surface of the larynx (where this forms a por- 

 tion of the anterior wall of the Pharynx). At the lateral parts of the en- 

 trance to the larynx, above the rima glottidis, the mucous membrane forms two 

 folds (ligg. ary-epiglottica), covers the superior vocal cords, is loosely suspended 

 in the pocket-like hollows which the ventriculi Morgagni form, but firmly and 

 thin to the inferior vocal cords, from which it passes over upon the internal 

 surface of the cricoid cartilage, the memb. crico-thyreoid and the Trachea. 



The mucous membrane is very thin, pale red, very sensitive (particularly 

 over the rima glottidis), and contains in the ligg. ary-epiglattica much (serous) 

 uniting tissue. 



d. Glands: 1. Gland, epiglotticce, small, numerous, under the mucous mem- 

 brane, on the posterior surface of the larynx; they open towards the sides of 

 the larynx. 



2. Gl. arytcenoidea (Morgagni), lie in the Plica (ligam.) ary-epiglottwa in the 

 shape of letter L, opening into the larynx. The vertical portion lies on 

 the anterior surface of the arytcenoid cartilages, the horizontal on the superior 

 vocal cord. 



e. Vessels: Jlrtt. and Fen. laryngea super, and infer, (from thyreoid super. 

 and infer.'). Lymphatics pass into the glands above the hyoid bone (in the 

 neck). 



f. Nerves: N. laryngeus superior and laryng. inferior (s. recurrens) from . 

 vagus. 



