480 THE LARYNX. 



the trachea, to the upper part of which is adapted an apparatus of 

 cartilages, constituting the organ of voice, or larynx. 



THE LARYNX. 



The Larynx is situated at the forepart of the neck, between the 

 trachea, and the base of the tongue. It is composed of cartilages, 

 ligaments, muscles, vessels, and nerves, and mucous membrane. 



The Cartilages are the 



Thyroid, 



Cricoid, 



Two Arytenoid, ' 



Epiglottis. 



The Thyroid (Svgios si'Sos, like a shield) is the largest cartilage of 

 the larynx : it consists of Iwo lateral portions, or alee, which meet 

 at an acute angle in front, and form the projection which is known 

 by the name of pomum Adami. Where the pomum Adami is promi- 

 nent, a bursa mucosa is often found between it and the skin. 



Each ala is quadrilateral, and forms a rounded border poste- 

 riorly, which terminates above, in the superior cornu, and below, in 

 the inferior cornu. Upon the side of the ala is an oblique line, into 

 which the sterno-thyroid muscle is inserted, and from which the 

 thyro-hyoid takes its origin. Behind this is a vertical line which 

 gives origin to the inferior constrictor muscle. In the receding 

 angle, formed by the meeting of the two alas upon the inner side of 

 the cartilage, and near to its lower border, are attached the epi- 

 glottis, the chordae vocales, the thyro-arytenoid, and thyro-epiglot- 

 tidean muscles. 



The Cricoid '(xg'nos '&, like a ring) is a ring of cartilage, narrow 

 in front and broad behind, where it is surmounted by two rounded 

 surfaces, which articulate with the arytenoid cartilages. Upon the 

 middle line, posteriorly, is a vertical ridge which gives attachment 

 to the oesophagus, and on each side of the ridge are the depressions 

 which lodge the crico-arytenoidei postici muscles. On either side 

 of the ring is a glenoid cavity, which articulates with the inferior 

 cornu of the thyroid cartilage. 



The Arytenoid cartilages (d^urai'va, a pitcher,)* two in number, are 

 triangular in form. They are broad below, where they articulate 

 with the upper border of the cricoid, and give attachment to the 

 crico-arytenoidei postici, crico-arytenoidei laterales, and thyro- 

 arytenoidei muscles, and chordas vocales ; and pointed above, where 



* This derivation has reference to the appearance of both cartilages taken together 

 and covered by mucous membrane. In animals, which were the principal subjects of 

 dissection among the ancients, the opening of the larynx with the arytenoid cartilages 

 bears a striking resemblance to the mouth of a pitcher having a large spout. 



