THE LARYNX. 



957 



Epiglottis. 



The lower border of the cricoid cartilage is horizontal, and connected to the 

 upper ring of the trachea by fibrous membrane. 



Its upper border is directed obliquely upward and backward, owing to the 

 great depth of the posterior surface. It gives attachment, in front, to the middle 

 portion of the crico-thyroid mem- 

 brane ; at the sides, to the lateral 

 portion of the same membrane and 

 to the lateral Crico-arytenoid mus- 

 cle ; behind, it presents, in the 

 middle, a shallow notch, and on 

 each side of this is a smooth, oval 

 surface, directed upward and out- 

 ward, for articulation with the 

 arytenoid cartilage. 



The inner surface of the cricoid 

 cartilage is smooth, and lined by 

 mucous membrane. 



The arytenoid cartilages are 

 so called from the resemblance they 

 bear, when approximated, to the 

 mouth of a pitcher (dpuratva, a 

 pitcher}. They are two in number, 

 and situated at the upper border 

 of the cricoid cartilage, at the back 



O ' 



of the larynx. Each cartilage is 

 pyramidal in form, and presents 

 for examination three surfaces, a 

 base, and an apex. 



The posterior surface is tri- 

 angular, smooth, concave, and 

 gives attachment to the Arytenoid 

 muscle. 



The anterior or external surface 

 is somewhat convex and rough. 

 It presents rather below its centre 

 a transverse ridge, to the inner ex- 

 tremity of which is attached the 

 false vocal cord, and to the outer 

 part, as well as the surfaces above 

 and below, is attached the Thyro- 

 arytenoid muscle. 



The internal surface is narrow, 



Smooth, and flattened, covered by FIG. 528.-The cartilages of the larynx. Posterior view. 



mucous membrane, and forms the 



lateral boundary of the respiratory part of the glottis. 



The base of each cartilage is broad, and presents a concave smooth surface, 

 for articulation with the cricoid cartilage. Two of its angles require special 

 mention : the external, which is short, rounded, and prominent, projects back- 

 ward and outward, and is termed the muscular process, from receiving the 

 insertion of the Posterior and Lateral crico-arytenoid muscles. The anterior angle, 

 also prominent, but more pointed, projects horizontally forward, and gives attach- 

 ment to the true vocal cord. This angle is called the vocal process. 



The apex of each cartilage is pointed, curved backward and inward, and sur- 

 mounted by a small conical, cartilaginous nodule, the corniculum laryngis. 



The cornicula laryngis (cartilages of Santorini) are two small conical nodules, 

 consisting of white fibro-cartilage, which articulate with the summit of the aryte- 

 noid cartilages and serve to prolong them backward and inward. To them are 



Insertion of 



CRICO-ARYTENOIDEUS 

 POSTICUS ET LATEHALFS 



Cricoid. 



Articular facet for 

 arytenoid cartilage. 



Articular facet for 

 inferior cornu of 

 thyroid cartilage. 



Thyroid. 



Cuneiform cartilage. 

 Arytenoid. 



Posterior 

 surface. 



Arytenoid cartilages, base. 



