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TEXT-BOOK OF PHYSIOLOGY 



runs from before backward, and is known as the false vocal band or cord 

 Between the true and false bands there is a cavity or space prolonged up- 

 ward and outward for some distance, forming what is known as the ventricle 



of the larynx. The space below the vocal 

 bands, the infra-glottic or infra-rimal space, 

 is narrow above and elongated from before 

 backward, but wide and circular below, cor- 

 responding to the lumen of the trachea. 

 (Fig. 270.) 



The Laryngeal Cartilages, Articula- 

 13 tions, and Ligaments. The cartilages which 

 12 compose the framework of the larynx are nine 

 in number, three of which are single: viz., the 

 cricoid, the thyroid, and the epiglottis, while 

 six occur in pairs: viz., the arytenoids, the 

 cornicula laryngis, and the cuneiform. (Figs. 

 271 and 272.) 



The cricoid cartilage is the foundation 

 cartilage, and affords support to "the remain- 

 ing cartilages and the structures attached to 

 them. In shape it resembles a signet-ring, 

 the broad quadrate portion of which is directed 

 backward, while the narrow circular portion 

 is directed forward. It rests upon the upper 

 ring of the trachea, to which it is firmly at- 

 tached by fibrous tissue. The posterior upper 

 border of the quadrate portion presents on 

 either side an oval convex facet for articula- 

 tion with the arytenoid cartilage. The long 

 axis of this facet is directed downward, out- 

 ward, and forward. 



The thyroid, the largest of the laryngeal 

 "cartilages, is composed of two flat quadrilat- 



terior portion of the cricoid carti- eral plates, united anteriorly at an angle of 

 lage. 8. Section of the anterior about oo degrees. Each plate is directed 



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20 



19 



FIG. 270. LONGITUDINAL SEC- 

 TION OF THE HUMAN LARYNX, 

 SHOWING THE VOCAL BANDS, i. 

 Ventricle of the larynx. 2. Supe- 

 rior vocal cord. 3. Inferior vocal 

 cord. 4. Arytenoid cartilage. 5. 

 Section of the arytenoid muscle. 6, 



portion of the cricoid cartilage. 

 9. Superior border of the cricoid 

 cartilage. 10. Section of the thy- 

 roid cartilage, n, n. Superior 

 portion of the cavity of the larynx. 

 12, 13. Arytenoid gland. 14, 16. 



backward and outward and terminates m a 

 free border, which is prolonged upward and 

 downward for some distance, terminating in 

 two processes, the superior and inferior cornua. 



Epiglottis. " 15, 17. Adipose tissue. The upper border to the thyroid is deeply 

 19,' 2 t C T?a C hU^(lS,y) ne ' I9 ' Botched in front. The inferior border over- 

 laps laterally the cricoid. 



The epiglottis is a leaf-shaped piece of cartilage attached to the thyroid 

 at the median notch. It is firmly united by membranes and ligaments to 

 the thyroid and arytenoid cartilages and to the base of the tongue. 



The arytenoid cartilages are two in number and symmetric in shape. 

 Each cartilage is a triangular pyramid, the apex of which is recurved, and 

 directed backward and inward. The base presents three angles an ante- 

 rior, an external, and an internal. The anterior angle is long and pointed 

 and projects forward in a horizontal plane. It serves for the attach - 



