VENTRICLES OF THE LARYNX. 



913 



wider in the centre ; when moderately open, as in easy respiration, its 

 shape is that of a long triangle, the pointed extremity being directed for- 

 wards, and the base being placed behind between the arytenoid cartilages ; 

 and in its fully dilated condition it has the figure of an elongated lozenge, 

 the posterior sides of which are formed by the inner sides of the bases of 

 the arytenoid cartilages, while the posterior angle is truncated. This aper- 

 ture is the narrowest part of the interior of the larynx ; in the adult male 

 it measures about eleven lines or nearly an inch in an antero-posterior 

 direction, and three or four lines across at its widest' part, which may be 

 dilated to nearly half an inch. In the female, and in males before the age 

 of puberty, its dimensions are less, its antero-posterior diameter being about 

 eight lines, and its transverse diameter about two. The vocal ligaments 

 measure about seven lines in the adult male, and five in the female. 



The ventricles, or sinuses of the larynx, situated between the superior and 

 inferior vocal cords on each side, are narrower at their orifice than in their 

 interior. The upper margin of each is crescentic, and the lower straight : 

 the outer surface is covered by the 



upper fibres of the corresponding Fig 633_ 



thyro-arytenoid muscle. 



Fig. 638. ANTERIOR HALF OF A TRANS- 

 VERSE VERTICAL SECTION THROUGH THE 

 LARYNX NEAR ITS MIDDLE. 



In order to bring the deepest part of one 

 of the sacculi into view, the section is car- 

 ried somewhat farther forward on the right 

 side : the space between the horizontal 

 dotted lines marked 1, comprises the upper 

 division of the laryngeal cavity ; that 

 marked 2, corresponds to the middle cavity 

 or that of the ventricles ; that marked 3, 

 indicates the lower division of the laryngeal 

 cavity, continued into 4, a part of the 

 trachea ; e, the free part of the epiglottis ; 

 e', its cushion ; h, the divided great cornua 

 of the hyoid bone ; ht, thyro-hyoid mem- 

 brane ; t, cut surface of the divided thyroid 

 cartilage ; c, that of the cricoid cartilage ; 

 r, first ring of the trachea ; ta, superior 

 and inferior parts of the thyro-arytenoid 

 muscle ; vl, thyro-arytenoid ligament in 

 the true vocal cord covered by mucous 

 membrane at the rima glottidis ; s, the 

 ventricle ; above this, the superior or false 

 cords or margin of the folds above the ven- 

 tricles ; a', the sacculus or pouch opened on 

 the right side. 



The small culs-de-sac named the laryngeal pouches lead from the anterior 

 part of the ventricles upwards, for the space of half an inch, between the 

 superior vocal cords on the inner side, and the thyroid cartilage on the outer 

 side, reaching as high as the upper border of that cartilage at the sides of 

 the epiglottis. The pouch is conical in shape, and curved slightly backwards. 

 Its opening into the ventricle is narrow, and is generally limited by two 

 folds of the lining mucous membrane. Numerous small glands, sixty or 

 seventy in number, open into its interior, and it is surrounded by a quan- 

 tity of fat. Externally to the fat, this little pouch receives a fibrous 

 investment, which is continuous below with the superior vocal cord. Over 



3 o 



