I8l8 



HUMAN ANATOMY. 



The inferior thyro-arytenoid ligaments ( ligaraenta vocalia) are a pair of 

 an, orf fibroua tissue chiefly elastic, supporting the free edges of the true vocal 

 conls, extending in.m the ai#ed the thyroid a httle below the false ones o the 

 vocal ,-roce^of the arytenokb. These ligaments are continuous with the lateral 

 ports 3 the cnro-thyroid membrane, as the thickened and modified upper borders 

 of which they may be regarded (Fig. 1544)- Each band is triangular on sec ion, 



having the free edge at that of the 



FIG. 1544- 



Epiglottis, bent forward 

 Thyroid cartilage, left ala 



r cornu 

 ot thyroid car- 

 tilage 



Cartilage of 

 Santonin 



Arytenoid 

 cartilage 



Articular facet 

 for inferior thyroid 

 cornu 



cord. There may be a minute 

 nodule of cartilage in the ligament 

 just in front of its posterior attach- 

 ment. 



Right thyroid 



ala (cut) 



Lateral part of 

 crico-thyroid mem- 

 brane attached to 



vocal process 



Median part of crico- 

 thyroid membrane 



.Cricoid cartilage 



Trachea 



T n 



Lateral view of larynx after removal of greater part of right 

 thyroid ala, showing attachment of crico-thyroid membrane to 

 aryteiioiil cartilage. The free border of the membrane constitutes 

 the thyro-arytenoid ligament and the framework of the vocal cord. 



Ossification of the Larynx. The 

 process, beginning as it does at about 

 twenty, is a normal change. Chievitz * 

 found some ossification in every male 

 larynx of over twenty and in every fe- 

 male one of over twenty-two. It ap- 

 pears at about the same time in the 

 cricoid and thyroid, namely, at about 

 the beginning of the twentieth year, 

 and in the arytenoid at about the mid- 

 dle of the twenties in man and nearer 

 the thirties in woman. 



The Cricoid. The first nucleus 

 appears on each side at the back of 

 the facet for the arytenoid, and almost 

 at the same time another appears at 

 its front. These are shortly followed 

 by one at the joint for the thyroid. 

 These three unite, forming a lateral 

 ossification which spreads across the 

 back. One or more points appear in 



. 



front near the upper border of the arch, which is thus ossified and joins with the sides. After 

 these various unions tin- entire lower border of the cricoid is still cartilaginous. The youngest 

 man observed by Chievitz with complete ossification was forty-four and the youngest woman 

 seventy six. 



The Thyroid. The process begins near the posterior inferior angle and invades the in- 

 ferior horn. It appears next near the lower part of the anterior angle, and these two centres 

 on each side join by spreading along the inferior border. The superior horn then ossifies either 

 by a separate centre or by extension along the hind border. Finally a tongue-like process, 

 starting near tin- inferior tubercle, extends upward and forward across the ala to meet the ossi- 

 fication which lias spread along the superior border, leaving before and behind it places which 

 are the last to ossifv. This tongue-like process is peculiar to the male ; in the female ossifica- 

 tion advances chiefly from the posterior border. The youngest man with complete ossification 

 of the thyroid was titty and the youngest woman seventy-six. 



The . \rytt-noids. The process begins in the base. In man the starting-point is the mus- 

 cular pi-ores-,, hut in woman it is less certain. The youngest man in whom the process was 

 complete \\as seventy live and the youngest woman eighty-five. 



The < -iirtila^n trificea, when present, also tends to ossify. 



nil. K>kM OF THE LARYNX AND ITS MUCOUS MEMBRANE. 



The shape ,f the larynx depends not only on the cartilages, but also on folds of 

 mucous membrane >t retched over bands of connective tissue and over muscles. 



The r.i\ity.>f the larynx is subdivided into three parts : the supraglottic, the 

 glottic, and the inftn^lottic. 



The supraglottic region f vestihulum larvimis ) begins with the entrance to the 

 l.uvnx. an o\.il (or rather a heart-shaped) plane, which, owing to the height and 

 the position of the larynx, faces nearly backward. It is bounded by the free border 

 of the epiglottis I,, front and by the" aryepighttic fold which passes from this on 

 either side lurk " V rr the top of the arytenoid cartilages. It is interrupted in the 

 median line In-hind by a notch. On either side of this the fold presents a small 

 suellm u (iiiu-iuilmii o.Miiail.itmu >, .-.nised by the cartilage of Santorini, anterior to 

 win. h is a lai iiilK-milimi ciiiu-i forme) containing that of Wrisberg. Between 



1 Archiv f. Anat. und Phys., Anat. Abth., 1882. 



