922 - ‘THE RESPIRATORY SYSTEM. 
and to a large extent the increase in the latter direction is produced by the strong develop- 
ment of the laryngeal angle or pomum Adami in the male. The great antero- posterior 
diameter of the male larynx necessarily implies a greater length of the vocal cords and a 
lower or deeper tone of the voice than in the female. 
In the newly-born child the larynx, in comparison with the rest of the body, is some- 
what large (C. L. Merker), and it continues to grow slowly and uniformly up to the sixth 
year of childhood. At this period there is a cessation of growth, which persists until 
puberty is reached, and then a stage of active growth supervenes. Up to this time the 
larynx in both sexes is similar in its Chardeters s, and although the growth which now 
occurs affects both the male and the female larynx, it is much more r: ipid and much more 
accentuated in the male than in the female. As a result of this the voice of the male 
breaks and assumes its deep tone, 
It is interesting to note that the growth activity of the larynx at puberty is intimately 
connected with the development of the sexual organs. In an individual who has been 
castrated when young the larynx attains a size which exceeds that of the female only to 
a very small degree, and the high pitch of the voice is retained. 
Appearance presented by the Interior of the Larynx when examined by the Laryngo- 
scope.—Whien the cavity of the larynx is illuminated and examined by the laryngoscopic mirror 
the parts which sur ‘round the superior aperture of the larynx, as well as the interior of the organ, 
come into view. 
Not only this, but 
when the vocal 
cords are widely 
separated it 1s pos- 
sible to inspect the 
interior of the 
trachea as low 
down as its bifur- 
cation. 
In such an exa- 
mination the 
arched upper 
border of the epi- 
glottis constitutes 
a conspicuous 
object, whilst, 
behind this, the 
bulging on the 
A 
Fic. 624.—Cavity OF THE LARYNX, as seen by means of the laryngoscope. 
A. The rima glottidis closed. B. The rima glottidis widely open. anterior wall of the 
1. Rings of the trachea. 5. Laryngeal sinus. 10. Base of tongue. vestibule, formed 
2. Processus vocalis of the 6. Vallecula. 11. Epiglottis. by the cushion of 
arytenoid cartilage. 7. True vocal cord. 12. False voeal cord. [at eee Os an 
3. Aryteno-epiglottidean fold. 8. Cushion of epiglottis. 13. Cuneiform tubercle. the epiglottis, ay 
4. Sinus pyriformis. 9. Middle glosso-epiglottidean fold. 14. Tuberele of Santorini. constitutea feature 
of the picture. 
The middle glosso-epiglottidean ligament, with the vallecular fossa on either side of it, can also 
be inspected in the interval between the epiglottis and the base of the tongue. The sharp ary- 
epiglottidean folds are clearly visible, and in the back portion of each of these can be seen. the 
two prominent tubercles which are formed by the enclosed cuneiform cartilage and the cartilage 
of Santorini. Behind these tubercles is the posterior wall of the pharynx, whilst to their outer 
side the deep sinus pyriformis may be seen. In the interior of the larynx the false and the true 
vocal cords are easily recognised, and the interval between the false and the true cord, or, in 
other words, the entrance into the laryngeal sinus, appears as a dark line on the side w all of the 
larynx. The false vocal cords are red and fleshy-looking ; the true vocal cords during phonation 
are tightly stretched and pearly white—the white colour being usually more apparent in the 
female than in the male. The outline and yellowish tinge of the processus vocalis at its attach- 
ment to the true vocal cord, as well as, to a shght extent, the outline of the fore part of the base 
of the arytenoid cartilage, can in a successful laryngoscopic examination be made out. The true 
vocal cords during ordinary inspiration are seldom at rest, and with the laryngoscope their move- 
ments may be studied. It'should be borne-in mind that the picture afforded by the laryngoscope 
does not give a true idea of the level at which the different parts lie. The cavity appears greatly 
shortened, and its depth diminished. 
THE TRACHEA. 
The trachea or windpipe is a wide tube which is kept permanently patent by 
a series of cartilaginous rings embedded in its wall. These rings are deficient 
posteriorly, and consequently the tube is not completely cylindrical: its hinder — 
wall is flattened. The trachea begins above at the lower ‘border of the cricoid | 
