916 
‘THE RESPIRATORY SYSTEM. 
" 
superior thyro arytenoid ligament; (2) numerous glands which are chiefly aggre- 
gated in its middle part; and (3) a few muscle fibres. 
\ 
\ Hyoid bone 
vA Hyo-epiglottidean ligament 
Vd. 
\ 
_-Cartilage of epiglottis 
Fatty pad 
_ Thyro-hyoid membrane 
Thyroid cartilage 
Elevation produced by 
_ False vocal cord 
Filtrum ventriculi 
Elevation produced 
by arytenoid cartilage 
Laryngeal sinus 
aie 
7 fe — 
True vocal cord 
L\ 
et li 
[ 
\ Arytenoid nuscle 
~! Processus vocalis 
+ Cricoid cartilage 
Wests cartilage 
Fic. 618.— MgsiaL SECTION THROUGH LARYNX, 
to show the outer wall of the right half. 
The interval between the false vocal cords 
is sometimes termed the false glottis (glottis 
spuria), and is considerably wider than the 
interval between the true vocal cords, which 
is called the true glottis (glottis vera) or rima 
glottidis. It follows from this that when 
the cavity of the larynx is examined from 
above the four cords are distinctly visible, 
but when examined from below the true 
vocal cords alone can be seen. 
The true vocal cords (plicxe vocales), 
placed below the false cords, extend from 
the angle between the ale of the thyroid 
cartilage in front to the vocal processes of 
the arytenoid cartilages behind. The true 
vocal cord is sharp and prominent, and the 
mucous membrane which is stretched over 
it is very thin and firmly bound down to 
the subjacent ligament. In colour it is 
pale, almost pearly white, whilst posteriorly 
the point of the processus vocalis of the 
arytenoid, which stands out clearly in relief, 
presents a yellowish tinge. In cross-section 
the true vocal cord is prismatic in form, and 
its free border looks upwards as well as 
inwards. 
The true vocal cords are the agents by 
means of which the voice is produced. 
The false vocal cords are of little import-. 
ance in this respect; imdeed, they can 
in great part be destroyed and no appreciable difference in the voice result. 
5 
Glottis vera (rima glottidis)—This name 1s applied to the elongated fissure by 
means of which the middle compartment 
of the larynx communicates with the 
lower compartment. 
what below the middle of the laryngeal 
cavity, of which it constitutes the nar- 
rowest part. In front it corresponds to 
the interval between the true vocal 
cords; behind, it corresponds to the 
interval between the bases and vocal 
processes of the arytenoid cartilages. It 
is composed, therefore, of two distinct 
parts: (L) a narrow anterior portion, 
between the true vocal cords, involving 
more than half of its length, and called the 
glottis vocalis (pars intermembranacea) ; 
(2) a broader, shorter portion, between 
the arytenoid cartilages, and termed the 
glottis respiratoria (pars intercartilaginea). 
Bychanges in the position of the arytenoid 
cartilages the form of the rima glottidis 
undergoes constant alterations. In ordi- 
nary easy breathing it is somewhat lanceo- 
late in outline. The glottis vocalis 
presents under these conditions the form of an elongated triangle with the base 
directed backwards, and corresponding to an lmaginar 
It is placed some- . 
A. During ordinary easy breathing. 
Thyroid cartilage 
Inferior thyro- 
arytenoid ligament 
Rima 
of arytenoid 
cartilage, 
Arytenoid 
A cartilage 
Fic. 619.—D1aGRAM OF RIMA GLOTTIDIS. 
B. Widely open. 
y line drawn between the 
Vocal process 
