a 
INTERIOR OF THE LARYNX 
5 a) 
bounded by the arytenoid cartilage and the aryteno-epiglottidean fold, whilst on 
the outer side it is limited by the inner surface of the ala of the thyroid cartilage 
clothed by the pharyngeal mucous membrane. 
>] 
Upper Subdivision of the Laryngeal Cavity (vestibulum laryngis).— The 
upper subdivision of the laryngeal cavity extends from the superior opening of the 
larynx down to the false vocal cords. In its 
lower part it exhibits a marked lateral com- 
pression. Its width, therefore, diminishes from 
above downwards, whilst, owing to the obliquity 
of the upper aperture of the larynx, its depth 
rapidly diminishes from before backwards. Jn 
front it is bounded by the posterior surface of 
the epiglottis, clothed by mucous membrane. 
This wall descends obliquely from above down- 
wards and forwards, and becomes narrower as it 
approaches the anterior ends of the false vocal 
cords. The upper part of the posterior surface 
of the epiglottis is convex, owing to the manner 
in which the upper ae is curved forwards 
towards the tongue; below this there is a 
shght concavity, and still lower a marked bulg- 
ing or convexity over the upper part of the 
thyro-epiglottidean ligament. This swelling is 
called the cushion or tubercle of the epiglottis 
Epiglottis 
Hyoid bone 3) | 
i 
Aryteno- // 
epiglottidean--—~ 
fold 
Cushion of |i.8 
epiglottis |/ 
Thyroid \|_ 
cartilage | 
False vocal 
cord 
Laryngeal 
sinus 
True vocal 
cord 
Thyro- 
arytenoid 
muscle 
Cricoid 
(tuberculum epiglotticum), and it forms a con- cartilage 
spicuous object in laryngoscopic examinations 
of the larynx. The /ateral wall of the upper 
compartment or vestibule of the larynx is formed 
by the inner surface of the aryteno-epiglottidean 
fold. For the most part it is smooth and slightly. 
concave, and it diminishes considerably in F!. 617.—Corowan Section THROUGH 
‘ F : LARYNX, to show its three compartments. 
vertical depth as it passes backwards. In its 
posterior part the mucous membrane stands out in two elongated vertical elevations 
placed one behind the other (Fig. 618, p. 916). The anterior elevation is formed 
by the subjacent cuneiform cartilage with the mass of glands associated with 
it; the posterior elevation is produced by the anterior margin of the arytenoid 
cartilage and the cartilage of Santorini. A shallow groove (filtrum ventriculi of 
Merkel) descends between these rounded elevations, and terminates below by 
running into the interval between the false and true vocal cords. The anterior 
elevation comes to an end below in the posterior extremity of the false vocal cord ; 
the arytenoid or posterior elevation, in its inferior part, bends round the hinder end 
of the ventricle of the larynx and becomes lost in the true vocal cord. The posterior 
wall of the laryngeal vestibule is narrow, and corresponds to the interval between 
the upper parts of the two arytenoid cartilages. Its width, to a large extent, 
depends on the position of these cartilages, and when they are placed near each other 
the mucous membrane which covers this wall is thrown into longitudinal folds. 
Middle Subdivision of the Laryngeal Cavity.—The middle compartment of 
the larynx is much the smallest of the three. It is bounded above by the false 
vocal cords and below by the true vocal cords, whilst it communicates between these 
folds with the vestibule on the one hand and the inferior compartment of the 
larynx on the other. 
The false vocal cords (plicee ventriculares) are two prominent mucous folds 
which extend from before backwards on the side walls of the laryngeal cavity. In 
front they reach the angle between the two ale of the thyroid cartilage, but behind 
they do not extend so far as the posterior wall of the larynx. They come to an 
end on each side at the lower end of the elongated swelling produced by cuneiform 
cartilage. The false vocal cord is soft and somewhat flaccid, and presents a free 
border which is slightly arched—the concavity looking downwards. Within the 
fold of mucous membrane which forms this cord are contained: (1) the feeble 
58 a 
