414 DR MORRISON WATSON AND MR ALFRED H. YOUNG 
cartilage measures 1+ inch in length ; it is flat from above downwards and convex 
from within outwards. The posterior border of the cricoid is deeply notched 
in the middle line superiorly, the notch accommodating a corresponding pro- 
jection of the first tracheal rng. Approaching the inferior extremities of the 
cartilage this border is interrupted by a deep crescentic fissure near the 
posterior extremity of which is the articular depression for the inferior cornua 
of the thyroid cartilage. 
Arytenoid.—These cartilages, elongated and laterally compressed, measure 
41 inches in length. Each presents inferiorly an oblique basal surface 
and gradually tapers to a blunt and rounded apex, from which a spur-like 
process is prolonged obliquely downwards and outwards. The apices and pro- 
cesses of the two cartilages, when covered with mucous membrane, form the 
posterior thickened lip of the superior aperture of the larynx. The flattened 
inner surfaces of the arytenoid cartilages, though closely applied throughout 
their entire length, remain ununited except by fibrous membrane; there is no 
direct union such as Mayver* figures in Monodon monoceros. 
The posterior border of each cartilage is straight as far down as the articular 
surface, below which it curves outwards, downwards, and then inwards towards 
the interior of the larynx, where it recurves upon itself; situated upon this 
border, 34 inches below the apex, is a well-defined tubercle marked on its 
internal aspect by an articular surface, by means of which the arytenoid articu- 
lates with the cricoid. From the tubercle a ridge extends upwards, the lower 
part of which affords attachment by means of a fibrous membrane to the basal 
portion of the epiglottic cartilage. 
The cartilages of Santorini and of Wrisberg are entirely absent. 
The cartilage of the epiglottis, elongated equally with the arytenoids, forms 
about half a cylinder, broadest below, and narrowing gradually towards the 
apex. By its base it is attached anteriorly to the upper border of the thyroid 
cartilage, whilst its postero-superior angles are connected to the ridges before 
referred to of the arytenoid cartilages. The apex of the epiglottic cartilage is 
prolonged outwards and backwards on each side of the middle line, and with 
its mucous covering forms the anterior lip of the superior laryngeal aperture. 
Ligaments of Larynx. 
The thyro-hyoid ligament, broad, flat, and thin, occupies the interspace 
between the hyoid bone and the thyroid cartilage; it is attached along the 
entire length of their adjacent borders. A crico-thyroid ligament extends 
between the anterior border of the cricoid to the posterior border and deep 
* XIX. Taf. lxxxiv. 
