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JOINTS AND LIGAMENTS OF THE LARYNX. pki 
vocalis, It receives this name because it gives attachment to the inferior thyro- 
arytenoid ligament or supporting band of the true vocal cord. The base of the 
arytenoid cartilage presents on its under surface, and more particularly on the 
under surface of the processus muscularis, an elongated concave facet for articulation 
with the upper border of the posterior lamina of the cricoid cartilage. 
Cartilages of Santorini (cartilagines corniculat ).—The cartilages of Santorini, 
or the cornicula laryngis, are two minute conical nodules of yellow elastic cartilage 
which surmount the apices of the arytenoids, and prolong the upper curved ends of 
these cartilages in a backward and inward direction, Each cartilage of Santorini 
is enclosed within the posterior part of the corresponding aryteno-epiglottidean 
fold of mucous membrane. 
Cuneiform Cartilages (cartilagines cuneiformes)—The cuneiform cartilages 
are not invariably present. They are two minute rod-shaped pieces of yellow 
elastic cartilage, each of which occupies a place in the corresponding aryteno- 
epiglottidean fold of mucous membrane immediately in front of the arytenoid 
cartilage and the cartilage of Santorini. On the superficial surface of each a collec- 
tion of mucous glands is present, and this tends to make the cartilage stand out 
in relief under the mucous membrane. 
Epiglottidean Cartilage (cartilago epiglottica).—The epiglottis is supported 
by a thin leaf-lke lamina of yellow fibro-cartilage which is placed behind the 
root of the tongue and the body of the hyoid bone, and in front of the superior 
aperture of the lary nx. When divested of the mucous membrane, which covers it 
behind and also to some extent in front, the epiglottidean cartilage is seen to 
present the outline of a bicycle-saddle, and to be indented by pits and pierced by 
numerous perforations. In the former, glands are lodged, whilst through the latter, 
blood-vessels and in some cases nerves pass. The broad end of the cartilage is 
directed upwards, and is free. Its margins are, to a large extent, enclosed within the 
ary teno- -epiglottidean folds of mucous membrane. The anterior surface is only free 
in its upper part. This part is covered with mucous membrane, and looks towards 
the base of the ‘tongue. The posterior surface is covered throughout its whole 
extent by the lining mucous membrane of the laryngeal cavity. The lower pointed 
extremity of the cartilage i is carried downwards in the form of a strong fibrous band, 
termed the thyro- epiglottidean ligament. 
Ossification of the Cartilages of the Larynx. — The thyroid and cricoid 
cartilages and the greater part of the arytenoid cartilages are composed of the hyaline 
variety of cartilage. The apical parts, and also the vocal processes of the arytenoid 
cartilages, the cartilages of Santorini, the cuneiform cartilages, and the epiglottis, are 
formed of yellow fibro- cartilage, and at no period of life do they exhibit any tendency 
towards the ossific change. The thyroid, cricoid, and basal portions of the arytenoids, as 
life advances, become more or less completely transformed into bone. In males over 
twenty years of age, and in females over twenty-two years of age, the process will usually 
be found to have begun (Chievitz). It is impossible, however, by an examination of the 
laryngeal car tilages, to form an estimate of the age of the individual, although in old age 
it is usual to find the thyroid, ericoid, and the hyaline part of the ary tenoid completely 
ossified. It would wppear that the process is somewhat slower in the female than in the 
male. The thyroid is the first to show the change ; then, but almost at the same time, 
the cricoid, and lastly, a few years later, the arytenoid. 
JOINTS, LIGAMENTS, AND MEMBRANES OF THE LARYNX 
Crico-thyroid Joints (articulationes cricothyreoides).—These are diarthrodial 
joints, and are formed by the apposition of the circular facets on the tips of the 
inferior cornua of the thyroid cartilage with the elevated circular facets on the 
sides of the cricoid cartilage. A capsular ligament is thrown around each articula- 
tion, and this is lined by synovial membrane. On the posterior aspect of the joint 
a strengthening band is present in the capsule. The movements which take place 
at the crico- thy roid joints are of a twofold character, viz. gliding and rotatory. In 
the first case the thyroid facets glide upon the cricoid surfaces in different directions. 
The rotatory movement is one in which the thyroid cartilage rotates to a slight 
extent around a transverse axis which passes through the centre of the two joints. 
