CONTRIBUTIONS TO ZOOLOGICAL PATHOLOGY. 267 
that are peculiar to the special laryngeal cartilages. Under the 
first, therefore, are included the 
Hyo-thyroid. 
Hy o - epiglottidean. 
T racheo-cricoidean. 
And under the second, the 
Crico- thyroid. 
Crico-arytenoid. 
Thyro-arytenoid 
Aryteno-epiglottic. 
Thyro-epiglottic. 
The hyo-thyroid articulation is formed of a broad loose band of 
yellow elastic fibres, attached behind to the anterior edge of the 
thyroid cartilage ; and before, to the inner surface of the body 
and greater cornua of the os hyoides. It is thicker in the middle 
and towards its margins, and has consequently thereon been di- 
vided into three portions, a middle and two lateral ligaments. 
The inferior surface of the middle portion is covered by the 
thyro-hyoid, and the sterno-hyo-thyroid muscles ; and the superior 
surface forms a floor for the reception of the epiglottic gland. The 
lateral ligaments are short, thick and rounded, and attach the ex- 
tremities of the greater cornua of the os hyoides to the anterior 
cornua of the thyroid cartilage. 
The hyo-epiglottidean ligament is formed of an irregular band 
of very elastic fibres, attached before, partly to the concave sur- 
face of the body of the os hyoides, and partly to the linea al- 
bescens, or tendinous raphe of the tongue ; and behind, becomes 
inserted into the convex surface of the epiglottis, beneath the hyo- 
epiglottideus muscle. By its elastic properties it tends to keep 
the epiglottis securely in the vertical position. 
The tracheo-cricoidean articulation. — The posterior margin of 
the cricoid cartilage is connected to the first ring of the trachea 
by the same ligamentous fibres that connect the individual rings 
of the trachea to each other. In the mesial line below it is denser 
and stronger than above, and fills up the space between the edge 
of the cricoid cartilage and the trachea — the tracheo-cricoid mem- 
brane. As this membrane is attached around the inner surface of 
the cricoid cartilage, when the trachea is drawn forwards, the first 
ring slips under its cover. 
Under the extrinsic laryngeal articulations might also be in- 
cluded those which exist between the smaller cornua and the body 
of the os hyoides, and forming the chondro-hyoid articulation. 
These articulations consist of distinct capsular ligaments that con- 
nect the tubercles on the body of the bone to the facets on the 
extremities of the smaller cornua : they are lined within by perfect 
