ANATOMY OF B ALiEN OPTEE A EOSTEATA. 
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muscle. The posterior process was pyramidal, and prolonged downwards and inwards 
towards the median line, where it was united to its fellow of the opposite side by a 
strong round fibrous cord, about two lines thick and 1 inch in length, the transverse 
ligament of the arytenoid cartilage. The anterior process was flattened; it curved 
upwards and inwards, and terminated in a fibrous band, which was placed as a kind of 
support in the centre of the free tongue-shaped arytenoid body, this latter forming the 
posterior boundary to the rima glottidis. The entire length of this cartilage was 8 inches, 
its greatest width in the centre being 3f inches. 
The muscles of the larynx were seventeen in number, viz. on the anterior aspect there 
were, first, the thyrohyoid, a flat muscle, 4 inches long by 1 inch broad ; it arose fleshy 
from a ridge on the anterior and outer portion of the thyroid cartilage behind the base 
of the anterior cornu ; from this the fibres ran forwards and inwards to be inserted ten- 
dinous into the posterior part of the body of the os hyoides, extending outwards 1 inch 
from the median line. Second, the crico-thyroid, a strong and flattish muscle, measuring 
4 inches long by If inch wide ; it arose fleshy from the outer surface of the anterior 
extremity of the cricoid cartilage, passed forwards and upwards to be inserted into the 
lower and external edge of the inferior cornu of the thyroid cartilage ; it lay behind, and 
on a plane deeper than the sterno- thyroid. The muscles situated on the posterior 
aspect were, first, the crico-arytenoideus posticus, a large fleshy mass, which took its 
origin from the outer third of the posterior surface of the cricoid cartilage ; its fibres ran 
forwards and outwards, and embraced the posterior and external angle of the arytenoid 
cartilage into which they were inserted. Second, the arytenoideus proprius, a flat, 
azygos muscle, which consisted of slightly decussating fibres running obliquely from the 
inner edge of one arytenoid cartilage to the corresponding border of its fellow ; its lower 
fibres ran transversely, while the middle and upper were slightly curved. This muscle 
extended If inch above the superior border of the cricoid cartilage, and terminated 2f 
inches behind the commissure of the arytenoid bodies. 
Between the layers of mucous membrane that formed the arytenoepiglottidean folds, 
on each side the superior aryteno-epiglottideus muscle was enclosed ; it passed from the 
outer and anterior part of the arytenoid cartilage to be inserted into the external margin 
of the epiglottis. On the same plane, but posterior to it, the inferior aryteno-epiglot- 
tideus muscle was situated, whose attachments corresponded to those of the last de- 
scribed, the posterior border of the superior being in contact with the anterior edge of 
the inferior muscle. 
The hyoepiglottideus muscle was triangular in shape, the base being directed towards 
the os hyoides and the apex attached superiorly and posteriorly to the epiglottis. It 
arose from a vertical median ridge on the upper surface of the body of the os hyoides, 
ran backwards and upwards to be inserted into the anterior surface of the epiglottis ; 
this muscle was separated from its fellow of the opposite side by a narrow cellular in- 
terval, and lay beneath the frsenum epiglottidis. The superior laryngeal nerve, which 
entered above and in front of the thyroid cartilage, ran enclosed in the aryteno-epiglot- 
