ateral ligaments which connect the os hyoides and
thyroid cartilage. 5, 5, The posterior face of the thyroid cartilage. 6,
6, The arytenoid cartilages. 7, The cricoid cartilage. 8, 8, The junction
of the cricoid and the arytenoid cartilages. 12, The first ring of the
trachea.]

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589. Describe the thyroid cartilage. 590. From what does the cricoid
cartilage derive its name? Where is it situated? Explain fig. 102.
Fig. 103.

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591. The ARYTENOID CARTILAGES are small triangular bodies placed upon
the back part of the cricoid cartilage. They are connected with the
thyroid cartilages, by four ligaments, called _Vo'cal Cords_.

592. The EPIGLOTTIS is fibro-cartilaginous, and is placed behind the
base of the tongue. In shape it resembles a leaf of parsley.

593. The VOCAL CORDS, or ligaments, are formed of elastic and parallel
fibres, enclosed in a fold of mucous membrane. They are about two
lines in width, and pass from the anterior angle of the thyroid
cartilage, to the two arytenoid cartilages. The one is called the
superior, and the other the inferior vocal ligament. The cavity, or
depression between the superior and inferior ligament, is called the
_ventricle_ of the larynx. The aperture, or opening between these
ligaments, is called the _glot'tis_, or _chink of the glottis_. It is
about three fourths of an inch in length, and one fourth of an inch in
width, the opening being widest at the posterior part. This opening is
enlarged and contracted by the agency of the muscles appropriated to
the larynx.

[Illustration: Fig. 104. An ideal, lateral section of the larynx. 1, 1,
The upper vocal cords. 2, 2, The lower vocal cords. 3, 3, The glottis. 4,
4, The ventricles of the larynx.]

[Illustration: Fig. 105. A vertical section of the larynx. 2, The os
hyoides. 4, The apex of the epiglottis. 7, The superior vocal ligament.
9, The ventricle of the larynx. 10. The lower vocal ligament. 11, The
arytenoid cartilage. 12, 13, The cricoid cartilage. 14, The trachea. 18,
The oesophagus.]

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591. Describe the arytenoid cartilages. 592. What is said of the
epiglottis? 593. Give the structure of the vocal cords. Where is the
ventricle of the larynx? Where is the glottis situated? What is
represented by fig. 104? Explain fig. 105.

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[Illustration: Fig. 106. A view of the larynx from above, showing the
vocal ligaments.