ARY.

The larynx is the most important organ in voice-production, and
consists of cartilages, muscles, the vocal bands, true and false,
membranes and ligaments, folds of mucous membrane, etc. It is situated
between the hyoid (tongue) bone above and the trachea below. The
cartilages are the (1) epiglottis, (2) thyroid, cricoid, arytenoid,
the two small, unimportant cornicula laryngis, or cartilages of
Santorini, surmounting the arytenoids, and the two cuneiform, or
cartilages of Wrisberg, in the folds of mucous membrane on each side
of the arytenoids.

The muscles are attached to the main cartilages. In addition to the
muscles that are concerned with the movements of the vocal bands,
others that hold the larynx in place or raise and lower it are
attached _externally_ to these, especially to the large thyroid
cartilage. The epiglottis, the false vocal cords, the true vocal
cords, and the thyro-arytenoid muscles are attached to the interior
anterior surface of the thyroid in this order from above down.

The false vocal bands have no direct function in phonation. _The whole
larynx, so far as phonation is concerned, may be said to exist for the
true vocal bands._ They are attached close together to the internal
and anterior surface of the thyroid in front and to the lower anterior
angles (vocal processes) of the arytenoids behind. Between the false
vocal bands above and the true vocal bands below there is a cavity
(the ventricle of Morgagni). The false vocal bands are protective, and
approximate closely during coughing, swallowing, etc.

It is very important to note that the arytenoid cartilages move freely
on their base, swivel-like, so that nearly all the changes effected in
the movements and tension of the vocal bands are brought about through
alterations in the position of these cartilages; and this implies that
all the muscles concerned are attached to them. From above down, in
front, the order of structures is as follows:

Hyoid bone.
Membrane.
Thyroid cartilage.
Membrane.
Cricoid cartilage.
Trachea.

The hyoid bone is not a part of the larynx, but from it the larynx is
suspended. The bone itself gives attachment to the muscles of the
tongue. The glottis is the chink between the true vocal bands.

The muscles of the larynx may be divided into the following: (1) Those
that open and those that close the glottis; (2) those which regulate
the tension of the vocal bands. The latter