respect to the resonator and tongue. The position of the vocal cords is
shown, but really they would not be seen unless one half of the shield
cartilage were cut away so as to show the interior of the voice-box. Sound
vibrations are represented issuing from the larynx, and here they become
modified by the resonator; the throat portion of the resonator is shown
continuous with the nasal passages; the mouth portion of the resonator is
not in action, owing to the closure of the jaw and lips. The white spaces
in the bones of the skull are air sinuses. In such a condition of the
resonator, as in humming a tune, the sound waves must issue by the nasal
passages, and therefore they acquire a nasal character.]




III. THE RESONATOR AND ARTICULATOR


_The Resonator_.--The resonator is an irregular-shaped tube with a bend in
the middle; the vertical portion is formed by the larynx and pharynx, the
horizontal by the mouth. The length of the resonator, from the vocal cords
to the lips, is about 6.5 to 7 inches (_vide_ fig. 12). The walls of the
vertical portion are formed by the vertebral column and the muscles of the
pharynx behind, the cartilages of the larynx and the muscles of the pharynx
at the sides, and the thyroid cartilage, the epiglottis, and the root of
the tongue in front; these structures form the walls of the throat and are
all covered with a mucous membrane. This portion of the resonator passage
can be enlarged to a slight degree by traction upon the larynx below
(sterno-thyroid muscle), by looseness of the pharyngeal muscles, and still
more by the forward placement of the tongue; the converse is true as
regards diminution in size. The horizontal portion of the resonator tube