arynx is the thyroid or shield
cartilage, named from the Greek _thureos_ (shield). It really consists
of two shields joined along the edges in front (its most forward upper
projection being the Adam's apple) and opening out at the back. The
thyroid is the uppermost cartilage of the larynx and the Adam's apple
is the uppermost portion of the front of the larynx. But as the shields
open out back of the Adam's apple, they slope upward and at the extreme
back each shield has a marked upward prolongation like a horn. By these
horns, enforced by membrane, the thyroid cartilage and through it the
whole larynx is attached to and is suspended from the hyoid bone, or
tongue-bone. This gives mobility to the larynx and freedom of movement
to the neck; and the larynx, while mobile as a whole, furthermore is
capable of an infinite number of muscular adjustments and readjustments
within itself.

At the back the lower edges of the thyroid rest upon the cricoid
cartilage, which derives its name from the Greek _krikos_, a
signet-ring. This is next in size to the thyroid. The broader portion,
the part which corresponds to the seal in a signet-ring, is at the
back. Attached at the back, the two cartilages do not, however, meet in
front. Place a finger on the Adam's apple, slide it down a little way,
and the slight depression there met with locates the front opening,
covered with yielding membrane, between the thyroid and cricoid
cartilages.

On the broader part of the cricoid--that is, on the part in the back of
the larynx--and rising inside the thyroid are two smaller cartilages,
the arytenoid or ladle cartilages, named from the Greek _arutaina_, a
ladle. Though smaller than either thyroid or cricoid, they are highly
important, because they form points of attachment for the vocal cords.
These (the vocal cords) are attached in front to the inner part of the
angle formed by the two wings of the thyroid just back of the Adam's
apple, and behind to a forward projecting spur at the base of each of
the arytenoid cartilages, which for this reason often are spoken of as
the "vocal process."

The vocal cords, as has been stated, lie parallel to each other, and
the space between them is known as the glottis or chink of the glottis.
Above the glottis and on opposite sides are two pockets or ventricles,
and above these are the so-called false cords or ventricular bands. The
pockets are, in fact, bordered below by the vocal cords and above by
the