(c) Laryngopharynx. The part of the pharynx which is common to the
respiratory and digestive systems is the laryngopharynx. It is the part of the pharynx
below the edge of the epiglottis. The digestive and respiratory systems lead into this
part from above and lead off from it below.
The larynx (figure 1-6), also called the voice box, connects the pharynx with the
trachea. The larynx is located in the anterior region of the neck and has a box-like
shape (see figure 1-3). The voice box of the male becomes larger and heavier during
puberty causing the male's voice to get deeper. An adult male's voice box tends to be
located lower in the neck than the female's voice box. The female's larynx remains
higher and smaller causing the female's voice to be a higher pitch.
a. Structure. Nine pieces of cartilage support the larynx: three single pieces of
cartilage and three paired pieces of cartilage. The three single pieces are the thyroid
cartilage, epiglottic cartilage (epiglottis), and cricoid cartilage. The three paired pieces
of cartilage are arytenoid cartilages, corniculate cartilages, and cuneiform cartilages.
(1) Thyroid cartilage. Sometimes called the Adam's apple, this cartilage is
made up of two fused plates which form the anterior wall of the larynx. These plates
cause the larynx to be triangular in shape. The thyroid cartilage is larger in males than
(2) Epiglottic cartilage (epiglottis). This cartilage lies on top of the larynx
and is shaped like a large leaf. The "stem" of the epiglottis is attached to the thyroid
cartilage. The "leaf" of the epiglottis is unattached and moves up and down freely.
During swallowing, the larynx moves up causing the free edge of the epiglottis to form a
lid over the glottis, and the glottis is closed. The glottis is the hole between the vocal
cords in the larynx. Air passes through the glottis into the main chamber of the larynx
(below the cords) and then into the trachea. The covering over the glottis allows the
larynx to be closed off. Liquids and foods then move into the esophagus and are kept
out of the trachea. A cough reflex takes place in an effort to expel anything other than
air that gets into the larynx.
(3) Cricoid (KRI-koyd) cartilage. This is a ring of cartilage that forms the
interior wall of the larynx. It is attached to the first ring of the trachea.
(4) Arytenoid (ar-i-TE-noyd) cartilages (paired). The arytenoid cartilages
are located at the superior border of the cricoid cartilage and are shaped like pyramids.
These cartilages are attached to the vocal folds and pharyngeal muscles. The action of
these cartilages causes the vocal cords to move.
(5) Corniculate (kor-NIK-yoo-lat) cartilages (paired). These cartilages are
located at the apex of each arytenoid cartilage. They are shaped like a cone.