The Human Respiratory System - Computational Fluid and Particle Dynamics in the Human Respiratory System - page 29

Fig. 2.9 Anterior, mid-saggital (cut-away) and posterior views of the larynx

closes off the trachea during the act of swallowing to direct food into the oesopha-
gus instead of the trachea. The laryngeal skeleton consists of nine cartilages, three
single (thyroid, cricoid, and epiglottis) and three paired (arytenoid, corniculate, and
cuneiform), connected by membranes and ligaments. The hyoid bone is connected
to the larynx but is not considered part of the larynx. The single laryngeal cartilages
are:
• The epiglottis —a leaf-shaped piece of elastic cartilage located at the top of the

larynx. It is inferiorly anchored at one end between the back of the tongue and
the anterior rim of the thyroid cartilage. The free superior end bends up and down
like a flap to open and close the opening into the larynx.

• The thyroid cartilage ( Adam's apple )—formed by the fusion of two cartilage

plates and is the largest cartilage of the larynx. It is shaped like a triangular shield
and is usually larger in males than in females due to male sex hormones stimulating
its growth during puberty.

• The cricoid cartilage —a signet ring shaped cartilage so-called because the signet

end forms part of the posterior wall of the larynx. It is attached to the top of trachea
and is the most inferiorly placed of the nine cartilages.

The paired laryngeal cartilages form part of the lateral and posterior walls of the
larynx, which are:

• The arytenoid cartilages—two upward protrusions located at the back of the

larynx. The arytenoid cartilages are attached to the cricoarytenoid muscles, an-
chored by the cricoid cartilage and attached to the vocal cords. They are the most
important because they influence the position and tension of the vocal folds.

• The corniculate cartilages —small and cone-shaped hyaline cartilages that sit on

top of each of the arytenoid cartilages. During swallowing of food, the epiglottis