The cricoid cartilage is shaped like a signet-ring; it is made of hyaline
cartilage and tends to ossify. The broad, posterior part, called the
lamina, is quadrangular in outline. Its upper border is occupied by a pair
of oval, convex facets separated by a shallow notch; these facets articulate
with the bases of the arytenoid
cartilages. The posterior surface of the lamina is divided by a median
ridge into two areas which give origin to the posterior cricoarytenoid muscles.
The median ridge itself gives attachment to a tendinous band which proceeds
upwards from the longitudinal fibres of the esophagus.
The anterior part of the cricoid cartilage is the arch. Its upper border
slopes rapidly upwards as it passes backwards to the lamina, and gives attachment
to the cricothyroid ligament
and cricovocal membrane.
| Profile view of cartilages and ligaments
in the larynx
The facet for the thyroid is on the side of the ring at the junction of
arch and lamina. The lower border of the ring is horizontal, and is connected
to the first tracheal ring by the cricotracheal ligament; and the inner
surface of the ring is lined with mucous membrane.
The arch of the cricoid cartilage lies below the anterior part of the thyroid
cartilage, but the lamina is received into the interval between the
posterior portions of the thyroid laminae.