This
film uses the natural air of the pharynx and larynx as contrast medium. The cartilages
of the larynx are seen and undergo true ossification rather than calcification.
The retropharyngeal space between the posterior wall of the trachea and the
anterior border of the cervical spine should not exceed the AP diameter of one
vertebral body. Note the following: the articulation of the thyroid and cricoid
cartilages; the air in the ventricle of the larynx between the true and false
cords; and the position of the larynx extending from C3 to C6. The pharynx can
also be seen in its anatomical divisions of nasopharynx, above the soft palate,
oropharynx between soft palate and base of tongue, and hypopharynx from base of
tongue inferiorly.
