The plane of the section is parallel with the vocal cords.
]
The =vestibule= of the larynx (Vestibulum laryngis) is that part of the
cavity which extends from the aditus to the vocal cords. On its lateral
walls are the =false vocal cords= (Plicæ ventriculares), each of which
consists of a fold of mucous membrane covering the anterior part of the
thyro-arytenoid ligament and the cuneiform process. Between the false
and true vocal cord there is a pocket-like depression termed the
=lateral ventricle= of the larynx (Ventriculus lateralis laryngis). This
is the entrance to the =laryngeal saccule= (Appendix ventriculi
laryngis), a cul-de-sac of the mucous membrane which is about one inch
(ca. 2 to 3 cm.) long and extends upward and backward on the inner
surface of the thyroid lamina. There is a small =middle ventricle=
(Ventriculus laryngis medianus) at the base of the epiglottis.
The middle, narrow part of the cavity is termed the =glottis= or =rima
glottidis=.[123] It is bounded on either side by the true vocal cord and
the inner surface of the arytenoid cartilage. The =true vocal cords=
(Labia vocales) are situated behind the false cords and the lateral
ventricles. They extend from the angle between the body and laminæ of
the thyroid cartilage to the vocal processes of the arytenoid
cartilages. They are prismatic in cross-section, and their free edges
look forward and somewhat upward. The mucous membrane of the cord (Plica
vocalis) is very thin and smooth, and is intimately attached to the
underlying ligament. In ordinary breathing the rima is somewhat
lanceolate in form; when dilated, it is diamond-shaped, the widest part
being between the vocal processes. The narrow part of the glottis
between the vocal cords is termed the glottis vocalis (Pars
intermembranacea), while the wider part between the arytenoid cartilages
is the glottis respiratoria (Pars intercartilaginea).
The =posterior compartment= of the laryngeal cavity is directly
continuous with the trachea. It is inclosed by the cricoid cartilage and
the crico-thyroid membrane. It is oval in form, the transverse diameter
being an inch and a half to two inches (ca. 4 to 5 cm.), and the
dorso-ventral diameter two to two and a half inches (ca. 5 to 6 cm.).
The =mucous membrane= which lines the larynx (Tunica mucosa laryngis) is
reflected around the margin of the aditus to become continuous with that
of the pharynx, and behind it is continuous with that which lines the
trachea. It is closely attached to the pharyngeal surface of the
epiglottis, but elsewhere in the aditus and vestibule it is loosely
attached by submucous tissue which contains many elastic fibers.[124] It
is thin and very closely adherent over the vocal cords and the inner
surfaces of the arytenoid cartilages. The epithelium is of the
stratified squamous type from the aditus to the glottis, beyond which it
is columnar ciliated in character. There are numerous =mucous glands=
(Glandulæ laryngeæ), except over the glottis and the pharyngeal surface
of the epiglottis, in which situations they are scanty.
=Blood-supply.=—Thyro-laryngeal artery.
=Nerve-supply.=—Superior laryngeal and recurrent laryngeal nerves (from
the vagus).