The vocal folds are ridge-like structures that are oriented in an anteroposterior (ventral-dorsal) direction. In frontal sections, the vocal folds (VF ) are cross-sectioned, giving the appearance seen here. The two vocal folds and the space between them constitute the glottis. Just above each vocal fold is an elongated recess called the ventricle (V ), and above the ventricle is another ridge called the ventricular fold (VnF ) or, sometimes, the false vocal fold. Below and lateral to the vocal folds are the vocalis muscles (VM ). Within the vocal fold is a considerable amount of elastic material, although it is usually not evident in routine H&E preparations. This elastic material is part of the vocal ligament. It lies in an anteroposterior direction within the substance of the vocal fold and plays an important role in phonation.
Ventricular and vocal folds, larynx, monkey, H&E ×160. the contact between surfaces is considerable. Laterally, the surfaces consist of stratified columnar epithelium (SCE). The contact between these surfaces
The surfaces of a vocal fold and the facing ventricular fold is less wearing. Small glands (Gl) are in the lamina propria of the laryngeal within rectangle 1 in top figure are turned 90° clockwise and mucosa.
shown at higher magnification in this figure. Medially, both are lined by stratified squamous epithelium (SSE). Here,
Infraglottic cavity, larynx, monkey, H&E ×160. infraglottic cavity. It shows the junction between the stratified squamous epithelium (SSE ), with its flat surface cells, and the stratified columnar
Rectangle 2 in top figure is shown at higher magnification in epithelium (SCE ), with its columnar surface cells. The lamina propria this figure. This area of the larynx below the ventricles  and consists of loose connective tissue in which glands (Gl ) are present.
rima glottidis communicates with trachea and is called the
Infraglottic cavity, larynx, monkey, H&E ×160.
Epithelium of the infraglottic cavity of the larynx just below the portion shown in top figure changes again, giving way, below, to the ciliated pseudostratified columnar epithelium (PSE) shown here. Note the cylinders of cytoplasm that clearly indicate the columnar nature of the surface cells. In the upper part of the figure, the epithelium is stratified columnar; in the lower part of the figure, it is pseudostratified columnar. This distinction is difficult to make from the examination of a single sample such as that shown here, and other information is needed to make the assessment. The additional information is the presence of cilia on the pseudostratified columnar epithelium; this epithelium is typically ciliated. Although not evident in the photomicrographs, note that stratified columnar epithelium has a very limited distribution, usually occurring between stratified squamous epithelium and some other epithelial types (e.g., pseudostratified columnar here or simple columnar at the anorectal junction, Plate 64). The lamina propria is a loose cellular connective tissue, and it also shows some glands (Gl ).
KEY Gl, glands PSE, pseudostratified columnar epithelium SCE, stratified columnar epithelium SSE, stratified squamous epithelium V, ventricles VF, vocal folds VM, vocalis muscles VnF, ventricular folds