RESPIRATORY SYSTEM OF THE HORSE 
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 (Plicze ventriculares), each of which consists of a fold of mucous mem- 
brane covering the ventricular ligament and the cuneiform process. Between the 
false and true vocal cord there is a pocket-like depression termed the lateral ven- 
tricle of the larynx (Ventriculus lateralis laryngis). This is the entrance to the 
laryngeal saccule (Sacculus laryngis), a cul-de-sac of the mucous membrane which 
is an inch or more (ca. 2.5 to 3 em.) long and extends upward and backward on the 
medial surface of the thyroid lamina. There is a small middle ventricle (Ventric- 
ulus laryngis medianus) at the base of the epiglottis. 
The term ‘laryngeal saccule’’ seems decidedly preferable to the “appendix ventriculi lar- 
yngis” of the B. N. A. The saccule is in relation with the ventricular and vocal muscles, and 
/ —»—— Body of thyroid 
cartilage 
oN, 
/ Base’ \\ 
f ° 
ff. Epiglittis 
Lamina | 4 
of thyroid +f 
cartilage 
Tic. 466.—Cast or Ricar LareraLt VENTRICLE 
AND SaccuLe or Horse; Mepiar Virw. 
Vocal fe ve ed ularis 1, Ventricle; 2, saccule. Figure is a little less than 
= uscle 
cords MUSE three-fourths of natural size. 
+— Lateral 
ventricle 
— Laryngeal 
saccul 
- Vocalis 
muscle 
Crico- 
arytenoideus 
dorsalis 
muscle 
Fria. 467.—Cast or Lerr LATERAL VENTRICLE AND 
SaccuLe or Larynx or Horse; LATERAL VIEW. 
Fie. 465.—Srction or Larynx or Horst 
The section cut is parallel with the vocal cords. 
1, Ventricle; 2, saccule; 3, impression of ventricu- 
laris muscle; 4, impression of vocalis muscle. 
when the latter are atrophic (as in hemiplegia laryngis or ‘‘roaring’’), the pouch is considerably 
larger on the affected side, having occupied the space vacated by the muscles. The blind end of 
the saccule lies just below the level of the muscular process of the arytenoid cartilage. It is loosely 
attached to the contiguous structures. The average capacity of the saccule is about 5 to 6 c.c. 
The middle, narrow part of the cavity is termed the glottis or rima glottidis. 
It is bounded on either side by the true vocal cord and the medial surface of the ary- 
tenoid cartilage. The true vocal cords (Labia vocales) are situated behind the 
false cords and the lateral ventricles. They extend from the angle of junction of 
the body and lamine 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 voealis) is very 
thin and smooth, and is intimately attached to the underlying vocal ligament. In 
