112 
goes a sudden development, whilst in the female 
it remains stationary. The comparative length of 
the chink in the male and female is proportional 
to the relative lengths of the vocal ligaments 
already detailed. The length of the rima glot- 
tidis bears no relation to the stature of the indi- 
vidual. In the adult male it is about eleven 
lines, of which the boundaries formed by the 
arytenoid cartilages are four, and the thyro-ary- 
tenoid ligaments seven lines. In the male and 
female it is on a mean average as three in the 
former to two in the latter. In a female, M. 
Lauth however found the rima glottidis to mea- 
sure from ten to eleven lines, whilst that of a 
tall male extended only from eight to nine lines ; 
but this is a rare instance. 
The pomum Adami on the thyroid has a 
corresponding concavity within, which affords 
a greater length in the mesial section of the 
larynx, and which tends to increase the longi- 
tudinal dimensions of the glottis. In several 
of the ruminantia the concavity is very con- 
spicuous.* The breadth of the glottis is much 
less than its length. In a state of repose its 
transverse section is not more in the adult than 
about two or three lines, or with respect to its 
length as two to eleven, but the diameter varies 
with the intensity of the forces of the intrinsic 
muscles of the larynx. 
The ventricles. Ventricule ou sinus du laryne. 
Cruv.— These are oval or elliptical cavities 
directed from before backwards, between the 
superior and inferior ligaments. The depths of 
the ventricles are effected by the distance from 
the free margin of the vocal ligaments to the 
internal surface of the thyroid, or rather to the 
thyro-arytenoid muscles, which constitute the 
bottom of the ventricles. The internal part of 
the posterior cavity of the ventricles is enlarged 
and deepened by a duplicature of the mucous 
membrane passing external to the arytenoid 
cartilage, which has been described by Mor- 
gagni, and recently more particularly by Mr. 
Hiltont under the name sacculus laryngis, 
The ventricles are prolonged anteriorly, extend- 
ing along the vocal cords on each side of the 
epiglottis. In size the ventricles vary with the 
general dimensions of the larynx; they are 
each divided into an interior and posterior 
cavity by a transverse ridge. The ventricles 
afford greater freedom of motion to the inferior 
thyro-arytenoid ligaments. 
Nerves.—The larynx is exquisitely sensible, 
and, as we have seen, combines complex and 
delicate motions with secreting surfaces. These 
properties result from its nervous endowment, 
which is derived from two branches of the 
pneumo-gastric nerve, namely, the superior 
and the inferior laryngeal nerves. 
It will be unnecessary to enter into any de- 
tailed description of these nerves here. Their 
distribution will be found fully described in 
the article Par vaGuM, to which we refer. 
Let it suffice to mention, that the superior la- 
ryngeal nerve by its external branch gives fila- 
ments, 1, to the inferior constrictor of the pha- 
* Vide Pallas Spicil. Zool. Trans. xii, 
t Guy’s Hosp. Reports, No. v. 
NORMAL ANATOMY OF TILE LARYNX. 
A view, from Mr. Swan, of the superior @ 
inferior la nerves. a, a portion of 
tongue ; b, the epiglottis ; c, the thyroid cartila 
d, the posterior arytenoid muscle divided for s) 
ing a branch of the recurrent nerve passing to | 
oblique and transverse muscles; e, the late 
crico arytenoid muscle; f, the thyro- 101 
muscle ; g, the arytenoideus obliquus ; A, the ar 
tenoideus transversus ; i, the crico-thyroid 5 j, 
1, the superior laryngeal nerve; 2, a branch 
this nerve to the membrane connected with tl 
covering the epiglottis ; 3, a branch of the 
laryngeal to the membrane placed between 
superior extremities of the arytenoid ¢ 
4, the recurrent nerve; 5, a branch of the rm 
rent given off to the membrane lying betwee; 
larynx and pharynx; 6,a hence of th pcur 
nerve to communicate with a branch of the 
rior laryngeal nerve ; 7, a branch of the recurre 
to the posterior crico-arytenoid muscle ; 8, a bram 
to the crico-thyroid and crico-arytenoid le 
9, abranch giving filaments to the posterior 
arytenoid, and passing between this m 
the arytenoid cartilage, to terminate in the obliqa 
and transverse arytenoid muscles. 
rynx; 2, to the thyro-hyoid muscle and 
brane ; 3, to the laryngeal plexus; 4, to 1 
crico-thyroid muscle ; 5, to the thyroid glan 
The internal branch of the superior ynge 
nerve supplies filaments, 1, to the epiglottis 
2, to the adipose and mucous membrane 
4, to the arytenoid muscles; 4, to the thyro- 
arytenoideus; 5, to the crico-arytenoideus late 
ralis; 6,a descending anastomotic branch to th 
