3, 4. UPPER BORDER OF THE RING.
5. SHIELD (THYROID) CARTILAGE.
6, 7. UPPER HORNS OF THE SHIELD.
8. RIGHT LOWER HORN OF THE SHIELD.
9. POINT WHERE THE SHIELD MOVES UPON THE RING.
10. RING-SHIELD (CRICO-THYROID) APERTURE COVERED BY MEMBRANE.
11. LID (EPIGLOTTIS).
12. WINDPIPE (TRACHEA).
]
[Illustration: PLATE VI.
FRONT VIEW OF THE VOICEBOX, OR LARYNX.
1, 2. UPPER HORNS OF THE SHIELD.
3. TONGUE (HYOID) BONE.
4, 5. HORNS OF THE TONGUE-BONE.
6, 7. BANDS UNITING THE SHIELD WITH THE TONGUE-BONE.
8, 9. LID.
10, 11. PLATES OF THE SHIELD.
12. RING.
13. ELASTIC BAND UNITING THE SHIELD WITH THE RING.
14. WINDPIPE.
]
This is a very particular point, and I beg the reader particularly to
notice that if the shield cartilage (pl. V, 5) were gradually drawn
downwards and forwards, the space which we now see between the shield
and the ring (pl. V, 10) would get smaller and smaller, until at last it
quite disappeared; and the distance between the front of the shield (pl.
V, 1) and the highest part of the back of the ring (pl. V, 4) would be
increased.
I may observe here that authorities differ as to whether the shield
moves upon the ring, or the ring upon the shield, and that some
maintain the one is drawn down while the other is tipped upward. It
is sufficient for our purpose, however, that a movement as upon a
hinge takes place, whereby, as explained just now, the distance
between the front of the shield and the highest part of the back of
the ring is increased.
3rd. =The Lid= (pl. V, 11) is an elastic cartilage which serves to close
the voicebox in the act of swallowing, in order to protect it against
any intruding foreign substances. The food we take has to pass over it,
and it sometimes happens, when the lid has not been pulled down tight
enough, that a particle of food enters the voicebox, in which case we
say it has "gone the wrong way," and there is then no peace until the
intruder has been got rid of, generally by a violent fit of coughing.
The lid, it is true, is not the only means of protection which the
voicebox possesses. Professor C. J. Eberth, for instance, mentions
(Archiv fuer pathol: Anatomie, vol. lxiii., p. 135, Berlin, 1868)
the case of a woman who, upon dissection, was found to be entirely
without the free upper part of the lid, which could alone cover the
voicebox. She had never experienced any difficulty in swallowing,
and it is therefore clear that with her the closing of some of the
parts immediately below was sufficient to prevent the food from
getting into the voicebox. But "the exception proves the rule," and
in spite of this and other similar cases, the fact remains that the
lid is obviously the first and most natural protector of the
voicebox.
4th and 5th. We have thus far become acquainted with three cartilages
out of the five. Let us now remove one plate of the shield, as though
cutting it off with a knife (pl. VII, 1 and 2), in order that we may
look inside and see the remaining two cartilages which have hitherto
been hidden by it. These are--
=The Pyramids= (pl. VII, 1 and 2), so called because of their shape. Their
bases are triangular and hollowed out; their sides taper upwards and
terminate in points which are bent slightly backwards, and they have
each two projections, one pointing forwards (pl. VII, 3) and the other
outwards and backwards (pl. VII, 4). It will be convenient to have a
special name for the projections pointing outwards and backwards, which
we will therefore call the Levers.
The Pyramids are attached with their hollow bases to the borders of the
ring (pl. VII, 5), and they are capable of executing rotary movements
with surprising freedom and rapidity. Their inner sides may be made to
run parallel or to diverge. In addition to this they can be drawn
towards each other, or away from each other, so that their summits may
either be widely separated or brought close together.
=The Vocal Ligaments= are two ledges of elastic tissue covered with a very
delicate membrane. Each one of them is connected along its whole length,
on one side, with the shield cartilage. The vocal ligaments are attached
by their hinder ends to those little projections of the pyramids which
point forwards (pl. VII, 3, 3), and by their front ends to the centre of
the shield (pl. VII, 6), where the two plates meet under a more or
less acute angle.
[Illustration: PLATE VII.
SIDE VIEW OF THE VOICEBOX, OR LARYNX, SHOWING THE INTERIOR OF IT, THE
RIGHT PLATE BEING REMOVED.
1, 2. PYRAMIDS (ARYTENOID CARTILAGES).
3, 3. FRONT PROJECTIONS OF THE PYRAMIDS.
4. LEVER OF THE RIGHT PYRAMID.
5. UPPER BORDER OF THE RING.
6, 3, 3. VOCAL LIGAMENTS.
7. LID.
8. SHIELD.
9. LEFT UPPER HORN OF THE SHIELD.
10. RING.
11. WINDPIPE.
]
These vocal ligaments are generally called the vocal cords, but
this term is misleading, as it implies strings like those, for
instance, of the violin, which are attached only at either end and
are free at every other point. This, however, as we have just seen,
is not the case, the "Cords" being free only along their inner
edges. The name "Vocal Bands," which German physiologists have
substituted for "Vocal Cords," does not mend the matter, as it is
open to exactly the same objections. The term "Vocal Lips," also
used by some writers, is, in my judgment, the most unfortunate of
all, because it conveys a totally wrong idea of these parts, as
will be seen from a description in another chapter of their
movements in the act of singing. I have, therefore, sought for a
word which, as a proper description of the thing it is to
designate, shall always call a correct image to the reader's mind,
and as I cannot find a better one than "Ligament," I have adopted
it. I shall consequently in these pages always speak of the
tone-producing element as the "Vocal Ligaments."
The vocal ligaments, having met, are struck by the air blown against
them from below, and being elastic they yield, allowing themselves to be
forced upwards. A little air is thereby set free, and the pressure from
below diminished, in consequence of which the vocal ligaments resume
their former position, and even move a little more downwards. The
renewed pressure of the air once more overcomes the resistance of the
vocal ligaments, which again recede as soon as another escape of air has
taken place, and this process is repeated in rapid and regular
succession. In this manner, and in this manner alone, is vocal tone
produced, whether it be called chest, falsetto, head, or by any other
name.
There are still some writers who teach a different doctrine. For
instance, Miss Sabilla Novello, in her "Voice and Vocal Art,"
embodied in the "Collegiate Vocal Tutor," published by Novello,
Ewer, and Co., says on p. 9, that "The head voice results from the
upper [_i.e._, the false] vocal cords" (these we shall see
presently), and on page 13, that the falsetto tones "are created
principally by the action of the trachea [windpipe] and not by that
of the vocal ligaments." Another writer, Mr. Rumney Illingworth, in
a paper "On the Larynx and its Physiology," read before the Royal
Medical Society of Edinburgh, on March 3rd, 1879, and communicated
to "The Students' Journal and Hospital Gazette" (Vol. IV., No. 91,
p. 151), says that "The falsetto voice is produced by the laryngeal
sacculi [the pockets of the voicebox, which will be described
further on] acting in the same way as a hazel-nut can be made to
act as a whistle, when the kernel has been extracted through a
small hole in the shell; or as part of the cavity of the mouth acts
in whistling." I shall refer to these theories again as the
opportunity for their proper discussion arises; for the present I
will quote a few authorities on the subject.
Dr. CARPENTER, in his "Human Physiology," eighth edition, page 914,
says, "The true theory of the voice may now be considered as well
established in regard to this essential particular that the sound
is the result of the vibrations of the vocal cords," &c.
Professor MARSHALL, in his "Outlines of Physiology," page 255,
says: "Experiments on living animals show that the vocal cords are
alone the essential organs for the production of voice, for so long
as these remain untouched, although all the other parts in the
interior of the larynx be destroyed, the animal is able to emit
vocal sounds.... The existence of an opening in the larynx of a
living animal, or of man, _above_ the glottis [glottis means the
vibrating element of the voicebox] in no way prevents the formation
of vocal sound; such an opening if situated in the trachea
[windpipe] causes total loss of voice, but by simply closing it,
vocal sounds can again be produced. Such openings, in man, are met
with, either as the results of accidents, of suicidal attempts, or
of operations performed on the larynx or trachea for the relief of
disease."
Dr. TOBOLD, Professor in the University of Berlin, in his
"Laryngoscopie and Kehlkopf Krankheiten" (Laryngoscopy and Diseases
of the Larynx), p. 131, says, "Soft palate, lid, pockets, and
pocket-bands are not directly active in the production of either
chest or falsetto tones; they only modify the tone produced in the
glottis."
Dr. LUSCHKA, Professor in the University of Tubingen, in his great
work "Der Kehlkopf des Menschen" (The Human Larynx), says in the
introduction: "Only the vocal cords, with the slit they form, have
specifically functional signification, in a narrower sense, of a
voice apparatus, as the parts of the larynx which lie under and
over them have no material and deciding influence on the production
of sound."
I will bring my quotations to a close with the following, which
seeks to prove the contrary. Dr. C. B. GARRETT ("The Human Voice,"
J. and J. Churchill, London, 1875, p. 17) says, "It is recorded
that the larynx of a blackbird was removed by severing the windpipe
just below it; that the poor 'thing continued to _sing_, though in
a feebler tone.' This proves that notes can be formed _behind the
instrument_ and before the air reaches it." This argument, however,
is of no value, because it so happens that birds have two larynges,
one at the bottom and the other at the top of the windpipe. Dr.
Garrett seems not to have been aware of this fact.
The vocal ligaments in the adult male are, in a state of rest, about
three-quarters of an inch long, and in the female about half an inch. I
pointed out before that the vocal ligaments are attached in front to the
shield (pl. VII, 6) and behind to the pyramids (pl. VII, 3, 3). Let it
now be borne in mind--1st, That the pyramids, in their turn, are
fastened to the upper border of the ring cartilage; and 2nd, That by
drawing the shield downwards and forwards upon the ring, the distance
between the upper border of the ring (pl. VII, 5) and the front of the
shield (pl. VII, 6) is increased, and it will be easily seen that this
movement must of necessity have the effect of stretching the vocal
ligaments.
This drawing of the shield downwards and forwards upon the ring is
brought about by a pair of muscles ascending on either side, in the
shape of a fan, from the ring to the shield cartilage (pl. VIII, 1, 2).
These muscles we name the "Ring-Shield Muscles." In opposition to them
there is another pair inside the shield, running parallel with the vocal
ligaments (pl. IX, 1, 2, 3). They are attached (like the vocal
ligaments) in front to the shield cartilage and behind to the pyramids.
These muscles we will call the "Shield-Pyramid Muscles." They counteract
the ring-shield muscles, and having overcome their resistance, pull the
shield cartilage up again, thereby, of course, relaxing the vocal
ligaments. The ring-shield muscles, therefore, _stretch_ the vocal
ligaments and the shield-pyramid muscles _relax_ them. The
shield-pyramid muscles have an additional function--that of pressing
together the vocal ligaments, under certain circumstances, thereby
narrowing the opening between them. They have therefore been, in these
later days, called the Sphincter[G] muscle of the glottis. They have
also been called the Vocal Muscles, since they play so important a part
in the formation of all vocal tone that a paralysis of them causes total
loss of voice.
[Illustration: PLATE VIII.
SIDE VIEW OF THE VOICEBOX, OR LARYNX.
1, 2. RING-SHIELD MUSCLE (CRICO-THYROIDEUS).
3. LID.
4. SHIELD.
5, 6. UPPER HORNS OF THE SHIELD.
7. RING.
8. WINDPIPE.
]
[Illustration: PLATE IX.
SIDE VIEW OF THE VOICEBOX, OR LARYNX, SHOWING THE INTERIOR OF THE LEFT
HALF.
1, 2, 3. SHIELD-PYRAMID MUSCLE (THYRO-ARYTENOIDEUS).
4, 5. RING-PYRAMID MUSCLE (CRICO-ARYTENOIDEUS).
6. SHIELD.
7. LEFT UPPER HORN.
8. PYRAMID.
9. RING.
10. WINDPIPE.
]
It may be observed here that it is impossible to imitate, in the
dead subject, the contraction of the vocal muscles. All
conclusions, therefore, drawn from experiments upon exsected
larynges, with regard to tone-production in living man are
necessarily quite untrustworthy, and cannot for one moment be
admitted as evidence against observations made upon singers with
the laryngoscope.
These two pairs of muscles, then, namely the ring-shield muscles (pl.
VIII, 1, 2) and the shield-pyramid muscles (pl. IX, 1, 2, 3) by
stretching, slackening, and compressing the vocal ligaments, mainly
govern the pitch of the tones produced by their vibrations. The
ring-shield muscles receive some assistance in stretching the vocal
ligaments from another quarter, of which we shall speak later on.
We have now had a look at the vocal ligaments, and we have seen by what
means they are put on the stretch. As, however, in a state of repose
these ligaments diverge behind, they must be brought parallel to each
other before they are ready for the production of sound. Let us,
therefore, in order to explain how this is done, imagine that we have
cut off that part of the pyramids which is standing out above the vocal
ligaments (pl. VII), and let us now have a look at these parts from
above. You see the ligaments (pl. XA, 1, 2), a section of the pyramids
(pl. XA, 3, 4), and uniting these an elastic band (pl. XA, 5). The space
between these parts is commonly called the Glottis, but as this
appellation belongs more properly to the vocal ligaments, it is
manifestly wrong to give the same name to the _space_ which they
inclose. This space should be distinguished as the "_Chink_ of the
Glottis" or the "Vocal Chink."
I have been blamed for making this distinction in the face of
almost universal usage. But I can point to the great anatomist
Professor Luschka as having set the example, and while it is true
that in most physiological works "Glottis" is used for the _slit_
between the vocal ligaments, yet the appellations "Rima glottidis"
and "Aperture of the glottis" are also employed for the same thing.
Medical men, moreover, speak of "Spasm of the glottis," and singing
masters of the "Shock of the glottis," which terms are clearly
quite meaningless when applied to a space.
Dr. Garrett says, on page 12 of the book quoted before, that "The upper
portion of the larynx above the false vocal cords is termed the
glottis." He might as well say, "The upper portion of the face above the
nose is termed the mouth." I really should not notice so astounding a
statement were it not made by one signing himself an M.D., and published
by so eminent a firm of Medical publishers as Messrs. J. and A.
Churchill.
[Illustration: PLATE X.
A. GLOTTIS IN REPOSE.
B. GLOTTIS IN RESPIRATION.
C. GLOTTIS IN THE PRODUCTION OF SOUND.
A. 1, 2. VOCAL LIGAMENTS.
3, 4. SECTION OF THE PYRAMIDS.
5. ELASTIC BAND.
6, 7. LEVERS OF THE PYRAMIDS.
]
On plate XI you see all parts in a state of rest. To the levers of the
pyramids (pl. XI, 1, 2) a pair of muscles is attached, the bases of
which are fixed upon the back of the ring cartilage below (pl. XI, 3, 6,
3). The action of these "Back Ring-Pyramid Muscles" (pl. XI, 4, 1 and 5,
2) is to contract as soon as we take breath, thereby drawing together
the pyramids _behind_ and separating them _in front_, at the same time
stretching the elastic band behind (pl. X, A, 5). By this movement the
chink of the glottis is thrown _wide open_ into the shape depicted on
pl. X, B. During expiration these relax, the elastic band contracts, and
the vocal chink resumes the shape as on pl. XI. These movements go on
from the beginning of our lives to the end, whether we are asleep or
awake, with more or less vigour, according as we take a slight or a deep
inspiration. The back ring-pyramid muscles (pl. XI, 4, 1 and 5, 2), have
consequently the all-important function of keeping open the gate through
which the air we breathe enters the lungs. They have, therefore, been
poetically called the "Guardians of the Portal of Life." By their action
of pulling the pyramids backwards, they also assist the ring-shield
muscles (pl. VIII, 1, 2) in stretching the vocal ligaments.
* * * * *
In opposition to these "Opening Muscles" there is another pair rising
from the side borders of the ring (pl. XI, 3, 3) which are fastened to
the front part of the levers of the pyramids (pl. XI, 1, 2), serving to
draw together their front projections to which the vocal ligaments are
attached, and which are thereby brought parallel with each other.
[Illustration: PLATE XI.
VIEW OF A SECTION OF THE VOICEBOX, OR LARYNX, FROM ABOVE.
1, 2. SECTION OF THE PYRAMIDS WITH VOCAL LIGAMENTS AND ELASTIC BAND.
3, 6, 3. RING.
7. PYRAMID MUSCLE (ARYTENOIDEUS TRANSVERSUS).
8, 9, 10. SHIELD.
11. BANDS BY MEANS OF WHICH THE PYRAMIDS ARE ATTACHED TO THE RING.
4 & 5. BACK RING-PYRAMID MUSCLES (POSTERIOR CRICO-ARYTENOIDEI).
1, 3 & 2, 3. SIDE RING-PYRAMID MUSCLES (LATERAL CRICO-ARYTENOIDEI).
NOTE.--The shield-pyramid muscles (Thyro-Arytenoidei) which run parallel
with the vocal ligaments are, for the sake of clearness, omitted from
this diagram.]
These "Side Ring-Pyramid Muscles" (pl. XI, 3, 1 and 3, 2; see also pl.
IX, 5, 4) are assisted by a single muscle uniting the pyramids behind
the elastic band which we have already noticed. This muscle we will call
the "Pyramid Muscle" (pl. XI, 7). By the united action of the muscles
which have just been described the vocal chink is thrown in the shape
shown on pl. X, C, and the vocal ligaments are now in a proper position
for the production of tone.
* * * * *
Before proceeding any farther it will be well if we once more glance at
the muscles with which we have become acquainted, so that we may be
quite sure about their functions.
MUSCLES:
I. GOVERNING THE SHAPE OF THE VOCAL CHINK.
The Back Ring-Pyramid} OPENING
Muscles } THE VOCAL CHINK.
THESE ARE OPPOSED BY--
The Side Ring-Pyramid }
Muscles, and the Pyramid} CLOSING
Muscles, assisted by the} THE VOCAL CHINK.
Shield-Pyramid Muscles }
II. GOVERNING THE PITCH OF THE TONES.
The Ring-Shield Muscles, } STRETCHING
assisted by the Back Ring-Pyramid }
Muscles } THE VOCAL LIGAMENTS.
THESE ARE OPPOSED BY--
The Shield-Pyramid } SLACKENING
Muscles } THE VOCAL LIGAMENTS.
=The Pocket Ligaments= (called "False Vocal Cords," pl. XII, 1 and 2) are
a pair of horizontal projections running above and parallel with the
vocal ligaments (pl. XII, 3 and 4). The pocket ligaments are, like the
vocal ligaments, attached in front to the shield and behind to the
pyramids. They may be described as two ledge-shaped pads mainly formed
of glands. They are very sensitive and movable, and ready on the
smallest incitement to meet with great rapidity in order to protect the
vocal ligaments from any harm. They must, therefore, be chiefly regarded
as safeguards of the vocal apparatus, though it is probable that by
breaking the stream of air passing through the chink of the glottis,
they also exercise considerable influence upon the _quality_ of the tone
emitted. It may be affirmed, however, without the slightest hesitation,
that they have absolutely nothing to do with the _production_ of tone.
We shall see these glandular ledges again during our observations upon
the living subject, and I shall therefore say no more about them at
present.
[Illustration: PLATE XII.
VIEW OF THE VOICEBOX, OR LARYNX, WHICH HAS BEEN CUT OPEN FROM BEHIND.
1, 2. POCKET LIGAMENTS (FALSE VOCAL CORDS).
3, 4. VOCAL LIGAMENTS (VOCAL CORDS).
5, 6. SHIELD (THYROID) CARTILAGE.
7, 8. CARTILAGES OF SANTORINI.
9. LID (EPIGLOTTIS).
14, 10 & 15, 11. FOLDS OF MUCOUS MEMBRANE (ARYTENO-EPIGLOTTIC FOLDS).
12, 13. WEDGES (CUNEIFORM CARTILAGES).
14, 15. CARTILAGES OF WRISBERG.
16, 17. PYRAMID MUSCLE (ARYTENOIDEUS TRANSVERSUS).
18, 19. RING (CRICOID) CARTILAGE.
20, 21. TONGUE (HYOID) BONE.
]
The space between the pocket ligaments and the vocal ligaments (pl. XII,
1, 2, 3, 4) is the entrance to two pouches or pockets which extend
outwards and upwards. The dimensions of these pockets vary very much in
different individuals. As a rule their height does not exceed two-fifths
of an inch, so that their terminations do not reach the upper borders of
the shield cartilage (pl. XII, 5 and 6). But there are instances in
which the pockets are nearly three-quarters of an inch high, and where
such is the case they, as a necessary consequence, reach beyond the
shield. Sometimes they are so high as nearly to touch the root of the
tongue. Their outer walls are chiefly formed of loose fatty cellular
tissue, and the pockets are almost entirely surrounded by a large number
of small glands.
Now these are the "Laryngeal sacculi" which, according to Mr.
Illingworth, produce the falsetto voice by "acting in the same way
as a hazel-nut can be made to act as a whistle, when the kernel has
been extracted through a small hole in the shell," &c. I think,
however, that the reader will, from the description given above,
agree with me that the acoustic properties of the pockets of the
voicebox cannot be very great, and that, at all events, there is a
vast difference between their construction and that of a hazel-nut,
either with or without the kernel. Then there is this additional
difficulty, that even if one could whistle upon the pockets in the
manner suggested, there are two of them, covered, let it be
remembered, with a multitude of glands, continually producing
moisture, and liable to enlarge or to diminish. How, I should like
to know, could two such cavities be so tuned as under any
circumstances to produce exactly the same tones? Would not rather
frightful discords be the inevitable result? And again, what
provision is there in the pockets for the gradations of pitch? But
quite apart from these considerations, this and other similar
theories are completely disproved by the fact that every tone which
the human voice is capable of producing can be produced by
_inspiration as well as by expiration_. The tones sung by
inspiration are, as might be expected, wholly devoid of beauty,
because the vocal apparatus is, as it were, put upside down, and
the position of bellows and resonator reversed. But that does not
alter the question. The fact remains, and clearly proves that the
pockets have no more to do with the falsetto than with the chest
voice, because in inspiration the air strikes the vocal ligaments
_after it has passed_ the pockets, and yet the result is, beauty of
tone apart, exactly the same.
The function of the pockets, in my opinion, is this: They are the means
of isolating the vocal ligaments, thus enabling them to vibrate freely
and without hindrance. They also allow the sound-waves to expand
sideways, thereby materially adding to their resonance. Lastly, they
with their many little glands produce and supply the vocal ligaments
with that moisture without which, according to the investigations of J.
Mueller,[H] the production of tone cannot be carried on.