Muscular stiffness is indeed possible in any part of the body. It can be well illustrated as follows: Take a pencil and a sheet of paper and copy a few lines of what you are reading; grasp the pencil with all the strength of your fingers and exert all the power of your hand and arm in forming the letters. You will find that your arm and hand tire after a few minutes of writing in this manner. This follows from the expenditure of vastly more effort than is required for the purpose of writing.
All the muscles of the body are arranged in opposed pairs and groups. As your hand rests on the table, the contraction of one set of muscles brings the thumb and the first two fingers together so as to grasp the pencil. An opposed set will, by their contraction, spread these fingers apart, and the pencil will be released. If, now, both these sets of muscles are contracted at the same time the pencil is held stiffly, and the hand moves to form the letters only by the exertion of considerable effort. The muscles themselves are stiffened by this simultaneous contraction of opposed pairs and groups.
Throat stiffness, the characteristic feature of all incorrect vocal actions, is exactly similar in its nature to the stiffness of the hand and arm just considered. The laryngeal muscles are also arranged in sets which oppose their action one to another. One set (the posterior crico-arytenoids) opens the glottis, another set (the arytenoideus and the lateral crico-arytenoids) closes the glottis and brings the vocal cords on tension. Now, if the glottis opening muscles are contracted during tone production, the opposed muscles must put forth enough strength to overcome the effects of this contraction in addition to that which they are normally called upon to exert. This applies also to all the other sets of laryngeal muscles. Through this excessive tension the delicate laryngeal muscles are strained and weakened, and in the course of time the voice is permanently injured. This condition of throat stiffness is by no means uncommon, a matter for which modern methods of voice culture are to a certain degree responsible. The attempt to manage the vocal organs directly is very apt to lead to excessive tension of the muscles.
Throat stiffness is very insidious in its workings. It tends always to become more pronounced and to impose a constantly greater strain on the voice. Yet in its beginnings the singer may be completely unaware of any trouble. The muscles of the larynx are very poorly supplied with sensory nerves, so poorly, indeed, that under ordinary circumstances we are utterly unconscious of their movements. Owing to this fact, a condition of strain may exist without making itself manifest by any painful sensation. It thus comes about that a singer may suffer from the constantly progressing effects of throat stiffness before its results are so pronounced as to be painful.
Yet there is one infallible way of determining whether a voice is correctly used, or whether, on the contrary, its production is characterized by excessive muscular tension. This is found in the sound of the tones. Any degree of throat stiffness is invariably reflected in the sound of the voice. A throaty quality of tone always results from an incorrect manner of production, and this quality can result in no other way. While a keen and highly experienced ear is needed to detect a slight degree of throatiness, any ordinary observer can hear this condition when it is very pronounced. True, it is very much easier to detect a throaty quality in the voice of some one else than in one’s own voice. The singer labors under this disadvantage, that he can never hear his own voice as clearly and with the same discrimination as can the people who listen to him. Yet by practice and careful attention this difficulty can in great measure be overcome.
For the cure of throat stiffness and its attendant ills the physician can do but little. Even the diagnosis of the condition can hardly be said to lie within his province. In very bad cases a swelling of the muscles inside the larynx can be detected, as well as a sympathetic congestion of the mucous membranes. The existence of nodes on the vocal cords, rather a rare condition resulting from long-continued vocal strain, can also be determined by laryngoscopic examination. But in the case of the great majority of singers suffering from the effects of throat stiffness the only competent diagnosis is made by the vocal teacher, whose ear is sufficiently trained and experienced to hear the exact nature of the trouble. Further, it is the vocal teacher alone who can relieve and permanently cure the condition. The physician can allay the inflammation of the mucous membranes and can temporarily stimulate the vocal muscles. But no lasting relief can be given in this way. Only one real cure is possible. That is the abandonment of the incorrect habits of tone production and the adoption of the correct manner of using the voice.
FOOTNOTES:
[1] A certain allowance must be made for popular forms of speech in dealing with the subject of chest resonance. It is plain that the air in the chest cavity could not possibly be thrown into regular vibrations. In the acoustic sense the chest is not a hollow space, but a solid body. Filled as it is with the spongy tissue of the lungs, as well as the heart and the great blood vessels, there is no room for the formation of air waves or the oscillation of air particles. Another form of resonance is involved here, what is known in acoustics as sounding-board resonance. The reinforcing vibrations of the chest are those of its bony structure, which vibrates according to the same principle as the sounding-board of a piano.
[2] Overtones, or harmonics, are the tones produced by the vibrations of the individual parts of a resonating body, into which it automatically divides itself. See Vol. XII.
[3] Overtones. Cf. note above.