THE STRUCTURE OF THE ORGANS ENGAGED IN VOICE-PRODUCTION. Ir is now necessary to acquaint ourselves with certain anatomical facts, without which it is impossible to Fig. 4. THE LARYNX OR VOICE-BOX, THE TRACHEA OR WINDPIPF, AND THE BRONCHI (FRONT VIEW). a, The Larynx; b, the Trachea; c, the Bronchi; d, the subdivisions of the Bronchi. understand the mechanism of voice-production. It will not be needful to give more than a very general account of the organs of speech, for, in the first place, it is impossible without making careful dissections to obtain a full knowledge of them, and if anyone has a mind for this, he can find all the necessary information in anatomical works; and, in the second place, a brief description will be sufficient to enable the reader to understand the general principles of voice-production. It may be urged that voice-production can be taught THE TRACHEA, AND THE BRONCHI, WITH THEIR SUBDIVISIONS The air-cells are formed by the expansion of the terminal portions of the Bronchi. thoroughly well without any knowledge on the part of the pupil of anatomical detail, and this indeed may be true; it is nevertheless certain that such knowledge will be very helpful to him, enabling him to make far more rapid progress than he otherwise would. During breathing the air passes to and from the lungs along the wind-pipe (Fig. 4). This tube can be distinctly felt in the middle of the neck in front, just above the breast-bone. It consists of several rings of gristle, separated by a softer tissue, and it divides in the chest into two bronchi, one for each lung; these again divide and subdivide, becoming smaller and smaller, until they finally expand into myriads of tiny bladders or air-cells, so called because they are filled with air (Fig. 5). On the exterior of these air-cells are a multitude of very minute blood vessels, so small as to be invisible to the naked eye, and with walls so thin that they may be compared to the film of an air-bubble. It will thus be seen that between the air in the air-vesicles and the blood outside is a filmy tissue, which permits the carbonic acid to escape from the blood into the airvesicles, whence it can readily pass out of the body, and the revivifying oxygen to pass from the air-vesicles Fig. 6. e Ъ ...d C GENERAL FORM OF THE LARYNX a, The Hyoid bone; b, the Epi- into the blood to be whirled away to the tissues in the torrent of the circulation. At the top of the wind-pipe is the larynx or voice box. It is chiefly made up (Fig. 6) of four pieces of gristle, forming the so-called shield, ring, and pyramids. The shield consists of two plates, united at an acute angle in front, thereby forming in the middle of the neck in front the prominence known as Adam's apple, a Fig. 7. CARTILAGES OR LARYNX (FRONT VIEW). a, The Shield; b, the Pyramids; c, the Ring. from the belief held by anatomists of medieval times that the fatal apple here stuck in the throat. The ring is narrow in front and broad behind, being in fact very like a signet ring, the broad posterior part corresponding to the seal. Attached to the upper part of the ring behind are the two pyramids, so called from their shape (Fig. 7). They are placed side by side, their bases downwards, their apices upwards, and they are capable of rotating on their vertical axes, when acted upon by certain muscles. The front of each affords attachment to the corresponding vocal chord, HORIZONTAL SECTION THROUGH THE LARYNX, ON THE LEVEL OF THE Showing how the Vocal Chords pass from the Pyramids behind to which may thus be separated from, and approximated to, the other (Fig. 8). The vocal chords are attached. The light dotted lines represent the Right Pyramid, and part of the Ring hidden by the Shield; the dark horizontal dotted lines represent the Vocal Chords hidden by the Shield. in front to the shield, near the angle formed by the junction of the two plates (Fig. 9), and they are |