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chorda vocalis. 4. Two capsular crico-arytenoid, which connect those cartilages. 5. Two superior thyro-arytenoid, thin bands between the receding angle of the thyroid and the anterior inner border of each arytenoid; the lower border constituting the upper boundary of the ventricle of the larynx. 6. Two inferior thyro-arytenoid, the chorda vocales, which are thicker than the superior, and, like them, composed of elastic tissue. Each ligament, or vocal chord, is attached in front to the receding angle of the thyroid, and behind to the anterior angle of the base of the arytenoid. The inferior border of the chorda vocalis is continuous with the lateral expansion of the crico-thyroid ligament. The superior border forms the lower boundary of the ventricle of the larynx. The space between the two chordæ vocales is the glottis or rima glottidis. 7. Three glosso-epiglottic, folds of mucous membrane connecting the anterior surface of the epiglottis with the root of the tongue. 8. The hyo-epiglottic, an elastic band connecting the anterior aspect of the epiglottis with the hyoid bone. 9. The thryo-epiglottic, a slender elastic slip embracing the apex of the epiglottis, and inserted into the thyroid above the chordæ vocalæs.

"The muscles are eight in number: five larger ones of the chordæ vocales and glottis, and three smaller of the epiglottis. The origin, insertion, and use of each is expressed by its name. They are the crico-thyroid, posterior and lateral crico-arytenoid, thyro-arytenoid, arytenoid thyro-epiglottic, and superior and inferior arytenoepiglottic. The posterior crico-arytenoid opens the glot tis; the arytenoid approximates the arytenoid cartilages posteriorly, and the crico-arytenoideus lateralis and thyroarytenoidei anteriorly; the latter also close the glottis mesially. The crico thyroidei are tensors of the vocal chords,

and with the thyro-arytenoidei, regulate their position and vibrating length. The remaining muscles assist in regulating the tension of the vocal chords by varying the position of their cartilages.

"The aperture of the larynx is a triangular opening, broad in front and narrow behind; bounded in front by the epiglottis, behind by the arytenoid muscle, and on the sides by the folds of the mucous membrane. The cavity is divided into two parts by an oblong constriction produced by the prominence of the vocal chords; the part above the constriction is broad above and narrow below, and the part beneath is narrow above and broad below, while the space included by the constriction is a narrow, triangular fissure, the glottis, bounded on the sides by the chordæ vocales and inner surface of the arytenoid cartilages, and behind by the arytenoid muscle; it is nearly an inch in length, somewhat longer in the male than female. Immediately above the prominence caused by the chorda vocalis, and extending nearly its length on each side of the cavity of the larynx is the ventricle of the larynx, an elliptical fossa which serves to isolate the chord.

"The mucous membrane lines the entire cavity of the larynx, its prominences and depressions, and is continuous with that of the mouth and pharynx, which is prolonged through the trachea and bronchial tubes into the lungs. In the ventricles of the larynx the membrane forms a cæcal pouch, called sacculus laryngis, on the surface of which are the openings of numerous follicular glands, whose secretion lubricates the vocal chords."

The abdominal muscles are important parts of the respiratory machinery; comparing the lungs to a bellows, these muscles constitute the handles, and unless they are well developed and in vigorous condition, the voice be

correspondingly feeble and imperfect. The relation of these muscles to the thorax directly, and to the lungs and vocal apparatus indirectly, is shown in figs. 5 and 6.

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In Fig. 5 are seen the muscles of the trunk anteriorily. The superficial layer is seen on the left side. and the deeper on the right. 1, Pectoralis major. 2. Deltoid. 3. Anterior border of the latissimus dorsi. 4. Serrations of the serratus magnus. 5. Subclavius of the right side. 6. Pectoralis minor. 7. Coracho-brachialis. 8. Upper part of the biceps, showing its two heads. 9. Coracoid process of the scapula. 10. Serratus magnus of the right side. 11. External intercostal. 12. External oblique. 13. Its aponeurosis; the median line to the right of this number is the linea alba; the flexuous line to the left is the linea semilunaris; the transverse lines above and below the number are the lineæ transversæ. 14. Poupart's ligament. 15. External abdominal ring; the margin above is called the

superior or internal pillar; the margin below the inferior or external pillar; the curved intercolumnar fibres are seen proceeding upward from Poupart's ligament to strengthen the ring. The numbers 14 and 15 are situated upon the fascia lata of the thigh; the opening to the right of 15 is called saphenous. 16. Rectus of the right side. 17. Pyramidalis. 18. Internal oblique. 19. The common tendon of the internal oblique and transversalis descending behind Poupart's ligament to the pectineal line. 20. The arch formed between the lower curved border of the internal oblique and Poupart's ligament beneath which the spermatic cord passes, and hernia occurs.

Fig. 6 is a side view of the muscles of the trunk. 1. Costal region of the latissimus dorsi. 2. Serratus magnus. 3. Upper part of external oblique. 4. Two external intercostals. 5. Two internal intercostals. 6. Transversalis. 7. Its posterior aponeurosis. S. Its anterior. 9. Lower part of the left rectus. 10. Right rectus. 11. The arched opening where the spermatic cord passes and hernia takes place. 12. The gluteus maximus, and medius, and tensor vaginæ femoris muscles invested by fascia lata.

Fig. 6.

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The oblique muscles flex the thorax on the pelvis; either acting singly, twists the body to one side. Either transversalis muscle by contracting diminishes the size of the abdomen, and both acting together constrict its general cavity. The recti muscles, and the pyramidalis pull the thorax forward when acting together. All of the abdominal muscles are auxiliary to respiration, and as they constitute the chief forces in expelling the air from the lungs, their relation to voice is obvious. As respiratory muscles they are aided by the muscles of the loins and back; the united action of all these muscles compresses the abdomen in all directions, as may be noticed in prolonged coughing or severe vomiting.

MUSCLES OF THE TRUNK LATERALLY.

CHAPTER II.

PHYSIOLOGY OF THE VOICE.

Fig. 7.

NATURAL SPINE.

PHYSICAL uprightness is as important for a public speaker as moral rectitude is for a private citizen. Other things being equal, every person will have a power to please and persuade, influence and direct the minds of others, through the media of speech and music, measurable generally by the integrity of the whole bodily organization, and especially by the erectitude of the spinal column (Fig. 7), without which the extensive and complicated machinery of respiration and vocalization cannot act harmoniously.

The vocal apparatus has been compared to a stringed, tubular, and reeded instrument, as the violin, flute, and clarionet; it has many properties in common with each, and, indeed, with all musical instruments; yet it differs in many respects from either. No mechanical contrivance can rival the variety and delicacy of action of the living structure,

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