A system of practical medicine. By American authors. Vol. 3

by Unknown

Paralysis of the Whole Larynx.

Paralysis of all of the muscles of the larynx gives rise to a position of the parts which has, as before stated, been called the cadaveric condition. The vocal cords are neither abducted nor adducted. The opening of the glottis is sufficiently wide to admit of easy respiration, but the cords are so far apart as to make phonation impossible. The effort to articulate is not attended with any change in the position of the vocal bands. In respiration there is no additional widening of the glottic chink. The superior portion of the larynx is also in a peculiar condition. The epiglottis is erect, standing against the dorsum of the tongue; the vestibule of the larynx is widely open; deglutition is difficult.

ETIOLOGY.—So far as we know, the causes are to be found either in central disease or hysteria. When the cause is in the centres, there is almost of necessity functional lesion of other parts of the muscular apparatus, especially of the parts supplied by the glosso-pharyngeal nerve. There will, therefore, be dysphagia. It is possible that the central lesion may be very circumscribed; in such cases we may have paralysis of individual laryngeal muscles or parts of muscles. These cases are probably very rare, and the indication of more general paralysis is, in fact, the point upon which the diagnosis of central disease depends. Tumor or other disease along the track of the spinal accessory before it unites with the pneumogastric may produce the same effect. When the affection is upon one side only the paralysis is also unilateral. There are, as before noted, exceptions to this statement. In these instances it is probable that the innervation of the affected part or side is supplied by branches from the opposite trunk. Such cases have been reported by George Johnson, Lefferts, and others. It has also been found that injury or paralysis of one recurrent nerve is sometimes followed by bilateral paralysis. Schnitzler reports a case in the Wiener Med. Report for 1882. The left recurrent was compressed by aneurism of the arch of the aorta; the right was normal. There was, however, bilateral paralysis. Experiment by Tourgues¹⁰ demonstrated the fact that powerful excitation and consequent exhaustion of one of the pneumogastrics may result in paralysis of the other. This result is in accordance with facts seen occasionally in traumatism of one of the pneumogastrics.

¹⁰ Reported in the Gazette de Montpellier, Nos. 35 and 36, 1882.

A pure, uncomplicated paralysis, in which all of the muscles of the larynx are implicated, and in which no other muscles are concerned, will almost always be found to depend upon some lesion of the pneumogastrics or the spinal accessories after they leave their point of origin. Whether the paralysis is dependent upon the lesion at one point or another, the symptoms are the same so far as the larynx is concerned. The vocal cords are in a state of absolute rest between abduction and adduction; the effort at phonation gives rise to no contraction of the tensors; the arytenoids leave the cartilages slightly separated; and the state of the organ is that of muscular death.

When the lesion upon which a paralysis of the muscles of the larynx depends is below the point at which the superior laryngeal nerves leave the pneumogastrics, the paralysis is limited to the phonators and respirators. The muscular bands and fibres by which the glottis is constricted are, in part at least, still capable of being thrown into contraction. This condition of recurrent paralysis may be due to a disease of the nerve-trunks, tumor pressing upon the nerves, cicatricial tissue by which the nerves are compressed, aneurism of the arch of the aorta or right subclavian artery, disease of the apex of the lung, especially of the right side, pleuritic adhesions, or, in fact, any injury or lesion along the trunks of the recurrents or pneumogastrics. The paralysis may of course be partial or complete.

The SYMPTOMS vary according to the extent of the muscular disability. In case of complete paralysis of one side there may be aphonia, but not dyspnoea. The glottis admits a sufficiency of air, but does not close so as to allow of the vibration of the cords. Where there is complete paralysis on one side only, the voice is not necessarily entirely suppressed, but it is changed in its quality; it becomes rough, weak, and in its use gives rise to great fatigue. In long-continued cases there is in part a compensation for the want of motion of one of the vocal bands. The muscles of the sound side act with increased vigor, so as to carry the sound cord at its posterior extremity beyond the median line. The result is, that the two cords are brought so near each other that phonation is possible. The arytenoid of the non-paralyzed side is drawn forward beyond its fellow. The cord upon the affected side is less tense than that on the healthy side. The vibrations are therefore not equal; the pitch is different; the voice is therefore unnatural, rattling, uncertain.

As we proceed to discuss the lesions in individual muscles or sets of muscles we shall have occasion to refer to these etiological considerations, as well as to some of the symptoms noted with partial or complete loss of power of the whole group of muscles of the organ.

Paralysis of the Constrictors.

Complete paralysis of the muscles, by which the vestibule of the larynx is closed, is rare. The partial paralysis of these muscles is, however, by no means uncommon. As we have already endeavored to show, it is probable that the motor functions of the muscular fibres in the ary-epiglottic folds—the superior constrictors—are mixed. Probably both the superior and inferior laryngeal nerves are concerned in their movements. It is not, therefore, easy to group these disorders according to the nerves involved, as has been done by Von Ziemssen, Mackenzie, and others.