Biographies de neurologues
Nouvelle Iconographie de La Salpêtrière
 L'histoire des neurosciences à La Pitié et à La Salpêtrière J Poirier
The history of neurosciences at La Pitié and La Salpêtrière J Poirier 

mise à jour du
28 décembre 2015
page 466-469
The study of medicine
John-Mason Good
Clonus pandiculatio


Transient elongation of the extensor muscles usually with deep inspiration and a sense of lassitude.
This is, perhaps, the slightest modifications of spasmodic actions; but as it often occurs, as in nausea on the first satge of a febrile paroxysm, whether the will consents or not, and is frequently and irregularly repeated, it cannot but be regarded as belonging to the present family on many occasions. The muscles chiefly concerned are these extensors of the lower jaw and of the limbs: the particular kind of pandiculation, to which the first of these movements gives rise being called OSCITANCY, YAWNING, or GAPING; and that produced by the second, STRETCHING.
The muscles are excited to this peculiar action by a general feeling of restlessness or disquiet; and the spread of the action from one muscle, or set of muscles, to another is from that striking sympathy, or tendency to catenate is like movements, which we so often behold in different parts of the body without being able to explain. It is possible, however, that the synchronous motion of the muscles of the lower jaw and of the limbs, for it is rarely that yawning and stretching do not accompany each others may be dependent upon the same line of intercourse, by which trismus so often accompanies a wound in one of the extremities, and which we have already attempted to illustrate; the irritant power, in the one case, leading to a fixed or entastic, and in the other, to a transient and clonic spasm.
Pandiculation, considered physiologically, is an instinctive exertion to recover a balance of power between the extensor and flexor muscles, in cases in which the former have been encroached upon and held in subjection by the latter.
A very slight survey of the animal frame will show us, that the flexor muscles have, in every part, some preponderancy over the extensors; and that this preponderancy is perpetually counteracted by the stimulus of the instinct or of the will. We see it from the first stage of life to the last, and most distinctly in those states in which there is most feebleness, and consequently in which the controlling powers are least capable of exercising and maintaming a balance. In the fetus, therefore, in which the weakness is most pressing, the power of instinct is merely rising into existence, and no habit of counterpoise established in the nascent fabric, every limb, and part of every limb capable of bending, undergoes sonie degree of flexure, and the entire figure is rolled into a ball, as the hedgehog habitually rolls himself, even after birth. As the fetus, however, increases in size and age and the powers of instinct, sensation, and volition become more perfect, this general conflexure produces occasionally a sense of uneasiness; and hence every parturient mother is sensible of frequent internal movements and stretchings of the litle limbs of the fetus to take off the uneasiness, by restoring some degree of balance to the antagonist powers. After birth, and during wakefulness the stimulus of the will, directed rather to the extensor thea the flexor muscles, renders the counterpoise complete for all the purposes for which it may be necessary. But the moment we repose ourselves in sleep, and the will becomme inactive and withdraws its control, the flexor muscles exercise their preponderancy afresh, though in a less degree than in fetal life, since the extensors, from habitual use, have acquired a more than proportionate increase of power. The preponderancy, however, when long exerted, still produces some degree of disquiet, and hence, occasionnally during sleep, and still more vigorously the moment we begin to awake, we instinctively rouse the extensor muscles into action; or, in other words, yawn, strech the limb, and breathe deeply, to restore the equipoise that has been lost during unconsciousness.
 james mason good
In all these cases, pandiculation is a naturel action; it is an effect produced by the will when it is called to the particular state of these two state of muscles, or by the instinctive or remedial power of nature, which supplies its place, when it is dormant or inattentive, to restore case to a disquieted organ. But, in an infirm or debilitated condition of the system, it evinces a morbid and couvulsive character, and takes place without our being able to prevent it, even when the will uses its utmost effort to resist, instead of to encourage it.
How far its repetition may be of use in the shivering fit of an ague, or in a nauseating deliquium of the stomach, it is difficult to say. Yet we are at no loss to account for its frequency of recurrence: for as the whole system is, in such circumstances, thrown into a sudden prostration of strength, the extensor-muscles, in consequence of being naturally weaker than their antagonists, must become soonest exhausted, and give way with a more than ordinary submission to their power. And hence we behold a painful retraction over the whole system, and the preponderancy assumes a rigid and spastic character, and we may fairly conclude, that much of the yawning and stretching, which ensue, is for the purpose of getting rid of the constrictive spasm, though these counteractions themselves often run, in the attempt, into a spasm of another kind, and become convulsive.
Yawning and stretching then, are among the signs of debility and lassitude. And, hence, every one who resigns himself ingloriously to a life of lassitude and indolence, will be sure to catch these motions, as a part of that general idleness which be covets. And, in this manner, a natural and useful action is converted into a morbid habit; and there are loungers to be found in the world, who, though in the prime of life, spend their days as well as their nights in a perpetual routine of these convulsive movements, overwhich they have no power; who cannot rise from the sofa witb. out stretching their limbs, nor open their mouths to answer a plain question without gaping in one's face. The disease is here idiopathic and chronic: it may, perhaps, be eured by a permanent exertion of the will, and ridicule or hard labour will generally be found the best remedies for calling the will into action.
mason good
John Mason Good
The Study of Medicine with a Physiological System of Nosology
Philadelphia. Bennett & Walton, et al. 1824 (first in USA)
jm good pandiculatio