46 Ollivier, Archives de Physiol., 1876.
Since the trophic centres for the muscles are situated in the spinal cord, cerebral hemiplegia, which does not cut off their connection, does not produce the rapid wasting seen in some cases of spinal paralysis, unless descending degeneration involves the anterior gray columns. The limbs preserve their fulness for a time, although the muscular masses become flabby and slowly atrophy for want of use. This atrophy, however, seldom becomes extreme. The skin of the hands becomes dry, the folds at the knuckles disappear, and the hand loses its expression, looking more like a stuffed glove. The change, however, is not much greater than may be seen in a hand kept for a long time in a bandage. The growth of the nails is retarded, as may be seen by staining them with nitric acid.
If there is any tendency to œdema, as when nephritis is complicated with hemiplegia, the swelling is likely to be much greater upon the paralyzed side. In the adult, of course, there can be no question of the growth of limbs, but when a child becomes hemiplegic from cerebral disease, the limbs grow more slowly and remain smaller, as in a case of ordinary infantile palsy or anterior poliomyelitis.
Much importance has been attached to the fact that large sloughs form with great rapidity upon the nates of the paralyzed side, and Charcot says that this tendency is greater than can be accounted for in any mechanical way. He therefore thinks that a direct trophic influence of the brain upon nutrition is shown. At the very most, however, that can only be a contributory cause, and the freedom of other portions from a similar condition—and that, too, in regions farther removed from the centres of circulation—makes it highly improbable that anything more is necessary to account for it than the less sensitiveness of that side to irritation from urine, roughnesses in the bed, or pressure, and hence neglect. The writer, among a very considerable number of hemiplegias, fatal and otherwise, does not remember to have seen a well-marked case of the kind. Scrupulous cleanliness and changing the position sufficiently often make the preference for the paralyzed side a very slight one.
Arthropathies, consisting in a vegetating, and sometimes an exudative, synovitis, and accompanied by swelling, redness, and pain, are sometimes observed, especially in the upper extremity. They do not appear until fifteen days or a month after the attack.
The most significant change which occurs in the course of a hemiplegia is the development of increased reflexes and rigidity and contracture. After some weeks or months, during which the aspect of the case has not essentially changed, the limbs remaining in the same condition, it will be found on examination that the patellar reflex has become quite energetic, and ankle clonus developed upon the paralyzed side; the arm reflexes from the triceps, biceps, and supinator longus are much exaggerated. This has the same meaning as when similar phenomena are found with spinal disease, and signifies descending degeneration of the postero-lateral columns of the spinal cord, the crossed peduncular tracts. This degeneration may sometimes be traced completely down from the situation of the lesion in the cortical motor centres through the basal ganglia, crura, decussation, and cord. The fuller development of this condition is the contracture or rigidity, which was at one time referred to secondary changes taking place in the neighborhood of the original lesion, as well as to a purely reflex action having no relation to the degeneration of the cord.
The arms are usually flexed at the elbow, the wrists on the arm, and the fingers in the hand. Sometimes, however, the arm is straight. The leg, which is not always affected to the same extent, is generally in extension, though the toes are likely to be flexed. Attempts to move the limbs are resisted strongly, and in such a way as to show the reflex nature of the phenomenon. If an attempt be made to open the fingers of a contractured hand slowly and carefully, it can be often accomplished and the hand held open with but little pressure, but if it is twitched the fingers resist like a spring. The violent attempt to overcome rigidity is often painful.
In some rare cases rapid atrophy of the muscles of one limb may take place. This has been found to coincide with extension of degenerative changes in the cord to the anterior gray columns.
Late rigidity is an unfortunately clear symptom. There is little if any hope of complete recovery of the use of the limb after it has made its appearance, though it does not prevent walking. After long-continued contracture the activity of the muscles diminishes, but the increase of connective tissue and changes in the joints hold the limb in its fixed position, and the contracture is a more passive one. The electrical reactions of the muscles and their nerves in cerebral hemiplegia are not materially altered, but the neuro-muscular irritability may be somewhat increased for a time by the irritating influence of the cerebral lesion.
In most cases of flaccid cerebral hemiplegia the electrical irritability is somewhat decreased, though retaining the normal character with both currents. Since the muscles and their nerves retain their connection with the spinal nuclei which are their trophic centres, and these nuclei are uninjured, their nutrition does not undergo the changes which affect electric excitability.