Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/274

256 weeks or mouths, and is in general first indicated by a return of motor power in the leg, that of the arm following at a longer or shorter interval. Such recovery of move ment is, however, in a large proportion of cases only partial, and the side remains weakened. In such instances the gait of the patient is characteristic. In walking he leans to the sound side and swings round the affected limb from the hip, the foot scraping the ground as it is raised and advanced. Besides this the evidence of the " shock " is felt more or less upon the system generally, the patient rarely (though occasionally) recovering his nervous stability. The paralysed parts retain as a rule their electric con tractility, but they are apt to suffer in their nutrition both from disuse and also from certain degenerative changes which the interruption of nervous influence is apt to exer cise upon them. It is to be observed that in many instances the hemi- plegia is only partial, and instead of the symptoms of complete paralysis above described there exist in varied combination only certain of them, their association depend ing on the extent and locality of the lesion in the brain. Thus there may be impairment of speech and some amount of facial paralysis, svhile the arm and leg may be unaffected, or the paralysis may be present in one or both extremities of one side while the other symptoms are absent. Further, the paralysis may be incomplete throughout, and the whole of the side be weak, but not entirely deprived of motor power. To partial paralysis of this latter description the term " paresis " is applied. Besides hemiplegia, various other forms of paralysis may arise from cerebral disease. Thus occasionally the paralysis is crossed, one side of the face and the opposite side of the body being affected simultaneously. Or again, as is frequently observed in the case of tumours of the brain, the paralysis may be limited to the distribution of one of the cranial nerves, and may produce an association of phenomena (such as squinting, drooping of the eyelid, and impairment or loss of vision) which may enable the seat of the disease to be accurately localized. 2. Paralysis due to Disease of the Spinal Cord. Of paralysis from this cause there are numerous varieties depending on the nature, the site, and the extent of the disease. Some of the more important only can be noticed. Paraplegia, paralysis of both lower extremities, including usually the lower portion of the trunk, and occasionally also the upper portion indeed the whole parts below the seat of the disease in the spinal cord is a form of paralysis which is a not unfrequent result of injuries or disease of the vertebral column ; also of inflammation affecting the spinal cord (MYELITIS, q.v.}, as well as of haemor rhage or morbid growths involving its substance. When due to disease, the lesion is generally situated in the lower portion of the cord. The phenomena necessarily vary in relation to the locality and the extent of the disease in the cord. Thus, if in the affected area the posterior part of the cord, including the posterior nerve roots, suffer, the function of sensation in the parts below is impaired because the cord is unable to transmit the sensory impressions .from the surface of the body to the brain. If on the other hand the anterior portion of the cord and anterior nerves be affected, the motor impulses from the brain cannot be conveyed to the muscles below the seat of the injury or disease, and consequently their power of movement is abolished. In many forms of this complaint, particularly in the case of injuries, the whole thickness of the cord is involved, and both sensory and motor functions are arrested. Further, the functions of the bladder and bowels are apt to suffer, and either spasm or paralysis of these organs is the result. The nutrition of the paralysed parts tends to become affected, and bed-sores and wasting of the muscles are common. Occa sionally, more especially in cases of injury, recovery takes place, but in general this is incomplete, the power of walking being more or less impaired. On the other hand the patient may linger on for years bedridden, and at last succumb to exhaustion or to some intercurrent disease. A form of spinal paralysis, often showing itself as paraplegia, occasionally occurs in children, and is termed Infantile or Essential Paralysis. It is caused by an inflammatory affection limited to the anterior portion of the grey matter of the spinal cord throughout a greater or less extent, and affects therefore the function of motion, leaving that of sensation unimpaired. This disease is most common during the period of first dentition (although a similar affection is sometimes observed in adults). The commencement may be insidious, or there may be an acute febrile attack lasting for several days. In either case paralysis comes on, at first very extensive, involving both upper and lower extremities, but tending soon to become more limited and confined to one or other limb or even to a group of muscles. The affected muscles lose their electric contractility and are apt to waste. Hence limbs become shortened, shrivelled, and useless, and deformities such as club foot may thus be readily produced. In many instances fortunately recovery is complete, and the pro spect of amendment is all the greater if the muscles show any reaction to electricity. There is throughout an absence of some of the more distressing of the phenomena of paraplegia, such as disturbances of the bladder and bowels or extensive bed-sores, and in general the health of the child does not materially suffer. Progressive Muscular Atrophy or Wasting Palsy is a disease usually occurring in early or middle life. It is characterized by the wasting of certain muscles or groups of muscles accompanied with a corresponding weakness or paralysis of the affected parts, and is believed to depend on a slow inflammatory change in the anterior cornua of the grey matter of the spinal cord. It is insidious in its onset, and usually first shows itself in the prominent muscular masses in the palm of the hand, especially the ball of the thumb, which becomes wasted and deficient in power. The other palmar muscles suffer in like manner, and as the disease advances the muscles of the arm, shoulders, and trunk become implicated if they have not themselves been the first to be attacked. The malady tends to spread symmetrically, involving the corresponding parts of the opposite side of the body in succession. It is slow in its progress, but, notwithstanding it may occasion ally undergo arrest, it tends to advance and involve more and more of the muscles of the body until the sufferer is reduced to a condition of extreme helplessness. Should some other ailment not be the cause of death, the fatal result may be due to the disease extending so as to involve the muscles of respiration. Another form of paralysis in certain respects resembling the last, and supposed by some to be due to a similar cause, is Pseudo-hypertrophic Paralysis, a condition occur ring most frequently in male children, in whom in such cases there exists at first a remarkable enlargement of certain muscles or groups of muscles, followed sooner or later by wasting and paralysis. The enlarged muscles are chiefly those of the calf and hips, and their abnormal size is caused by an over-development of their connective tissue, and is therefore not a true hypertrophy. The child acquires a peculiar attitude and gait. He stands with his legs widely separated, his body arched forward, and in walking assumes a rocking or waddling movement. Later on the enlarged muscles lose their bulk, and at the same time become weakened in power, so that walking becomes impossible, and the child is completely paralysed in the