SPINAL CORD, DISEASES OF.
General Considerations.—The diseases of the spinal cord, including the various congenital and acquired deformities and anomalies of development, together with the primary or complicating affections of the meninges, are more than fifty in num ber. Of this list, however, more than half represent rare and sometimes exquisitely refined distinctions in type both clinic ally and pathologically, that are rela tively unimportant to the general prac titioner. Of the diseases that are com mon there are less than a dozen. In fantile spinal paralysis, myelitis, and loco motor ataxia constitute collectively prob ably three-fifths of the entire number.
Numerous attempts have been made to classify the diseases of the cord, but so far such attempts have been largely sterile in practical results. Our knowl edge of the anatomy and localization of function as well as of the pathology of the cord is constantly undergoing modi fication, necessitating changes in opinion and in teaching. The old division into systemic and non-systemic affections still obtains, but its limitations are constantly relaxing and its advantages becoming more and more problematical. Function is undoubtedly systemized, but contigu ity as well as continuity is a factor in dis ease in the cord as elsewhere. The terms acute and chronic, inflammatory and de generative, no longer represent clear-cut types, but are more likely to simply dis tinguish stages of progress in what is often the same affection. Sclerosis as distinguished from gliosis is probably— almost positively—not a primary condi tion, but may attend secondarily any acute lesion of the cord. It is equally true, however, that certain spinal-cord affections are inherently degenerative in tendency ab initio, the acute stage, if there be such, being clinically indefina ble. In view of these facts I shall make no attempt to classify the diseases to be considered, an omission the more legiti mate here since many of the diseases properly belonging in this article have been treated elsewhere. LOCOMOTOR ATAXIA has been, on account of its im portance, described in a separate article; so also has multiple sclerosis and the forms of meningitis. Abscess of the cord is best studied in connection with caries of the vertebra, with which it is often associated. The vascular diseases
of the cord — hxmorrhage, embolus, thrombus, and aneurism—are exceed ingly rare, and this is true also of tu mors, though perhaps less so. The spinal type of progressive muscular atrophy has been included among the diseases of the muscles. (See also CHRONIC POLIOMYE LITIS.) It is impossible to overestimate the essential importance of a knowledge, more or less complete, of the anatomy and physiology of the cord. The facts and theories of localization should also be familiar. The limits of this article, however, do not permit an elaborate con sideration of this aspect of the subject.
The numbers opposite the names of the following diseases of the spinal cord represent the chief anatomical location of the morbid process in each disease:— Poliomyelitis, 2.
Primary lateral sclerosis, 5 and 4. Amyotrophic lateral sclerosis, 2, 5, and 4.
Locomotor ataxia, S, 9, 10, 6, 7, 11, and 3.
Syringomyelia, 1 and any one or sev eral others.
Ataxic paraplegia, 5, 7, S, 9, and 10. Progressive muscular spinal atrophy, 2. Transverse myelitis complete, 1 to 11, inclusive.
Friedreich's ataxia, 4, 5, 7, S, 9, 10, and sometimes 6.
Myelitis.
Synonyms.—Inflammation of the spi nal cord; softening of the spinal cord.
Definition.—Myelitis is an inflamma tion, localized or general, with secondary softening or sclerosis of the spinal cord, with irritative and paralytic motor and sensory as well as special symptoms, varying in character and distribution with the localization and degree of the morbid process at different levels or areas of the cord. illany varieties are recognized. The anatomical division includes the cervical, dorsal, and lum bar varieties; the transverse (imper fect or complete); the diffuse, or dis seminated; the focal; the central; and the marginal. The last mentioned is frequently associated with and often dependent upon a meningitis, the re sultant condition being known as me ningomyelitis. The etiological division includes at least three varieties of im portance: the traumatic, the syphilitic, and the tubercular. The terms acute, subacute, and chronic appear in the liter ature, although Striimpell and others dispute the existence of a primary chronic myelitis. The type of all forms is acute transverse myelitis.