Classification of Neuromuscular Disorders

Abstract

There are many different neuromuscular diseases and some are difficult to classify under a single heading. The World Federation of Neurology (1968) has proposed a classification, but many of the disorders included in their large list may not, in fact, be nosologically distinct, and others are very rare. We prefer a simpler classification which omits the rare disorders. None the less, some of them will be discussed in the relevant chapters. It should be noted that neurogenic disorders are generally classified according to the site of the major pathological process, for example anterior horn cell disorders are classified separately from neuropathies. Myopathies, on the other hand, are classified according to whether they are congenital or acquired, and those myopathies about which more is known, such as polymyositis, are classified separately. This difference in classification is due to the fact that in neurogenic disorders anterior horn cells, nerve roots, peripheral nerves with their myelin sheaths and the motor end-plates are vulnerable to different pathological processes whereas muscle itself is a more homogeneous tissue.