In metallic and infectious disorders a history of definite causation is present. Metallic disorders may present special distinctive signs, such as lead-line, wrist-drop, etc.
In hysteria a precedent characteristic history is usual. The onset is often sudden and an emotional element is present. The symptoms are bilateral and protean. Trophic changes are absent. No reactions of degeneration are present.
(2) Local Diagnosis.—It may be said of spinal tumors in a modified sense, as it can be said of brain tumors, that they are not good pathological experiments for illustrating the functions of the exact areas which they occupy. The spinal canal has such narrow limits, the tumor itself soon attains such a relatively large size and causes such wide vascular engorgement, and the different tracts and systems of the cord are so closely packed together, that the tumor does not often invade only one functional area and escape another. Hence the regional diagnosis presents special and greater difficulties than the diagnosis of the level of the cord at which the tumor presents itself. A tumor which destroys the trophic centres for the arm in the anterior cornua might exert sufficient backward pressure to paralyze the motor tracts running to the leg; or a cervical tumor, as in Case 5, might produce symptoms which are almost wholly observed in the legs. It will be seen, however, by reference to the table, that in Case 3, reported by Wilks, we have a tumor whose exact anatomical seat could have been predicted, and which seems to have reproduced almost the upper-arm paralysis of Remak. When we compare these two cases, in which the pathological conditions are so similar, it will be observed that the paralyzed arm is much wasted, which indicates a lesion of its trophic centre, whereas the affected legs in the other case are irritated by pressure and by isolation, but are not wasted, because their trophic centres are far below the point of lesion. The invasion of the trophic centres, and the accompanying wasting of particular groups of muscles, especially when this occurs early in the case, with the consequent reactions of degeneration in these muscles, would furnish very valuable indications both as to the region and the level of the cord involved (Case 29). Unfortunately, the exact observations are wanting in most of the cases as reported.
M. Allen Starr, in a recent paper,7 has devoted much labor to the elucidation of the functions of different segments and regions of the cord. He demonstrates the existence of groups of cells in the gray matter, especially in the anterior horns, each of which he believes constitutes a physiological unit. He affirms that these cell-groups preside over certain associated movements or combinations of certain muscles, and, quoting from Spitzka, says that “the nearer a muscle is to the ventral aspect of an animal the nearer will its nucleus be to the median line of the cord; and the nearer the muscle is to the dorsal aspect of the animal the nearer will its nucleus be to the lateral cornua of the cord. Flexor nuclei are therefore in internal, extensor nuclei in external and posterior, cell-groups.” The only light that such a theory throws upon the subject of diagnosis is by affording a possible explanation of the fact that spastic flexion is much more common than spastic extension, and may be due to the fact that the cell-groups for flexion lie deeper and are more protected than those for extension; and the additional fact above referred to, that a paralysis of associated muscles or groups of muscles, with degeneration, as in the types of Remak, would indicate with great clearness the destruction of the cell-group which presides over them. Starr, in his article, also tabulates the various reflexes and their seats in the cord. As this subject is of much importance in any exact study of spinal-cord diseases, we will state here some of the facts as given in that article: The neck-pupil reflex (dilatation of the pupil on irritation of the neck) has its seat from the fourth to the seventh cervical segment; the elbow-tendon reflex in the fifth and sixth cervical; the wrist tendons from the sixth to the eighth cervical; the palmar in the seventh and eighth cervical; the epigastric and abdominal skin reflexes in the fourth to the eleventh dorsal segments; the cremasteric reflex in the first to the third lumbar; the patellar tendon in the second to the fourth lumbar, and bladder and sexual centres in same; the rectal centre in the fourth lumbar to the third sacral; the foot-clonus and Achilles-tendon reflex in the first sacral. A destructive lesion, such as a tumor, at any one of these points would cause abolition of that particular reflex, and this would probably occur early in the case. Our table of cases does not present any such observation, whereas exaggerated reflexes, such as occur from a compressing lesion above the seat of the excited centre, are recorded in abundance. Many of these deductions are of course only possible early in the history of the case, as at a late stage the secondary degenerations have caused too widespread havoc to admit of any exact localization. The distinction must also be sought for between a destructive lesion and the symptoms of irritation which it may project to distant parts. Fürstner's cases of syringo-myelia,8 in which were marked vaso-motor changes, such as pallor, flushings, copious sweat, and trophic disorders in the integument and its appendages, seem to show that a lesion in the gray matter just posterior and external to the central canal is necessary for such phenomena. Similar vaso-motor changes may be observed in some of the tabulated cases, as in No. 4, in which there were islands of heat and cold in the leg, with a hydromyelia in the cord. Sensory symptoms are very common in cases of spinal tumor, but they furnish indications rather of the exact level of the lesion than of its region.
7 “Localization of the Functions of Spinal Cord,” Am. Journ. Neur. and Psych., 2-3, p. 443.
8 Quoted by Starr.
FIG. 45.
