Neuralgia and the Diseases That Resemble It. Francis Edmund Anstie
of both thighs. So great an aggravation of the pain is produced by any muscular movement, that the patient can only walk at the slowest possible pace, moving each foot forward only a few inches at a time. The bilateral distribution of the pain is remarkable in this case; but there can be no doubt of its really neuralgic character, from the truly intermittent way in which it recurs, and the absence of any history whatever to point in the direction of rheumatism, gout, or syphilis.
The nervous supply to the skin of the anterior and external portion of the thigh includes: (1) The middle cutaneous, (2) the internal cutaneous, and (3) the long saphenous branch of the anterior crural nerve; (4) the cutaneous branch of the obturator; and (5) the external cutaneous nerve, derived from the loop formed between the second and third lumbar nerve. The sensitive twigs derived from the two latter sources, equally with the branches of the anterior crural, are liable to be secondarily affected by neuralgia, which commences in the lumbo-abdominal nerves; but it must be a rare event for them to be the seat of a primary neuralgia. The only occasion on which I have seen anything which looked like the latter was in the case of a porter, who, in straining to lift a very heavy load, ruptured some part of the attachment of the tensor vaginæ femoris. But the susceptibility of all the nerves of the front of the thigh to secondary or reflex neuralgia receives numerous illustrations. The extremely severe pain at the internal aspect of the knee-joint, which is such a common symptom in morbus coxæ, is evidently a reflex neuralgia of the long saphenous nerve, the ultimate irritation being situated in the branches of the obturator nerve which supply the hip-joints. For some reason unexplained, it happens that this saphenous nerve is specially liable to be affected in a reflex manner: for instance, this happens in a considerable number of cases of sciatica. I have a lady now under my observation, in whom the secondary neuralgia of the saphenous nerve has become even more intolerable than the pain in the sciatic, which was the nerve primarily affected. The pain in these cases very frequently runs down the inner and anterior surface of the leg to the internal ankle. Sometimes the branches of the anterior crural become the seat of intensely painful points in the course of a long-persisting sciatica. A patient at present under my care has a spot, about the size of a shilling, just at the emergence of the middle cutaneous branch from the fascia lata, which is intensely and persistently tender to the touch, and the skin here is so exquisitely sensitive to the continuous galvanic current that the application of moistened sponge-conductors, with a current of only fifteen Daniell's cells, causes intolerable burning pain; whereas at every other part of the limb the current from twenty-five cells can be borne without much inconvenience.
(g) Femoro-popliteal Neuralgia, or Sciatica.—This is one of the most numerous and important groups of neuralgia; but, notwithstanding that there are plenty of opportunities for studying it, I venture to think it is very commonly mistaken for different and non-neuralgic diseases, and they for it. The rules of diagnosis which will be laid down for all the neuralgiæ would nevertheless prevent these errors, if carefully attended to.
Sciatica is a disease from which youth is comparatively exempt. Valleix had collected one hundred and twenty-four cases, and in not one was the patient below the age of seventeen, only four were below twenty. In the next decade there were twenty-two; in the next, thirty; and the largest number of cases, thirty-five, occurred between the ages of forty and fifty. This completely tallies with my own experience, and appears to afford some support to a suspicion I have formed, that the chief exciting cause of sciatica is the pressure exercised on the nerve in locomotion, and that this cause exercises its maximum influence when the period of bodily degeneration commences. It is further remarkable that, in elderly persons (whose habits of locomotion are of course more limited), the proportion of fresh cases rapidly diminishes; and also that above the age of thirty the number of male patients greatly exceeds that of female patients attacked. All this seems to point in the same direction.
According to my observation, there are three distinct varieties of sciatica. The first of these is obscure in its origin, but may be said, in general terms, to be connected with a nervous temperament of the highly impressible kind, which is more or less like what we call "hysteric," not only in the female, but also in male patients. The subjects of this kind of sciatica are mostly young persons, and hardly ever more than middle-aged; they are generally found to be liable to other forms of neuralgia; and the actual attack of sciatica is produced by some fatigue or mental distress, which at other times might have brought on sick headache, or intracostal neuralgia, etc. Very many of these patients are anæmic; and chlorotic anæmia seems specially to favor the occurrence of the affection. The greater number of the victims are females, and in very many, whether as cause or effect, there is impeded, or at least imperfect, menstruation. This kind of sciatic pain is not usually of the highest degree of intensity, but it generally spreads into a great many branches, both in a direct and a reflex manner. It is probable that this variety of the disease is, at least very often, dependent upon, or much aggravated by, an excited condition of the sexual organs; certainly, I have observed it with special frequency in women who have remained single long after the marriageable age, and in several male patients there has been either the certainty or a strong suspicion of venereal excess. Sciatica of this kind also occurred in the case of a single woman aged about thirty, who to my knowledge was excessively addicted to self-abuse.
The second variety of sciatica occurs for the most part in middle-aged or old persons who have long been subject to excessive muscular exertion, or have been much exposed to damp and cold, or who have been subject to the combined influence of both these kinds of evil influence. One must also include, I think, in this group a considerable number of cases where the age is not so advanced, but the patient has been obliged, by the nature of his business, to maintain the sitting posture daily, for hours together, exercising pressure on the nerve; this is especially liable to happen in these persons.
The sufferers from this variety of sciatica are mostly, as already said, of middle age or more; but this statement must be understood to be made in the comparative sense, which refers rather to the vital status of the individual than to the mere lapse of years. Many of these people have hair which is prematurely gray, and in some the existence of rigid arteries, together with arcus senilis, completes the picture of organic involution, or senile degeneration. In particular cases, where depressing influences have been at work for a long time, or unusually active, these appearances rectify the false impression we should otherwise derive from learning the mere nominal age of the person; this is especially often the case with regard to patients who have for a long time drunk to excess. The prematurely and permanently gray hair (it will be seen hereafter that permanency of grayness is an important point), together with well-marked inelasticity of arteries, very often tells a tale which is most useful in informing us, not only of the vital status of the patient, but of the kind of sciatica under which he labors; and also influences our prognosis seriously. There is otherwise a somewhat deceptive air about the appearance of many of these degenerative cases; for instance, a ruddy complexion is not uncommon, nor the retention of considerable, or even great, muscular strength. It is probable that these appearances deceived Valleix and many others, or they could hardly have failed, as they have, to observe the frequency of the degenerative type among the most numerous group of sciatic patients, namely, those between thirty and fifty years of age. These persons are not truly "robust," although at a hasty glance they might at first seem to be so. It would be a serious mistake to omit the search for the important vital evidences which have been referred to, since these therapeutic and prognostic indications are of the highest value.
A prominent feature in this kind of sciatica is its great obstinacy and intractability. Another, equally marked, is the tendency to the development of spots around the foci of severest pain which are intensely and permanently tender, and the slightest pressure on which is sufficient to set up acute pain. This is a symptom much less developed, if developed at all, in the variety of sciatica which we first discussed. The places which are especially apt to present this phenomenon of tenderness are as follows: (1) A series, or line of points, representing the cutaneous emergence of the posterior branches, which reaches from the lower end of the sacrum up to the crista ilii; (2) a point opposite the emergence of the great and small sciatic nerves from the pelvis; (3) a point opposite the cutaneous emergence of the ascending branches of the small sciatic, which run up toward the crista ilii; (4) several points at the posterior aspect of the thigh, corresponding to the cutaneous emergence of the filets of the crural branch; (5) a fibular point, at the head of the fibula,