and the humeral cutaneous branches of the musculo-spiral are much exposed to bruises and to cutting wounds. So far as I know, it is only when a nerve trunk of some size has been wounded that neuralgia is a probable result. Wounds of the small nervous branches in the fingers, for instance, are very seldom followed by neuralgia. I have no statistics to guide me as to the effect of long-continued irritation applied to one of these small peripheral branches, but it is probable that that might be more capable of inducing neuralgia. As far as my own experience goes, however, it would appear that a more common result is convulsion of some kind, from reflex irritation of the cord.
(d) Dorso-intercostal Neuralgia.– This is one of the commonest varieties of neuralgia, and yet it is very likely to be confounded with other affections not neuralgic in their nature. The disorder with which it is especially liable to be confounded is myalgia, which will be fully described in another chapter, and which, when developed in the region of the body to which we are now referring, is commonly spoken of as pleurodynia, or lumbago (according as it affects the muscles of the back or of the side), or muscular rheumatism. It must be owned that the severer forms of this affection can scarcely be distinguished from true intercostal neuralgia by anything in the character or situation of the pains. It will be seen, hereafter, however, that myalgia has its own specific history, which is very characteristic; at present, it is sufficient to remember that it is often extremely like neuralgia when situated in the dorso-intercostal region.
Dorso-intercostal neuralgia is an affection of certain of the dorsal nerves. These nerves divide, immediately after their emergence from the intervertebral foramina, into an interior and a posterior branch. The latter sends filaments which pierce the muscles to be distributed to the skin of the back; the former, which are the intercostal nerves, follow the intercostal spaces. Immediately after their commencement they communicate with the corresponding ganglia of the sympathetic. Proceeding outward, they at first lie between two layers of intercostal muscles, and, after giving off branches to the latter, give off their large superficial branch. In the case of the seventh, eighth and ninth intercostal nerves, which are those most liable to intercostal neuralgia, the superficial branch is given off about midway between the spine and the sternum. The final point of division, at which superficial filets come off, in all the eight lower intercostal nerves, is nearer to the sternum; and is progressively nearer to the latter in each successive space downward. There are thus, as Valleix observes, three points of division: (1) At the intervertebral foramen; (2) midway in the intercostal space; (3) near to the sternum. And there are three sets of branches (reckoning the posterior division) which respectively make their way to the surface near to these points.
In one of its forms, intercostal neuralgia is one of the commonest of all neuralgic affections. I refer to the pain beneath the left mamma, which women with neuralgic tendencies so often experience, chiefly in consequence of over-suckling, but also from exhaustion caused by menorrhagia or leucorrhœa, and especially from the concurrence of one of the latter affections with excessive lactation. It is especially necessary, however, to guard against mistaking for this affection a mere myalgic state of the intercostal or pectoral muscles, which often arises in similar circumstances with the addition of excessive or too long continued exertions of these muscles. "Hysteric" tenderness also sometimes bears a considerable resemblance, superficially, to true intercostal neuralgia, in cases where the genuine disease does not exist.
A less common but very remarkable variety of intercostal neuralgia than that just mentioned, is the kind of pain which attends a good many cases of herpes zoster, or shingles. It is only of recent years that any essential connection between zoster and neuralgia has been suspected. The occurrence of neuralgia as a sequel to zoster had indeed been mentioned by Rayer, Recamier, and Piorry, but the essential nature of the connection between the two diseases was evidently not suspected by Lecadre, when, as late as 1855, he published his valuable essay on intercostal neuralgia. M. Notta was one of the first to present connected observations on the subject. But it was much more fully discussed in a paper published by M. Barensprung, in 1861. [Ann. der Charite-Krakenhauser zer Berlin, ix., 2, p. 40. Brit. and For. Med. Rev., January, 1862.] This author showed the absolute universality with which unilateral herpes, wherever developed, closely followed the course of some superficial sensory nerve, and gave reasons, which will be discussed hereafter, for supposing that the disease originates in the ganglia of the posterior roots, and that the irritation spreads thence to the posterior roots in the cord, causing reflex neuralgia. We shall have more to say on this matter. Meantime, it seems to be established, by multiplied researches, that, though unilateral herpes may and often does occur without neuralgia, and neuralgia without herpes, the concurrence of the two is due to a mere extension of the original disease, which is a nervous one.
In young persons, zoster is not attended with severe neuralgia, but a curious half-paretic condition of the skin, in which numbness is mixed with formication, or with a sensation as of boiling water under the skin, precedes the outbreak of the eruption by some hours, or by a day or two. Painless herpes is commonest in youth. I remember, for instance, that, in an attack of shingles which I suffered about the age of eleven, there was at no stage any acute pain; only, in the pre-eruptive period, for a short time, I had the curious sensations referred to above: and the same thing has occurred in all the patients below puberty that I have seen, if they complained at all. From the age of puberty to the end of life, the tendency of herpes to be complicated with neuralgia becomes progressively stronger. The course of events varies much in different cases, however. In adult and later life the symptoms usually commence with a more or less violent attack of neuralgic pain, which is succeeded, and generally, though not always, displaced by the herpetic eruption. The latter runs its course, and after its disappearance the neuralgia may return, or not. In old people it almost always does return, and often with distressing severity and pertinacity. Six weeks or two months is a very common period for it to last, and in some aged persons it has been known to fix itself permanently, and cease only with life. In these subjects a further complication sometimes occurs. The herpetic vesicles leave obstinate and painful ulcers behind them, which refuse to heal, and which worry the patient frightfully, the merest breath of air upon them sufficing to produce agonizing darts of neuralgic pain. I have known one patient, a woman over seventy years of age, absolutely killed by the exhaustion produced by protracted suffering of this kind.
The foci of pain in intercostal neuralgia are always found in one or more of the points, already enumerated, at which sensory nerves become superficial. In long-standing cases acutely tender points are developed in one or more of these situations; not unfrequently the most decided of these spots is where it gets overlooked, namely, opposite the intervertebral foramen. H. G., a young woman aged twenty-six, who applied to me at Westminster Hospital, had suffered for twelve months from an irregularly intermitting but very severe neuralgia at the level of the seventh intercostal space of the left side. The violence of the pain was sometimes excessive, and when the paroxysm lasted longer than usual it generally produced faintness and vomiting. This patient had no sign of tenderness anywhere in the anterior or lateral regions, though the pain seemed to gird round the left half of the chest as with an iron chain, but an exquisitely tender spot, as large as a shilling, was found close to the spine; pressure on this always induced a strong feeling of nausea.
As an illustration of the herpetic variety of dorso-intercostal neuralgia, running a severe but not protracted course, I may relate the case of a medical man whom I formerly attended. This gentleman was about thirty-two years of age, and a highly neurotic subject: inter alia, he had already suffered from a severe and protracted sciatica; and, very shortly before the herpetic attack, had been jaundiced from purely nervous causes. His nervous maladies were undoubtedly caused by over-brain-work. In this case the neuralgia developed itself during the latter half of the eruptive period, which was rather unusually lengthened. It occupied the seventh, eighth, and ninth intercostal spaces of the side affected with herpes, and was very violent and acute, so that the patient expressed himself as almost "cut in two" with it. The pain ceased even before the vesicles had perfectly healed; a rather unusual occurrence in my experience. I shall refer to this case hereafter, as an example of what I believe to be the effect of a particular method of treatment in lessening the tendency to after-neuralgia. The result of my experience is certainly this – that if a case of herpes in an adult, or still more in an aged person, be left to itself, the amount of after-neuralgia will very closely correspond with the severity of the eruptive symptoms.
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