4. Neuralgia cervico-brachialis (first noticed by Professor Fulci of.
Catana), is seated in the internal cutaneous nerve, a branch furnished by the brachial plexus. The pain begins at the anterior and internal part pf the shoulder, and descends along the inner side of the arm and fore-arm to the wrist. Sometimes it extends not only to all the branches of the internal cutaneous nerve, but also to those of the external, and then becomes confounded with the following species.
5. Neuralgia museulo-cutanealis was first described by M. Martinet, and occupies the external cutaneous (or musculo-cutancous) nerve, another branch derived from the brachial plexus. The pain commences at the shoulder, descends along the anterior external surface of the arm and fore-arm as far as the wrist. 6. Neuralgia supra-scapularis was also first described by M. Martinet, and is seated in the suprascapular nerve, another branch given off from the brachial plexus. The pain begins at the inferior angle of the scapula, passes along its posterior surface, and sometimes descends along the radial border of the fore-arm to the thumb and fore-finger. 7. Neuralgia mamma, first described by Dr. Good as consisting of "sharp, lancinating pains, ffivaricating from a fixed point in the breast, and shooting equally down the course of the ribs and of the arm to the elbow ; the breast retaining its natural size, complexion, and softness." 8, and last, Neuralgia of the facial nerve, or portio Jura of the seventh pair, about the existence of which there is great room for doubt ; for as this is a nerve of motion and not of sensation, it is not easy to understand how it should be liable to be affected by a disease which is in general simply and purely painful. However, it is still more difficult to deny the fact ; numerous instances have occurred in which the disease has (to all appearance) been seated in this nerve, and several wherein the pain has not only followed its ramifications with great exactness, but has also been attended by convulsive twitchings of the facial muscles, and even by their paralysis.
But besides these external forms of neuralgia, the disease has some times been found to attack various internal organs. This was first suggested by Dr. John Fothergill in 1773, who says (in Vol. v. of the Med. Observ. and Enquiries,') " There are few physicians, I believe, who may not in reviewing many cases, which have occurred to them, of anomalous pains in different parts of the body, so as sometimes to counterfeit gouty, bilious, and other internal affections of the stomach and bowels, perceive some analogy between them and the complaint here pointed out ;" but it is only lately that pathologists have begun to enumerate these " anomalous pains," and class them as so many distinct species of neuralgia. Sometimes the central mass of the
nervous system is affected, and we find the terms " Cerebralgia " and " Myelalgia" employed by some modern French authors to designate neuralgia of the brain and of the spinal chord. (Racihorski, Précis du Diagnostic,' 1837.) Sometimes, instead of the branches of a nerve, the extreme filaments only are diseased, as would appear to be the case in many of those kinds of pain commonly called " rheumatic " (MM. Jolly and Piorry, quoted in Raciboraki). To these have been added torticollis, lumbago, angina pectoris, neuralgia of the arteries, gastralgia, enteralgia, hepatalgia, nephralgia, hysteralgia, neuralgia of the heart, testicle, bladder, urethra, diaphragm, &c. (Rociborski, Rowland, Elliot son, &c.) It may perhaps be rather fanciful to give the name " neu ralgia " to all these eases, and it would take up too much space to describe each separately ; but they are all characterised by an increased sensibility of the nerve, and have the same general character of coming on in paroxysms at regular or irregular intervals.
Of the remote or predisposing causes of neuralgia very little is known, but it has been supposed to attack females more frequently than males, the rich than the poor, those that live in towns rather than the inhabitants of the country. It is also most common among persons of a nervous temperament, and both infancy and old age are comparatively safe from its attacks. The immediate or exciting causes are very numerous, and sometimes extremely obscure. Among the most common may be mentioned, exposure to wet and cold, mental excitement and agitation in persons of an irritable temperament, and a deranged state of the digestive organs. Local injuries of various kinds are another very frequent cause of the disease ; such as the lodgment of any foreign body in the branch of a nerve, wounds, contusions, cicatrices, the too great distension of a nerve, carious teeth, &c. Sir Henry Halford has published in his ' Essays; five cases showing that sometimes " the disease is connected with some preternatural growth of bone, or a deposition of bone in a part of the animal economy where it is not usually found in a sound and healthy condition of it, or with a diseased bone ;" and Sir Benjamin Brodie, in his Lectures on Local Nervous Affections,' mentions several where the pain was occasioned by the pressure of an aneurysmal or other tumour. Another cause is exposure to malarious poison. This is more especially the case in those attacks which are regularly intermittent, and which yield to the same treatment a3 ague. Puerperal women are also subject to this disease, especially after largo floodings during labour.