In the cases in which the contusion was not of extreme degree, hyperæsthesia often developed as a later sign, and was probably due to the irritation of hæmorrhage, when the sensory portion of the nerve began to regain functional capacity. The date of appearance of the hyperæsthesia varied from a few days to a week or later. It might then persist for weeks or many months.
In a few instances large blebs rose on the back of the hand, or patches of vesicles appeared over the terminal distribution of the nerve, pointing to early trophic changes.
The period of recovery varied greatly; in some instances of very complete paralysis, function was regained and became apparently normal at the end of three or four weeks; in others, even after severe wasting of muscles for weeks, rapid improvement occurred often suddenly, while in some there was no apparent recovery at the end of months. In cases of long-deferred improvement, wasting of the muscles became a very prominent feature; but this without complete loss of reaction of the muscles to electrical stimulation.
Recovery of sensation usually preceded by some time that of motion, the former often reappearing in some degree at an early date, and, even if very modified in character, it formed a most useful and valuable aid both in diagnosis and prognosis.
When in a position allowing of direct examination, the contused portion of the nerve sometimes developed a palpable fusiform thickening, manipulation of which might give rise to formication in the area of distribution—a favourable prognostic sign.
Many of the cases bore a very marked resemblance in character to those in which paralysis results from tight constriction of the limb, as in the arm after the application of an Esmarch's tourniquet.
Laceration.—If incomplete, the signs corresponded very nearly to those of severe contusion, since partial section is impossible without the occurrence of the latter. The condition indeed was only to be distinguished by the partial nature of the recovery, and even this latter might be only more prolonged.
The same remarks hold good with regard to perforation of the nerve trunks; but, as regards function, these injuries are not so serious in prognosis as very much more limited transverse divisions or mere notching, and in some cases the disturbance of function was by no means profound or prolonged.
Absolute loss of reaction to electrical stimulus from above was the only pathognomonic sign of actual section, unless the position of the nerve was such as to allow of palpation, when the presence of a bulbous end at once settled the difficulty. In many cases of superficial tracks with division of such nerves as the long or short saphenous, the early development of bulbs in the course of the trunks gave positive information, and these were often observed.
Traumatic neuritis.—This was a common sequence of contusion of the nerve itself, or of its subsequent inclusion in a cicatrix or callus. It was evidenced by hyperæsthesia both superficial and deep, pain, contracture, wasting of the muscles, local sweating, and the development of glossy skin.