In the case of completely divided nerves the development of a bulbous enlargement on the proximal end was constant, and very marked in degree. I saw few cases in which primary effects could be certainly referred to pressure or laceration by bone spicules, excepting in some fractures of the humerus, and perhaps some injuries of the seventh nerve accompanying perforating wounds of the mastoid process.
IV. Secondary implication of the nerves.—This was a striking characteristic in many at first apparently simple wounds of the soft parts. In such cases it was due to implication of the contiguous trunk in the process of cicatrisation, and its importance varied with the size of the nerve in question. In the smaller sensory trunks it was often evidenced by the occurrence of neuralgic pain, especially liable to be influenced by climatic changes; in the larger, by signs of more or less severe motor, sensory, and trophic disturbance. Musculo-spiral paralysis from implication in, or pressure from, callus in cases of fracture of the humerus was very frequent. This would naturally be expected from the extreme degree the comminution of the bone often reached, and the consequently large amount of callus developed.
The effect of cicatrisation of the tissues surrounding the nerves varied somewhat according to the degree of fixation of the individual nerve implicated. Thus if a nerve lay in a fixed bed some form of circular constriction resulted; if, on the other hand, the nerve was readily displaceable, the cicatrix often drew it considerably out of its course; in either case symptoms corresponding with those of pressure resulted.
Symptoms of nerve lesion.—These differed little in character from those common to such injuries in civil practice, except in the relative frequency with which they assumed a serious aspect. After all in civil practice nerve concussion is most familiar to us in the degree common after knocking the elbow against a hard object, and the same may be said in regard to the allied injury of contusion. It is in small-calibre bullet wounds alone that the occurrence of such severe and sharply localised injury to deep parts as was observed is possible.
Concussion.—Temporary loss of function was often observed in the limbs, corresponding to the distribution of one or more nerve trunks when wound tracks had passed in their vicinity. Interference with function sometimes amounted to loss of sensation alone: in others to loss of both sensation and motor power. Such symptoms were of a transitory character, lasting for a few days or a week; if both sensation and motion were impaired, sensation was usually the first to be regained. In these cases secondary trouble was not uncommon, since the near proximity of the track to the originally affected nerve offered every chance for implication of the latter in the resulting cicatrix. This sequence was often observed, and its symptoms are described under the heading of secondary implication below. Equally striking were the instances of concussion in the case of the nerves of special sense and their end organs, temporary loss of smell, vision, or hearing being not uncommon, often passing off in the course of a few days with no apparent ulterior ill-effect.
One of the most interesting illustrations of the occurrence of concussion was furnished by cases in which complete paralysis of a limb rapidly cleared up with the exception of that corresponding to a single individual nerve of the complex apparently originally implicated. Instances of severe contusion or division of one nerve of the arm, for instance, accompanied by transient signs of concussion of varying degrees of severity in all the others, were by no means uncommon.
Contusion.—The symptoms of contusion were somewhat less simple, since, in addition to lowering or loss of function, signs of irritation were often observed. In the slighter cases irritation was often a marked feature, as was evidenced by hyperæsthesia and pain combined with loss of power. In cases in which pain and hyperæsthesia were primary symptoms, these were often transitory. I will quote an illustrative case which, though affecting the nerve roots, is characteristic of the effects of slight contusion in the case of the nerve trunks in any part of their course:—
(107) Contusion of cervical nerve roots.—Range probably about 1,000 yards. Wounded at Belmont. Aperture of entry (Lee-Metford), immediately posterior to the right fifth cervical transverse process; exit, immediately anterior to the space between the third and fourth left cervical transverse processes. The movements of the neck were perfect, there was neither pain nor difficulty in swallowing. Extreme hyperæsthesia was present in both palms and down the front of the forearms. The grip in either hand was weak, this being possibly explained in part by the hyperæsthesia of the palms, as all movements of the upper extremities could be made, although not with full power. On the fourth day the condition was much improved on the left side, and at the end of a week the left upper extremity was normal; the right (side of entry, and therefore exposed to greater force from the bullet) improved more slowly, becoming normal only at the end of three weeks.
I observed an identical case of injury to the cervical roots, and many similar instances in injuries of the nerve trunks of the limbs in which the course was exactly parallel. In the more severe, pain was often added to hyperæsthesia.
In the most severe cases the signs corresponded in all particulars, except in the early entire loss of reaction of the muscles to electricity, with those of complete section. Loss of sensation and motion was immediate, complete, and prolonged, the limbs being lowered in temperature, flaccid, and powerless. General systemic shock was also severe. In the case either of plexus or multiple contusions, or where the injury was more local, correspondingly complete signs were present in the area supplied by the affected nerves.