Again, it was rare for fissuring to extend from these tunnels to the articular surfaces; thus many instances could be given of perforation of the head of the humerus, the olecranon, or the femoral condyles, in which no evidence of joint fissure was discoverable. The slight amount of resistance offered by the cancellous ends was also clinically illustrated by the absence of severe synovial effusions when they were struck. When the joint cavity was not crossed, slight effusion only resulted, while in the case of fractures of the femoral shaft great effusion into the knee-joint, resulting from the forcible vibration transmitted to the limb, was a common feature, even when the point fractured was situated above the centre of the bone. Again, when the joint cavity was crossed a moderate degree only of hæmarthrosis was the most common result.
With regard to the implication of joints, either primary or secondary, in connection with fractures of the articular ends, I am inclined to place the lesions of the upper end of the tibia in a more important position than those of any other bone. Evidence of this implication was in my experience more frequent here than in any other situation. This may in part be attributable to the complexity of structure of this epiphysis, and perhaps more correctly to the influence of its irregular outline in favouring lateral forms of impact on the part of the bullet and consequent increase in the area of damage.
Next to tunnelling, grooving was the most common form of injury to the short bones. In the case of superficial tracks the compact tissue might be considerably comminuted, but not, as a rule, over a width greatly exceeding the calibre of the bullet.
Comminution and crushing of a single or several bones were rare in proportion to the occurrence of similar injuries produced by Martini-Henry or large leaden bullets. When the condition was produced by bullets of small calibre, I believe it was in the majority of cases the result of irregular impact on the part of the projectile. In support of this view it may be added that such injuries were most common in the bones of the tarsus, bones especially liable to be struck by ricochet bullets.
It was generally believed that bullets travelling at a very high degree of velocity were liable to cause severe comminution of the short bones, but I never saw any cases supporting this opinion; in point of fact, all the short-range lesions of this nature that I saw were of the clean perforating variety. I believe that this is capable of satisfactory explanation on the ground of the thin character of the layer of compact tissue which for the most part ensheaths the short bones; this decreases the resistance offered to the bullet and so tends to localise the lesion. This statement may be supported by two observations with regard to the long and flat bones. First, if the shaft of a long bone be hit above the junction of diaphysis and epiphysis, the cancellous tissue in and extending from the medullary cavity is pulverised, and examination of fragments from such fractures gives the impression of the inner aspect having been scraped clean. Secondly, I saw one fracture of the ilium produced by a bullet taking a course between its compact layers for 3 inches from the notch between the anterior superior and anterior inferior spines; the bone to the extent of 2½ square inches was pulverised, the cancellous tissue blown away as dust, and the compact tissue only represented by scales still adhering by their periosteum to the muscles attached to the two surfaces of the bone. This injury was produced from a rifle fired at five yards distance, and was an extreme example; but, on the other hand, it illustrates only what we are thoroughly well acquainted with in the case of flat bones, such as those of the cranium, where the compact element is abundant in comparison with the cancellous, and the resistance offered to the bullet is consequently great.
Some remarks on transverse fractures of the patella will be found under the heading devoted to that bone.
Lesions of the flat bones are considered at some length in Chapter VII., which deals with injuries to the head, and their special features are there described; some further remarks on these injuries will be found under the headings of the individual bones.
Special characters of the symptoms observed, and of the course of healing of the fractures.—Peculiarities in the initial signs may be rapidly passed over. The first depended on the large number of lesions of the bone which were unaccompanied by loss of continuity. In the case of perforations attention to the course of the track, external palpation, and possibly the detection of bone dust in the aperture of exit, were usually sufficient to indicate injury to the bones. When these did not suffice the introduction of a probe would usually set the question at rest; but this is always to be avoided if possible, as adding a fresh item of risk to the wound. The X rays were not always to hand, and are not always capable of giving reliable information in the matter of perforations, although very useful in detecting grooves or notching. The latter injuries are those in which information as to the condition of the bones is often of most interest in view of the characters of the external wounds.
Fractures with solution of continuity were, as a rule, easy of detection, but the relative prominence of the classical signs varied somewhat from what we are accustomed to see in civil practice.
The first striking peculiarity noted in comminuted fractures of the long bones was the degree of local shock; the limbs were often quite powerless, the muscles flaccid, and common sensation lowered. This was of importance in two ways; firstly, shortening of the limb was often absent as a sign, and, secondly, pain was sometimes not at all pronounced even when the patient was moved. The primary absence of shortening, even persisting for the first two or three days, was a phenomenon always important to bear in mind, as it affected the degree of extension needed in the treatment of the fracture, which, if sufficient at the moment, often proved quite inadequate with the return of tone in the muscles. Secondly, abnormal mobility was usually strongly marked, and this sometimes without very definite crepitus, as a result of the fine nature of the comminution and the displacement of the small fragments.