The shrapnel ball in such cases would lie just beneath the skin or escape through an adjacent wound.
Plate 148.
Shrapnel—Plate 148.
LOWER EXTREMITY.
Gunshot (Pott’s) Fracture of the Left Ankle.
As the heel lies next to the plate, the left ankle is easily identified.
The course of the missile is shown by a metallic track from the internal to the external malleolus, and by a point of greater contact with the internal malleolus at the upper border of its articulation with the astragulus, resulting in an oblique fracture, separating the tip of the external malleolus.
At the point of first impact the posterior faciculus of the internal lateral ligament was severed. The missile therefore passed directly through the ankle joint, entering just behind the tip of the external malleolus, coursing over the posterior portion of the superior tibial articulation of the astragalus in front of the tendo Achillis to strike the upper articular surface of the external malleolus, with the resulting fracture. By this mechanism, the joint mortise has been widened by outward displacement of the external malleolus, while the rupture of the internal lateral ligament permitted the outward rotation of the astragulus, thus producing rather faithfully, by direct violence, a condition which might be called a “simulated Pott’s fracture” of the first degree.
By the metallic path of the missile it is known that its soft metal mass was not protected by a hard metal jacket; by the slight damage done to the bone, which lay directly in its path, its velocity and consequent energy are revealed as very slight; by the absence of larger metallic fragments it is shown that the missile was not deformed nor robbed of its energy through ricochet; and as only these conditions can be furnished by a lead ball, undeformed and traveling at low velocity, the missile was a shrapnel ball.