The hard metal jacket of a rifle bullet would not give off its particles in contact with the bone unless it were so greatly deformed as to have almost entirely lost its jacket. In this state the energy of a rifle ball must be so greatly reduced, through the violence of ricochet, that it would not retain enough striking force to cause its disintegration on impact with the bone. Besides, some particles of the jacket could be identified, as they are always bent or twisted so that their character is recognized in the shadow. [Illustration: Plate 128.] SHRAPNEL--PLATE 128. LOWER EXTREMITY. Gunshot Wound of the Left Knee, with Lodgment of the Missile in the Joint. The slight enlargement and moderate density of the shadow of the projectile indicates a position a short distance from the plate. A slight shadow dependent from the external condyle on the outside of the ball and a metallic marking just outside of the upper contour of the outer tuberosity indicate an injury to the joint and the path of the ball from above the outer tuberosity into the joint capsule. The probabilities are that the ball lies between the head of the tibia and the patellar notch of the femur, but the absolute certainty of this deduction must be supported by an exposure in a lateral plane, which is shown in plate 129. [Illustration: Plate 129.] SHRAPNEL--PLATE 129. LOWER EXTREMITY. Gunshot Wound of the Left Knee, with Lodgment of the Missile in the Joint. As the fibular shadow is about the normal size and clearly outlined, the fibular side of the leg lay next to the plate. As the shadow of the ball is dense and not much enlarged, it must lie near the plate. A light shadow in front of the ball, which shows the anterior crucial ligament, and a metallic marking above the patella, suggests the path of the ball. As this is a lateral projection of the same case that is shown in plate 128 in an antero-posterior projection, these conclusions are thus verified. The missile lies in the joint capsule between the head of the tibia, in front of the spine, and the patellar notch of the femur. As a foreign body in the knee joint which seriously interferes with its function, removal is indicated when surgical facilities are at hand. The results in such cases are usually good. [Illustration: Plate 130.] SHRAPNEL--PLATE 130. LOWER EXTREMITY. Gunshot Wound of the Left Knee, with Lodgment of the Missile in the Joint.