To diminish further the tendency of the stump to tilt forward the posterior edge of the bucket is flattened so that the shape of the top of the bucket is triangular with curved sides and angles much rounded (the anterior angle over the tuberosity of the tibia being obtuse). This is the natural shape of a section of the top of the calf. In this way the posterior muscles are flattened and no longer tend to escape from the bucket when the knee is flexed. In figures 110 and 111 are shown two ways in which this flattened posterior margin may be shaped. [Illustration: FIG. 109.] [Illustration: FIG. 110. FIG. 111.] B. SUSPENSION APPARATUS.--The leg is attached (_a_) by a thigh corset taking its hold on the femoral condyles, and (_b_) by braces over the shoulders. (_a_) _The thigh corset_ is made of leather laced in front. Two lateral steels curving in sharply against the upper part of the condyles (Fig. 112) form the most effective part of the support. At their lower ends they are articulated with two steels passing up from the top of the leg to which they are attached. The joint (Fig. 113) is composed of a nut, A, into which fits a screw. Around the nut is a copper ring made to move with the femoral steel by means of a stop-notch. When the knee flexes and extends the wear comes upon this copper ring. The steels remain intact. If the joint works loose it is sufficient to renew the ring. [Illustration: FIG. 112. FIG. 113. FIG. 112.--The thigh steels, curved in above the condyles, hold the limb on very securely.[10] FIG. 113.--Details of the joint at the knee.] [10] In this illustration the joints are placed too low. They should be opposite the centre of rotation of the knee joint, _i.e._ a transverse line passing through the femoral condyles. (ED.) (_b_) _The braces_ are a very useful addition which French orthopædists should employ systematically. They increase the stability of the limb and allow the thigh piece to be laced less tightly, so that contraction of the thigh muscles is facilitated. [Illustration: FIG. 114.] [Illustration: FIG. 115.]