Popliteus muscle assists in flexing the leg upon the thigh; when the leg is flexed, it will rotate the tibia inward. It is especially called into action at the beginning of the act of bending the knee, inasmuch as it produces the slight inward rotation of the tibia, which is essential in the early stage of this movement. When the knee is in full extension, the femur slightly medially rotates on the tibia to lock the knee joint in place. Popliteus is often referred to as the "Key" to unlocking the knee since it begins knee flexion by laterally rotating the femur
Eolambia is expanded forwards. Like the humerus, the femur is bowed, but outwards. However, characteristically, the bottom half of the femur is straight. The fourth trochanter, located halfway down the femur, is vertically tall and triangular, similar to "Probactrosaurus", "Gongpoquansaurus", and other iguanodonts but dissimilar to more basal ornithopods. Like the ulna and radius, the tibia and fibula have straight shafts, and they articulate with each other; a roughened projection on the bottom of the fibula fits between two bulb-like condyles located just behind the cnemial crest on the bottom end of the tibia. The top of the tibia is rough,