Femur bone extends from the hip to the knee joint. Large muscles are attached to this rear limb for flexion and extension of the femur. The femur forms a ball and socket hip joint at the top while at the bottom it articulates with the tibia in the knee joint. Problems linked to the femur are mostly related to developmental abnormalities, dislocation from the hip joint, fracture, bone infection, and tumors. Any problem related to the femur makes it exercise intolerant and slow to rise. In severe cases, it is incapable of bearing the weight and appears swollen.