Femur is present between the knee joint and the hip joint. Flexion and extension of the hind limb are made possible through large muscles present in groups. These muscles are attached to the femur bone. The femur is attached with the hip bone on the proximal end forming a ball and socket joint. It articulates with the tibia bone in the knee joint at the distal end. Femur is a long bone and several abnormalities can arise. These include developmental abnormalities, dislocation, bone infection, tumor growths, fractures, etc. Signs shown by pets suffering from femur pain include exercise intolerance, lethargy, and reluctance to move. A severe problem in the femur is sometimes visible as inflammation and the pet does not bear any weight on the affected leg.