It is this depression which best distinguishes the femur from the humerus. The shaft of the femur is quite long. Both ends of the femur are normally quite smoot, lending themselves to smooth joint movement in the hip and knee. This bone shows rough edges and deposits at both the proximal and distal ends. This could be a sign of osteoarthritis, a condition in which the bone begins to wear away under use because the cartilage is worn down.
Cartilage is a very tough tissue which provides a cushion-like pad between the bones in a joint.
Wearing down normally accompanies aging, but it can be sped up by misuse, injury, infection, or possibly even genetics. It does not normally regrow itself. At the proximal end of the tibia, or at the Epiphysis of other bones found in synovial joints. It occurs normally with aging, but can also be brought on by injury, misuse, infection, or even by a genetic predisposition. It leads toward the individual being elderly, but this is not conclusive because their are other causes.