Longest Bone in Human Body? Q. What is the longest bone in human body? Ans : T he femur or thigh bone , is the longest bone in human body. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint , while the distal part of the femur articulates with the tibia and patella forming the knee joint . By most measures the two and right) femurs are the strongest bones of the body, and in humans, the largest and thickest. Longest Bone Femur The body of the femur (or shaft) is large, thick and almost cylindrical in form. It is a little broader above than in the center, broadest and somewhat flattened from before backward below. It is slightly arched, so as to be convex in front, and concave behind, where it is strengthened by a prominent longitudinal ridge, the linea aspera which diverges proximally and distal as ...