The femur (Latin: os femoris), also known as the thigh bone, is the only bone forming the thigh. Inside the body of the femur is the medullary cavity, which contains bone marrow. At the ends of the femur are areas of compact and solid bone. Surrounding this is spongy bone, which has lots of small cavities dispersed throughout it. The neck and head of the femur are made up of spongy bone. The femur is the longest, heaviest, and strongest bone in the human body. The main function of the femur is weight bearing and stability of gait. An essential component of the lower kinetic chain. The robust shape of the femur provides many sturdy attachment points for the powerful muscles of the hip and knee that contribute to walking and other propulsive movements. [1] Femur : Three Divisions The femur acts as the site of origin and attachment of many muscles and ligaments, and can be ... Learn about the femur bone/thigh bone, what it looks like, where it is located, its definition, functions, parts, & structure, along with labeled pictures