The three major bones of the human leg are the femur in the thigh and the tibia and fibula of the lower leg. Although the kneecap is also a bone it does not support the weight of the body and is actually located inside the patellar tendon.
Femur
The femur is the bone in the thigh. It has joints at the hip and knee where it articulates with the pelvis and the tibia, respectively. The femur has a rounded head that is offset at an angle from the main shaft of the bone at the hip joint. There are two major bony landmarks of the upper femur called the greater and lesser trochanter. These trocanters are where the muscles of the hip and groin attach to the femur. At the knee, there are two bony masses on either side of the joint where ligaments connect to stabilize the knee. These are called the epicondyles.
The kneecap, or patella, is a sesimoid-type bone that forms inside the patellar tendon. The patella protects the knee joint when the leg is flexed.
Tibia
The tibia is the larger of the two lower leg bones, and has joints at both the knee and ankle. The tibia has a large flat area where it articulates with the femur called the tibial plateau. There is a bony landmark at the front of the knee called the tibial tuberosity where the patellar ligament inserts. The tibia articulates with the tallus and has a bony projection on the inner portion of the ankle that stabilizes the ankle joint.
Fibula
The other bone of the lower leg is the fibula. At the ankle, the fibula is larger and forms a yoke with the tibia that creates a stable joint with the tallus of the foot. Near the knee, the fibula is smaller and has a relatively fixed joint with the tibia below the tibial plateau. The two bones of the lower leg are joined along their length by an interosseous membrane. This is a tendon-like structure that keeps the bones tightly bound and provides stability to the lower leg and ankle joint.
References
- "Gray's Anatomy: The Anatomical Basis of Clinical Practice", Susan Standring (Editor), 2008
- "Trail Guide to the Body: How to locate muscles, bones and more."Andrew Biel, 2005
