Popliteus muscle assists in flexing the leg upon the thigh; when the leg is flexed, it will rotate the tibia inward. It is especially called into action at the beginning of the act of bending the knee, inasmuch as it produces the slight inward rotation of the tibia, which is essential in the early stage of this movement. When the knee is in full extension, the femur slightly medially rotates on the tibia to lock the knee joint in place. Popliteus is often referred to as the "Key" to unlocking the knee since it begins knee flexion by laterally rotating the femur
Tibia shaft fracture Tibia shaft fracture Tibia shaft fracture is a fracture of the proximal (upper) third of the tibia (lower leg bone). Due to the location of the tibia, it is frequently injured. Thus it is the most commonly fractured long bone in the body. Patients with tibial shaft fractures present with pain and localized swelling. Due to the pain they are unable to bear weight. There may be deformity, angulation, or malroation of the leg. Fractures that are open (bone exposed or breaking the skin) are common. Since approximately one third of the tibia lies directly beneath the skin, open fractures