Joint locking (medicine) symptom of: Locking of the knee happens during the last stages of extension when a person is standing up. Medial rotation of femur occurs as the space available at the lateral condyle of tibia is being used up by the lateral condyle of femur during extension. Therefore, lateral femoral condyle acted as an axis for medial femoral condyle to rotate backwards. This movement is aided by oblique pull of the ligaments of the knee joint and contraction of the quadriceps muscles. The ligaments are pulled taut when the knee joint is locked in place during standing. When the knee is
Tibia Clausa rank. A few of the largest theatre organs, and some church organs, may have a separate 32′ Tibia Clausa rank of 12 pipes. In smaller organs, a "Bourdon" or "Stopped Diapason" may be substituted for a Tibia Clausa at 16′ pitch. The Tibia may be voiced on wind pressures from 10″ to 25″. The Tibia is generally used as a chorus stop, with or without tremulant; it is not normally used as a solo stop due to its relatively dull tone. Other variants of the Tibia Clausa include: Tibia Bass, Tibia Flute, Tibia Major, Tibia Plena (open tibia) and Tibia