The Lachman's test (aka Ritchie test) is the preferred method of assessing for instability of the anterior cruciate ligament. The patient is supine on the table with their knee flexed approximately 20-30 degrees. The examiner grasps the medial proximal tibia with one hand and the distal thigh with the other. The examiner then applies a posteromedial to anterolateral force to the knee, essentially pulling the tibia anteriorly on the femur. The amount of translation is compared bilaterally to determine the presence and/or extent of instability. Alternative methods have been developed to accomodate examiners with small hands and for use with patients with large extremities.