The Relationship of the Quadriceps Vector to the Femur

To explain the knee kinematics, the vector of the quadriceps muscle, the primary extensor, is important and the relationship of the quadriceps vector (QV) to other kinematic and anatomic axes will help in understanding the knee.Knee kinematics is important for understanding knee diseases and is critical for positioning total knee arthroplasty components. The relationship of the quadriceps to knee has not been fully elucidated. Three-dimensional imaging now makes it possible to construct a computer based solid model of the quadriceps and to calculate the vector of the muscle as individual parts and as a whole. Two studies are presented, one American and one Japanese subjects.Using CT data from subjects who had CT for reasons other than lower extremity pathology (American) or specifically for the study (Japanese), 3-D models of each quadriceps component (vastus medialis, intermedius, lateralis and rectus femoris) were generated. Using principal component analysis for direction and volume for length, a vecto...