ABSTRACT
Quadriceps: vastus medialis (1), lateralis (2) and intermedius arise from the femur; rectus femoris (3) arises from the ilium and overlies intermedius. They insert via the patella (4), into the tibial tuberosity (5) to extend the knee. Rectus femoris also flexes the hip (the kicking muscle). The lower fibres of medialis help prevent lateral patellar dislocation. Sartorius (6), the longest muscle in the body, passes from the anterior superior iliac spine to the tibia. It flexes and externally rotates the hip, while also flexing the knee to sit crosslegged. The femoral nerve (L2,3,4) supplies all these muscles (knee jerk L3,4). Rectus femoris, crossing two joints, is more susceptible to injury. Quadriceps are essential for knee stability and must not be allowed to waste following joint injury or surgery.
