<prompt> In patients with osteoahritis of knee joint, atrophy occurs most commonly in which muscle :Qudriceps onlyHamstrings onlyBoth a and bGastrocnemius  <response>: Quadriceps only Met Maheshwari 3e, p 253;Apleys 8e, p 472 In osteoahritis of knee joint, the quadriceps muscle is usually wasted. 