<prompt> K nail work on the pricliple of -One point fixationTwo point fixationThree point fixationFour point fixation  <response>: Ans. is c i.e., Three point fixation K-nail is used for transverse or short oblique fracture of femur, especially in isthemic area. K-nail Kuntscher cloverleaf intramedullary nail provides three points fixation due to elastic deformation. These three points of fixation are both ends of bone 2 points and isthmus 3rd point. 