<prompt> Which of the following causes rib-notching on the chest radiograph?IVC occlusionCoarctation of aoaBidirectional Glem shuntModified Blalock-Taussing shunt  <response>: Coarctation of aoa is associated with notching, typically of the inferior posterior aspects of the ribs 3rd through 8th. The number and location of notched ribs provides information regarding location of the coarctation. Ref: CURRENT Diagnosis Treatment: Nephrology Hypeension chapter 42; Essence of Paediatrics By Khan, 4e page 153-8. 