<prompt> Rib notching is seen in all EXCEPT-Coarctation of aortaClassical Blalock Tausing operationIVC obstructionNeurofibromatosis  <response>: Ans. is c ie IVC obstruction CAUSES OF RIB NOTCHINGRib notching Inferior surface Rib notching - Superior surfaceArterial A Connective tissue diseasesCoarctation of the aorta Rheumatoid arthritisrib signs are unusual before 10 yrs of age SLEAffects 4th to 8th ribs bilaterally, not the upper two ribs SclerodermaUL and right sided ribs are affected if the coarctation is proximal to the left subclavian artery Sjogrens syndrome B MetabolicAortic thrombosis HyperparathyroidismSubclavian obstruction C Miscellaneousmost commonly post Blalock operation for fallots Petrology Neurofibromatosis Restrictive lung diseaseunilateral upper three or four ribs on the operation side Poliomyelitisare affected. Marfans syndromePulmonary oligaemia Osteogenesis imperfectaVenous ProgeriaChronic superior vena caval obstruction or IVC obstructionArteriovenousPulmonary arteriovenous malformationChest wall arteriovenous malformationNeurogenicNeurofibromatosisThough IVC obstruction is mentioned as a cause of inf. rib notching, in Sutton Grainger it is a very rare cause. 