RIB NOTCHING ON CXR

caused by dilated intercostal arteries:

coarctation of aorta (commonest cause; bilateral 4th - 8th ribs notched; right side only if coarctation proximal to origin of left subclavian artery)

subclavian artery obstruction (ipsilateral notching of upper 3-4 ribs)

Blalock shunt (operation for treatment of Fallot's tetralogy; right upper 3-4 ribs notched)

severe atheroma or obstruction of abdominal aorta (bilateral lower 3 ribs notched)

caused by dilated intercostal veins:

SVC or IVC obstruction

enlarged intercostal nerves:

neurofibromatosis