Question

Radiological features of coarctation of aorta is/are -

• A. Reverse figure of 3 sign
• B. Rock sign
• C. Double aortic knuckle
• D. All of the above

Hint:

Think of the aortic contour, rib changes, and the reversed 3 outline together.

Answer 1

The Correct Option is D

Step 1: In coarctation of aorta the aortic lumen is constricted, so imaging shows both the pinch point and the changes that develop around it from altered haemodynamics.

Step 2: On the chest film the aortic shadow forms two convexities separated by a notch. Read together they look like a reversed number 3, which is why this is named the reverse figure of $3$ sign; the same paired convexities account for the double aortic knuckle appearance.

Step 3: Chronic shunting of blood through enlarged intercostal collateral vessels scallops the undersurface of the ribs. This rib notching, described as the rock or Dock sign in this context, is another hallmark of long-standing coarctation.

Step 4: Because each listed sign is genuinely associated with the lesion, no single option can be excluded.

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