Rib notching is primarily associated with which cardiovascular condition?

Rib notching is primarily associated with coarctation of the aorta due to the way this condition leads to changes in blood flow. In coarctation, which is a narrowing of the aorta typically occurring just distal to the left subclavian artery, there is an interruption of normal blood flow to the lower half of the body. This causes the collateral circulation to develop in order to bypass the narrowed segment of the aorta.

The collateral vessels, which often involve the intercostal arteries, become enlarged as they carry increased blood flow to bypass the obstruction. This chronic increased pressure from these collateral vessels can erode the underlying bone, leading to the characteristic notching seen along the inferior margins of the ribs, particularly in the lower ribs.

Understanding rib notching is important in the context of diagnosing coarctation of the aorta, especially in patients who may present with hypertension in the upper extremities and lower blood pressure in the lower extremities, along with classic radiographic findings. This distinct presentation makes coarctation of the aorta the condition primarily associated with rib notching.