A 28-year-old man with hypertension and radiofemoral delay undergoes imaging that shows coarctation of the aorta distal to the left subclavian artery with notching of the inferior surfaces of several ribs. Which vessels are responsible for the rib notching?
- A Dilated posterior intercostal arteries acting as collaterals ✓
- B Anterior intercostal branches of the internal thoracic artery
- C Lateral thoracic arteries
- D Superior epigastric arteries
Correct answer: A. Dilated posterior intercostal arteries acting as collaterals
Explanation
In coarctation, blood bypasses the obstruction through enlarged anastomoses between the subclavian system (internal thoracic, scapular arteries) and the descending aorta via the posterior intercostal arteries. These chronically dilated, tortuous posterior intercostal arteries run along the inferior border of each rib and erode its lower margin, producing the classic notched appearance. Anterior intercostals are too small to cause erosion.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.