due to external pressure on rib
superior rib notching
- connective tissue disease: rheumatoid arthritis, SLE, Sjogren, scleroderma
- metabolic: hyperparathyroidism
- neurofibromatosis
- restrictive lung disease
- poliomyelitis
- Marfan syndrome
- osteogenesis imperfecta
- progeria
inferior rib notching
- arterial: coarctation of aorta, aortic thrombosis, subclavian obstruction, cause of pulmonary oligemia
- venous: superior vena cava obstruction
- arteriovenous: pulmonary AV malformation, chest wall arterial malformation
- neurogenic: neurofibromatosis (ribbon ribs)