Commonest part of subclavian artery to be affected by stenosis is:

MC site of subclavian artery stenosis is the first part of the subclavian artery. • MC cause of subclavian artery stenosis: Atherosclerotic disease • Left subclavian artery stenosis is significantly more common than right • MC site of stenosis: First part of the subclavian artery • Stenosis typically occurs just distal to the origin of the subclavian artery and lies proximal to the origin of the vertebral artery. • Stenosis of the first part of the subclavian artery may give rise to the subclavian steal syndrome • Subclavian steal syndrome is characterized by reversed flow in the vertebral artery to compensate for a proximal stenosis in the ipsilateral subclavian artery there by stealing blood from the ‘brain’ to feed the ‘arm’.