<prompt> Which of the following statement is true regarding subclan steal syndromeReversal of blood flow in the ipsilateral veebral aeryReversal of blood flow in the contralateral carotid aeryReversal of blood flow in the contralateral veebral aeryBilateral reversal of blood flow in the veebral aeries  <response>: Subclan steal syndrome may occur if it is the first pa of the subclan aery that is obstructed, with the veebral aery providing a collateral circulation into the arm by reversing its direction of flow. It is associated with neck pathology like cervical rib.This may cause periods of cerebral ischaemia. However, the classic syndrome of syncopal attack and visual disturbance associated with arm exercise and a diminished blood pressure in the affected limb is rare,asymptomatic reversal of flow in the veebral aery is much more common. In symptomatic patients, PTA or operation is indicated. Reference:Bailey Loves sho practise of surgery,25th edition,page no:909 