Which anatomic lesion can create a vertebral steal phenomenon?

The vertebral steal phenomenon occurs when blood flow is reversed or redirected due to a significant occlusion or stenosis in an artery that affects collateral circulation. In the context of the choices provided, the most relevant anatomically related condition is the occlusion of the innominate artery.

When there is occlusion of the innominate artery, blood flow to the right subclavian and right common carotid arteries is compromised. As a result, there can be a reduction in the blood supply to the vertebral artery from the basilar circulation. This leads to the steal phenomenon, where blood that would ordinarily flow through the vertebral artery is diverted to supply the areas with compromised blood flow in the innominate artery. Consequently, to maintain perfusion to critical areas like the brain, the body may reroute blood flow away from the vertebral artery, highlighting the essence of the vertebral steal phenomenon.

In contrast, occlusion of the common carotid artery, lesions distal to the vertebral artery, and stenosis of the axillary artery would not create the same anatomic condition conducive to vertebral steal. While they can cause other forms of reduced perfusion or altered hemodynamics, they do not specifically induce the phenomenon related to the