AssessmentsSubclavian steal syndrome
USMLE® Step 1 style questions USMLE
A 76-year-old man comes to the clinic with right arm pain and numbness, especially during exertion. He also complains of dizziness and vertigo. Blood pressure is 142/88 in the left arm and 108/66 in the right arm. Angiogram shows stenosis of the right subclavian artery just proximal to the origin of the vertebral artery. Which of the following is the most likely mechanism that maintains blood flow to the right extremity?