A subclavian aneurysm is weakness or bulging in the wall of the subclavian artery, which is located below the collarbone. If the aneurysm ruptures, it can cause life-threatening, uncontrolled bleeding. Blood clots caused by the aneurysm can potentially lead to stroke or loss of fingers, the hand or, in rare cases, the entire arm. [ https://heart.uvahealth.com/services/aneurysms/subclavian-aneurysm ]