A patient's physical exam reveals aphasia, left amaurosis fugax, and right hemiparesis. What is the source of these symptoms?

The symptoms presented, including aphasia, left amaurosis fugax, and right hemiparesis, suggest a specific vascular issue related to the lateralization of brain functions and blood supply. Aphasia typically occurs when there is damage to the language centers in the brain, which are primarily located in the left hemisphere for most individuals, especially right-handed ones. The presence of left amaurosis fugax indicates temporary vision loss in the left eye due to an issue with blood flow, which connects to the right hemisphere. Furthermore, right hemiparesis (weakness on the right side of the body) further supports that the problem is located in the left side of the brain, as motor function pathways cross over.

In this case, the left internal carotid artery (ICA) is the source of blood supply to these affected areas of the brain. Due to the symptoms aligning with dysfunction of the left hemisphere, the left ICA is the artery that, when compromised, would lead to the observed neurological deficits, such as aphasia and the contralateral hemiparesis.

The other arteries mentioned would not typically account for the combination of symptoms observed in this scenario. The right ICA would primarily affect the left side of the body, but would not