What is the largest branch of each internal carotid artery?

• A. Anterior cerebral artery
• B. Middle cerebral artery
• C. External carotid artery
• D. Vertebral artery

Answer: (B)

The largest branch of each internal carotid artery is the middle cerebral artery. This artery supplies a significant portion of the lateral aspect of the cerebral hemisphere, including areas responsible for motor and sensory functions, speech, and higher cognitive processes.

The middle cerebral artery's prominence and size stem from its extensive coverage; it serves major territories of the brain, such as the frontal, parietal, and temporal lobes. Because it branches off quite early after the internal carotid artery bifurcates and is responsible for crucial vascular supply to a broad region, it is functionally the most substantial in comparison to other branches.

In context, while the anterior cerebral artery is a notable branch, it is smaller in size and supplies a more limited area of the medial frontal and parietal lobes. The external carotid artery is not a branch of the internal carotid; it primarily supplies the face and neck and branches off from the common carotid artery. The vertebral artery, which is part of the posterior circulation, does not branch from the internal carotid artery but rather arises from the subclavian arteries. Thus, in terms of size and anatomical significance, the middle cerebral artery stands out as the largest branch of the internal carotid arteries.