Functional and Vascular Anatomy of the Brain

Introduction

The human brain, a highly complex organ, relies on a robust vascular system for its function. Blood supply is crucial in delivering oxygen and nutrients while removing metabolic waste. The cerebral circulation is provided by an intricate network of arteries that ensure perfusion to critical brain regions.

Major Arterial Systems Supplying the Brain

1. Internal Carotid Arteries (ICA)

The ICAs are the primary arteries supplying the anterior portion of the brain. They bifurcate from the common carotid arteries and ascend through the carotid canal to enter the cranial cavity. Key branches include:

• Anterior Cerebral Artery (ACA): Supplies the medial portions of the frontal lobes and superior medial parietal lobes.
• Middle Cerebral Artery (MCA): Supplies the lateral surfaces of the cerebral hemispheres, including motor and sensory cortices and speech centers.

2. Vertebral Arteries

These arteries arise from the subclavian arteries and traverse the transverse foramina of the cervical vertebrae before merging to form the basilar artery. Key branches include:

• Posterior Cerebral Artery (PCA): Supplies the occipital lobe and inferior temporal lobe.
• Basilar Artery: Gives rise to pontine arteries and cerebellar arteries.

Circle of Willis

This arterial ring at the base of the brain provides collateral circulation. It connects the internal carotid and vertebrobasilar systems through communicating arteries:

• Anterior Communicating Artery
• Posterior Communicating Arteries

Clinical Relevance

Understanding the vascular territories is essential for diagnosing strokes and aneurysms. For instance, occlusion of the MCA leads to contralateral motor deficits and aphasia.

Conclusion

The brain's vascular anatomy is vital for maintaining neurological health. Familiarity with the major arteries enhances the ability to assess cerebrovascular conditions and plan appropriate medical or surgical interventions.