Internal Carotid Artery, Its Branches, and the Circle of Willis: Anatomical and Clinical Significance

The internal carotid artery is one of the principal arterial structures supplying the brain, orbit, and deep intracranial formations. Its branches provide oxygenated blood to essential functional centers responsible for consciousness, motor activity, sensory integration, and autonomic regulation. The Circle of Willis represents a critical arterial anastomotic network located at the base of the brain that maintains collateral cerebral circulation during vascular obstruction or stenosis. Variations in the anatomy of the internal carotid artery and the Circle of Willis are closely associated with ischemic stroke, cerebral aneurysms, transient ischemic attacks, and cerebrovascular insufficiency. According to recent epidemiological studies, cerebrovascular diseases account for approximately 11% of all global deaths, while ischemic stroke constitutes nearly 85% of these conditions. Morphological abnormalities of the Circle of Willis are present in more than 50% of the population and may significantly influence the severity and prognosis of cerebral ischemia. This article analyzes the anatomical structure, branches, embryological development, and clinical importance of the internal carotid artery and the Circle of Willis using the IMRAD scientific format, emphasizing their relevance in neurology, neurosurgery, radiology, and vascular surgery. 3,7,11