Anomalous formation of the circulus arteriosus and its clinico-anatomical significance

Area of Science:

• Neuroanatomy
• Vascular Neurology
• Neurosurgery

Background:

• The Circle of Willis is a critical brain vascular structure connecting the internal carotid and vertebrobasilar systems.
• It plays a vital role in collateral circulation and blood flow regulation to the brain.
• Anatomical variations in its구성 vessels are common and can impact neurological function.

Purpose of the Study:

• To investigate the prevalence and patterns of anatomical variations within the Circle of Willis.
• To analyze the calibre variations, particularly in the posterior communicating artery and its relationship with the posterior cerebral artery.
• To highlight the clinical significance of these variations in neurosurgical procedures and stroke etiology.

Main Methods:

• A retrospective anatomical study of 35 formalin-embalmed adult human brains.
• Detailed tracing and measurement of the posterior cerebral artery and posterior communicating artery segments.
• Classification of posterior communicating artery configurations into fetal, transitional, and adult types.

Main Results:

• Anomalous formation of the Circle of Willis was observed in 8.6% of the studied specimens.
• A smaller calibre of the pre-communicating (P1) segment of the posterior cerebral artery relative to the posterior communicating artery was noted in anomalous cases.
• The study identified a fetal configuration where the posterior cerebral artery appeared as a continuation of the posterior communicating artery, originating from the internal carotid system.

Conclusions:

• Variations in the Circle of Willis anatomy, especially involving the posterior communicating artery, are significant.
• These anatomical anomalies are linked to an increased risk of cerebrovascular events such as stroke.
• A thorough understanding of these vascular variations is essential for neurosurgeons to enhance procedural success and patient safety.