Understanding the Embryology of Vertebral Basilar Circulation: A Key to Unraveling Variations in Spinal Arterial Supply

The embryology of vertebralis basilar circulation plays a crucial role in explaining various patterns seen in the radiculomedullary and radiculopial arteries. These arteries supply both the anterior and posterior spinal systems simultaneously, sometimes via a coronary artery and at other times through separate connections to the posterior spinal system.

A fundamental understanding of spinal vasculature is essential for grasping the complexities of spinal arterial anatomy. The Spinal Vascular Anatomy section provides an in-depth discussion on this topic, particularly focusing on the radiculomedullary and radiculopial arteries.

In classical disposition, the anterior inferior cerebellar artery (AICA) and superior cerebellar artery (SCA) arise from the basilar artery. Additionally, there are multiple short basilar perforators that supply a limited area of the brainstem. The radiculomedullary and radiculopial arteries, on the other hand, supply the posterior spinal system.

Practically speaking, these two types of arteries are fewer in number and may arise from longitudinal vessels other than the vertebral artery. The entire spinal cord system is supplied by segmental radiculomedullary arteries, which connect the vertebral artery to the anterior spinal artery. When these arteries arise from the anterior spinal artery and penetrate through the ventral cord sulcus, they are referred to as 'sulco-comissural' arteries.

The anterior and posterior spinal systems are connected by anastomoses that run along the circumference of the cord. These anastomoses, also known as 'coronary' arteries, may seem conceptually unclear at first, but a closer examination reveals their importance in maintaining blood flow to the spinal cord.

To better understand cervical spinal cord arterial supply, it is essential to consider the anterior spinal artery and paired posterior spinal arteries. The image on the left represents the cervical spinal cord arterial supply, which consists of the anterior spinal artery and a loose network of posterolateral vessels known as the posterior spinal arteries. These vessels are conceptually represented here as contiguous vessels, although this representation is at least mostly true in the cervical spine.

In conclusion, understanding the embryology of vertebralis basilar circulation is crucial for unraveling variations in spinal arterial supply. By grasping the complexities of spinal vasculature and spinal arterial anatomy, healthcare professionals can better diagnose and treat conditions affecting the spinal cord and its blood supply.

Pica definition