Stylized illustration of a human brain highlighting variations in the basilar artery.

Unlocking the Secrets of Your Brain: Exploring Basilar Artery Variations

Elliot Brynn in Health & Wellness June 2025 • 4 min read.

"A new study reveals fascinating insights into the basilar artery's diverse forms and their potential impact on brain health."

The basilar artery (BA) is a major blood vessel that sits at the base of the brain, playing a vital role in supplying oxygen-rich blood to the brainstem, cerebellum, and parts of the cerebrum. Because of its crucial location and function, any variations in its structure or path can have significant consequences for neurological health.

While the 'typical' anatomy of the basilar artery is well-documented, the reality is that this vessel exhibits a remarkable range of variations. These variations, which can affect its origin, length, trajectory, and diameter, are not necessarily abnormalities, but rather natural differences in human anatomy.

Researchers have long been interested in understanding these basilar artery variations and their potential impact on various neurological conditions. A recent study conducted in Colombia has provided valuable insights into the morphological expression of the BA in a specific population, offering new data for comparison with previous studies and enhancing our knowledge of this vital artery.

What This Study Reveals About Basilar Artery Variations

Stylized illustration of a human brain highlighting variations in the basilar artery.

Researchers in Colombia meticulously examined 100 brainstems obtained from autopsies, focusing on the basilar artery and its surrounding structures. They carefully measured and analyzed several key features, including the artery's:

The study's findings revealed a fascinating array of variations:

Trajectory: While most arteries (68%) followed a straight path, others exhibited deviations to the right (12%), left (10%), or a sinuous course (10%).
Origin Point: The basilar artery typically forms at the junction of the vertebral arteries. However, the study found that this origin point varied relative to a specific anatomical landmark called the pontomedullary sulcus. In 43% of cases, the origin was at the level of the sulcus, while in 30% it was above, and in 27% it was below.
Size Differences: The study also noted variations in the diameter (caliber) of the basilar artery at its origin and end points.
Vertebral Artery Hypoplasia: Researchers observed hypoplasia (underdevelopment) in one of the vertebral arteries (the arteries that merge to form the basilar artery) in some cases, with the left vertebral artery being slightly more affected than the right.

These variations, while seemingly minor, can have implications for blood flow dynamics and the potential development of neurological issues.

Why Understanding Basilar Artery Variations Matters

The Colombian study, along with previous research, highlights the importance of recognizing and understanding the diverse ways in which the basilar artery can present. This knowledge can be valuable for:

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.4067/s0717-95022013000300050, Alternate LINK

Title: Expresión Morfológica De La Arteria Basilar: Un Estudio Con Material De Autopsia De Individuos Colombianos

Subject: Anatomy

Journal: International Journal of Morphology

Publisher: SciELO Agencia Nacional de Investigacion y Desarrollo (ANID)

Authors: Pedro Luis Forero, Luis Ernesto Ballesteros, Luis Miguel Ramírez

Published: 2013-09-01

Everything You Need To Know

What is the basilar artery and why is it important?

The basilar artery is a major blood vessel located at the base of the brain. Its primary function is to supply oxygen-rich blood to critical areas such as the brainstem, cerebellum, and parts of the cerebrum. This makes it essential for various neurological functions, and any structural or positional variations can potentially impact brain health. Variations include trajectory deviations (straight, right, left, or sinuous), origin point differences relative to the pontomedullary sulcus, and size variations in the artery's diameter. These variations, while natural, can affect blood flow dynamics.

Why is it important to understand the variations in the basilar artery?

Variations in the basilar artery are significant because they can influence blood flow dynamics within the brain. The basilar artery's trajectory, origin point, and diameter can affect how efficiently blood is delivered to the brainstem, cerebellum, and cerebrum. If the basilar artery is underdeveloped (hypoplasia) or follows an atypical path, it might increase the risk of neurological issues due to altered blood supply. Understanding these variations is crucial for medical professionals in diagnosing and treating neurological conditions.

What does the origin point of the basilar artery refer to and why does it vary?

The origin point of the basilar artery is the location where it forms from the merging of the vertebral arteries. The typical point is at the junction of the vertebral arteries. Variations occur relative to the pontomedullary sulcus. The origin point can be at the level of, above, or below this sulcus. The location of the origin point can affect blood flow dynamics and may have implications for the development of neurological problems. If the origin is significantly displaced, it could impact the efficiency of blood supply to the brainstem and other vital areas.

What is vertebral artery hypoplasia and how does it relate to the basilar artery?

Vertebral artery hypoplasia refers to the underdevelopment of one of the vertebral arteries, which are the arteries that merge to form the basilar artery. When one vertebral artery is hypoplastic, it means it is smaller than usual, which can affect the overall blood flow to the basilar artery. This asymmetry in blood supply can influence the dynamics of blood flow in the brain. The study observed that the left vertebral artery was slightly more affected by hypoplasia than the right. This variation is important because it contributes to the overall understanding of how blood flow patterns can differ among individuals.

What does trajectory mean in the context of the basilar artery, and why are its variations significant?

The trajectory of the basilar artery refers to the path it takes as it ascends towards the brain. While the typical trajectory is straight, variations can include deviations to the right, left, or a sinuous (curved) course. This is important because a deviated or sinuous trajectory can affect blood flow dynamics. A more tortuous path may impede blood flow, potentially increasing the risk of neurological issues. The Colombian study noted that while most arteries followed a straight path, a notable percentage exhibited these deviations.