The human brain requires a constant supply of oxygenated blood to function properly. This supply comes from a complex network of blood vessels, with the vertebral arteries playing a significant role. It is possible to live a healthy life with only one vertebral artery, as the body often adapts to such variations, maintaining adequate blood flow to the brain.
Understanding Your Vertebral Arteries
The vertebral arteries are a pair of major blood vessels located in the neck. These arteries originate from the subclavian arteries and ascend through the vertebrae into the skull. Inside the skull, they usually merge to form a single basilar artery.
This combined system, the vertebrobasilar system, supplies blood to several posterior parts of the brain. These areas include the brainstem, cerebellum, and the posterior cerebrum. The brainstem controls basic life functions, while the cerebellum is involved in balance, movement, and coordination. Most individuals are born with two functioning vertebral arteries, ensuring a consistent blood supply to these regions.
How the Body Compensates
The human body has a capacity to adapt when one vertebral artery is absent or compromised. A primary component of this adaptability is the Circle of Willis, an anastomotic ring of arteries at the base of the brain. This network connects the two major arterial systems supplying the brain: the internal carotid arteries and the vertebrobasilar system.
The Circle of Willis acts as a natural bypass system, rerouting blood flow if a contributing vessel experiences reduced flow or blockage. If one vertebral artery is not fully functional, blood can be directed from the other vertebral artery or from the carotid arteries through these interconnected pathways. This collateral circulation ensures that the brain continues to receive sufficient oxygen and nutrients, even with a variation in the vertebral artery anatomy. Anatomical variations in the Circle of Willis are common, but these connections generally provide a protective mechanism against reduced blood flow.
Potential Implications and Symptoms
Despite the body’s compensatory abilities, there are situations where having one vertebral artery can lead to issues. If the compensatory mechanisms of the Circle of Willis are insufficient or if the remaining vertebral artery becomes narrowed, symptoms can arise. Conditions like atherosclerosis (plaque buildup) or arterial dissection can compromise blood flow in the remaining artery.
Reduced blood flow to the posterior brain can manifest in various symptoms, including:
Dizziness or vertigo
Problems with balance or coordination
Visual disturbances, such as double vision or temporary loss of vision
Slurred speech
Difficulty swallowing
Numbness or weakness
Sudden, severe headaches
These symptoms are possibilities and do not affect everyone with a single vertebral artery.
Medical Considerations and Living with One Artery
The absence or compromise of a vertebral artery is often discovered incidentally during medical imaging for other reasons. If symptoms related to reduced blood flow to the brain are present, a medical evaluation is important. This assessment helps understand overall cerebrovascular health and determine if interventions are necessary.
Many individuals with a single vertebral artery live normal, symptom-free lives without knowing about this anatomical variation. For those who do experience symptoms or have a compromised remaining artery, managing cardiovascular risk factors is important. This includes addressing conditions like high blood pressure and elevated cholesterol, which can help protect the remaining blood vessels and maintain healthy blood flow.