Blood Supply to the Brain


Arterial blood supplies the brain with the necessary blood flow via four vessels. Near the pituitary gland, these four vessels converge to create one unified vessel. This can be located in the inferior surface of the brain. These four vessels are each one set of paired arteries, a set of internal carotid arteries and a pair of vertebral arteries. The design of these vessels, and the unique structure of their convergence, allows the brain to receive adequate blood flow in the event that one particular artery becomes blocked or can not function properly.


The vertebral arteries stem from the subclavian artery which is found at the base of the neck. These arteries pass through the foramen magnum to enter the skull, rising superiorly through the transverse foramina of the vertical vertebrae. Once they are inside the cranium, these two arteries conjoin in order to form the basilar artery positioned at the base of the pons.


The basilar artery climbs along the lower plane of the brain stem and then concludes where it creates the two posterior cerebral arteries. The posterior cerebral arteries are responsible for the blood supply to the posterior section of the cerebrum.


Blood Supply to the Brain
Image: Blood Supply To The Brain

The posterior cerebral arteries form branches known as the posterior communicating arteries. The posterior communicating arteries are largely responsible for the creation of the circle of Willis, also known as the cerebral arterial circle which encompasses the pituitary gland.


The common carotid arteries branch off to create the internal carotid arteries. The internal carotid arteries rise along the neck until it enters the base of the skull. At the base of the skull, the temporal bone creates the carotid canal, allowing the internal carotid arteries access. Once the internal carotid arteries enter the skull, along the surface of the brain they branch off to create a new network along the inferior brain surface.

One of the most vital of these branches includes the ophthalmic artery which supplies the necessary blood flow to the eye as well as the associated ensemble which creates the eye.

The other two most important branches from the internal carotid artery include the anterior and middle cerebral arteries. These are responsible for supplying the appropriate blood supply to the cerebrum. Part of the cerebral arterial circle, the posterior cerebral arteries conjoin the internal carotid arteries.
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