The anterior cerebral artery (ACA) supplies oxygenated blood to specific brain areas. Arising from the internal carotid artery, the ACA is part of the Circle of Willis, an arterial network at the base of the brain ensuring continuous blood flow. This network provides a protective collateral pathway, allowing for blood redistribution if one vessel becomes obstructed. The ACA travels along the midline of the brain, delivering nutrients and oxygen.
Brain Regions Supplied
The anterior cerebral artery primarily supplies the medial surfaces of the frontal and parietal lobes. Its branches cover a portion of these cortical areas. Orbitofrontal branches provide blood to the olfactory cortex, gyrus rectus, and medial orbital gyrus. Other branches vascularize the medial frontal gyrus.
The ACA also supplies several deep brain structures through its central branches. These include the anterior four-fifths of the corpus callosum, a large bundle of nerve fibers connecting the two cerebral hemispheres. Parts of the basal ganglia, such as the head of the caudate nucleus and the anterior portion of the putamen, receive blood from the ACA. The anterior limb of the internal capsule is also within the ACA’s supply territory.
The ACA provides blood to components of the limbic system, including the cingulate gyrus and the paracentral lobule. The precuneus, located in the medial parietal lobe, also receives its blood supply from branches of the ACA. The olfactory bulb and tract are also nourished by this artery.
Functions Governed by Supplied Regions
The brain regions supplied by the anterior cerebral artery govern various neurological functions. The paracentral lobule plays a role in motor control and sensory processing, particularly for the lower limbs and feet. This area also contains centers for voluntary bladder control. The supplementary motor area is involved in planning and initiating complex movements.
The frontal lobe supply supports higher-order cognitive functions. These include executive functions such as planning, decision-making, problem-solving, and abstract thinking. Motivation, judgment, and the regulation of social behavior and personality are also linked to these frontal regions.
The corpus callosum is essential for interhemispheric communication, allowing the two halves of the brain to share information and coordinate functions. The cingulate gyrus influences emotional regulation, memory formation, and the integration of sensory input with emotional responses. The olfactory bulb and tract are important for the perception of smells.
Clinical Implications of Impaired Supply
When the blood supply from the anterior cerebral artery is compromised, specific clinical symptoms can arise. Weakness or paralysis is a common manifestation, predominantly affecting the leg on the side opposite to the brain lesion. While the leg is most affected, there can be milder involvement of the arm, with the face often spared.
Sensory deficits accompany motor weakness, particularly in the contralateral leg and perineum. Changes in personality and behavior are also characteristic of ACA compromise, including apathy and disinhibition. These behavioral alterations stem from damage to the frontal lobe regions involved in executive function and emotional regulation. Damage to these areas can also impact an individual’s drive and ability to engage in purposeful activities.
Cognitive impairments include difficulties with planning, problem-solving, and executive functions. Speech disturbances, such as transcortical motor aphasia, where a person struggles with spontaneous speech but can repeat words, may also occur. Urinary incontinence is a frequent symptom, linked to the disruption of bladder control centers in the paracentral lobule. Gait disturbances, affecting the way a person walks, can also be observed.