Anterior communicating artery
The anterior communicating artery (AComm) is a short vessel that connects the left and right anterior cerebral arteries, forming the anterior border of the cerebral arterial circle of Willis. Together with the basilar artery, it is one of the two brain vessels that are not paired.
Besides forming the anastomotic channel between the anterior cerebral arteries, the functions of the anterior communicating artery are also to contribute to the blood supply of certain parts of the brain. Via its anteromedial central branches, this artery supplies parts of the optic chiasma, lamina terminalis, preoptic and supraoptic areas of the hypothalamus, parolfactory areas of the frontal cortex, anterior columns of fornix and the cingulate gyrus.
This article will discuss the anatomy and function of the anterior communicating artery
|Origin||Anterior cerebral artery|
|Branches||Anteromedial central arteries|
|Supply||Optic chiasma, lamina terminalis, preoptic and supraoptic areas of hypothalamus, parolfactory areas of frontal cortex, anterior columns of fornix, cingulate gyrus|
Origin and course
The anterior communicating artery connects the one anterior cerebral artery to the other transversely across the longitudinal cerebral fissure. It is located within a small subarachnoid space called the cistern of the lamina terminalis.
This cistern lies directly below the third ventricle and besides the AComm, it is also traversed by a part of the anterior cerebral artery. The location of AComm is important because a ruptured aneurysm may cause an intraventricular hemorrhage into the third ventricle through the membrane of the lamina terminalis.
Branches and supply
The anterior communicating artery gives off 1-4 perforating branches called the anteromedial central arteries. These arteries penetrate the medial part of the anterior perforated substance and supply the optic chiasma, lamina terminalis, preoptic and supraoptic areas of the hypothalamus, parolfactory areas of the frontal cortex, anterior columns of the fornix and cingulate gyrus.
One of the most frequent variations of the anterior communicating artery is the duplication of this vessel. The extra artery is called the superior anterior communicating artery and it is often associated with aneurysms.
Berry aneurysms, or saccular aneurysms, are saccular dilations that occur in the branching areas of the arteries that comprise the circle of Willis. Most frequently (around 30%) these aneurysms affect the anterior communicating artery.
These aneurysms are rarely discovered before they rupture since the symptomatology varies from very unspecific (e.g. headache) to none. However, if an aneurysm compresses the surrounding cranial nerves resulting in their altered function, it may be discovered during neuroimaging procedures.
The AComm aneurysm is no different. The presence of the anterior communicating artery aneurysm is usually followed by headaches and impaired vision. The rupture of the AComm aneurysm can be fatal as it quickly progresses to a subarachnoid hemorrhage (SAH) in the third ventricle. In this case, the symptoms progress dramatically, with patients describing their condition as “the explosive onset of the worst and most painful headache they have ever had in their life”. The patients often show the disturbances of consciousness ranging from confusion to coma, as well as epileptic seizures. The diagnostic methods are the CT, lumbar puncture and digital subtraction angiography. Urgent therapy includes the stabilization of vital functions (breathing, heart rate) and surgical treatment of the aneurysm.