The posterior meningeal artery is a blood vessel branch supplying the posterior meninges. It is connected to the external carotid artery through the opening in the base of the skull (foramen jugulare). Diseases in this context include meningitis (meningitis), meningiomas (tumors of the meninges), hematomas (hemorrhages), malformations (malformations) of the vessels, arteriosclerosis (deposits in the vessel walls, so-called “plaque“), thrombi (formation of plugs from blood platelets), and aneurysms (vascular dilatation/tears), and as a possible consequence, infarctions.
What is the posterior meningeal artery?
The posterior meningeal artery – or posterior meningeal artery – is an arterial branch in the meninges, or “meninges,” that supplies arterial blood, and therefore oxygen, to the brain and meninges. As a small vascular branch, the posterior meningeal artery is connected to the arteries from the neck. Through the foramen jugulare, the opening at the base of the skull, the arteries enter the cranial cavity and the vascular branches enter the meninges. Anastomoses are a special feature. The posterior meningeal artery forms anastomoses with two other arteries, the anterior meningeal artery (anterior meningeal artery) and the middle meningeal artery (middle meningeal artery): an anastomosis should be understood as an anatomical connection, in this case between blood vessels, that serves to regulate blood circulation in the brain and prevents the surrounding tissue from dying if a vessel fails.
Anatomy and structure
The brain is protected from the outside by the skullcap. Beneath it are the meninges, venous blood vessels, branches of arteries, and cerebrospinal fluid (CSF). Meninges, or meninges, are those layers of connective tissue located between the brain and the skullcap. There are three forms of meninges: hard meninges (dura mater), cobweb meninges (arachnoid), and tender meninges (pia mater). These connective tissue layers within the skull are referred to as intracranial. The posterior meningeal artery is an intracranial vascular branch of the “ascending pharyngeal artery” (Arteria pharyngea ascendens), which in turn is the main vascular branch arising from the “external carotid artery” (Arteria carotis externa). In rare cases, the ascending artery may also be connected to the “internal carotid artery” (the internal carotid artery). This is the case in about 1-2% of the population. The posterior meningeal artery supplies the dura mater, the outermost meninges of the posterior skull wall. The arteries pass through the jugular foramen (the “throttle hole”) into the neck region. The foramen jugulare is located between the petrous and occipital bones as an opening at the base of the skull, and other important pathways such as cranial nerves, veins, and arteries responsible for supplying the brain pass through it.
Function and tasks
The primary function of the posterior meningeal artery is to supply the brain with arterial and therefore oxygenated blood. After passing through the brain, the deoxygenated blood drains through the venous blood conduits. If the brain is supplied with slightly less blood, this can be compensated by a higher exhaustion of oxygen. However, if this blood flow rate drops below 10ml per 100g of tissue, cell death occurs. The anastomotic connection of the posterior meningeal artery with the anterior meningeal artery and the media meningeal artery prevents tissue cell death (tissue necrosis occurs) to some degree and maintains the circulation of blood in the brain. This function of cerebral blood flow is called autoregulation. An important aspect related to blood circulation in the brain is the blood-brain barrier: it is constructed by the capillary system, which extends as a network over the entire brain, and can be understood as a kind of filter. The blood-brain barrier functions, among other things, through enothelial cells and represents a physiological barrier of the fluid spaces in the blood circulation and central nervous system. The blood-brain barrier keeps toxic substances out before they enter the cerebral circulation. Methods for visualizing the vascular branches in the brain are imaging procedures: angiography draws the vessels by administering a contrast medium. Magnetic resonance (MR)-assisted angiography in 3D represents a technical advancement.
Diseases
If anastomoses involving the posterior meningeal artery are malformed from birth, the condition is called cerebral arteriovenous malformation. Due to this malformation, the arteries are connected to the veins without a capillary system. Consequences of such vascular anomalies are internal bleeding, stroke and aneurysms. A common disease is arteriosclerosis. In this case, the arterial walls are affected by deposits (plaque) caused by blood lipids, clots and calcium. As a result, the vessels narrow, and blood can no longer pass through them properly to supply the regions with oxygen. It is particularly difficult for blood to pass through the fine vascular branches of the arteries. As a result of plaque, clots of blood platelets (thrombi) often form and cause infarctions. An aneurysm occurs when the vessel wall dilates or ruptures and can occur in the artery or brain (cerebral aneurysm). If the cerebral aneurysm cannot be operated on, damage to the brain or death are consequences. In addition to hematomas (bleeding into the brain), there are serious diseases of the meninges: meningitis, caused by viruses or bacterial infestation, or inflammation of the brain (meningoencephalitis). Degeneration of cells in the arachnoid region may result in a meningeal tumor (meningioma).