Meningeal arteries are blood vessels located within the skull, positioned between the bone and the brain’s protective coverings. Their primary role involves supplying blood to the dura mater, which is the outermost and toughest layer of these protective membranes, as well as the inner surface of the skull bones. These arteries are part of a complex network that safeguards the brain by providing a supportive framework for its vascular system.
What Meningeal Arteries Are
Meningeal arteries are distinct from the arteries that directly supply blood to the brain tissue itself. Instead, meningeal arteries focus their supply on the dura mater, a thick, fibrous membrane directly beneath the skull. The dura mater functions to anchor the central nervous system and act as a shock absorber against trauma.
This membrane, along with other meninges, receives its vascular supply from these arteries and veins. This network helps maintain the health and structural integrity of the meninges, which are layered membranes that cushion the brain and spinal cord from mechanical injury. They also support the drainage system for blood and cerebrospinal fluid away from the brain.
Major Meningeal Arteries
Among the meningeal arteries, the Middle Meningeal Artery (MMA) is the largest and most clinically significant. It originates from the maxillary artery, a branch of the external carotid artery. The MMA ascends and enters the skull through a small opening called the foramen spinosum, located in the sphenoid bone.
Once inside the skull, the MMA courses forward in a groove along the great wing of the sphenoid bone before dividing into anterior (frontal) and posterior (parietal) branches. The larger anterior branch extends beneath the pterion, a thin, vulnerable area of the skull where four cranial bones meet. Its branches supply the dura mater and the inner periosteum of the cranial bones. Other meningeal arteries, such as the anterior meningeal artery and posterior meningeal artery, also contribute to the dural vascular network, though the MMA is the dominant supply for the cranial dura.
Understanding Meningeal Artery Injuries
Injury to a meningeal artery, particularly the Middle Meningeal Artery, is a common cause of an epidural hematoma. This occurs when bleeding happens in the space between the skull and the dura mater. Such injuries result from head trauma, often a direct impact to the side of the head or a skull fracture, especially in the temporal bone area where the skull is relatively thin.
The mechanism involves the force of impact pulling the dura mater away from the inner surface of the skull or tearing the artery directly. Because meningeal arteries are part of the arterial circulatory system, the blood is under high pressure, causing the hematoma to expand rapidly. The rapid expansion creates a lens-shaped mass that presses on the brain, increasing intracranial pressure. Common symptoms include:
Initial loss of consciousness
A “lucid interval” where the person may regain consciousness before rapid neurological deterioration
Severe headache
Confusion
Vomiting
Paralysis
Identifying and Treating Injuries
Diagnosing a meningeal artery injury and the resulting epidural hematoma relies on rapid imaging techniques. A computed tomography (CT) scan of the head is the primary diagnostic tool, as it can quickly show the characteristic lens-shaped collection of blood between the skull and the dura mater. Prompt diagnosis is important because rapid expansion of an epidural hematoma can lead to increased pressure on the brain, causing severe complications if left untreated.
Treatment often involves surgical intervention to relieve pressure and stop bleeding. The most common surgical procedure is a craniotomy, where a section of the skull is temporarily removed to access and evacuate the hematoma. The surgeon removes accumulated blood and cauterizes any actively bleeding vessels. In some cases, a less invasive burr hole drainage might be performed, or endovascular embolization, a procedure to block the bleeding artery, may be considered. The goal of these treatments is to alleviate pressure on the brain and prevent further neurological damage.