Central nervous system disorders

III./1.5.: Blood supply of the meninges

The dura mater is supplied by the meningeal arteries of the external carotid artery. It's largest artery is the medial meningeal artery, a branch of the maxillary artery entering through the foramen rotundom. Usually it bifurcates into the superior and inferior trunks. The trunk and their smaller branches make a deep indention in the calvarium forming the arterial sulci. They supply the medial cranial fossa and the decisive part of the dura beyond the convexity.

Occasionally the accessory meningeal artery, branch of the medial meningeal artery is present, it supplies the dura of the medial cranial fossa. The dura of the posterior cranial fossa is supplied by the posterior meningeal artery - branch of the ascending pharyngeal artery entering through the jugular foramen - and the superior and inferior meningeal branches of the occipital artery. The dura of the anterior cranial fossa and the convexity of the frontal lobe is supplied by the anterior meningeal artery, it derives from the internal carotid artery through the ophtalmic and anterior ethmoidal arteries.

The arachnoid mater is referred as an avascular membrane, however smaller vessels are documented in some of the trabeculae bridging the subarachnoid cavity.

The arteries of the pia mater derive from the internal carotis and the vertebral arteries.

As follows from the above, the meninges not only envelope the central nervous system, but they form a clinically relevant connection between the vessels and themselves and their actual or virtual spaces. This situation is determining in the pathology of the intracranial hemorrhages. The origin of the epidural hematoma could be both arterial or venous due to the dural sinuses or the meningeal arteries. Subdural hematoma usually arises from the bridge veins connecting the superficial veins with the sinuses, however the subarachoid hemorrhage mostly originates from the pathologic dilatation of the larger arteries coursing along the cisterns (aneurysm). The causes and origins of the subpial hemorrhages vary greatly, anyhow they arise from the superficial arteries.