Meningeal Arteries Flashcards
describe the cerebral arteries
- vertebral and internal carotid arteries anastomose at the basal diencephalon (by forming the Circle of Willis)
- these major arteries supply the basilar, cerebellar and cerebral arteries
_______ arteries feed the middle and anterior cerebral arteries
internal carotid arteries feed the middle and anterior cerebral arteries
middle arteries emit the ______ arteries that supply the _____ and ______
middle arteries emit the lenticulostriate arteries that supply the internal capsule and basal ganglia
the _____ _____ artery connects the anterior cerebral arteries
the anterior communicating artery connects the anterior cerebral arteries
describe the posterior cerebral arteries
- posterior cerebral arteries arise from the basilar artery, anastomosing with the internal carotid system via the posterior communicating arteries
descrbie an epidural hemorrhage
- epidural hemorrhages commonly reflect the traumatically induced rupture of meningeal arterties (e.g. middle meningeal artery) with a fractured bone cutting the vessel
- during the episode, blood forces the stiff periosteal dura to separate from the skull, yielding a characteristic biconvex mass adjacent to the fracture
- dangers peak within hours of arterial involvement
describe origin of lenticulostriate arteries and what they supply
- lenticulostriate arteries branch from the middle cerebral artery and supply the internal capsule and basal ganglia
- internal capsule = connects cortical and subcortical sites aka projection
describe a subdural hemorrhage
- subdural hemorrhages reflect trauma-induced ruptures of the delivate veins that traverse the meningeal layer of the dura from the subarachnoid space
- because the pressure in the venous system is much lower than in the arterial system, crescent-shaped subdural masses of blood develop slowly before manifestation (hours to weeks)
describe a subarachnoid hemorrhage
- many arteries reside between the arachnoid and pia mater (surrounded by CSF within the subarachnoid space)
- these vessels may rupture with trauma or spontaneously (in cases of aneurysm)
- the leaking blood assumes a tree-like appearance while following the sulci
describe an intracerebral hemorrhage
- intracerebral hemorrhages reflect rupture of intraparenchymal branches of subarachnoid arteries such as the lenticulostriate arteries which branch from the middle cerebral artery, supplying the internal capsule and basal ganglia
as opposed to the arachnoid layer which is _____, the pia mater is highly _____
as opposed to the arachnoid layer which is avascular, the pia mater is highly vascular
the _____ ______ artery runs medially and anterior the optic chiasm
the anterior cerebral artery runs medially and anterior the optic chiasm
describe origin of striate arteries and what they supply
- striate arteries (early branches of the anterior cerebral artery) supply the basal ganglia and anterior limb of the internal capsule
describe what the anterior cerebral arteries supply
- major branches of the anterior cerebral arteries pass to the medial aspect of the frontal and parietal lobes, anterior perforated substance, septum pellucidum and corpus callosum (feeding all but the most posterior zones of this commissure)
describe what middle cerebral arteries supply
- the middle cerebral artery extends laterally in lateral fissures over the insula, sending branches to the lateral aspect of frontal, temporal and parietal lobes
- during its early course, the middle cerebral a. emits the lenticulostriate arteries, which supply the basal ganglia and internal capsule
- these arteries are vulnerable to rupture and are a major source of intracerebral (periventricular) hemorrhage
describe the origin of posterior cerebral arteries and what they supply
- posterior cerebral arteries are the terminal branches of the basilar artery
- they travel laterally and dorsally around the midbrain to reach the thalamus and third ventricle
- cerebral branches supply medial temporal, occipital and parietal structures
occlusion of the ____ ____ a. often yields language deficits, as this artery normall supplis cortical regions subserving verbal and literal elements of speech
occlusion of the middle cerebral artery often yields language deficits, as this artery normall supplis cortical regions subserving verbal and literal elements of speech
describe autoregulation of blood flow in the CNS
- brain arterioles constrict when system blood pressure is raised and dilate when it is lowered so that the cerebral blood flow is constant over an arterial pressure range of 60-150 mmHg
- mediates through Arg>NO>cGMP pathway
