What Is the Middle Cerebral Artery?

It is a direct continuation of the internal carotid artery and does not participate in the formation of the cerebral artery ring. Before entering the lateral sulcus of the brain, it sends out many central branches to supply the inner capsule and basal ganglia; on the lateral side of the dorsal side of the brain, its trunk runs in the lateral sulcus of the brain, and finally terminates in the angular gyrus. The dorsal lateral surface of the cerebral hemisphere outside the frontal pole and occipital lobe, including below the frontal middle gyrus, the lower 3/4 of the central anterior and posterior gyrus, the inferior parietal lobes, and the superior or upper margins of the superior, intermediate, and inferior temporal gyrus The inner and outer sides of the temporal pole and the cortex of the insular lobe, the cortex before the lateral occipital sulcus. It involves sports area, pre-exercise area, somatosensory area, listening area and contact area. If the central branch of the middle cerebral artery (the most common is the striated artery) is bleeding, that is, internal capsule bleeding, typical "trilateral" symptoms can occur, that is, the bleeding of the contralateral limbs, the lower half of the facial muscles and the tongue muscles, and the contralateral deviation Physical dysfunction, contralateral blindness.

It is a direct continuation of the internal carotid artery and does not participate in the formation of the cerebral artery ring. Before entering the lateral sulcus of the brain, it sends out many central branches to supply the inner capsule and basal ganglia; on the lateral side of the dorsal side of the brain, its trunk runs in the lateral sulcus of the brain, and finally terminates in the angular gyrus. The dorsal lateral surface of the cerebral hemisphere outside the frontal pole and occipital lobe, including below the frontal middle gyrus, the lower 3/4 of the central anterior and posterior gyrus, the inferior parietal lobes, and the superior or upper margins of the superior, intermediate, and inferior temporal gyrus The inner and outer sides of the temporal pole and the cortex of the insular lobe, the cortex before the lateral occipital sulcus. It involves sports area, pre-exercise area, somatosensory area, listening area and contact area. If the central branch of the middle cerebral artery (the most common is the striated artery) is bleeding, that is, internal capsule bleeding, typical "trilateral" symptoms can occur, that is, the bleeding of the contralateral limbs, the lower half of the facial muscles and the tongue muscles, and the contralateral deviation Physical dysfunction, contralateral blindness.

If the middle cerebral artery is blocked near the lateral sulcus, it can produce paralysis of the contralateral upper limbs, facial muscles, and tongue muscles, and sensory disturbances of the contralateral upper limbs and head and face, including loss of physical consciousness and inability to distinguish different degrees of stimulation; Patients may also have motor aphasia, which is due to the involvement of the speech motor area in the posterior frontal gyrus; inability or apraxia occurs when the marginal gyrus is involved; aphasia occurs when the angular gyrus is involved; Sensory aphasia can occur in the affected part; dyslexia can occur in the affected part of the frontal middle back.

Chinese name

Middle cerebral artery

Foreign name

Middle cerebral artery

Features

Coarse

Main branch

Cortical branch, central branch

Middle Cerebral Artery

(A) itinerary

In the image, the middle cerebral artery is usually divided into five segments.

1. M1 segment posterior orbital segment (horizontal segment). After separating from the C1 segment of the internal carotid artery, it travels horizontally outward along the lateral fissure pool and is about 3 cm long.

2. Island leaf section of M2 section (roundabout section). In a U-shaped line in front of the island threshold, it moves upwards and backwards. This segment emanates from the anterior temporal artery.

3. The lateral groove of M3. This section is long, close to the outer side of the island leaf to the lateral posterior sulcus branch, and the orbitofrontal artery, frontal ascending artery, central sulcus artery, central anterior sulcus artery and central posterior sulcus artery are called along the way. Taiwan artery.

4. The M4 segment is the bifurcation segment. Separate posterior parietal artery and posterior temporal artery for middle cerebral artery.

5.M5 segment is the terminal branch of the middle cerebral artery-the horn gyrus.

M2, M4, and M5 are collectively called the lateral cerebral fossa artery group.

(II) Branching and Distribution

The cortical branches of the middle cerebral artery include the lateral frontal artery, central anterior sulcus artery, central sulcus artery, central posterior sulcus artery, posterior parietal artery, temporal polar artery, anterior temporal artery, intermediate temporal artery, posterior temporal artery, and hornular gyrus. Most of its upper and outer sides of the cerebral hemisphere are associated with island leaves. The central branch of the middle cerebral artery is the lateral lenticular artery, which is composed of 10 to 20 branches, all of which originate from the M1 segment and supply the anterior commissure of the lateral part, the large part of the shell, the inner and outer pale balls, and the inner capsule. Upper half and nearby corpus callosum radiate, head and body of caudate nucleus.

Middle cerebral artery and middle cerebral artery related diseases

1. Middle cerebral aneurysms: Middle cerebral aneurysms account for about 18% to 20% of the total number of intracranial aneurysms. 85% of them occur in the super cerebral segment of the middle cerebral artery, which is the island threshold (Limen isula), and the remaining 15% are located elsewhere in the middle cerebral artery. There are more giants and spindles. Symptoms are the ischemic symptoms and local occupying symptoms in the middle cerebral artery blood supply area, which are convulsions, hemiplegia, mental symptoms, etc. Those who are on the dominant side still have aphasia. Hemorrhage can cause spontaneous SAH or intracerebral hematoma, half have hemiplegia, and about 1/3 can have aphasia. Hemiplegia is more severe in the upper limbs than in lower limbs. Among all intracranial ANs, the middle cerebral aneurysm is the one with the most seizures.

2. Middle cerebral artery occlusion: It is more common clinically, accounting for 79.6% of occlusive cerebrovascular disease, and the age of onset is more than 40 years old, male and female is 3: 2. The clinical manifestations are contralateral hemiplegia, hemiplegia, hemianopia of the same name, complete aphasia, severe disturbances of consciousness and seizures, and cerebral hernia due to cerebral edema and intracranial hypertension. Or internal cystic hemiplegia (there is no significant difference in the degree of paralysis between the upper and lower limbs, and between the proximal and distal limbs), without accompanying blindness and sensory impairment, and early atrophy (occlusion of the sagittal branch of the perforating artery-striated artery, This artery supplies only the cone bundle in the inner capsule). Or progressive stroke, cortical symmetrical lateral hemiparesis (the degree of paralysis is that the head, face and upper limbs are heavier than the lower limbs, and the distal limbs are heavier than the proximal ones), which may be accompanied by isotropic hemianopia. This type of aphasia, apraxia and loss of recognition, contracture is not obvious, and there may be seizures.

3. Middle cerebral artery embolization cerebral infarction:

Cerebral embolism refers to the result of emboli entering the blood circulation and suddenly blocking the cerebral arterial system, so it is also called embolic cerebral infarction. It usually occurs suddenly, and it is a complete stroke at the beginning, accounting for 30% to 50% of cerebral infarction. The sources of emboli can be divided into three categories: Cardiogenic: mainly found in patients with subacute infective endocarditis, rheumatic heart disease, mitral stenosis with atrial fibrillation; noncardiogenic emboli: more common Atherosclerotic plaques fall off, there are also fat, tumors, and air emboli; iatrogenic emboli: such as caused by angiography and surgery. This case was caused by angiography, and the onset was rapid.

CT findings: fan-shaped or irregular low-density areas, similar to the performance of ischemic cerebral infarction; large areas of infarcted areas with high density or multiple cortical area infarcts, accompanied by signs of bleeding; cerebral infarction has More than 50% are hemorrhagic infarcts. This is because the thrombus that occludes the artery is usually dissolved within 1 to 5 days, and the vascular bed in the ischemic area reopens. The permeability increases and destroys, causing excessive perfusion and causing hemorrhagic infarction.

The differential diagnosis is mainly the identification of cerebral infarction and thrombosis of cerebral infarction, which is mainly based on the summary of clinical history and the onset of slow onset. CT found early bleeding in the infarct or bleeding in multiple infarcts, which is helpful for the diagnosis of cerebral embolism.