By Dr Rabia Shafique
Brain stem vascular lesions
Occlusion of the anterior spinal artery causes medial medullary syndrome, presenting with inferior alternating hemiplegia.
Ipsilateral paralysis of tongue.
Contralateral sensory deficits.
Occlusion of the posterior inferior cerebelllar artery causes lateral medullary syndrome featured
Contralateral hemianaesthesia of the body below the head.
Ipsilateral hemianaesthesia of the face.
Speech and swallowing disorders.
Occlusion of the paramedian branches of the basilar arteries causes middle alternating hemiplegia.
Medial deviation of the eyeball.
Obstruction of the short circumferential arteries from the basilar artery cause
Ipsilateral cerebellar dysfunction
Occlusion of the mesencephalic branch of the posterior cerebral artery causes Weber’s syndrome
Ipsilateral lateral deviation of the eyeball
Cerebral Cortical Vascular Lesions
Occlusion of the anterior choroidal artery causes a triad of:
Occlusion of anterior cerebral arteries may cause
Contralateral hemianaesthesia ( both mainly affect the lower limb)
Occlusion of the calcarine artery causes homonymous hemianopia with macular sparing (Tunnel vison)
Occlusion of the middle cerebral artery near the origin of its cortical branches causes
Contralateral hemiplegia , most marked in the upper extremity and face.
Contralateral loss of position sense and discriminatory touch.
Global aphasia if its on the dominant side.
Components of the BBB
Tight junctions between the capillary endothelial cells
Continuous homogenous basement membrane
Numerous astrocytic processes
Parts devoid of Blood Brain Barrier – circumventircular organs (CVO).
The pineal body
The subcommissural organ
The subfornical organ
The organum vasculosum of the lamina terminalis (supra-optic crest)
The median eminence
The area postrema
Formation of Circle of Willis
This is the communication between vessels about the interpeduncular fossa.
It encircles the optic chiasma, tuber cinereum and interpeduncular region.
Formed by these arteries:
The Internal Carotid Artery
Summary of the branches
Hypophyseal branches to the hypophysis cerebri
Posterior communicating artery
Anterior choroidal artery
Middle cerebral artery
Anterior cerebral artery