Circle of willis : clinical importance

Clinical aspect of arteries

I. Anterior cerebral artery

Blockage of anterior cerebral artery or its branches

Clinical features

• 1. Paralysis of opposite foot and leg- motor leg area on homonculus


• 2. Opposite paresis (minimal)- corona radiata involvement


• 3. Sensory loss (cortical) on toes, foot and leg- sensory area for foot and leg on sensory cortex


• 4. Unwitting urinary incontinence- sensorimotor area in the paracentral lobule


• 5. Contralateral grasp reflex: medial surface of posterior frontal lobe


• 6. Abulia - lesion is uncertain


• 7. Impairement of gait and stance - Frontal cortex


• 8. Mental impariment and affection of memory- unknown


• 9. Dyspraxia of left limbs, Tactile aphasia pf left limbs - all via the corpus callosum


• 10. Cerebral paraplegia bilateral lesion of anterior cerebral artery

II. Middle cerebral artery

Clinical features of middle cerebral artery blockage.

• 1. Paralysis of contralateral face, arm and leg- somatic motor area


• 2. Motor aphasia- Dominant hemispheres speech area


• 3. Central aphasia word deafness- Speech area and parieto-occipital cortex of dominant hemisphere


• 4. Conduction aphasia- Central speech area


• 5. Apractognosia- Non dominant suprasensory zone which corresponds to speech area in dominant hemisphere


• 6.Homonymous hemianopsia- Optic radiation deep to the second temporal convolution


• 7. Paralysis of conjugate gaze to the opposite side- frontal contraversive field


• 8. Avoidance reaction of opposite limbs- parietal lobe lesion


• 9. Frontal ataxia- frontopontine tract lesion


• 10. Loss or impairment of optokinetic nystagmus-  affects supramarginal or angular gyrus


• 11.Cerebral paraplegia- posterior limb of internal capsule.

III. Posterior cerebral artery

This artery supplies the visual cortex, the thalamus and internal capsule

Signs

• 1. Homonymous hemianopssia - calcarine sulcus


• 2. Bilateral homonymous hemianopsia- bilateral occipital lobe


• 3. Verbal dyslexia without agraphia, and with color anomia- dominant calcarine lesion


• 4. Memory defect- hippocampal lesion


• 5. Topographical disorientation nondominant calcarine and lingual gyri


• 6. Simultanagnosia- dominant visual cortex


• 7. Unformed visual hallucinations- calcarine cortex


• 8. Thalamic syndrome - postero-anterior nucleus of thalamus


• 9. Thalamoperforate syndrome- dentatothalamic tract


• 10. Weber's syndrome- Third nerve and cerebral peduncle


• 11. Contralateral hemiplegia- cerebral peduncle


• 12. paralysis of vertical eye movement- nuclei of Cajal and Darkschewitsch


• 13. Contralateral rhythmic, ataxic action tremor- dentatothalamic tract