circle of Willis.pptx

BLOOD SUPPLY OF THE BRAIN

1. BLOOD SUPPLY OF THE BRAIN

2. Table of CONTENTS Arteries of the brain Circle of willis Veins of the brain Name: Moustafa Gouda Under supervision of Dr: Hadeel saed blood supply of the brain & circle of Willis

3. Arteries of the Brain Two pairs of large arteries: Vertebral artery Internal carotid artery

4. Internal Carotid Artery It pierces roof of cavernous sinus At medial margin of anterior clenoid process. It lies lateral to optic chiasma close to anterior perforated substance.

5. Branches of internal carotid arteries Anterior cerebral artery Middle cerebral artery Posterior communicating artery Ophthalmic artery Anterior choroidal artery Superior and inferior hypophyseal arteries Hypothalamic artery

6. Anterior Cerebral Artery It passes above optic chiasma into longitudinal fissure. It runs on medial surface above corpus callosum. It ends at parieto- occipital sulcus. It is connected by its fellow of opposite side by short anterior communicating artery

7. Central branches (striate arteries): Small arteries pierce ant. perforated substance. Supply a part of caudate nucleus and putamen. Supply anterior limb of internal capsule. Branches: Cortical branches: supply Large part of medial surface Upper most one finger’s breadth of superolateral surface as far as parieto- occipital sulcus Medial part of orbital surface of frontal lobe

8. Middle Cerebral Artery It runs laterally in stem of lateral sulcus. On cortex of insula it divides into cortical branches supplying the superolateral surface.

9. Cortical branches They supply cortex of greater part of superolateral surface. Supply motor and sensory areas of trunk and face by: Rolandic artery Pre-Rolandic artery Post central artery Broca’s area. arteries. Central branches: Medial and lateral lenticulo - striate arteries pierce A.P.S. to supply: caudate nucleus putamen and globus pallidus Anterior and posterior limbs of internal capsule.

10. Ophthalmic Artery: Enters orbit via optic canal with optic nerve. Central artery of retina a branch of ophthalmic artery is an end artery and its occlusion results in blindness. Posterior Communicating artery: Arises from I.C.A. before giving terminal branches It joins posterior cerebral artery. Supplies optic chiasma, tract, hypothalamus, subthalamus and ant. half of thalamus by anterior thalamo - striate artery.

11. Superior and inferior hypophyseal arteries: They supply pituitary gland. Hypothalamic artery: supplies hypothalamus Anterior choroidal artery: Supplies choroid plexus of inf. Horn of lateral ventricle. Supplies optic tract, L.G.B. and part of optic radiation. Supplies globus pallidus and part of post. Limb of internal capsule. Supplies hippocampus and amygdaloid body.

12. Vertebral Artery It is a branch of first part of subclavian artery. It enters cranial cavity through foramen magnum. Both arteries ascend on either side of medulla oblongata. They unite at lower border of pons to form basilar artery

13. Branches of Vertebral Artery in Cranial Cavity Posterior spinal artery: one on each side of spinal cord. Anterior spinal artery: joins its fellow ant. To medulla to form single median artery. Posterior inferior cerebellar artery: supply post. Part of inferior surface of cerebellum and forms choroid plexus of 4th ventricle. Medullary branches

14. Basilar Artery It begins at lower border of pons by union of two vertebral arteries. It ascends in median sulcus on ventral surface of pons. It ends at upper border of pons by dividing into 2 posterior cerebral arteries.

15. Branches of basilar artery Pontine branches. Labyrinthine artery: runs laterally with 7th& 8th cranial nerves to internal auditory meatus. Anterior inferior cerebellar artery: supply anterior part of inferior surface of cerebellum. Superior cerebellar artery: from upper part of the artery to supply superior surface of cerebellum. Posterior cerebral artery: terminal branch of basilar artery.

16. Posterior Cerebral Artery It runs backwards on lateral aspect of midbrain. It is separated from superior cerebellar artery by 3rd& 4th cranial nerves. It reaches lower and medial surfaces of occipital lobe where it divides into: Parieto- occipital artery 2. Calcarine artery

17. Cortical branches: supply The whole occipital lobe including visual cortex. Inferior surface of temporal lobe except its pole. Lower most one finger’s breadth of lat. surface of temporal lobe. Central branches : Perforating arteries pierce post. Perforated substance. They supply crus cerebri of midbrain and medial and lateral geniculate bodies. Posterior thalamo - striate artery supply post. Half of thalamus. Lateral and medial posterior choroidal arteries supply dorsum of thalamus, pineal body and choroid plexus of 3rd v. and lateral v.

18. Circle of Willis It lies on the base of the brain and is related to inter- peduncular fossa.

19. It is formed by: Anteriorly; - Anterior cerebral arteries and - Anterior communicating artery Posteriorly; - 2 posterior cerebral arteries. Laterally; - Posterior communicating arteries - Internal carotid arteries It gives penetrating arteries to thalamus, hypothalamus, subthalamus and midbrain.

20. Veins of The Brain 1- Superior cerebral veins; end in SSS. 2- Inferior cerebral veins; end in superficial middle cerebral vein. 3- Superficial middle cerebral vein; ends in cavernous sinus and anastomoses with SSS and transverse sinus. 4-Deep middle cerebral vein; lies deep to gyri of insula and ends in basal vein. A- Superficial Cerebral Veins:

21. Basal Vein Formed at anterior perforated substance by: Deep middle cerebral vein. Anterior cerebral vein. Striate vein. 2 basal veins encircle the brain stem and drain into great cerebral vein Receives tributaries from optic chiasma,& tract, hypothalamus, corpus striatum, tectum and inferior cerebral vein

22. B- Deep Cerebral Veins Internal cerebral veins: Each one starts at interventricular foramen by: Thalamostriate vein Superior choroid vein It runs backwards between two layers of tela choroidea of 3rd ventricle. Below splenium of CC it units with its fellow to form great cerebral vein

23. Great Cerebral Vein Located below splenium of CC. It receives 2 internal cerebral veins, 2 basal veins, posterior callosal; vein and 2 internal occipital veins. It joins inferior sagittal sinus to form straight sinus

24. Thank You