Circle Of Willis by Krishna Patel

Hey!!

I am sharing this ppt to make it easy to understand the concept of circle of willis which is one of the important topic of anatomy.

I hope this helps you!!

1. Circle of Willis:-

2. What is the Circle of Willis? It is an arterial circle, situated at base of brain. It is formed by the anterior and middle cerebral branches of internal carotid and posterior cerebral branches of basilar artery, forming the six sided polygon of the arteries called Circle of Willis or Circulus Arteriosus.

3. Formation:- It is formed around interpeduncular fossa, contributes most of arterial blood supply of brain. Anteriorly = By anterior communicating and anterior cerebral arteries. Posteriorly = By basilar artery dividing into 2 posterior cerebral arteries. Laterally on each side = By posterior communicating arteries.

4. Branches:- The branches of the circulus arteriosus are cortical and central. The central branches are arranged in six groups:- Anteromedial :- The largest branch is called medial striate or recurrent artery of Heubner. It is supplies corpus striatum and internal capsule which has motor fibres for face, tongue and shoulder. Anterolateral :- These are in two groups. The largest branch is called lenticulostriate or Charcot's artery of cerebral haemorrhage. It supplies internal capsule which has motor fibres for one side of body. Posterolateral or thalamogeniculate :- They supply thalamus and geniculate bodies. Posteromedial:- Supply thalamus and hypothalamus.

5. Blood Supply to the Brain:- Artery Origin Course Cortical Branches Central Branches Middle Cerebral Largest and direct branch of internal carotid artery In the lateral sulcus and on insula Orbital, Frontal, Parietal, Temporal Lateral striate artery in two groups Anterior Cerebral Smaller terminal branch of internal carotid artery Two arteries are connected by the anterior communicating artery Orbital, Frontal, Parietal Central branches including a heubner's recurrent artery in one group Posterior Cerebral Terminal branch of basilar artery Winds round cerebral peduncle to reach the tentorial surface of cerebrum Temporal, Occipital, Parieto-occipital Posteromedial central branches in one group, Posterolateral central branches in two branches Posterior inferior cerebellar Largest branch of vertebral artery Tortuous course in relation of olive, lower border of pons and vallecula of cerebellum Posterolateral part of medulla, Lower part of pons, Inferior surface of cerebellum

6. Clinical Anatomy:- 1 Thrombosis Thrombosis of lateral striate branches of branches of middle cerebral artery causes motor and sensory loss to most of opposite side of body except lower limb. 2 Hemiplegia It is a common condition. It is an upper motor neuron type of paralysis of one half of the body, including the face. It is usually due to internal capsule lesion caused by thrombosis of one of lenticulostriate branches of middle cerebral artery. 3 Thrombosis of Heubner's recurrent branch It is of the anterior cerebral artery causes contralateral upper monoplegia.

7. Blood - Brain Barrier:- The existence of blood brain barrier ( BBB or Haematoencephalic barrier ) is due to endothelial cells of brain capillaries are held to each other by tight junctions. The BBB is formed by structures between blood and nerve cells of brain. The blood in lumen of the capillary is separated from neurons by:- Capillary endothelium Basement membrane of endothelium Intimately applied to the capillaries there are numerous processes cover about 80% of the capillary surface. Some areas of brain are devoid of blood- brain barrier. These include pineal body, hypophysis cerebri, choroid plexuses and area postrema in fourth ventricle of brain. BBB exist in newborn but is more permeable to certain substance than in adult. Function of blood- brain barrier:- To modulate entry of metabolic substrate notably glucose It allows entry of gases, water, electrolytes, amino acids and lipid soluble substrates It blocks entry of transmitters from blood, notably of epinehrine It restricts entry of macromolecules that is lipid insoluble substances and thus block entry of toxins as either these are bound to plasma albumin or their solubilities are inappropriate.

8. Treatment Options:- 1 Medication Prescription of drugs to manage blood pressure, prevent clot formation, and reduce the risk of further complications. 2 Endovascular Procedures Minimally invasive techniques, such as coiling or stenting, to repair blood vessels affected by aneurysms or other abnormalities in the Circle of Willis. 3 Open Surgical Procedures Surgical interventions, like clipping or bypass surgery, may be necessary for more complex cases requiring direct access to the Circle of Willis.

9. THANK YOU !! MADE BY:- KRISHNA PATEL