Khanna Session 19 2024 PBC9102 Post Bacc Anatomy II Head & Neck PDF

Nova Southeastern University Dr. Kiran C. Patel College of Osteopathic Medicine Pre-medical Post-Baccalaureate Program BRAIN & NERVOUS SYSTEM - 4 DEEPESH KHANNA, MD, PH.D., MPH, MBA, MS, CPH LEARNING OBJECTIVES Identify the structural components of the Circle of Willis  Describe saccular aneurysm ...

Nova Southeastern University Dr. Kiran C. Patel College of Osteopathic Medicine Pre-medical Post-Baccalaureate Program BRAIN & NERVOUS SYSTEM - 4 DEEPESH KHANNA, MD, PH.D., MPH, MBA, MS, CPH LEARNING OBJECTIVES Identify the structural components of the Circle of Willis  Describe saccular aneurysm  Identify the arterial supply to the cerebral cortex   Name the structural components of the diencephalon ARTERIAL SUPPLY ARTERIES SUPPLYING THE BRAIN Two paired arteries which are responsible for the blood supply to the brain; the vertebral arteries, and the internal carotid arteries These arteries arise in the neck, and ascend to the cranium Within the cranial vault, the terminal branches of these arteries form an anastomotic circle, called the Circle of Willis From this circle, branches arise which supply most of the cerebrum ARTERIAL SUPPLY ARTERIES SUPPLYING THE BRAIN Internal carotid arteries (ICA): ▪ Internal carotid arteries (ICA) originate at the bifurcation of the left and right common carotid arteries, at the level of the fourth cervical vertebrae (C4) Each ICA gives rise to: Ophthalmic artery – supplies the structures of the orbit Posterior communicating artery – acts as an anastomotic ‘connecting vessel’ in the Circle of Willis Anterior choroidal artery – supplies structures in the brain important for motor control and vision Anterior cerebral artery – supplies part of the cerebrum ▪ Right and left vertebral arteries arise from the subclavian arteries ▪ The vertebral arteries enter the cranial cavity via the foramen magnum ▪ Within the cranial vault, some branches are given off: ✓ Meningeal branch – supplies the falx cerebelli, a sheet of dura mater ✓ Anterior and posterior spinal arteries – supplies the spinal cord, spanning its entire length ✓ Posterior inferior cerebellar artery – supplies the cerebellum ✓ The two vertebral arteries converge to form the basilar artery ✓ Several branches from the basilar artery originate and go onto supply the cerebellum and pons ✓ The basilar artery terminates by bifurcating into the posterior cerebral arteries. ARTERIES SUPPLYING THE BRAIN ARTERIAL SUPPLY CIRCLE OF WILLIS Anterior communicating artery Anterior cerebral artery Middle cerebral artery Internal carotid arteries Vertebral arteries Posterior communicating artery Posterior cerebral artery Basilar artery Internal carotid artery Superior cerebellar artery Anterior inferior cerebellar artery Vertebral artery Posterior inferior cerebellar artery CIRCLE OF WILLIS SACCULAR (BERRY)ANEURYSMS https://www.youtube.com/watch?v=9hhfM7rQHiM PD ARTERIES MEDIAL VIEW Anterior cerebral Posterior cerebral ARTERIAL SUPPLY ANTERIOR CEREBRALARTERY Medial frontal and parietallobes Anterior limb of internal capsule Most of corpus callosum ARTERIAL SUPPLY MIDDLE CEREBRAL ARTERY ARTERIAL SUPPLY POSTERIOR CEREBRAL ARTERY Midbrain Thalamus Posterior Limb of Internal Capsule Optic Tract Choroid Plexus Splenium of Corpus Callosum Large part of Occipital Lobe Arterial Supply Homunculus Anterior cerebral artery Middle cerebral artery Arterial Supply Internal Capsule ARTERIAL SUPPLY WATERSHED TERRITORY Anterior cerebral artery Middle cerebral artery Posterior cerebral artery CLINICAL ASPECTS Stroke- It is the interruption of blood flow in the brain. It is of two types Ischemic Stroke-it is dangerous because presence of plaque in the internal carotid artery can lead to the formation of thrombus(emboli) which travels to the circle of Willis and can obstruct blood flow causing an ischemic stroke Hemorrhagic Stroke- It can occur because of an aneurysm that grows and ruptures at a certain point which can cause hemorrhage and ultimately a stroke. Aneurysms are mostly formed at the division points of arteries as division points are considered as weak spots in a circulation.