This document discusses cerebral blood flow, its autoregulation, clinical relevance, and the role of collaterals in ischemic stroke. It begins with an overview of cerebral blood supply and drainage, then describes the autoregulation mechanism and its importance. It also discusses cerebral collaterals and their significance in acute ischemic stroke. The majority of the document provides detailed descriptions of the anatomy of cerebral arteries, veins, and sinuses. It explains factors that regulate cerebral blood flow and perfusion pressure, including metabolism, carbon dioxide, oxygen, and autoregulation.
The internal capsule is a white matter structure that contains association, commissural, and projection fibers. It has five segments and is supplied by branches from the anterior, middle, and posterior cerebral arteries. Injury to different parts of the internal capsule can cause various neurological deficits, such as hemiparesis, aphasia, or sensory loss, depending on the fibers and brain regions affected. Common causes of internal capsule injury include lacunar infarcts and watershed ischemic syndromes.
brachial plexus, branches of brachial plexus, main nerves of brachial plexus and their innervations, disorders of brachial plexus injury, Erb's palsy, Klumpke's palsy, compression of brachial plexus
The brachial plexus is formed by the ventral rami of cervical and thoracic spinal nerves C5-T1. It provides motor and sensory innervation to the upper limb. It forms trunks, divisions, and cords which branch into individual nerves that innervate specific muscles and skin areas. Anatomical variations are common and can impact techniques for brachial plexus blockade, which is used for surgeries on the shoulder, arm, elbow, and forearm. Injuries to different parts of the plexus can cause distinct nerve palsies like Erb's palsy or Klumpke's paralysis.
The thalamus is a paired symmetrical structure located in the center of the brain that relays sensory and motor signals between the brainstem and cerebral cortex. It is divided into several nuclei that have distinct connections and functions. The document provides detailed information on the anatomy, physiology, functional organization and clinical syndromes associated with lesions of different thalamic nuclei. Key points include a description of the gross anatomy and location of the thalamus, its blood supply, the nuclei and their connections, and syndromes associated with infarcts in the posterolateral and medial thalamic territories.
The brain receives its blood supply from two internal carotid arteries and two vertebral arteries. These vessels anastomose to form the circle of Willis at the base of the brain. The internal carotid artery gives off branches that supply the anterior circulation, including the anterior cerebral artery and middle cerebral artery. The vertebral arteries join to form the basilar artery, which supplies the posterior circulation via branches such as the posterior cerebral artery. Various arteries anastomose to provide collateral circulation. Venous drainage involves superficial and deep veins that drain primarily into the dural venous sinuses.
The brain receives its blood supply from two internal carotid arteries and two vertebral arteries. These vessels anastomose at the base of the brain to form the Circle of Willis. The internal carotid artery gives off branches that supply the anterior circulation, including the anterior cerebral artery and middle cerebral artery. The vertebral arteries join to form the basilar artery, which supplies the posterior circulation via the posterior cerebral artery. Venous drainage follows complex patterns into dural sinuses and cerebral veins before emptying into the internal jugular veins.
The document summarizes the development, anatomy, and histology of the pons and midbrain. It describes that the pons develops from the metencephalon and receives cells from the myelencephalon. The midbrain develops from the mesencephalon. The document then provides detailed descriptions of the structures, tracts, nuclei, and blood supply of both the pons and midbrain through multiple sections and diagrams.
The internal capsule is a white matter structure that contains association, commissural, and projection fibers. It has five segments and is supplied by branches from the anterior, middle, and posterior cerebral arteries. Injury to different parts of the internal capsule can cause various neurological deficits, such as hemiparesis, aphasia, or sensory loss, depending on the fibers and brain regions affected. Common causes of internal capsule injury include lacunar infarcts and watershed ischemic syndromes.
brachial plexus, branches of brachial plexus, main nerves of brachial plexus and their innervations, disorders of brachial plexus injury, Erb's palsy, Klumpke's palsy, compression of brachial plexus
The brachial plexus is formed by the ventral rami of cervical and thoracic spinal nerves C5-T1. It provides motor and sensory innervation to the upper limb. It forms trunks, divisions, and cords which branch into individual nerves that innervate specific muscles and skin areas. Anatomical variations are common and can impact techniques for brachial plexus blockade, which is used for surgeries on the shoulder, arm, elbow, and forearm. Injuries to different parts of the plexus can cause distinct nerve palsies like Erb's palsy or Klumpke's paralysis.
The thalamus is a paired symmetrical structure located in the center of the brain that relays sensory and motor signals between the brainstem and cerebral cortex. It is divided into several nuclei that have distinct connections and functions. The document provides detailed information on the anatomy, physiology, functional organization and clinical syndromes associated with lesions of different thalamic nuclei. Key points include a description of the gross anatomy and location of the thalamus, its blood supply, the nuclei and their connections, and syndromes associated with infarcts in the posterolateral and medial thalamic territories.
The brain receives its blood supply from two internal carotid arteries and two vertebral arteries. These vessels anastomose to form the circle of Willis at the base of the brain. The internal carotid artery gives off branches that supply the anterior circulation, including the anterior cerebral artery and middle cerebral artery. The vertebral arteries join to form the basilar artery, which supplies the posterior circulation via branches such as the posterior cerebral artery. Various arteries anastomose to provide collateral circulation. Venous drainage involves superficial and deep veins that drain primarily into the dural venous sinuses.
The brain receives its blood supply from two internal carotid arteries and two vertebral arteries. These vessels anastomose at the base of the brain to form the Circle of Willis. The internal carotid artery gives off branches that supply the anterior circulation, including the anterior cerebral artery and middle cerebral artery. The vertebral arteries join to form the basilar artery, which supplies the posterior circulation via the posterior cerebral artery. Venous drainage follows complex patterns into dural sinuses and cerebral veins before emptying into the internal jugular veins.
The document summarizes the development, anatomy, and histology of the pons and midbrain. It describes that the pons develops from the metencephalon and receives cells from the myelencephalon. The midbrain develops from the mesencephalon. The document then provides detailed descriptions of the structures, tracts, nuclei, and blood supply of both the pons and midbrain through multiple sections and diagrams.
The spinal cord receives its blood supply from the anterior and posterior spinal arteries as well as segmental arteries. The anterior spinal artery arises from the vertebral arteries and runs down the anterior median fissure. It supplies the anterior two thirds of the cord. Occlusion of the anterior spinal artery can cause motor and bilateral loss of pain/temperature sensation symptoms. The posterior spinal arteries originate from the vertebral or posterior inferior cerebellar arteries and run down the posterolateral sulcus. Segmental arteries reach the cord along spinal nerve roots and nourish the roots. The venous drainage involves two median longitudinal veins and two anterolateral and posterolateral veins that drain into the internal vertebral venous plexus.
This document summarizes the functional anatomy of the cerebral hemispheres. It describes the six layers of the cerebral cortex and areas related to somatosensory, motor, visual, auditory, and olfactory functions. It discusses association areas including the parietooccipitotemporal area, prefrontal cortex, Wernicke's area, and angular gyrus. It also briefly mentions control of eye movements, face recognition, speech processing, and functions of the non-dominant hemisphere.
The spinal cord receives its blood supply from the anterior and posterior spinal arteries as well as radicular arteries. Venous drainage occurs through six irregular plexiform channels along the midlines and roots that drain into the epidural venous plexus and Batson's plexus, which may transport tumor cells. The anterior spinal artery arises from the vertebral artery and supplies the anterior two-thirds of the cord. Posterior spinal arteries from the vertebra arteries supply the posterior horns and dorsal funiculi. Radicular arteries from the intercostal arteries supply peripheral areas and anastomose with the anterior and posterior spinal arteries.
Venous drainage system of brain - Dr Sameep Koshti (Consultant Neurosurgeon)Sameep Koshti
The venous drainage of the brain occurs through a complex system of deep and superficial veins. The superficial system drains the superficial fifth of the cerebrum while the deep system drains the remaining four-fifths. These veins pierce the arachnoid mater and dura mater to open into dural venous sinuses. The major veins include the superior and inferior cerebral veins, internal cerebral veins, basal vein of Rosenthal, vein of Galen, and petrosal and galenic vein groups which drain into dural sinuses like the superior sagittal sinus and transverse sinus. The brain's venous system lacks valves and has thin walls to facilitate drainage.
The major arteries supplying the brain and spinal cord are the internal carotid arteries, vertebral arteries, and their branches. The internal carotid arteries enter the cranium and give rise to the anterior and middle cerebral arteries. The vertebral arteries join to form the basilar artery, which branches into the posterior cerebral arteries. These arteries anastomose to form the Circle of Willis, supplying different regions of the brain. The vertebral and basilar arteries also give rise to branches that supply the brainstem and cerebellum. The spinal cord receives blood from the anterior and posterior spinal arteries as well as segmental arteries originating from nearby vessels. Occlusion of cerebral arteries can cause strokes with deficits corresponding to the territory of the occluded vessel
The spinal cord extends from the skull to the lower back, and has sensory and motor functions. It contains gray matter in an H-shape containing nuclei, and white matter containing ascending and descending tracts. The spinal cord is surrounded by meninges and has 31 pairs of spinal nerves that connect it to the body. It carries sensory information from the body to the brain via ascending tracts, and carries motor commands from the brain to the body via descending tracts.
Digital Subtraction Neuroangiography: What a Resident Should Know Dr. Shahnawaz Alam
This document provides an overview of digital subtraction neuroangiography for residents. It begins with an introduction to the principles and importance of neuroangiography. It then provides detailed descriptions of normal neurovascular anatomy and angiographic views of the extracranial carotid system, anterior and posterior circulations. It discusses indications, contraindications, patient preparation, technique, complications and case examples to illustrate pathologies. The goal is to equip residents with the basic knowledge to interpret images and safely perform neuroangiography.
Cerebral blood flow is tightly regulated to meet the high metabolic demands of the brain. Blood circulates to the brain through the carotid and vertebral arteries which connect at the circle of Willis. Factors like blood pressure, carbon dioxide levels, oxygen, temperature and various chemicals regulate blood flow. The brain has autoregulatory mechanisms to maintain constant blood flow over a range of pressures. Failure of autoregulation can lead to ischemia or hyperperfusion. Clinical considerations include risks for hypertensive or elderly patients and treatments focus on preventing hypotension and ischemia.
A 78-year-old man was admitted to the hospital after collapsing suddenly. He had a history of hypertension and smoking. Examination found right-sided weakness and abnormal reflexes, and CT scan showed areas of brain infarction. The document discusses the anatomy of the brain's blood supply through the circle of Willis and its branches, which areas of the brain each branch supplies, and clinical presentations that can result from occlusions or issues with different arteries like anterior cerebral artery occlusion causing paraplegia or middle cerebral artery occlusion causing face/arm weakness and neglect. It also covers venous drainage and conditions like cavernous sinus thrombosis.
The document summarizes the autonomic nervous system. It describes the central nervous system as consisting of the brain and spinal cord. The peripheral nervous system is divided into the somatic and autonomic systems. The autonomic system is further divided into the sympathetic and parasympathetic systems. The sympathetic system is activated during stress and fights or flight responses. It increases heart rate, blood pressure, and lipolysis to provide energy. The parasympathetic system is active during rest and digestion and maintains normal functions.
The document discusses the blood supply of the brain. It begins by describing the two pairs of arteries that supply the brain - the vertebral and internal carotid arteries. These arteries are interconnected to form the circle of Willis at the base of the brain. The vertebrobasilar system arises from the vertebral arteries and forms the basilar artery, which divides into the posterior cerebral arteries. The internal carotid system gives rise to the anterior and middle cerebral arteries. These arteries and their branches supply different regions of the brain. The circle of Willis provides an important anastomosis between the two systems to ensure adequate blood flow to the brain.
Brain vascular anatomy with MRA and MRI correlationArif S
This document provides an overview of the vascular anatomy of the brain. It discusses the arterial supply, venous drainage, and dural venous sinuses of the brain. For arterial supply, it describes the anterior and posterior circulations, including the internal carotid, vertebral, basilar, anterior cerebral, middle cerebral, and posterior cerebral arteries. It also discusses branches and territories of these vessels. For venous drainage, it outlines the internal cerebral veins and external cerebral veins, as well as dural venous sinuses such as the superior sagittal sinus. Watershed zones and vascular territories on cross sections are also depicted.
The internal capsule is divided into superior and inferior parts. It is located medially between the caudate nucleus and thalamus, and laterally between the lentiform nucleus. It contains ascending and descending tracts that connect the cortex to lower brain structures. The internal capsule has anterior, genu, posterior, retrolentiform, and sublentiform parts that contain different tracts. We need to learn about the internal capsule because it is important for understanding the pathways involved in motor and sensory functions.
This document summarizes the arterial supply and venous drainage of the brain and spinal cord. It discusses how the brain receives blood from the internal carotid and vertebral arteries, which connect at the circle of Willis to provide an interconnected blood supply. It describes the branches of these arteries and their territories. It also outlines the venous drainage pathways and discusses the blood-brain barrier. For the spinal cord, it explains that the anterior and posterior spinal arteries are the main arterial supply, along with segmental arteries.
The brainstem is located between the cerebrum and spinal cord. It consists of the midbrain, pons, and medulla oblongata. The midbrain connects the pons and cerebrum and contains the superior and inferior colliculi. The pons connects to the cerebellum via peduncles and contains pontine nuclei and cranial nerve nuclei. The medulla oblongata connects to the spinal cord and contains cranial nerve nuclei, the inferior olives, and tracts such as the gracile and cuneate fasciculi.
PHYSIOLOGY OF CSF PRODUCTION AND CIRCULATION, ALTERATIONS IN VARIOUS PATHOLOGYUnnikrishnan Prathapadas
This document discusses the physiology of cerebrospinal fluid (CSF) production and circulation, and how it can be altered in various pathologies. It covers the anatomy and function of the choroid plexus, CSF composition and circulation pathways, methods to measure CSF formation rate and resistance to absorption, effects of various drugs on CSF dynamics, and alterations seen in different diseases. Key points include how CSF is formed at the choroid plexus, circulates through the ventricles and subarachnoid space, and is reabsorbed into venous sinuses. Inhalational and intravenous anesthetics can impact CSF formation rate and resistance in different ways.
The spinal cord has 31 pairs of spinal nerves that emerge from its sides. It occupies the upper two-thirds of the vertebral canal and is protected by bony vertebrae and meninges. The spinal cord receives its blood supply from the anterior and posterior spinal arteries as well as segmental arteries. It has an anterior median fissure and posterior median sulcus that contain the arteries supplying the cord. Lesions of the spinal cord can result in deficits depending on the location and structures involved, and the cord can be surgically approached through laminectomy.
This document describes the anatomy of the neck region. It outlines the boundaries, landmarks, triangles, skin, fascia, muscles, vessels and nerves found in the neck. Key structures mentioned include the thyroid gland, larynx, trachea, esophagus, sternocleidomastoid muscle, occipital and supraclavicular triangles, carotid sheath, brachial plexus and spinal accessory nerve.
The brachial plexus is formed by the ventral rami of cervical and thoracic spinal nerves C5-T1. It has roots, trunks, divisions, cords, and branches. The document outlines the formation of the brachial plexus from the spinal nerves and its relationship to the clavicle and axillary artery. It also lists the branches of the brachial plexus in the neck and axilla that arise from the lateral, medial, and posterior cords.
The document summarizes the arterial blood supply and venous drainage of the brain. It discusses the two main sources of arterial blood - the internal carotid and vertebral arteries. It describes the branches of these arteries and their territories. It also discusses the clinical consequences of occlusions in different arteries. The circle of Willis and venous drainage routes are also summarized.
The document describes the major blood vessels that supply the brain. The common carotid arteries and vertebro-basilar arteries provide oxygenated blood to the head and neck. These vessels form a circle known as the Circle of Willis at the base of the brain, which allows for collateral blood flow if one portion of the circle is blocked. The main arteries that branch off from the circle include the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery, each supplying different regions of the brain. The lenticulostriate arteries are also described as smaller deep penetrating vessels.
The document discusses the anterior cerebral circulation, including the internal carotid artery, anterior cerebral artery, and middle cerebral artery. It describes the typical vascular territories and clinical deficits that can result from occlusions or infarctions in different segments of these arteries. Key points include that unilateral middle cerebral artery occlusion can cause contralateral hemiplegia and homonymous hemianopia, while bilateral anterior cerebral artery occlusion can lead to paraplegia and urinary incontinence.
The spinal cord receives its blood supply from the anterior and posterior spinal arteries as well as segmental arteries. The anterior spinal artery arises from the vertebral arteries and runs down the anterior median fissure. It supplies the anterior two thirds of the cord. Occlusion of the anterior spinal artery can cause motor and bilateral loss of pain/temperature sensation symptoms. The posterior spinal arteries originate from the vertebral or posterior inferior cerebellar arteries and run down the posterolateral sulcus. Segmental arteries reach the cord along spinal nerve roots and nourish the roots. The venous drainage involves two median longitudinal veins and two anterolateral and posterolateral veins that drain into the internal vertebral venous plexus.
This document summarizes the functional anatomy of the cerebral hemispheres. It describes the six layers of the cerebral cortex and areas related to somatosensory, motor, visual, auditory, and olfactory functions. It discusses association areas including the parietooccipitotemporal area, prefrontal cortex, Wernicke's area, and angular gyrus. It also briefly mentions control of eye movements, face recognition, speech processing, and functions of the non-dominant hemisphere.
The spinal cord receives its blood supply from the anterior and posterior spinal arteries as well as radicular arteries. Venous drainage occurs through six irregular plexiform channels along the midlines and roots that drain into the epidural venous plexus and Batson's plexus, which may transport tumor cells. The anterior spinal artery arises from the vertebral artery and supplies the anterior two-thirds of the cord. Posterior spinal arteries from the vertebra arteries supply the posterior horns and dorsal funiculi. Radicular arteries from the intercostal arteries supply peripheral areas and anastomose with the anterior and posterior spinal arteries.
Venous drainage system of brain - Dr Sameep Koshti (Consultant Neurosurgeon)Sameep Koshti
The venous drainage of the brain occurs through a complex system of deep and superficial veins. The superficial system drains the superficial fifth of the cerebrum while the deep system drains the remaining four-fifths. These veins pierce the arachnoid mater and dura mater to open into dural venous sinuses. The major veins include the superior and inferior cerebral veins, internal cerebral veins, basal vein of Rosenthal, vein of Galen, and petrosal and galenic vein groups which drain into dural sinuses like the superior sagittal sinus and transverse sinus. The brain's venous system lacks valves and has thin walls to facilitate drainage.
The major arteries supplying the brain and spinal cord are the internal carotid arteries, vertebral arteries, and their branches. The internal carotid arteries enter the cranium and give rise to the anterior and middle cerebral arteries. The vertebral arteries join to form the basilar artery, which branches into the posterior cerebral arteries. These arteries anastomose to form the Circle of Willis, supplying different regions of the brain. The vertebral and basilar arteries also give rise to branches that supply the brainstem and cerebellum. The spinal cord receives blood from the anterior and posterior spinal arteries as well as segmental arteries originating from nearby vessels. Occlusion of cerebral arteries can cause strokes with deficits corresponding to the territory of the occluded vessel
The spinal cord extends from the skull to the lower back, and has sensory and motor functions. It contains gray matter in an H-shape containing nuclei, and white matter containing ascending and descending tracts. The spinal cord is surrounded by meninges and has 31 pairs of spinal nerves that connect it to the body. It carries sensory information from the body to the brain via ascending tracts, and carries motor commands from the brain to the body via descending tracts.
Digital Subtraction Neuroangiography: What a Resident Should Know Dr. Shahnawaz Alam
This document provides an overview of digital subtraction neuroangiography for residents. It begins with an introduction to the principles and importance of neuroangiography. It then provides detailed descriptions of normal neurovascular anatomy and angiographic views of the extracranial carotid system, anterior and posterior circulations. It discusses indications, contraindications, patient preparation, technique, complications and case examples to illustrate pathologies. The goal is to equip residents with the basic knowledge to interpret images and safely perform neuroangiography.
Cerebral blood flow is tightly regulated to meet the high metabolic demands of the brain. Blood circulates to the brain through the carotid and vertebral arteries which connect at the circle of Willis. Factors like blood pressure, carbon dioxide levels, oxygen, temperature and various chemicals regulate blood flow. The brain has autoregulatory mechanisms to maintain constant blood flow over a range of pressures. Failure of autoregulation can lead to ischemia or hyperperfusion. Clinical considerations include risks for hypertensive or elderly patients and treatments focus on preventing hypotension and ischemia.
A 78-year-old man was admitted to the hospital after collapsing suddenly. He had a history of hypertension and smoking. Examination found right-sided weakness and abnormal reflexes, and CT scan showed areas of brain infarction. The document discusses the anatomy of the brain's blood supply through the circle of Willis and its branches, which areas of the brain each branch supplies, and clinical presentations that can result from occlusions or issues with different arteries like anterior cerebral artery occlusion causing paraplegia or middle cerebral artery occlusion causing face/arm weakness and neglect. It also covers venous drainage and conditions like cavernous sinus thrombosis.
The document summarizes the autonomic nervous system. It describes the central nervous system as consisting of the brain and spinal cord. The peripheral nervous system is divided into the somatic and autonomic systems. The autonomic system is further divided into the sympathetic and parasympathetic systems. The sympathetic system is activated during stress and fights or flight responses. It increases heart rate, blood pressure, and lipolysis to provide energy. The parasympathetic system is active during rest and digestion and maintains normal functions.
The document discusses the blood supply of the brain. It begins by describing the two pairs of arteries that supply the brain - the vertebral and internal carotid arteries. These arteries are interconnected to form the circle of Willis at the base of the brain. The vertebrobasilar system arises from the vertebral arteries and forms the basilar artery, which divides into the posterior cerebral arteries. The internal carotid system gives rise to the anterior and middle cerebral arteries. These arteries and their branches supply different regions of the brain. The circle of Willis provides an important anastomosis between the two systems to ensure adequate blood flow to the brain.
Brain vascular anatomy with MRA and MRI correlationArif S
This document provides an overview of the vascular anatomy of the brain. It discusses the arterial supply, venous drainage, and dural venous sinuses of the brain. For arterial supply, it describes the anterior and posterior circulations, including the internal carotid, vertebral, basilar, anterior cerebral, middle cerebral, and posterior cerebral arteries. It also discusses branches and territories of these vessels. For venous drainage, it outlines the internal cerebral veins and external cerebral veins, as well as dural venous sinuses such as the superior sagittal sinus. Watershed zones and vascular territories on cross sections are also depicted.
The internal capsule is divided into superior and inferior parts. It is located medially between the caudate nucleus and thalamus, and laterally between the lentiform nucleus. It contains ascending and descending tracts that connect the cortex to lower brain structures. The internal capsule has anterior, genu, posterior, retrolentiform, and sublentiform parts that contain different tracts. We need to learn about the internal capsule because it is important for understanding the pathways involved in motor and sensory functions.
This document summarizes the arterial supply and venous drainage of the brain and spinal cord. It discusses how the brain receives blood from the internal carotid and vertebral arteries, which connect at the circle of Willis to provide an interconnected blood supply. It describes the branches of these arteries and their territories. It also outlines the venous drainage pathways and discusses the blood-brain barrier. For the spinal cord, it explains that the anterior and posterior spinal arteries are the main arterial supply, along with segmental arteries.
The brainstem is located between the cerebrum and spinal cord. It consists of the midbrain, pons, and medulla oblongata. The midbrain connects the pons and cerebrum and contains the superior and inferior colliculi. The pons connects to the cerebellum via peduncles and contains pontine nuclei and cranial nerve nuclei. The medulla oblongata connects to the spinal cord and contains cranial nerve nuclei, the inferior olives, and tracts such as the gracile and cuneate fasciculi.
PHYSIOLOGY OF CSF PRODUCTION AND CIRCULATION, ALTERATIONS IN VARIOUS PATHOLOGYUnnikrishnan Prathapadas
This document discusses the physiology of cerebrospinal fluid (CSF) production and circulation, and how it can be altered in various pathologies. It covers the anatomy and function of the choroid plexus, CSF composition and circulation pathways, methods to measure CSF formation rate and resistance to absorption, effects of various drugs on CSF dynamics, and alterations seen in different diseases. Key points include how CSF is formed at the choroid plexus, circulates through the ventricles and subarachnoid space, and is reabsorbed into venous sinuses. Inhalational and intravenous anesthetics can impact CSF formation rate and resistance in different ways.
The spinal cord has 31 pairs of spinal nerves that emerge from its sides. It occupies the upper two-thirds of the vertebral canal and is protected by bony vertebrae and meninges. The spinal cord receives its blood supply from the anterior and posterior spinal arteries as well as segmental arteries. It has an anterior median fissure and posterior median sulcus that contain the arteries supplying the cord. Lesions of the spinal cord can result in deficits depending on the location and structures involved, and the cord can be surgically approached through laminectomy.
This document describes the anatomy of the neck region. It outlines the boundaries, landmarks, triangles, skin, fascia, muscles, vessels and nerves found in the neck. Key structures mentioned include the thyroid gland, larynx, trachea, esophagus, sternocleidomastoid muscle, occipital and supraclavicular triangles, carotid sheath, brachial plexus and spinal accessory nerve.
The brachial plexus is formed by the ventral rami of cervical and thoracic spinal nerves C5-T1. It has roots, trunks, divisions, cords, and branches. The document outlines the formation of the brachial plexus from the spinal nerves and its relationship to the clavicle and axillary artery. It also lists the branches of the brachial plexus in the neck and axilla that arise from the lateral, medial, and posterior cords.
The document summarizes the arterial blood supply and venous drainage of the brain. It discusses the two main sources of arterial blood - the internal carotid and vertebral arteries. It describes the branches of these arteries and their territories. It also discusses the clinical consequences of occlusions in different arteries. The circle of Willis and venous drainage routes are also summarized.
The document describes the major blood vessels that supply the brain. The common carotid arteries and vertebro-basilar arteries provide oxygenated blood to the head and neck. These vessels form a circle known as the Circle of Willis at the base of the brain, which allows for collateral blood flow if one portion of the circle is blocked. The main arteries that branch off from the circle include the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery, each supplying different regions of the brain. The lenticulostriate arteries are also described as smaller deep penetrating vessels.
The document discusses the anterior cerebral circulation, including the internal carotid artery, anterior cerebral artery, and middle cerebral artery. It describes the typical vascular territories and clinical deficits that can result from occlusions or infarctions in different segments of these arteries. Key points include that unilateral middle cerebral artery occlusion can cause contralateral hemiplegia and homonymous hemianopia, while bilateral anterior cerebral artery occlusion can lead to paraplegia and urinary incontinence.
The brain receives a large portion of the body's blood supply and oxygen consumption despite being only 2% of body weight. The internal carotid arteries supply the anterior circulation while the vertebral arteries supply the posterior circulation, with these systems connecting at the circle of Willis. Occlusion of cerebral arteries can cause neurological deficits corresponding to the brain areas supplied, such as hemiplegia from middle cerebral artery occlusion or homonymous hemianopia from posterior cerebral artery occlusion. Proper blood flow is crucial for brain function.
This document discusses cerebral circulation and factors that regulate cerebral blood flow. Three main factors control cerebral blood flow: carbon dioxide concentration, hydrogen ion concentration, and oxygen concentration. Increased carbon dioxide or hydrogen ions cause vasodilation and increased blood flow, while low oxygen triggers the oxygen deficiency mechanism to increase flow. Cerebral blood flow is also autoregulated between arterial pressures of 60-140 mmHg. The cerebrospinal fluid acts as a cushion for the brain and is circulated and absorbed via the choroid plexus and arachnoid villi. Increased cerebrospinal fluid pressure can cause papilledema and hydrocephalus. The blood-brain barrier tightly regulates molecular exchange between blood and brain tissue.
Cerebral blood flow is dependent on cerebral perfusion pressure and the radius of cerebral blood vessels. Neurons require a constant blood flow and oxygen supply to produce energy. Without oxygen, energy processes cease within 4-10 minutes leading to cell injury. Cerebral blood flow is regulated by factors like cerebral metabolism, carbon dioxide levels, oxygen levels, autoregulation, and other influences on blood pressure and vessel diameter. Impairments can occur in many pathological conditions.
1) The document discusses various syndromes that can result from lesions or occlusions in different parts of the posterior circulation arteries that supply the brainstem and cerebellum.
2) Specific syndromes are described based on the location of the lesion, including PCA, vertebral artery, and basilar artery syndromes. Onset, signs and symptoms on both sides of the lesion are outlined.
3) Midbrain, pontine, and medullary syndromes are also detailed. Bilateral lesions causing Anton's syndrome and Balint's syndrome are mentioned. A variety of resulting neurological deficits are associated with different posterior circulation artery occlusions.
Cerebral blood flow is regulated by carbon dioxide, hydrogen ion, and oxygen concentration to ensure adequate blood supply to the brain. Increased carbon dioxide and hydrogen ions cause vasodilation to increase blood flow, while low oxygen triggers vasodilation to boost supply. Cerebral blood flow is maintained within a range of arterial pressures through autoregulation. Metabolic byproducts act as vasodilators or vasoconstrictors to adapt blood flow to metabolic demand.
1. The document describes various large vessel stroke syndromes involving the anterior and posterior circulations. Anterior circulation strokes can affect the internal carotid, anterior cerebral, or middle cerebral artery territories and cause symptoms like weakness or sensory loss on one side of the body.
2. Posterior circulation strokes involving the vertebral, basilar, or posterior cerebral arteries can cause visual field defects, memory problems, or lateral medullary syndrome with dizziness and sensory loss on one side of the face and trunk.
3. Small deep strokes in the pons, internal capsule, or thalamus can cause pure motor, sensory, or sensorimotor deficits localized to one side of the body.
Here are my analyses of the fecal electrolyte cases:
I. High sodium, low potassium - suggestive of pancreatic insufficiency
II. Normal values - no clear abnormality
III. Normal values - no clear abnormality
IV. Low values - possible malabsorption
V. Low stool osmolality and large osmotic gap - suggestive of osmotic diarrhea
In summary, cases I and V show clear electrolyte abnormalities diagnostic of specific conditions (pancreatic insufficiency and osmotic diarrhea respectively), while cases II-IV are non-diagnostic based on electrolytes alone. Measuring stool volume and performing other tests would be needed to establish a diagnosis in those cases.
Slideshow is from the University of Michigan Medical School's M1 Cardiovascular / Respiratory sequence
View additional course materials on Open.Michigan:
openmi.ch/med-M1Cardio
Cerebrospinal fluid (CSF) is a clear fluid that surrounds the brain and spinal cord. It is produced by choroid plexuses in the ventricles and absorbed through arachnoid villi. The blood-brain barrier (BBB) protects the brain by preventing many substances in blood from entering brain tissue while allowing important nutrients to pass through. It is formed by tight junctions between endothelial cells in brain capillaries and surrounding astrocyte foot processes. Together, CSF and the BBB help maintain a stable environment for the brain.
Collateral blood flow is important for sustaining brain tissue after an occlusion of major arteries to the brain. There are three principal pathways for collateral circulation: extracranial-intracranial communications, the circle of Willis, and leptomeningeal anastomoses. Several imaging techniques can provide insight into collateral flow, such as digital subtraction angiography, CT angiography, magnetic resonance angiography, and trans-cranial Doppler. Therapies aimed at augmenting cerebral blood flow in acute stroke have included plasma expanders, vasodilators, and induced hypertension to potentially increase collateral flow.
Posterior circulation ischaemic stroke and tiaRaeez Basheer
Posterior circulation strokes involve the vertebrobasilar arteries and account for about one-fifth of ischemic strokes. They are associated with a high risk of early recurrent stroke. Clinical features can include dizziness, limb weakness, dysarthria, and nausea. Investigations like MRI and MRA are important for diagnosis but may be normal for small brainstem infarcts. There is a higher risk of early recurrent stroke after posterior circulation events compared to carotid events. Secondary prevention focuses on antiplatelet drugs and controlling risk factors like blood pressure, though aggressive lowering is not recommended in some cases of vertebrobasilar stenosis due to risk of recurrent stroke.
Is characterized by the sudden loss of blood circulation to an area of the brain, resulting in a corresponding loss of neurologic function. Acute ischemic stroke is caused by thrombotic or embolic occlusion of a cerebral artery and is more common than hemorrhagic stroke.
It can occur
in the carotid
artery of the
neck as well as
other arteries.
When an artery is acutely occluded by thrombus or embolus, the area of the CNS supplied by it will undergo infarction if there is no adequate collateral blood supply.
Surrounding a central necrotic zone, an ‘ischemic penumbra’ remains viable for a time, i.e. it may recover function if blood flow is restored.
CNS ischemia may be accompanied by swelling for two reasons:
● cytotoxic oedema – accumulation of water in damaged glial cells and neurones,
● vasogenic oedema – extracellular fluid accumulation as a result of breakdown of the blood–brain barrier.
In the brain, this swelling may be sufficient to produce clinical deterioration in the days following a major stroke, as a result of a rise in intracranial pressure and compression of adjacent structures.
Presentation1.pptx, radiological imaging of cerebral ischemia.Abdellah Nazeer
This document summarizes radiological imaging techniques for diagnosing and characterizing cerebral ischemia (lack of blood flow to the brain). CT and MRI are useful for detecting early signs of ischemia and identifying the location and size of infarcts (areas of dead brain tissue). CT perfusion and angiography can further identify regions of critically low blood flow termed the "ischemic penumbra" that may be salvaged by rapid reperfusion. Different sequences on MRI such as DWI, T2, and T1 weighted imaging can detect ischemia at various time points and characterize the progression of injury over time. Together, these advanced imaging modalities aid in diagnosis, prognosis, and guiding of acute stroke treatment.
The document discusses electroencephalography (EEG) patterns during wakefulness and sleep. It describes different brain wave patterns seen on EEG such as alpha, beta, theta, and delta waves. It also summarizes the stages of non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep, and how brain wave activity changes between the sleep cycles and stages. The importance of sleep for physical and mental restoration is highlighted. Common sleep disorders are also briefly mentioned.
Cerebral circulation and brain stem syndromesDrRudra Naresh
This document discusses cerebral circulation and brainstem syndromes. It begins by outlining the major regions of the brain and noting that the brain receives a large portion of cardiac output due to its high metabolic needs. It then describes the anterior and posterior circulations, focusing on the branches and territories of the internal carotid and vertebral arteries. Specific syndromes that can result from occlusions or lesions in different vessel segments are outlined, such as anterior cerebral artery syndromes and middle cerebral artery syndromes. Blood supply and clinical syndromes involving the brainstem structures like midbrain, pons, and medulla are also summarized. The document provides an in-depth overview of cerebral vasculature and the neurologic deficits that can arise from
This document discusses the effects of anesthetics on cerebral blood flow and cerebral metabolic rate of oxygen. It explains that anesthetics generally suppress brain metabolism and appetite, leading to decreased cerebral blood flow and intracranial pressure. Specific anesthetics like barbiturates, propofol, volatile agents, and nitrous oxide are discussed in terms of their effects on cerebral blood flow, cerebral metabolic rate, intracranial pressure, and other factors. The importance of maintaining proper cerebral perfusion pressure during neuroanesthesia is also emphasized.
The document discusses the arterial supply of the brain. It describes the major arteries originating from the aorta including the brachiocephalic artery, common carotid arteries, vertebral arteries, and branches of these arteries. It discusses the segments and branches of the internal carotid artery as it passes through the cervical, petrous, cavernous, clinoid, and communicating segments. It also describes the circle of Willis and its variants. Key arteries discussed include the anterior, middle, and posterior cerebral arteries as well as the basilar and vertebral arteries.
CT carotid and cerebral angiography is used to study the neck arteries (carotid arteries) and brain arteries (cerebral arteries) using a CT scanner. It can detect aneurysms, narrowing of arteries in the brain, abnormal blood vessels, stenosis, and narrowing or blockage of the carotid arteries. The procedure involves inserting a cannula if needed, obtaining plain CT images of the neck and brain, injecting contrast dye using a pressure injector, and obtaining images of the arteries. It can help determine the risk of future strokes and identify issues like strictures of the carotid arteries.
The document summarizes the blood supply of the brain. It begins by noting the brain's high metabolic demands and sensitivity to hypoxia. It then discusses the various arterial systems that supply the brain, including the internal carotid and vertebral arteries, as well as the arterial circle of Willis. It provides details on the territories supplied by the anterior, middle, and posterior cerebral arteries. It also briefly discusses the venous drainage of the brain and blood-brain barrier.
The brain receives blood from two sources: the internal carotid arteries, which arise at the point in the neck where the common carotid arteries bifurcate, and the vertebral arteries . The internal carotid arteries branch to form two major cerebral arteries, the anterior and middle cerebral arteries. The right and left vertebral arteries come together at the level of the pons on the ventral surface of the brainstem to form the midline basilar artery. The basilar artery joins the blood supply from the internal carotids in an arterial ring at the base of the brain (in the vicinity of the hypothalamus and cerebral peduncles) called the circle of Willis. The posterior cerebral arteries arise at this confluence, as do two small bridging arteries, the anterior and posterior communicating arteries. Conjoining the two major sources of cerebral vascular supply via the circle of Willis presumably improves the chances of any region of the brain continuing to receive blood if one of the major arteries becomes occluded
This document summarizes the anatomy of the circle of Willis and cerebral blood supply. It describes the circle of Willis as a polygonal anastomotic channel at the base of the brain supplied by the internal carotid and vertebral arteries. It then discusses the branches and functions of the circle of Willis, cortical and central arteries, lenticulostriate arteries, and the blood-brain barrier. Finally, it provides details on the regional arterial supply of different brain regions and applied anatomy related to various neurological syndromes.
Blood supply of the brain & spinal cord by dr sarwarporag sarwar
The document summarizes the blood supply of the brain and spinal cord. There are two main systems - the carotid system supplying 80% and the vertebrobasilar system supplying 20%. The vertebrobasilar system supplies the brainstem, cerebellum and parts of the diencephalon and telencephalon. It is formed from the two vertebral arteries joining to form the basilar artery. The basilar artery then gives off branches including the posterior cerebral arteries. The carotid system arises from the internal and external carotid arteries. The internal carotid artery gives off branches including the anterior and middle cerebral arteries. These arteries anastomose to form the circle of Willis at the base of the brain.
A stroke occurs when blood supply to the brain is disrupted, either from a blockage (ischemic stroke) or bleeding (hemorrhagic stroke). Imaging plays an important role in the evaluation and management of acute stroke. Non-contrast CT is used initially to rule out hemorrhage. CT angiography can identify potentially treatable vessel occlusions. CT and MRI perfusion can identify irreversibly damaged tissue and the ischemic penumbra that may be salvaged with reperfusion. The ASPECTS score on CT assesses early ischemic changes and prognosis.
Vascular brain anatomy for Radiology by Dr Soumitra HalderSoumitra Halder
The document provides an overview of cerebral arterial and venous anatomy. It discusses:
1) The anterior and posterior cerebral circulations, including the internal carotid artery (ICA) and its branches that form the anterior circulation, and the vertebrobasilar system that forms the posterior circulation.
2) The branches of major arteries like the external carotid, vertebral, and basilar arteries.
3) Anatomical variations that can be seen, like hypoplastic vessels, fenestrations, and duplications.
4) Venous anatomy, including the dural venous sinuses and cerebral veins.
Radiologic Anatomy of the Blood Supply to the Brain.pptxWilliamsMusa1
The document summarizes the radiologic anatomy of the arterial blood supply to the brain using various imaging modalities. It describes the relevant gross anatomy of the major cerebral arteries, including branches and segments. MR angiography is discussed as the preferred noninvasive method for evaluating the cerebral vasculature. CT angiography and conventional angiography provide detailed images but are more invasive. Ultrasound can also be used to image intracranial vessels through various acoustic windows. Variations in anatomy, such as those seen in the circle of Willis, are commonly observed.
This document summarizes the major arteries of the brain. It describes the circle of Willis and its components. It then discusses the internal carotid artery and its segments. It provides details on the branches and segments of the anterior, middle, and posterior cerebral arteries. It also describes the basilar artery and its branches before terminating into the posterior cerebral arteries. In summary, it provides an overview of the major arteries that supply blood to the brain.
This document provides an overview of the normal anatomy and variants of intracranial arteries, with a focus on the internal carotid artery. It describes the typical course and branches of the internal carotid artery and its major divisions including the anterior, middle, and posterior cerebral arteries. Various anatomical variants are also discussed, such as fenestrations, hyperplastic anterior choroidal arteries, fetal-type posterior cerebral arteries, posterior communicating artery infundibula, and persistent carotid-basilar anastomoses like the trigeminal artery. Clinical correlations including aneurysm formation and hemorrhagic risk are also mentioned.
This document provides an overview of normal variants and anatomy of the intracranial arteries, beginning with abbreviations used. It then describes the gross anatomy and specific segments of the internal carotid, basilar, vertebral, and posterior cerebral arteries. Vascular territories supplied by each artery are outlined. Finally, the document discusses normal variants and anomalies that can occur in the internal carotid artery anatomy. In particular, it notes that fenestration of the distal internal carotid artery is a rare finding associated with aneurysm formation. It also describes hyperplastic anterior choroidal arteries as a normal variant where the artery is enlarged beyond typical size.
BLOOD SUPPLY of brain and spinal cord.pptxmunnam37
The document summarizes the blood supply of the brain and spinal cord. It discusses the major arteries including the internal carotid, vertebral, and basilar arteries. It describes the branches and territories supplied by the anterior, middle, and posterior cerebral arteries. It also discusses important anastomoses like the Circle of Willis. Various artery syndromes are summarized such as anterior cerebral artery occlusion presenting with contralateral leg weakness. Important veins are also mentioned along with clinical correlations of arterial occlusions.
Arterial and venous supply of brain part2 Sameeha Khan
1. The document describes the anatomy and branches of the major cerebral arteries including the anterior, middle, and posterior cerebral arteries.
2. It discusses the typical branching patterns and territories supplied by each artery and their segments.
3. Variations in arterial anatomy are also summarized such as fenestrations, duplications, hypoplasia.
لقطة شاشة ٢٠٢٣-١١-١٢ في ١١.٤٥.٤٨ ص.pdfahmad2100799
The document summarizes the vascularization of the brain. There are two main arterial circuits that supply the brain - the anterior circulation supplied by the internal carotid arteries, and the posterior circulation supplied by the vertebrobasilar system. These arteries anastomose to form the Circle of Willis at the base of the brain. The anterior circulation includes the internal carotid arteries, anterior cerebral arteries, anterior communicating artery, and middle cerebral arteries. The posterior circulation is supplied by the vertebral arteries, basilar artery, posterior cerebral arteries, and posterior communicating arteries.
This document discusses the vascular anatomy of the head, including the common carotid artery, external carotid artery, internal carotid artery, and their branches. It provides details on the origin, course, branches, and key relationships of these arteries. The internal carotid artery is discussed in particular depth, outlining its 7 segments and typical branches within the cervical, petrous, lacerum, cavernous, clinoid, ophthalmic, and communicating segments. Key anatomy and variations are highlighted throughout.
The origin, course, branches, and distribution of internal carotid artery.
The origin, course, branches, and distribution of basilar artery.
Describe the formation, branches and distribution of circulus arteriosus.
Outline the venous drainage of the brain.
This document provides an overview of cerebral vascular anatomy, including the major arteries supplying blood to the brain. It describes the internal carotid artery and its segments. It then discusses the anterior, middle, and posterior cerebral arteries, their segments, and key branches. The document also reviews the posterior circulation, including the vertebral artery, basilar artery, and posterior cerebral artery. Finally, it briefly mentions venous drainage from the brain.
The document discusses vascular anatomy of the brain. It notes that 18% of total blood volume circulates through the brain, which accounts for 2% of body weight. Loss of consciousness occurs within 15 seconds and irreversible brain damage within 5 minutes if blood flow to the brain stops. It then describes the various arteries that supply the brain, including the carotid arteries, vertebral arteries, and branches within the brain. It provides details on imaging techniques used to evaluate the vasculature such as angiography, CTA, MRA. Overall, the document provides an overview of the anatomy and imaging of brain vasculature.
imaging and anatomy of blood supply of brainSunil Kumar
The summary provides an overview of the arterial supply of the brain in 3 sentences:
The brain receives its arterial blood supply from the internal carotid and vertebral arteries. The internal carotid arteries give rise to branches that supply the anterior circulation including the anterior cerebral artery and middle cerebral artery. These arteries anastomose at the circle of Willis and give off numerous smaller branches to perfuse the brain.
The document provides an overview of the major arteries of the head and neck, including their origins, courses, branches, and clinical significance. It discusses the common carotid artery, external carotid artery, internal carotid artery, and their branches such as the lingual, facial, occipital, and maxillary arteries. The summary highlights the arterial supply of the head and neck originating from branches of the aortic arch and their roles in supplying surrounding structures.
The document summarizes the arterial and venous anatomy of the brain. It describes the major arteries that supply blood to the brain, including the internal carotid, vertebral, and basilar arteries. It discusses the circle of Willis and territories supplied by the anterior, middle, and posterior cerebral arteries. It also outlines the dural venous sinuses and cerebral veins that drain blood from the brain. Key structures mentioned include the cavernous sinus and superior sagittal sinus.
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
1. CEREBRAL BLOOD FLOW, ITS
AUTOREGULATION , CLINICAL
RELEVANCE AND
ROLE OF COLLATERALS IN
ISCHEMIC STROKE
By-Varun Kumar Singh
18/12/2015
2. OVERVIEW
• CEREBRAL BLOOD SUPPLY(ARTERIAL AND VENOUS)
• AUTOREGULATION MECHANISM AND ITS CLINICAL
IMPORTANCE
• CEREBRAL COLLATERALS AND ITS SIGNIFICANCE IN
ACUTE ISCHEMIC STROKE
3. AORTIC ARCH
1.Innominate artery (IA) /
Brachiocephalic trunk
• Rt subclavian artery (SCA)- Right
vertebral artery
• Rt common carotid artery (CCA)
2.Left Common Carotid Artery (CCA)
3.Left Subclavian Artery (SCA)
• Left Vertebral Artery (VA)
4. Major Arteries
1.INTERNAL CAROTID-
-TWO IN NO.
• ARCH OF AORTA-
BRACHIOCEPHALIC-INTERNAL
+EXTERNAL CAROTID AT
SUPERIOR BORDER OF THYROID
CARTILAGE(C3-C4)
• ENTER THE BRAIN-CAROTID
CANAL
2. VERTEBRAL ARTERIES
-TWO IN NO.
• FROM 1st PART OF SUBCLAVIAN
ARTERY.
• TRAVERSE FROM C6 TO C1 –
FORAMAN MAGNUM
• UNITES TO FORM BASILAR
ARTERY AT THE LOWER BORDER
OF THE PONS
6. Cervical segment
– From the bifurcation of CCA
– Enters the skull through carotid canal in
petrous part of temporal bone
– No branches
– Persistent embryonic vessels may give
rise to ECA – ICA anastomoses
7. PETROUS SEGMENT
-Extends from base of skull
to the petrous apex
-Ascending , Genu, Horizontal
-Enters cranial vault via
foramen lacerum.
-Branches :
Carotico tympanic A & A of pterygoid canal
8. CAVERNOUS SEGMENT
• S- shaped course in sinus
referred to as CAROTID SIPHON
• Passes through cavernous sinus
• In proximity to CN III, IV, V1, V2
and VI
• Ascending sympathetic fibres
surround artery
• Branches supply posterior lobe
of pituitary and adjacent
meninges
(Meningohypophyseal Artery)
11. OPHTHALMIC ARTERY
1st intradural branch of ICA
Supplies globe, orbit, frontal and
ethmoidal sinuses, & frontal
scalp
Central retinal A, Long & Short
posterior ciliary branches
Branches of Ophthalmic A
anastamose with Maxillary A
branches - potential for collateral
flow in cases of proximal carotid
occlusion
12. POSTERIOR COMMUNICATING A
• Branches enters the base of brain between
infundibulum and optic tract
• Supply anteromedial thalamus and walls of
third ventricle
13. ANTERIOR CHOROIDAL A
• Branch of supraclinoid segment of ICA close to
its terminal bifurcation
• Passes backward along the optic tract and
around the cerebral peduncle as far as the
lateral geniculate body
• Enters the inferior horn of the lateral ventricle
14. ANTERIOR CHOROIDAL A
• Supplies the choroid plexus of lateral ventricle
• Branches to optic tract, hippocampus, tail of
caudate nucleus, medial and intermediate
portions of globus pallidus, posterior 2/3 of
internal capsule along with retro and
sublenticular part, middle third of cerebral
peduncle and outer part of lateral geniculate
body
15.
16. ANTERIOR CEREBRAL ARTERY
Three segments:
A1 –Horizontal/Pre
communicating segment
Medial lenticulostriate
branches
A2-Vertical/Post
communicating segment
From its connection to
the AComA to its
bifurcation into the
pericallosal and
callosomarginal arteries
Recurrent artery of
Heubner
Orbitofrontal
Frontopolar
A3- distal ACA / cortical
branches
Pericallosal
Callosomarginal
17. ACA SUPPLY
• Medial and orbital surface of frontal lobe
• Medial surface of the parietal lobe as far as the
parietooccipital fissure
• Genu and Anterior 4/5th of the corpus callosum
• A longitudinal 2 cm wide strip of superior surface of
the frontal & parietal lobes next to the central
sulcus
• Anterior parts of Basal Ganglia & Anteroinferior
parts of Internal Capsule
19. RECURRENT ARTERY OF HEUBNER
• Also called medial striate artery
• Give few branches to orbital cortex, passes
through anterior perforated space to join deep
branches of MCA
• Supplies lower part of head of caudate, lower part
of frontal pole of putamen, frontal pole of globus
pallidus, frontal half of anterior limb of internal
capsule, and anterior portions of external capsule
and lateral ventricle
21. MIDDLE CEREBRAL ARTERY
Four segments:
• M1- horizontal /
sphenoidal segment:
The stem of MCA 5-15
lenticulostriate branches
• M2- insular segment:
Runs deep in sylvian fissure
and along insula ; Superior
& Inferior divisions
• M3- opercular segment:
Follows the curvature of
operculum and ends as
terminal branches of MCA
• M4- cortical branches:
Terminal segment as it
emerges from the sylvian
fissure
23. MCA SUPPLY
• Most of the convex surface of the brain, except
the frontal (ACA)and occipital(PCA) poles & the
superior rim of the convex surface(ACA)
• Lenticulostriate arteries (Artery of cerebral
hemorrhage) supply
-All of the putamen except for its anterior pole
-Upper part of head of caudate N and all of its
body
-Lateral part of globus pallidus
-Posterior part of anterior limb, genu and anterior
third of posterior limb
24. Posterior cerebral artery
P1Segment
(Precommunicating/mesencephalic)
short segment from the basilar tip to the
PComA
– Mesencephalic br. – Cr. Nv. Nuclei 3 - 6
– Thalamoperforating arteries -
diencephalon and midbrain
P2 or ambient segment
runs in the ambient cistern from the PComA
to the posterior aspect of the midbrain
– Thalamogeniculate br.
– Medial posterior choroidal arteries
– Lateral posterior choroidal arteries
P3 or quadrigeminal segment
runs within the quadrigeminal cistern behind
the brainstem
– Hippocampal artery
– Antetior, middle, and posterior
temporal arteries
– Parieto-occipital artery
– Calcarine artery
– Posterior pericallosal artery
P4 –DISTAL SEGMENT
26. PCA SUPPLY
-Uncus
-Medial and inferior surface of temporal lobe
(Temporal pole- MCA)
-Thalamus, midbrain
-Cuneus and splenium of corpus callosum
-Medial surface of occipital lobe including entire
visual cortex
27.
28.
29. VERTEBRAL ARTERY
• V1(EXTRAOSSEOUS):
Segmental cervical muscular
and spinal branches -
passing into spinal canal via
intervertebral foramina and
reinforce blood supply of
spine and vertebrate.
• V2 (FORAMINAL):
-In foramina transversaria of
C6-C2
-meningeal/muscular/spinal
branches
30. VERTEBRAL ARTERY
• V3 (EXTRASPINAL): Posterior meningeal
artery
• V4(INTRADURAL):
– Anterior and posterior spinal arteries(Two anterior
spinal A join to supply lower medulla,
cervicomedullary junction and upper spinal cord)
– Perforating branches to medulla
– PICA: Arises from distal Vertebral Artery, supply
medulla and cerebellum
31. BASILAR ARTERY
• Forms at pontomedullary junction from two
vertebral artery
• Ends at the upper border of pons
• Major 5 branches
1.The pontine arteries
2. The labyrinthine
3. The anterior inferior cerebellar artery
4. The superior cerebellar artery
5.The posterior cerebral
32. BASILAR ARTERY
1.The pontine arteries
2. The labyrinthine
-the internal ear.
- often arises as a branch of the anterior
inferior cerebellar artery.
3. The anterior inferior cerebellar artery
-the anterior and inferior parts of the
cerebellum
- A few branches pass to the pons and
the upper part of the medulla
oblongata.
4. The superior cerebellar artery
-arises close to the termination of the
basilar artery
-supply superior surface of the
cerebellum, pons, the pineal gland,
and the superior medullary velum.
5.The posterior cerebral
33. • Medulla-Vertebral
Pons – Basilar
Midbrain- Basilar and proximal Posterior
cerebral Artery
• Two vertebral artery are rarely the same size.
Left is most often dominant; Right can be
smaller or completely atretic
• SCP-SCA, ICP-PICA, MCP-AICA and SCA
34. CIRCLE OF WILLIS
-In the interpeduncular
fossa at the base of
the brain.
-It is formed by the
anastomosis
between the two
internal carotid
arteries and the two
vertebral arteries
38. VENOUS DRAINAGE OF THE BRAIN
The characteristic features of venous drainage of the brain
are:
• The venous return in the brain does not follow the
arterial pattern
• The veins of the brain are extremely thin-walled due to
absence of muscular tissue in their walls
• The veins of the brain possess no valves
• The veins of the brain run mainly in the subarachnoid
space
• The cerebral veins, generally enter obliquely into the
dural venous sinuses against the flow of blood in the
sinuses to avoid their possible collapse following an
increased intracranial pressure as they are thin walled
39. SINUSES OF THE DURA MATER
.
(1) Postero-superior at the upper and back part of the skull.
1 Superior Sagittal (Convex or attached margin of falx cerebri)
2 Straight sinus
3 Inferior Sagittal (free or inferior margin of falx cerebri)
4 Two Transverse.
5 Occipital
(2) Antero-inferior at the base of the skull.
1 Two Cavernous
2 Two Superior Petrosal
3 Two Intercavernous
4 Two Inferior Petrosal
5 Two sphenoparietal
40. VENOUS DRAINAGE OF BRAIN
• Anterior cerebral vein + Deep middle cerebral Vein
+ Striate veins = Basal Vein of Rosenthal
• Thalamostriate vein + Choroidal vein = Internal
cerebral vein
• Internal cerebral vein + Basal Vein of Rosenthal =
Great vein of Galen
• Great vein of Galen + ISS = Straight sinus
41.
42. • Superior cerebral vein drain to SSS
• SSS + straight sinus + Occipital sinus = Transverse
sinus(Attached margin of tentorium cerebelli)
• Inferior cerebral vein drain to superficial middle
cerebral vein terminates to cavernous sinus
• SSS connects to superficial middle cerebral vein by
Troland’s vein AND Transverse sinus to superficial
middle cerebral vein by vein of Labbe’
• Cavernous sinus (drain to transverse and IJV via
superior and inferior petrosal sinus.
VENOUS DRAINAGE OF BRAIN
44. CEREBRAL BLOOD FLOW
AUTOREGULATION
• Neurons produce energy (ATP) almost entirely by
oxidative metabolism of substrates including
glucose and ketone bodies, with very limited
capacity for anaerobic metabolism.
• Without oxygen, energy-dependent processes cease
leading to irreversible cellular injury if blood flow is
not re-established rapidly (4 to 10 minutes under
most circumstances)
45. REGULATION OF CEREBRAL BLOOD FLOW
Cerebral blood flow (CBF) is dependent on a number
of factors that can broadly be divided into:
a. those affecting cerebral perfusion pressure
b. those affecting the radius of cerebral blood vessels
46. • CBF = 50ml/100g/min (ranging from
20ml/100g/min in white matter to 70ml/100g/min
in grey matter)
• Adult brain weighs 1400g or 2% of the total body
weight.
• But CBF is 700ml/min or 15% of the resting cardiac
output
47. 1) CEREBRAL PERFUSION PRESSURE
• Perfusion of the brain is dependent on the
pressure gradient between the arteries and the
veins and this is termed the cerebral perfusion
pressure (CPP)
• This is the difference between the mean arterial
blood pressure (MAP) and the mean cerebral
venous pressure
CPP = MAP – ICP
48. • MAP can be estimated as equal to:
diastolic blood pressure + 1/3 pulse
pressure, usually around 90mmHg
• ICP is much lower and is normally less
than 13mmHg.
49. • An increase in CPP is usually the result of an
increase in MAP, the contribution made by
reducing ICP is minimal, apart from in pathological
states when ICP is very high
• In a normal brain, despite the potential for
changes in MAP (sleep, exercise etc.), CBF remains
constant over a wide range of CPPs.
This is achieved by a process called autoregulation
50. 2) THE RADIUS OF CEREBRAL BLOOD
VESSELS
This is regulated by four primary factors:
1. Cerebral metabolism
2. Carbon dioxide and oxygen
3. Autoregulation
4. Other factors
51. CEREBRAL METABOLISM
• Local or global increases in metabolic demand are
met rapidly by an increase in CBF and substrate
delivery and vice versa
• These changes are controlled by several vasoactive
metabolic mediators including hydrogen ions,
potassium, CO2, adenosine, glycolytic and
phospholipid metabolites and NO
52. CARBON DIOXIDE AND OXYGEN
• At normotension, the relationship between partial
pressure of carbon dioxide in arterial blood (PaCO2)
and CBF is almost linear and at a PaCO2 80mmHg CBF is
approximately doubled.
• No further increase in flow is possible at this point as
the arterioles are maximally dilated.
• Conversely at 20mmHg flow is almost halved and again
cannot fall further as the arterioles are maximally
vasoconstricted
53. • Arteriolar tone has an important influence on
how PaCO2 affects CBF.
• Moderate hypotension impairs the response of
the cerebral circulation to changes in PaCO2,
and severe hypotension abolishes it altogether
• Oxygen has little effect on the radius of blood
vessels at partial pressures used clinically
54. • Blood flow increases once PaO2 drops below
50mmHg.
• Hypoxia acts directly on cerebral tissue to promote
the release of adenosine, and in some cases
prostanoids that contribute significantly to
cerebral vasodilatation.
• Hypoxia also acts directly on cerebrovascular
smooth muscle to produce hyperpolarisation and
reduce calcium uptake, both mechanisms
enhancing vasodilatation.
55. • In adults under normal circumstances (ICP
<10mmHg), CPP and MAP are very similar and
CBF remains constant with a CPP of 60-160mmHg
• The higher the ICP the more CPP deviates from
MAP.
• Autoregulation is thought to be a myogenic
mechanism, whereby vascular smooth muscle
constricts in response to an increase in wall
tension and to relax to a decrease in wall tension
AUTOREGULATION
56. • At the lower limit of autoregulation, cerebral
vasodilation is maximal, and below this level the
vessels collapse and CBF falls passively with falls in
MAP.
• At the upper limit, vasoconstriction is maximal and
beyond this the elevated intraluminal pressure
may force the vessels to dilate, leading to an
increase in CBF and damage to the blood-brain-
barrier.
57. OTHER FACTORS
• Blood viscosity: As viscosity falls, CBF increases.
However, there will also be a reduction in oxygen-
carrying capacity of the blood
• Temperature: CMRO2 decreases by 7% for each
1°C fall in body temperature and is paralleled by a
similar reduction in CBF.
• Drugs: Cerebral metabolism can be manipulated
(reduced) and consequently CBF ,cerebral blood
volume and ICP is reduced.
58. Clinical implications
• Hyperventilation reduces the PaCO2 and causes
vasoconstriction of the cerebral vessels and therefore
reduces cerebral blood volume and ICP in patients with
raised intracranial pressure, for example after traumatic
brain injury.
• However if PaCO2 is reduced too much, it may reduce
CBF to the point of causing or worsening cerebral
ischaemia
• PaCO2 is therefore best maintained at level of 35-
40mmHg to prevent raising ICP. This reactivity may be
lost in areas of the brain that are injured.
59. Clinical implications
• Pressure autoregulation can be impaired in many
pathological conditions including patients with a
brain tumour, subarachnoid haemorrhage, stroke,
or head injury.
• The reduction in CMRO2 with decrease in
temperature is the factor that allows patients to
withstand prolonged periods of reduced CBF
without ischemic damage for example during
cardiopulmonary bypass (Hypothermia helps to
reduce excitatory neurotransmitter release,
important to central nervous system protection)
60. Clinical implications
• Infusions of the barbiturate thiopentone are used
to reduce cerebral metabolic rate and so
decrease high ICP after head injury
• Anaesthetic drugs (volatile agents) cause a
reduction in the tension of cerebral vascular
smooth muscle resulting in vasodilatation and an
increase in CBF(minimal with isoflurane)
61. •Arterial insufficiency due to thromboembolism,
hemodynamic compromise, or a combination of
these factors may lead to the recruitment of
collaterals
•The arterial anatomy of the collateral circulation
includes extracranial sources of cerebral blood
flow and intracranial routes of ancillary perfusion
COLLATERALS IN CEREBRAL CIRCULATION
62. • It is commonly divided into primary or
secondary collateral pathways
• Primary collaterals include the arterial
segments of the circle of Willis,
whereas,
the ophthalmic artery and leptomeningeal
vessels constitute secondary collaterals
63. • Interhemispheric blood flow across the anterior
communicating artery and reversal of flow in the
proximal anterior cerebral artery provide
collateral support in the anterior portion of the
circle of Willis
• Additional interhemispheric collaterals include
the proximal posterior cerebral arteries at the
posterior aspect of the circle of Willis.
• The posterior communicating arteries may supply
collateral blood flow in either direction between
the anterior and posterior circulations
64. • Anatomic studies note absence of the anterior
communicating artery in 1% of subjects, absence
or hypoplasia of the proximal anterior cerebral
artery in 10%, and absence or hypoplasia of either
posterior communicating artery in 30%
• The number and size of these anastomotic vessels
are greatest between anterior and middle
cerebral arteries, with smaller and fewer
connections between middle and posterior
cerebral arteries and even less prominent
terminal anastomoses between posterior and
anterior cerebral arteries.
65. • Distal branches of the major cerebellar arteries
similarly provide collateral links across the vertebral
and basilar segments of the posterior circulation
• Leptomeningeal and dural arteriolar anastomoses
with cortical vessels further enhance the collateral
circulation.
• Other collateral routes less commonly encountered in
acute stroke are tectal plexus joining supratentorial
branches of the posterior cerebral artery with
infratentorial branches of the superior cerebellar
artery
And the orbital plexus linking the ophthalmic artery
with facial, middle meningeal, maxillary, and
ethmoidal arteries
66. Extracranial arterial collateral circulation. Anastomoses from the facial (a), maxillary (b), and
middle meningeal (c) arteries to the ophthalmic artery and dural arteriolar anastomoses from
the middle meningeal artery (d) and occipital artery through the mastoid foramen (e) and
parietal foramen (f)
67. Intracranial arterial collateral circulation in lateral (A) and frontal (B) views. Posterior
communicating artery (a); leptomeningeal anastomoses between anterior and middle cerebral
arteries (b) and between posterior and middle cerebral arteries (c); tectal plexus between
posterior cerebral and superior cerebellar arteries (d); anastomoses of distal cerebellar
arteries (e); and anterior communicating artery (f)
68. • Moyamoya syndrome represents the ultimate
example of excessive collateralization over a
chronic time course, recruiting a wide range of
leptomeningeal and deep parenchymal vessels
69. VENOUS COLLATERALS
• Venous collaterals augment drainage of
cerebral blood flow when principal routes are
occluded or venous hypertension ensues
• The anatomy of venous collateral circulation
is highly variable, allowing diversion of blood
through numerous routes when exiting the
brain
70. Venous collateral circulation. Pterygoid plexus (a), deep middle cerebral vein (b), inferior
petrosal sinus and basilar plexus (c), superior petrosal sinus (d), anastomotic vein of Trolard (e),
anastomotic vein of Labbé (f), condyloid emissary vein (g), mastoid emissary vein (h), parietal
emissary vein (i), and occipital emissary vein (j).
71. • Primary collaterals provide immediate
diversion of cerebral blood flow to ischemic
regions through existing anastomoses
• Secondary collaterals such as leptomeningeal
anastomoses may be anatomically present,
although enhanced capacity of these
alternative routes for cerebral blood flow
likely requires time to develop.
72. • Specific pathophysiological factors leading to
the development of collaterals are uncertain,
diminished blood pressure in downstream
vessels is considered a critical variable
• Focal cerebral ischemia, a critical variable may
lead to the secretion of angiogenic peptides
with some potential for collateral formation
73. Factors determining functionality and
patency of LMCs
• The incipient development of collaterals does not
guarantee their persistence
• The efficacy of LMCs also depends upon age,
duration of ischemia, and associated
comorbidities.
• Hypertension may impair collateral
development in the setting of carotid
occlusion and therefore increase stroke risk.
74. • Chronic hypoperfusion due to arterial flow
restrictions such as extracranial carotid or
intracranial steno-occlusive disease promotes
collateral development
• Hemodynamic fluctuations may influence the
endurance of collaterals, possibly threatening
cerebral blood flow.
• Similarly, distal fragmentation of a thrombus
within the parent vessel may occlude distal
branches supplying retrograde collateral flow
from cortical arteries.
75. • The collateral circulation is also a critical
determinant of Cerebral Perfusion Pressure in
acute cerebral ischemia
• The hemodynamic effects of the collateral
circulation may be important in maintaining
perfusion to penumbral regions
76. • Deep parenchymal collaterals within the striatum
may be less effective, allowing undissolved
thrombus to be retained for longer periods of
time
• These factors may be involved in the
development of large subcortical infarcts with
cortical sparing of the basal ganglia in middle cerebral
artery occlusion and limited thalamic infarction in
posterior cerebral artery occlusion
77. Diagnostic Evaluation
• Numerous techniques, including xenon-
enhanced CT, SPECT, PET, CT perfusion, and
MR perfusion, assess cerebral blood flow and
thereby infer the status of collaterals
• CONVENTIONAL ANGIOGRAPHY remains the
gold standard for collateral flow evaluation,
given its high spatial resolution and the
possibility of dynamic evaluation
78. Collateral bloodflow distal to an occlusion of the middle cerebral artery manifest as vascular
enhancement (A, arrow) and FLAIR vascular hyperintensity (B, arrow)
79. Left ICA injection early (A) and late arterial phase.The left MCA is occluded. There is no filling of
the vascular territory. Leptomeningeal collaterals (arrows) are now filling the MCA territory. The
respective supply territories of the vessels are marked
80. Leptomeningeal collaterals (LMCs) also known as
pial collaterals, are small arterial connections
joining the terminal cortical branches of major
(middle, anterior and posterior) cerebral arteries
along the surface of the brain
• It remains dormant under normal conditions
when blood flow from all major cerebral arteries
is not impeded, but are recruited when one
major artery is either chronically or acutely
occluded.
81. • Their existence was first documented by Heubner in
1874. While trying to delineate the arterial territories
in cadaveric brains, he observed that the injected
product diffused in other arterial territories in the
absence of Willis circle connections
• The presence of LMCs has also been associated with
better outcomes, reduced infarct size, and faster
recanalization
Ringelstein EB, Biniek R, Weiller C et al. Type and extent of
hemispheric brain infarctions and clinical outcome in early and delayed
middle cerebral artery recanalization. Neurology. 1992;42:289-298
82. • In PROACT II trial investigators analysed pial
collateral formation on angiography and
categorized them as full, partial,or none and
found that presence of good collaterals influences
NIHSS score at initial presentation and infarct
volume on 24-hour CT scan in patients with MCA
occlusion
Roberts HC, Dillon WP, Furlan AJ et al. Computed
tomographic findings in patients undergoing intra-arterial
thrombolysis for acute ischemic stroke due to middle
cerebral artery occlusion: Results from the PROACT II trial.
Stroke. 2002;33:1557-1565
83. • Christoforidis et al22(2005) reviewed 65 patients
retrospectively who underwent thrombolysis for
acute ischemic stroke and reported that LMC
formation before thrombolytic treatment
predicted infarct volume and clinical outcome
independent of other predictive factors
Christoforidis GA, Mohammad Y, Kehagias D et al.
Angiographic assessment of pial collaterals as a prognostic
indicator following intra-arterial thrombolysis for acute
ischemic stroke. AJNR Am J Neuroradiol. 2005;26:1789-1797
84. • The presence of collateral sparing of penumbral
region may also because of enhanced blood flow
and retrograde collateral filling which allow
thrombolytic access to distal aspects of the clot
Caplan LR, Hennerici M. Impaired clearance of emboli
(washout) is an important link between hypoperfusion,
embolism, and ischemic stroke. Arch Neurol. 1998;55:1475–
1482
85. • The presence of leptomeningeal collaterals is also
predictive of improved long-term clinical
outcome in patients treated with and without
thrombolysis for middle cerebral artery occlusion
• In chronic ischemic conditions, such as
moyamoya syndrome and steno-occlusive carotid
disease, adequacy of collaterals may be used to
guide therapy
86. • The presence of collaterals on conventional
angiography has been associated with a
lower risk of hemispheric stroke and
transient cerebral ischemia in patients with
carotid stenosis
Henderson RD et al for the North American Symptomatic
Carotid Endarterectomy Trial (NASCET) Group.
Angiographically defined collateral circulation and risk of
stroke in patients with severe carotid artery stenosis. Stroke.
2000;31:128–132
87. • Hypertension may impair collateral development in the
setting of carotid occlusion and therefore increase stroke risk
• Several papers have found that the pre-morbid use of statins
is associated with better collateral flow in patients with
acute ischemic stroke
Hedera P et al. Stroke risk factors and development of collateral
flow in carotid occlusive disease. Acta Neurol Scand. 1998;98:182–
186
Lee M.J. et al. Role of statin in atrial fibrillation-related stroke: an
angiographic study for collateral flow. Cerebrovascular diseases
(Basel, Switzerland) 2014; 37:77-84.
Sargento-Freitas J et al. Preferential effect of premorbid statins
on atherothrombotic strokes through collateral circulation
enhancement. European neurology2012; 68:171-176
88. • Additionally, hemodynamic factors like arterial
blood pressure, central venous pressure,
intracranial pressure and distal micro-emboli can
alter the functionality of the collateral flow
Liebeskind D.S. Collateral therapeutics for cerebral ischemia. Expert
review of neurotherapeutics 2004; 4:255-265.
89. Two separate pathological processes have
been identified after an arterial occlusion
1)Arteriogenesisis(development of functional collateral
flow from pre-existing arterial anastomoses)
• This process starts immediately after the arterial
occlusion
• Opening of the anastomoses induced by mechanical
forces and involves endothelial cell activation,
infiltration of inflammatory cells and subsequent
inflammatory response leading to structural remodeling
and increased diameter
2. Angiogenesisis
• A much slower process that involves the proliferation of
endothelial cells and formation of new vessel
90. Temporal profile of development of
LMCs in acute ischemic stroke
• Yamashita et al 29 (1996) used Xenon enhanced CT rCBF
measurement with acetazolamide challenge in patients
with ICA stenosis and demonstrated that LMCs develop to
some extent immediately after occlusion and continue to
develop for some time
• The presence of secondary collateral pathways is
usually a marker of impaired cerebral hemodynamics.
• Secondary collateral pathways that require time to
develop are presumed to be recruited once primary
collaterals at the circle of Willis are inadequate
91. By understanding the role of LMA in acute stroke,
two avenues of research are opened.
• First, evaluation of collateral flow in the acute
setting can improve the clinical results of
revascularization treatments by helping identify
patients who benefit best and possibly extending
the currently accepted time window
• Second, a new generation of stroke treatments
can be developed, with the aim to improve
collateral flow.