scholarly journals Anatomical Variations of the Circulus Arteriosus in Cadaveric Human Brains

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
S. A. Gunnal ◽  
M. S. Farooqui ◽  
R. N. Wabale
Keyword(s):  
Internal Carotid ◽  
Anatomical Variations ◽  
Circle Of Willis ◽  
Normal Pattern ◽  
Surgical Interventions ◽  
Morphological Variations ◽  
Vertebrobasilar System ◽  
Different Types ◽  
Human Brains ◽  
The Brain

Objective. Circulus arteriosus/circle of Willis (CW) is a polygonal anastomotic channel at the base of the brain which unites the internal carotid and vertebrobasilar system. It maintains the steady and constant supply to the brain. The variations of CW are seen often. The Aim of the present work is to find out the percentage of normal pattern of CW, and the frequency of variations of the CW and to study the morphological and morphometric aspects of all components of CW.Methods. Circulus arteriosus of 150 formalin preserved brains were dissected. Dimensions of all the components forming circles were measured. Variations of all the segments were noted and well photographed. The variations such as aplasia, hypoplasia, duplication, fenestrations, and difference in dimensions with opposite segments were noted. The data collected in the study was analyzed.Results. Twenty-one different types of CW were found in the present study. Normal and complete CW was found in 60%. CW with gross morphological variations was seen in 40%. Maximum variations were seen in the PCoA followed by the ACoA in 50% and 40%, respectively.Conclusion. As it confirms high percentage of variations, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in neurovascular procedures.

Computational Fluid Dynamics Simulation of the Blood Flow in the Circle of Willis

2002 ◽  
Author(s):  
M. Harazawa ◽  
T. Yamaguchi
Keyword(s):  
Blood Flow ◽  
Blood Supply ◽  
Internal Carotid ◽  
Complex Geometry ◽  
Cerebral Aneurysms ◽  
Cerebrovascular Diseases ◽  
Circle Of Willis ◽  
Dynamics Simulation ◽  
The Brain ◽  
Internal Carotid Arteries

The blood supply for the brain is born by four arteries, that is, two internal carotid arteries and two vertebral arteries. They are mutually connected at the cerebral base, and form a closed arterial circle, called the circle of Willis, so that the safety of the brain blood supply is increased. However their anastomoses show a very wide variety of atypism. If some of anastomses are very thin, or even do not exist, the safety of the blood supply is not secured. This is particularly important when some diseases such as cerebral thrombosis occurs and the blood flow supply stops unilaterally. Redistribution of the blood supply in such cases is thought to be strongly affected by geometrical configuration of the anastomoses. It is also known that cerebral aneurysms, which may induce serious cerebrovascular diseases, preferentially occur at the circle of Willis. Complex blood flow pattern has been suspected of having an influence on this preference. This is again dependent on complex geometry of the circle.

scholarly journals Vertebrobasilar Contribution to Cerebral Arterial System of Dromedary Camels (Camelus dromedarius)

2021 ◽  
Vol 8 ◽  
Author(s):  
Ahmad Al Aiyan ◽  
Preetha Menon ◽  
Adnan AlDarwich ◽  
Moneeb Qablan ◽  
Maha Hammoud ◽  
...  
Keyword(s):  
Basilar Artery ◽  
Doppler Ultrasonography ◽  
Internal Carotid ◽  
Color Doppler ◽  
Arterial System ◽  
Vertebrobasilar System ◽  
Arterial Blood ◽  
Polyurethane Resin ◽  
Basilar Arteries ◽  
The Brain

It is hypothesized that in the “more highly evolved” mammals, including the domesticated mammals, that the brainstem and the cerebellum receive arterial blood through the vertebrobasilar system whilst the internal carotid arteries primarily supply the forebrain. In camels, the arterial blood supply to the brain differs from that of ruminants since the internal carotid artery and the rostral epidural rete mirabile (RERM) are both present and the basilar artery contributes a significant proportion of cerebral afferent blood. In this study, we described the anatomical distribution of the vertebrobasilar system arterial supply in the dromedary. Secondly, we determined the direction of blood flow within the vertebral and basilar arteries using transcranial color doppler ultrasonography. Thirdly, we quantified the percentage arterial contributions of the carotid and vertebrobasilar systems to the dromedary brain. Fifty-five heads of freshly slaughtered male Omani dromedaries aged 2–6 years were dissected to determine the distribution and topography of the arterial distribution to the brain. Their anatomical orientation was assessed by casting techniques using epoxy resin, polyurethane resin and latex neoprene. The epoxy resin and polyurethane resin casts of the head and neck arteries were used to measure the diameter of vertebrobasilar arterial system and carotid arterial system at pre-determined locations. These arterial diameters were used to calculate the percentage of blood supplied by each arterial system. The vertebrobasilar system in dromedary camels consists of paired vertebral arteries that contribute to the ventral spinal artery and basilar artery at multiple locations. In most specimens the vertebral artery was the primary contributor to the basilar artery compared to that of the ventral spinal artery. In four specimens the ventral spinal arteries appear to be the dominant contributor to the basilar artery. Transcranial color doppler ultrasonography confirmed that the direction of blood flow within the vertebral and basilar arteries was toward the brain in animals examined in ventral recumbency and when standing. The vertebrobasilar system contributes 34% of the blood supply to the brain. The vertebrobasilar system is the exclusive supply to the medulla oblongata, pons and cerebellum.

scholarly journals Study of the blood supply of the brain in sheep

1999 ◽  
Vol 23 (1) ◽  
pp. 59-66
Author(s):  
Khalid Kamil Kadhum
Keyword(s):  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Blood Supply ◽  
Basilar Artery ◽  
Internal Carotid ◽  
Ventral Surface ◽  
Circle Of Willis ◽  
Maxillary Artery ◽  
Cerebellar Artery ◽  
The Brain

The brain of the sheep receives its blood supply through the carotid rete and the basilar artery. The carotid rete formed of contribution of internal carotid artery and branches from maxillary artery. The internal carotid artery courses on the ventral surface of the cerebal crus to give the rostral cerebal artery and the caudal communicating artery . Thus , arteries excepted the middle cerebal artery forming with the same arteries of the opposite side , the cerebal arterial circle or circle of Willis. The internal caroted artery also gives off hypophysialartery to the  1999 ind, (1) swell, ügymielly wel dati', il pellilendiambell ileti  hypophysis. The caudal communicating artery give off the caudal cerebal artery and the rostral cerebellar artery and unite with the corresponding artery of the opposite side to form the basilar artery rostral to the pone . The basilar artery gives off the pontine artery , caudal cerebellar artery and the medullary branch. 

scholarly journals Anatomical variations of circle of Willis - a cadaveric study

2017 ◽  
Vol 4 (4) ◽  
pp. 1249 ◽  
Author(s):  
Ramanuj Singh ◽  
Ajay Babu Kannabathula ◽  
Himadri Sunam ◽  
Debajani Deka
Keyword(s):  
Cerebral Artery ◽  
Anterior Cerebral Artery ◽  
Anterior Part ◽  
Cerebral Arteries ◽  
Anatomical Variations ◽  
Circle Of Willis ◽  
Anterior Communicating Artery ◽  
Surgical Interventions ◽  
Collateral Channel ◽  
The Right

Background: The circle of Willis (CW) is a vascular network formed at the base of skull in the interpeduncular fossa. Its anterior part is formed by the anterior cerebral artery, from either side. Anterior communicating artery connects the right and left anterior cerebral arteries. Posteriorly, the basilar artery divides into right and left posterior cerebral arteries and each join to ipsilateral internal carotid artery through a posterior communicating artery. Anterior communicating artery and posterior communicating arteries are important component of circle of Willis, acts as collateral channel to stabilize blood flow. In the present study, anatomical variations in the circle of Willis were noted.Methods: 75 apparently normal formalin fixed brain specimens were collected from human cadavers. 55 Normal anatomical pattern and 20 variations of circle of Willis were studied. The Circles of Willis arteries were then colored, photographed, numbered and the abnormalities, if any, were noted.Results: Twenty variations were noted. The most common variation observed is in the anterior communicating artery followed by some other variations like the Posterior communicating arteries, Anterior cerebral artery and posterior cerebral artery (PCA) was found in 20 specimens.Conclusions: Knowledge on of variations in the formation of Circle of Willis, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in the neurovascular procedures.

Computations by different types of brain, and by artificial neural systems

2020 ◽  
pp. 609-633
Author(s):  
Edmund T. Rolls
Keyword(s):  
Food Intake ◽  
Brain Function ◽  
Neural Systems ◽  
Different Types ◽  
Computer Scientists ◽  
Artificial Neural Systems ◽  
Artificial Neural ◽  
Human Brains ◽  
The Brain ◽  
Intake Control

In this Chapter a comparison is made between computations in the brain and computations performed in computers. This is intended to be helpful to those engineers, computer scientists, AI specialists et al interested in designing new computers that emulate aspects of brain function. In fact, the whole of this book is intended to be useful for this aim, by setting out what is computed by different brain systems, and what we know about how it is computed. It is essential to know this if an emulation of brain function is to be performed, and this is important to enable this group of scientists to bring their expertise to help understand brain function more. The Chapter also considers the levels of investigation, which include the computational, necessary to understand brain function; and some applications of this understanding, to for example how our developing understanding is relevant to understanding disorders, including for example of food intake control leading to obesity. Finally, Section 19.10 makes it clear why the focus of this book is on computations in primate (and that very much includes human) brains, rather than on rodent (rat and mice) brains. It is because the systems-level organization of primate including human brains is quite different from that in rodents, in many fundamental ways that are described.

MODELING REDISTRIBUTION CEREBRAL CIRCULATION

2021 ◽  
Vol 1 (4) ◽  
pp. 13-18
Author(s):  
Vladislav Nikolaevich Nikitin ◽  
◽  
Ekaterina Valerevna Kozhemyakina ◽  
Keyword(s):  
Blood Flow ◽  
Internal Carotid ◽  
Cerebral Arteries ◽  
Circle Of Willis ◽  
Entire Body ◽  
Compensatory Mechanisms ◽  
Vertebral Arteries ◽  
The Central Nervous System ◽  
Flow Through ◽  
The Brain

The brain is one of the most important organs responsible for the health and functioning of the entire body. The blood supply to the brain is carried out through 2 internal carotid and 2 vertebral arteries in norm. The brain, like other body systems, has protective (compensatory) mechanisms aimed at maintaining the necessary blood flow, one of which is the circle of Willis. The article proposes a mechanism for how blood flow is redistributed through the arteries feeding the brain, which is based on the assumption that the central nervous system controls in such a way that it minimizes flows through the connective arteries of the circle of Willis, the flows along which are normal (with symmetry of the left and right sides) practically equal to zero. Сase of the structure of the circle of Willis is considered in norm. The indicated redistribution mechanism is still only the first step towards an attempt to predict cases of changes in blood flow through the cerebral arteries, especially in stroke. In further works, it is planned to consider the inverse problem, i.e. determine the flows through the internal carotid and vertebral arteries, provided that the flows through the cerebral arteries extending from the circle of Willis have normal flow values.

An Experimental Study of the Effects Anatomical Variations Have on Collateral Flows Within the Circle of Willis

2011 ◽  
Author(s):  
Paul Fahy ◽  
Patrick Delassus ◽  
Padraig O’Flynn ◽  
Liam Morris
Keyword(s):  
Experimental Study ◽  
Blood Flow ◽  
Cerebral Arteries ◽  
Anatomical Variations ◽  
Flow Patterns ◽  
Circle Of Willis ◽  
Collateral Flow ◽  
Arterial Network ◽  
Flow Feature ◽  
The Brain

The circle of Willis (CoW) is a complex arterial network comprising of major cerebral arteries that converge to form a pentagonal arrangement as shown in Figure 1(A). This arterial network supplies oxygen-enriched blood to the brain. An incomplete CoW can exist in up to 50% of cases [1]. These missing vessels can be accommodated by the collateral flow feature within the CoW configuration. In certain circumstances, anatomical variations within the CoW can result in undesirable flow patterns [2–3]. It is unclear from the literature what effects these variations can have on blood flow collision paths within a complete CoW.

A neurosurgical view of anatomical variations of the distal anterior cerebral artery: an anatomical study

2006 ◽  
Vol 104 (2) ◽  
pp. 278-284 ◽  
Author(s):  
Hasan Caglar Ugur ◽  
Gokmen Kahilogullari ◽  
Ali Firat Esmer ◽  
Ayhan Comert ◽  
Aysun B. Odabasi ◽  
...  
Keyword(s):  
Cerebral Artery ◽  
Anterior Cerebral Artery ◽  
Cerebral Arteries ◽  
Anatomical Study ◽  
Anatomical Variations ◽  
Main Trunk ◽  
Surgical Interventions ◽  
Parietal Lobes ◽  
Distal Anterior Cerebral Artery ◽  
Human Brains

Object The vascularization pattern of the anatomy of the distal anterior cerebral artery (ACA) remains a subject of debate. The authors provide detailed information about the distal ACA and shed light on issues concerning it that have not previously been adequately discussed. Methods Fifty adult human brains (100 hemispheres) were obtained during routine autopsies. Cerebral arteries were separately cannulated and injected with latex. The vascularization patterns of the cortical branches and the variations of the arteries were investigated. The authors found that the distal ACA supplied all the inner surfaces of the frontal and parietal lobes and a median of one third of the outer surfaces. The origin of the arteries from the main trunk and their exit angles affected the vascularization patterns of the hemispheres. The authors redefine controversial terminology regarding the callosomarginal artery. Conclusions In each hemisphere, the vascularization pattern of the distal ACA is different to a greater or lesser extent. An awareness of this fact will contribute significantly to surgical interventions.

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