Evaluación morfológica y variaciones del circulo arterial cerebral: un estudio con material cadavérico en una muestra de población colombianas / Morphological evaluation and variations of the cerebral arterial circle: a study with cadaveric material in a Colombian population sample

RESUMEN: El círculo arterial cerebral (CAC) mencionado también como polígono de Willis es una red de anastomosis vascular situado en la base del cerebro, constituido por ramas de la arteria carótida interna (ACI) y del sistema vertebro-basilar. Este estudio evaluó la morfología de las arterias que conforman el CAC en una muestra de individuos colombianos. Previa canalización de la ACI y de la arteria vertebral (AV), se perfundió con resina poliéster (palatal 85 % y estireno 15 %) los lechos vasculares del CAC de 70 encéfalos extraídos de cadáveres a quienes se les practicó necropsia en el Instituto de Medicina Legal de Bucaramanga, Colombia. La arteria comunicante anterior (ACoA) se observó en 68 encéfalos (97,1 %), con ausencia en 2 de las muestras (2,9 %); en promedio su diámetro fue de 1,91?1,04 mm y su longitud 2,21?0,97 mm respectivamente. Asimismo, se encontró hipoplasia en 6 muestras (8,4 %). La arteria comunicante posterior (ACoP) estuvo ausente en 2 de las muestras (5,7 %); su longitud fue 11,63?2,12 mm, mientras que su calibre fue de 1,21?0,58 mm, siendo ligeramente mayor en el lado derecho, sin diferencias estadísticamente significativas con relación al lado de presentación (p= 0,763). Se encontró hipoplasia de la ACoP en forma bilateral en 19 de las muestras (27,1 %) y unilateral en 15 muestras (21,4 %). En 8 muestras (20 %) de 35 CAC evaluados se observó configuración fetal. La incidencia de hipoplasia de la ACoP y de configuración fetal encontrados en el presente estudio, se ubican en el segmento superior de lo reportado en la literatura. Estas expresiones morfológicas han sido consideradas como coadyuvantes en el desarrollo de accidentes cerebro-vasculares (ACV).

SUMMARY: The cerebral arterial circle (CAC), also referred to as the polygon of Willis is a network of vascular anastomoses located at the base of the brain, consisting of branches of the internal carotid artery (ICA) and the vertebrobasilar system (VBS). This study evaluated the morphology of the arteries forming the CAC in a sample of Colombian individuals. After cannulation of the ICA and the vertebral artery (VA), the vascular beds of the ACC of 70 brains extracted from cadavers at the Institute of Legal Medicine of Bucaramanga, Colombia, were perfused with polyester resin (85 % palatal and 15 % styrene). The anterior communicating artery (ACoA) was observed in 68 brains (97.1 %), with absence in 2 of the samples (2.9 %); on average its diameter was 1.91?1.04mm and its length 2.21?0.97mm respectively. Likewise, hypoplasia was found in 6 samples (8.4 %). The posterior communicating artery (ACoP) was absent in 2 of the samples (5,7 %); its length was 11.63?2.12mm, while its caliber was 1.21?0.58mm, being slightly larger on the right side, with no statistically significant differences in relation to the side of presentation (p= 0.763). Hypoplasia of the ACoP was found bilaterally in 19 of the samples (27.1 %) and unilaterally in 15 samples (21.4 %). Fetal configuration was observed in 8 samples (20 %) of 35 CACs evaluated. The incidence of ACoP hypoplasia and fetal configuration found in the present study are in the upper segment of those reported in the literature. These morphological expressions have been considered as coadjuvants in the development of cerebrovascular accidents (CVA).

Anatomic study of the arterial vascularization of the brain base of paca (Cuniculus paca) / Estudo anatômico da vascularização arterial da base do encéfalo da paca (Cuniculus paca)

Paca (Cuniculus paca Linnaeus, 1766), rodent belong to the Cuniculidae family, has encouraged numerous scientific researches and for this reason could be an experimental model in both human and veterinary areas. And recently, the economic exploitation of the meat cuts, has being direct implication in its zootechnical importance. However, no anatomical descriptions regarding the vascularization of the base of the brain in this rodent has being found. Thus, the aim of the present study was to describe the arteries and the pattern of the vasculature and to compare it with the other species already established in the literature. For this, five pacas, donated by the Unesp Jaboticabal Wildlife Sector, were euthanized followed by the vascular arterial system was injected with red-stained-centrifuged latex by the common carotid artery. After craniectomy, the brains were removed and the arteries were identified and, in addition, compared with those described in other animal species. The presence of the right and left vertebral arteries, close to the medulla oblongata, was detected, originating the basilar artery, which divided into the terminal branches of the right and left basilar artery. Ventral to the optic tract there was the right internal carotid artery and the left, dividing the middle cerebral artery and left rostral and right; dorsal to the optic chiasm, the medial branch of the rostral cerebral arteries was identified. Based on the results, it is concluded that the vascularization of the paca brain base is supplied by the carotid and vertebrobasilar system.(AU)

A paca (Cuniculus paca Linnaeus 1766), roedor da família Cuniculidae, tem encorajado inúmeras pesquisas científicas, tornando-a modelo experimental tanto na área humana quanto na veterinária, além da recente exploração econômica de seus cortes cárneos, que favoreceu diretamente sua importância zootécnica. No entanto, não há até o momento, descrições anatômicas referentes à padronização da vascularização da base do encéfalo neste roedor. Assim, o objetivo do presente trabalho foi realizar tal delineamento arterial nessa região do sistema nervoso central e compará-lo com as demais espécies já estabelecidas na literatura. Para isso, foram eutanasiadas cinco pacas doadas pelo setor de Animais Silvestres da Unesp Jaboticabal, as quais foram submetidas posteriormente à injeção de látex centrifugado e corante líquido xadrez vermelho, pela artéria carótida comum. Após craniectomia e segregação do encéfalo de todos os cadáveres, realizou-se a identificação das artérias presentes na base deste órgão e, ademais, comparação destas com as descritas cientificamente em outras espécies animais. Detectou-se a presença das artérias vertebral direita e esquerda, próximas à medula oblonga, originando a artéria basilar, que se dividiu nos ramos terminais da artéria basilar direito e esquerdo. Ventral ao trato óptico verificou-se a artéria carótida interna direita e esquerda dividindo-se na artéria cerebral média e rostral direita e esquerda; ainda, dorsal ao quiasma óptico, identificou-se o ramo medial das artérias cerebrais rostrais. Com base nos resultados obtidos, conclui-se que a vascularização da base do encéfalo da paca é suprida pelo sistema carotídeo e vertebro-basilar.(AU)

Morphological evaluation of the distal medial striate artery. A study with cadaveric material / Evaluación morfológica de la arteria estriada medial distal. Un estudio con material cadavérico

Abstract Objective: To evaluate the morphology of the distal medial striated artery, taking into account biometric variables useful for clinical and surgical management. Methods: A descriptive transversal study was performed with a sample of brains, who underwent autopsy at the Institute of Legal Medicine and Forensic Sciences of Bucaramanga-Colombia, which were evaluated using the perfusion technique of vascular structures with polyester resin. Results: The distal medial striated artery was presented in 1.4% and 4.2% duplicated in the right and left hemispheres respectively. Agenesis was presented in 2.8% in the left hemisphere. Its origin was 44.6% of the anterior cerebral artery junction site with the anterior communicating artery and was observed in 6 cases (4.2%) presented with a common trunk with the orbitofrontal artery. The main qualitative finding was the sinuous trajectory that was observed in 57.7% on the right side and 45.1% in the left hemisphere. Also, an important alteration found at the biometric analysis was hypoplasia that could be related to the decreased blood supply to the basal nuclei. The diameter was 0.5 ± 0.2 mm and its total length was 20.3 ± 4.1 mm. Conclusions: The topographical knowledge of this structure determines the vulnerability of its morphology because it can complicate surgical procedures performed in the anterior segment of the arterial circle of the brain. Besides, the observed collateral circulation contributes to the blood supply and the perfect functionality of the subcortical nervous structures.

Resumen Objetivo: Evaluar la morfología de la arteria estriada medial distal, teniendo en cuenta variables biométricas útiles para el manejo clínico y quirúrgico. Métodos: Estudio descriptivo transversal con una muestra de cerebros que fueron sometidos a autopsia en el Instituto de Medicina Legal y Ciencias Forenses de Bucaramanga-Colombia, fueron evaluados mediante la técnica de perfusión de estructuras vasculares con resina de poliéster. Resultados: La arteria estriada medial distal se presentó en 1.4% y 4.2% duplicada en el hemisferio derecho e izquierdo respectivamente. Agenesia se presentó en 2.8% en el hemisferio izquierdo. Su origen fue 44.6% del sitio de unión de la arteria cerebral anterior con la arteria comunicante anterior y se observó en 6 casos (4.2%) que presentaban un tronco común con la arteria orbitofrontal. El hallazgo principal fue la trayectoria sinuosa que se observó en 57.7% en el lado derecho y 45.1% en el hemisferio izquierdo. También una alteración importante encontrada en el análisis biométrico fue la hipoplasia que podría estar relacionada con la disminución del suministro de sangre a los núcleos basales. El diámetro fue de 0.5 ±0.2 mm y su longitud total fue de 20.3 ±4.1 mm. Conclusiones: El conocimiento topográfico de esta estructura determina la vulnerabilidad de su morfología, porque puede complicar los procedimientos quirúrgicos realizados en el segmento anterior del círculo arterial del cerebro. Además, la circulación colateral observada contribuye al riego sanguíneo y al perfecto funcionamiento de las estructuras nerviosas subcorticales.

Systematization, distribution, and territories of the caudal cerebral artery on the surface of the brain in nutria (Myocastor coypus) / Sistematização, distribuição e territórios da artéria cerebral caudal na superfície do cérebro em Nutria (Myocastor coypus)

The nutria (Myocastor coypus) is a medium-sized, semi-aquatic rodent valued by the skin and meat industry. This study aimed to describe and systematize the caudal cerebral artery on the brain surface in nutria, establishing a standard model and its main variations in this species. The thirty animals used were euthanized according to animal welfare rules. The vessels were filled with latex stained with red pigment and the samples were fixed in formaldehyde. In nutria, the brain was vascularized by the vertebral basilar system. The terminal branches of the basilar artery originated the rostral cerebellar, caudal cerebral, rostral choroidal and middle cerebral arteries, and its terminal branch, the rostral cerebral artery. The terminal branch of the basilar artery projected the caudal cerebral artery, which is usually a single medium-caliber vessel, into the transverse fissure of the brain. The caudal cerebral artery was presented as a single (66.7% of the cases to the right and 76.7% to the left) and double vessel (33.3% of the cases to the right and 23.3% to the left). It originated the rostral mesencephalic artery, the proximal component, and the caudal inter-hemispheric artery. The terminal branches of the rostral and caudal tectal mesencephalic arteries formed a typical anastomotic network. The caudal inter-hemispheric artery emitted central branches, the caudal choroidal artery, hemispherical occipital arteries, rostral tectal mesencephalic branches and distal components, and anastomosed "in osculum" with the terminal branches of the rostral inter-hemispheric artery. The caudal choroidal artery anastomosed with the rostral choroidal artery, where it branched out on the thalamic mass, vascularizing all diencephalic structures and the hippocampus. The caudal cerebral artery and its terminal branches anastomosed with the terminal branches of the rostral and middle cerebral arteries in a restricted region of the caudal pole of the cerebral hemisphere. The vascularization area of the caudal cerebral artery and its central branches in the paleopallial of the piriform lobe is extremely restricted, caudomedially.(AU)

A nutria (Myocastor coypus) é um roedor semi-aquático de tamanho mediano, apreciado na indústria de peles e carne. Este trabalho tem por objetivo descrever e sistematizar a artéria cerebral caudal na superfície do cérebro em nutria, estabelecendo um modelo padrão e suas principais variações e territórios nesta espécie. Os trinta animais utilizados foram eutanasiados segundo as regras de bem-estar animal, os vasos foram preenchidos com látex, corado em vermelho e as peças foram fixadas em formoldeído. O cérebro foi vascularizado exclusivamente pelo sistema vértebro-basilar. Os ramos terminais da artéria basilar originaram as artérias cerebelar rostral, cerebral caudal, corióidea rostral, cerebral média e seu ramo terminal, a artéria cerebral rostral. O ramo terminal da artéria basilar lançou a artéria cerebral caudal, um vaso normalmente único, de médio calibre, para o interior da fissura transversa do cérebro. A artéria cerebral caudal foi um vaso único em 66,7% à direita e em 76,7% à esquerda e mostrou-se dupla em 33,3% à direita e em 23,3% à esquerda. Ela lançou a artéria tectal mesencefálica rostral, componente proximal e a artéria inter-hemisférica caudal. Os ramos terminais das artérias tectais mesencefálicas, rostral e caudal, formavam uma rede anastomótica típica. A artéria inter-hemisférica caudal lançou ramos centrais, a artéria corióidea caudal, as artérias hemisféricas occipitais, os ramos tectais mesencefálicos rostrais, componentes distais e anastomosou-se "em ósculo" com o ramo terminal da artéria inter-hemisférica rostral. A artéria corióidea caudal anastomosava-se com a artéria corióidea rostral, onde ramificavam-se sobre a massa talâmica, vascularizando todas as estruturas do diencéfalo e hipocampo. A artéria cerebral caudal com seus ramos terminais apresenta anastomoses com os ramos terminais das artérias cerebrais rostral e média em uma região restrita do pólo caudal do hemisfério cerebral. A área de vascularização da artéria cerebral caudal com seus ramos centrais no páleo-palio do lobo piriforme é extremamente restrita, caudo-medialmente ao mesmo.(AU)

Prevalencia de la arteria estriada medial distal en una muestra de poblaciones Colombiana y Peruana / Prevalence of distal medial striatal artery in a sample of Colombian and Peruvian populations

La arteria estriada medial distal hace parte de la circulación encefálica, nace de la arteria cerebral anterior generalmente a nivel de la arteria comunicante anterior, aunque según distintos estudios su origen varía, siendo así difícil de determinar con exactitud. Su importancia clínica radica en la prevalencia de aneurismas encontrados en esta arteria, que posteriormente podrían causar complicaciones debido a la región que irrigan, siendo estas las secuelas somático-vitales y neuropsicológicas, además de su inadecuado abordaje quirúrgico sin prever las alteraciones que puedan ser ocasionados; a causa de lo anterior es de vital importancia que los profesionales de la salud tengan previo conocimiento de la anatomía y la prevalencia de esta arteria en la población. Se realizó un estudio observacional de tipo descriptivo en donde se analizó la arteria estriada medial distal en 70 encéfalos, piezas de los anfiteatros de Medicina de la Universidad de Ciencias Aplicadas y Ambientales U.D.C.A. (Bogotá), la Universidad Científica del Sur UCSUR (Lima); fijados en formol al 10 %, se realizaron mediciones morfométricas mediante calibrador digital y se tomó el registro fotográfico con una cámara Canon. Posteriormente se ejecutó el análisis estadístico mediante el programa IBM SPSS Stadistics 24. Se encontró una prevalencia del 88,6 % de al menos una arteria estriada medial distal en población colombiana y un 97,1 % de la población peruana. Se identificó un diámetro externo promedio de 0,64 mm en población colombiana y de 0,68 mm en población peruana. Se observó una longitud promedio de 2,5 cm en ambas poblaciones. Se evidenció el mayor lugar de origen en la porción A2 de la ACA con un 37,1 % de población colombiana y un 51,4 % de población peruana. Se debe conocer adecuadamente la anatomía y las correspondientes variaciones anatómicas de esta arteria para así poder realizar un adecuado abordaje neurológico y neuroquirúrgico.

The distal medial striate artery is part of the brain circulation, born from the anterior cerebral artery generally at the level of the anterior communicating artery, although according to different studies its origin varies, being thus difficult to determine with accuracy. Its clinical importance lies in the prevalence of aneurysms found in this artery, which could later cause complications due to the region they irrigate, these being the somatic-vital and neuropsychological sequelae, in addition to its inadequate surgical approach without foreseeing the alterations that may be caused; Because of the above it is of vital importance that health professionals have prior knowledge of the anatomy and prevalence of this artery in the population. An observational descriptive study was carried out in which the distal medial striated artery in 70 brain cells, pieces from the Medicine amphitheatres of the Universidad de Ciencias Aplicadas y Ambientales U.D.C.A. (Bogotá), the Universidad Científica del Sur UCSUR (Lima); fixed in 10 % formalin, morphometric measurements were made by automatic calibrator and the photographic record was taken with a Canon camera. Subsequently, the statistical analysis was executed through the IBM SPSS Statistics program 24. A prevalence of 88.6 % of at least one distal medial striate artery was found in the Colombian population and 97.1 % of the Peruvian population. An average external diameter of 0.64 mm was identified in the Colombian population and 0.68 mm in the Peruvian population. An average length of 2.5 cm was observed in both populations. The largest place of origin was evidenced in the A2 portion of the ACA with 37.1 % of the Colombian population and 51.4 % of the Peruvian population. The anatomy and the corresponding anatomical variations of this artery must be adequately known to be able to perform an adequate neurological and neurosurgical approach.

Morphological configuration and topography of the brain arterial supply of the one-humped camel ( Camelus dromedarius, Linnaeus 1758) / Configuración morfológica y topografía del suministro arterial del encéfalo del camello de una joroba ( Camelus dromedarius, Linnaeus 1758)

This study investigated the anatomy of the arteries of the brain, including the arterial circle of the brain, its branches and junctions, in five camel (Camelus dromedarius, Linnaeus 1758) following intravascular injection of colored latex via common carotid artery. The course and distribution of the arterial supply to the brain was described and morphological analysis was made. The basilar artery contributed to the blood supply of the brain in the camel in contrast to the situation in other Artiodactyla order.

En presente estudio se analizó la anatomía de las arterias del encéfalo en cinco camellos (Camelus dromedarius, Linnaeus 1758). Después de administrar una inyección intravascular de látex coloreado en la arteria carótida común se estudiaron las arterias incluyendo al círculo arterial del cerebro, sus ramas y uniones. Fueron descritos en detalle el curso y la distribución del suministro arterial al encéfalo y se realizó un análisis morfológico. La arteria basilar contribuyó al suministro de sangre del encéfalo del camello, diferenciando este aspecto en otras especies de Artiodactyla.

Comparison of cerebral artery angle in adults and fetuses / Comparación del ángulo de arteria cerebral en adultos y fetos

In this study we generated casting specimens of human cerebral blood vessels for twenty-five fetuses and thirty-six adults. The degrees of the angles were measured and comprised for those blood vessels frequently involved in the interventional catheterization.

En este estudio generamos muestras de los vasos sanguíneos cerebrales humanos en veinticinco fetos y treinta y seis adultos. Fueron medidos y comprendidos los ángulos de aquellos vasos sanguíneos implicados frecuentemente en intervenciones de cateterismo.

Systematization, distribution and territory of the caudal cerebral artery on the brain's surface of the turkey (Meleagris gallopavo) / Sistematização, distribuição e território da artéria cerebral caudal na superfície do encéfalo em peru (Meleagris gallopavo)

Thirty Meleagris gallopavo heads with their neck segments were used. Animals were contained and euthanized with the association of mebezonium iodide, embutramide and tetracaine hydrochloride (T 61, Intervet ) by intravenous injection. The arterial system was rinsed with cold saline solution (15°C), with 5000IU heparin and filled with red-colored latex. The samples were fixed in 20% formaldehyde for seven days. The brains were removed with a segment of cervical spinal cord and after, the dura-mater was removed and the arteries dissected. The cerebral carotid arteries, after the intercarotid anastomosis, were projected around the hypophysis, until they reached the tuber cinereum and divided into their terminal branches, the caudal branch and the rostral branch. The rostral branch was projected rostrolateralwards and gave off, in sequence, two collateral branches, the caudal cerebral and the middle cerebral arteries and the terminal branch was as cerebroethmoidal artery. The caudal cerebral artery of one antimere formed the interhemispheric artery, which gave off dorsal hemispheric branches to the convex surface of both antimeres. Its dorsal tectal mesencephalic branch, of only one antimere, originated the dorsal cerebellar artery. In the interior of the cerebral transverse fissure, after the origin of the dorsal tectal mesencephalic artery, the caudal cerebral artery emitted occipital hemispheric branches, pineal branches and medial hemispheric branches, on both antimeres. The caudal cerebral artery's territory comprehended the entire surface of the dorsal hemioptic lobe, the rostral surface of the cerebellum, the diencephalic structures, the caudal pole and the medial surface of the cerebral hemisphere and in the convex surface, the sagittal eminence except for its most rostral third. Due to the asymmetry found in the caudal cerebral arteries' ramifications, the models were classified into three types and their respective subtypes.

Foram utilizadas 30 cabeças com o segmento de pescoço deMeleagris gallopavo. Os animais foram contidos e eutanasiados com a associação de iodeto de mebezônio, embutramida e cloridrato de tetracaína (T 61 Intervet ), via endovenosa. O sistema arterial foi lavado com solução salina resfriada (15°C), com 5000UI heparina e preenchido com látex corado em vermelho. As peças foram fixadas em formaldeído a 20% por sete dias. O encéfalo foi removido com um segmento de medula espinhal, a dura-máter removida e as artérias dissecadas. As artérias carótidas do cérebro, após a anastomose intercarótica, projetaram-se contornando a hipófise até alcançarem o túber cinéreo e dividiram-se em seus ramos terminais, o ramo caudal e o ramo rostral. O ramo rostral projetou-se rostro-lateralmente emitindo em sequência seus dois principais ramos colaterais, as artérias cerebral caudal e cerebral média terminado-se como artéria cerebroetmoidal. A artéria cerebral caudal de um antímero formava a artéria inter-hemisférica que lançava ramos hemisféricos dosais para a face convexa de ambos os antímeros. Seu ramo tectal mesencefálico dorsal de apenas um antímero originava a artéria cerebelar dorsal. No interior da fissura transversa do cérebro após a origem da artéria tectal mesencefálica dorsal artéria cerebral caudal lançou ramos hemisféricos occipitais, ramos pineais e hemisféricos mediais em ambos os antímeros. O território da artéria cerebral caudal compreendeu toda a superfície do hemi lobo óptico dorsal, a face rostral do cerebelo, as estruturas diencefálicas, o polo caudal e a face medial do hemisfério cerebral e na face convexa do hemisfério cerebral a eminência sagital exceto seu terço mais rostral. Devido à assimetria encontrada nas ramificações das artérias cerebrais caudais, foram classificados os modelos em três tipos com seus respectivos subtipos.

Variations in the brain circulation: the circle of Willis

Introduction: Despite being quite common, there is little information concerning the Brazilian population on anatomic variations and anomalies in the brain circulation. This study intends to describe the most common variations found during the autopsies for the AMA Study. Material and methods: Fifty cadavers had their circle of Willis dissected and analyzed. Results: 54% presented at least one variation, and they were more common in the posterior circulation (88.5%) and on the right side of the brain (59.7%); non-classical morphology was more common bilaterally and in the posterior circulation of the circle of Willis (37.1%). The most common finding was the absence of the posterior communicating artery (32%), followed by posterior cerebral arteries originated from the internal carotid artery (18%). There were no variations in the middle cerebral arteries. Accessory anterior cerebral arteries were present in 6%, and A1 segment hypoplasia was present in only 2% of the cases. Conclusion: Brazilian population variations are in accordance with the literature and there seems to be no difference between races in the variation of brain circulation.

Anatomia microcirúrgica das artérias infratentoriais: um estudo estereoscópico / Microsurgical anatomy of the infratentorial arteries: stereoscopic printing study

CONTEXTO: O espaço infratentorial do crânio é uma região que possui complexa rede de artérias que vascularizam o tecido cerebelar e o tronco encefálico. Sua complexa anatomia tridimensional deve ser profundamente entendida pelo neurocirurgião vascular e pelo radiologista intervencionista. OBJETIVO: Descrever as principais artérias do espaço infratentorial e seu trajeto, bem como sua relação com a topografia das estruturas neurais. MÉTODOS: Foram estudados 30 cérebros humanos, fixados em formalina e 6 cabeças de cadáveres dissecadas, utilizando-se microscópico cirúrgico com 3X a 40X de aumento. Os cérebros e todas as cabeças foram injetados com siloxanos polimerizados ou polisiloxanos (silicone) colorido. As dissecções anatômicas foram documentadas utilizando-se técnica para obtenção de imagens tridimensionais (3D), objetivando a produção de impressões estereoscópicas. RESULTADOS: São descritos o trajeto, segmentos e ramos das artérias basilar, cerebelar superior, cerebelar anteroinferior, cerebelar posteroinferior e vertebral. CONCLUSÃO: A anatomia das artérias infratentoriais é complexa e as imagens estereoscópicas apresentadas são um importante instrumento de documentação, pois permitem uma noção de profundidade da anatomia estudada.

BACKGROUND: The infratentorial space is a region with a complex network of arteries supplying the cerebellum and brainstem. Its complex three-dimensional anatomy must be thoroughly understood by the vascular neurosurgeon and the interventional radiologist. OBJECTIVE: To describe the main arteries of the infratentorial space and its trajectory and its relationship to the topography of the neural structures. METHODS: We studied 30 formalin-fixed human brains and we also dissected 6 cadaver heads, using a surgical microscope with 3X to 40X magnification. The brains and all heads were injected with colored silicone. The anatomical dissections were documented with a three-dimensional method, aiming to produce stereoscopic prints. RESULTS: The neurovascular relationships, segments and branches of the basilar artery, superior cerebellar, anteroinferior cerebellar, cerebellar and posteroinferior vertebral are described. CONCLUSION: The microsurgical anatomy of the infratentorial arteries is complex and the stereoscopic images presented are an important tool for documentation.

Systematization of the brain base arteries in ostrich (Struthio camelus)

Thirty ostrich (Struthio camelus) brains were used, injected with latex, to describe the arteries of the brain base.The largest occurrences of the arteries were: The cerebral carotid artery (100%), the intercarotid anastomosis(100%). The caudal branch of the cerebral carotid artery was, on the right (R), developed (53.3%) and vestigial(46.7%); on the left (L), developed (66.7%) and vestigial (33.3%). The ventral tectal mesencephalic artery onthe R (53.3%), on the L (66.7%), direct branch of the cerebral carotid artery on the R (43.3%), on the L (30%)and, direct branch of the basilar artery (3.3%) in both antimeres. The basilar artery was a single vessel (80%),double in (13.3%) and “in island” formation (6.7%). The caudal ventral cerebellar artery was single (96.7%),double (3.3%) on the R and, single (93.3%), double (6.7%) on the L. The dorsal spinal artery was a collateralbranch of the caudal ventral cerebellar artery on the R (96.7%), on the L (93.3%). The ventral spinal artery wasdouble (90%) and single (10%). The rostral branch of the cerebral carotid artery (100%). The caudal cerebralartery, on the R, was double (90%) and single (10%); on the L, was double (53.3%) and single (46.7%). Themiddle cerebral artery was a single vessel (100%). The cerebroethmoidal artery was single (100%). The rostralcerebral artery was single (90%), double (10%) on the R and single (96.7%), double (3.3%) on the L. Thecerebral arterial circle was rostrally open (100%) and, caudally, open (80%) and closed (20%).

The AMA study (Multi-Arterial Atherosclerosis): correlation ofmalformation of cardiac and cerebral arteries

We are performing a study on the distribution of atherosclerosis in the arteries and during our dissectionswe have found arterial malformations in the brain and heart. Of these, 6 are related to the posterior cerebralarteries and 3 are related to the posterior Interventricular artery of the heart. In all these three cases, suchaforementioned abnormality in the circle of Willis also occurred. It is an interesting and unexpected findingand we are still waiting for further development in our work in order to clarify these “related” malformations.

Systematization, distribuiton and Territory of the rostral cerebral artery on the brain surface in chinchilla

The present study has analyzed thirty chinchilla (Chinchilla lanigera) brains, injected with latex, aiming tosystematize and describe the distribution and the vascularization territories of the rostral cerebral artery. Therostral cerebral artery was the terminal branch of the terminal branch, right and left, of the basilar artery,projected from the emittion of the middle cerebral artery, rostromedially, crossing dorsally the optic nerve untilit reaches the cerebral longitudinal fissure, ventrally. Its branches were distributed mostly on the paleopallium,supplying the olfactory trigone, the medial olfactory tract, the olfactory peduncle and the olfactory bulb.The branches to the neopallium vascularized the entire medial surface, except for the tenctorial part of it, thefrontal pole and a zone that was extended from the frontal to the occipital poles, medially to the vallecula,on the convex surface of the cerebral hemisphere. The first collateral branch of the rostral cerebral artery wasthe medial branch, which entered into the longitudinal fissure of the brain and continued as rostral interhemisphericartery. The rostral cerebral artery continued rostrally emitting central branches and the medialand lateral arteries of the olfactory bulb, to the paleopallial region of the chinchilla brain. After the emittion ofthe medial artery of the olfactory bulb, the rostral cerebral artery continued to follow the cerebral longitudinalfissure, as internal ethmoidal artery, its terminal branch.

Anatomia arterial intracraniana: avaliação por angiotomografia computadorizada: [revisão] / Intracranial arterial anatomy: evaluation by computed tomography angiography: [review]

Durante muitos anos, o estudo arterial intracraniano foi realizado, exclusivamente, por meio daangiografia convencional, em que há cateterização seletiva das artérias. Hoje em dia, com a evoluçãotecnológica da tomografia computadorizada por meio de multidetectores permitindo aquisições com fatias de corte cada vez mais finas, maior velocidade e melhor resolução espacial, surgiucomo nova modalidade de investigação a angiotomografia, menos invasiva e com menor morbidade que a arteriografia convencional. Muitos estudos na literatura vêm analisando a sensibilidade deste novo método na detecção de aneurismas intracranianos e comparando seus resultados com aqueles obtidos pela arteriografia convencional. Para tal, percebe-se a necessidade doreconhecimento da anatomia arterial intracraniana normal e suas variações a partir de imagenscom reformações multiplanares, objetivando o fornecimento de importantes informações paradefinição de estratégias nas abordagens cirúrgicas, tais como calcificações parietais, posição docolo aneurismático e relações com estruturas anatômicas circundantes.

By many decades, the intracranial arteries study was realized exclusively by angiography through selective arterial catheterization.Nowadays, with the technologic evaluation of computerized tomography devices with multidetectors allowing acquisitions with even more thinner slices, higher speed and better resolution, it had appeared a new modality of investigation: the computed tomography angiography, less invasive and with minor morbidity than conventional arteriography. Many studies in the literature have been analyzing the sensibility of the new method for the detection ofintracranial aneurisms and comparing them with the conventional arteriography. There is a necessity to recognize the normal intracranial arterial anatomy and its variations using images obtainedfrom multiplanar reformations, in order to give important informationfor surgeries strategies, such as wall calcifications, aneurismatic neck position and relationships with surrounding anatomical structures.

Arterias comunicantes del círculo arterial del cerebro: características biométricas y relación con el índice cefálico / Communicating arteries of the cerebral arterial circle: biometric features and their relation with the cephalic index

La clínica neuroquirúrgica tiene la necesidad de un acabado conocimiento anatómico de las arterias comunicantes como integrantes del círculo arterial del cerebro, por su variabilidad morfológica, su relación compleja con las estructuras adyacentes y por la alta frecuencia observada en la conformación de aneurismas. Debido a la importancia de estos vasos, efectuamos un estudio biométrico de los mismas, relacionando datos de calibre y longitud con índice cefálico. En el sexo masculino, el calibre promedio de la ACoP fue de 1,07 mm en el lado derecho y de 1,06 mm en el izquierdo; en el sexo femenino fue de 1,12 mm en el lado derecho y de 1,14 mm en el izquierdo. En el grupo de individuos con índice braquicéfalo, el calibre de la ACoP fue de 1,15 mm y en el grupo dolicomesocéfalo fue de 1,05 mm. Su longitud fue de 18,65 mm en los braquicéfalos y de 16,44 mm en los dolicomesocéfalos.El calibre de la ACoA fue de 1,53 mm en el sexo masculino y de 1,05 mm en el femenino, mientras que su longitud fue de 2,81 mm en el sexo masculino y de 2,33 mm en el femenino. La descripción biométrica y bioantropológica muestra parámetros importantes a considerar en la clínica quirúrgica.

The neurosurgical clinic needs extensive and thorough anatomical knowledge of the communicating arteries as part of the cerebral arterial circle for their morphological variability, their complex relation as adjacent structures, and for the frequency observed in the formation of aneurisms. Considering the importance of these vessels, we conducted a biometric study of these, relating caliber and longitude information to the cephalic index. In the male, the mean caliber of the PCoA < p was of 1.07 mm on the right side and 1.06 mm on the left; in the female it was of 1.12 mm on the right side and of 1.14 mm on the left. In the group of individuals with brachiocephalic index, the caliber of the ACoP was of 1.15 mm and in the dolichomesocephalic groups was 1.05 mm. Its longitude was 18.65 mm in the brachiocephalous and of 16.44 mm in the dolichomesochephalic. The caliber of the ACoA was of 1.53 mm in the male and 1.05 mm in the female, while its longitude was of 2.81 mm in the male and 2.33 mm in the female. The biometric and bioanthropologic description shows important parameters to be considered in clinical surgery.

Frequência da artéria caroticobasilar em equinos mestiços: estudo anatômico destinado a pesquisa experimental e ao diagnóstico por imagem / Frequency of the caroticobasilar artery in crossbred horses: anatomical study for experimental research and diagnostic imaging

A busca pela compreensão do funcionamento do sistema nervoso resultou em um aumento de estudos morfológicos sobre a vascularização encefálica em diferentes espécies animais. As artérias encefálicas são a principal rota para transporte de sangue para o cérebro e, portanto têm um papel essencial na manutenção de atividade normal do mesmo, o que desperta, devido sua importância funcional, o interesse pela realização de vários estudos. A artéria caroticobasilar foi investigada em animais da ordem Perissodactyla, de espécies da família dos eqüídeos. Pesquisou-se a frequência da artéria caroticobasilar em 30 encéfalos de equinos adultos e mestiços, do sexo masculino. As observações realizadas mostraram que este importante vaso apresentou as seguintes frequências absolutas e percentuais: presente em 15(50 por cento) dos encéfalos examinados sendo 4 (13,3 por cento) no antímero direito, 6 (20 por cento) no antímero esquerdo e 5 (16,7 por cento) em ambos os antímeros.

The search for the functional understanding of the nervous system has resulted in an increase of morphological studies about encephalic vascularization in different animal species. The encephalic arteries are the main rote for blood transport to the brain and therefore have an essential role in the maintenance of normal brain activity. The functional importance of these vessels has led to various studies. The caroticobasilar artery was investigated in animals of order Perissodactyla, in species of Equidae family. The frequency of caroticobasilar artery was studied in 30 adult male crossbreed brain horses. The observations showed that this important vessel presented the following absolute and percentual frequencies: present in 15 (50 percent) brains 4 (13.3 percent) in the right antimere, 6 (20 percent) in the left antimere and 5 (16.7 percent) on both antimeres.

Estudio de la norma anatómica de las Arterias Parietales en cerebros humanos / Study of the anatomical norm of the Parietal Arteries in human brains

En la literatura se describen alteraciones interpretadas como anomalías en el Sistema de las arterias Parietales, que pudieran representar realmente una variante de la norma poco conocida y que resulta de gran importancia en las intervenciones neuroquirúrgicas que se relacionan con los aneurismas asociados. Se realizó el presente estudio descriptivo en cincuenta cerebros humanos, disecándose cada hemisferio cerebral, con su Sistema Arterial correspondiente, con el objetivo de obtener información acerca de estas variaciones. Se llegó a la conclusión que las arterias Parietales constituyen ramificaciones corticales de la arteria Cerebral Anterior distal o Pericallosa en la mayoría de los cerebros de la muestra.

Alterations interpreted as anomalies in the System of the Parietal arteries are described in Literature, it could really represent a variant of the little-known norm and it is from great importance in the neurosurgical interventions that are related to the associate aneurisms. The present descriptive study was carried out in fifty human brains, dissecting each cerebral hemisphere, with its corresponding Arterial System, with the aim of obtaining data about these variations. It was reached the conclusion that the Parietal arteries constitute cortical ramifications of the Anterior Cerebral Artery in the majority of the brains of the sample.

Estudio microanatómico de la arteria paracentral en cerebros humanos / Microanatomical study of the paracentral artery in human brains

En los últimos años se han incorporado a la descripción clásica de las arterias paracentrales nuevos datos que permiten un abordaje quirúrgico con menos riesgos, dado el origen variable desde el punto de vista topográfico de esta arteria; esto implica grandes dificultades para el cirujano, puesto que obstaculiza el proceder quirúrgico frente a innumerables entidades neurovasculares; teniendo como propósito establecer nuevos conceptos con relación a las variantes de la norma de este sistema arterial, se realizó el presente estudio descriptivo en cincuenta cerebros humanos, disecándose cada hemisferio cerebral, con su sistema arterial correspondiente. Se llegó a la conclusión que la arteria paracentral es un vaso variable por su inconstancia y origen. La misma se presentó generalmente como tronco único y como variantes se encontró doble o ausente. La presencia de troncos comunes con la arteria parietal constituyó una variable frecuente, alcanzando la mayoría de los troncos un grueso calibre, compatible con la realización de injertos para restablecer el flujo sanguíneo cerebral. Como ramificación terminal de la arteria cerebral anterior se considera una variante extrema en este universo de estudio. Los grosores externos de la arteria paracentral guardan relación con su gran territorio de irrigación.

O sistema carótico do encéfalo do Cebus apella sp., Linnaeus, 1766 / The carotid encephalic system of the Cebus apella sp., Linnaeus, 1766

The carotid system of the encephalon of thirty species of the primate Cebus apella sp. (Linnaeus, 1766) was studied in this research. The material was collected according to international bioethics parameters and animals' welfare. The arterial system was perfused (water at 40 ºC), injected with colored latex (Neoprene 450, Dupont® do Brasil and Sulvinil® coloring, Glassurit), fixed in formaldehyde aqueous solution (10%) and dissected under magnifying glass (RASOR, II-20) for the systematization of vessels. The carotid system is composed by the intracranial and internal portions of both right and left carotid arteries, the carotid arteries of the encephalon and their lateromedial and anteromedial branch divisions: the medial and rostral cerebral arteries, communicating caudal and interconnected arteries. It is interconnected through the caudal communicating arteries to the vertebral-basilar system (100%). The internal carotid artery ends up being divided into three: caudal communicating arteries, medial cerebral and rostral cerebral (50%) or into two: medial cerebral and rostral cerebral arteries (50%). The medial cerebral artery is the most stable branch of this circuit. and after ventricularizing the olfactory bulbs (93.3%), the rostral cerebral artery becomes anastomosis with the contralateral artery, forming the interhemispheric artery that connects the blood layers of the arterial circuit of the encephalon base. It can be considered that Cebus apella sp. depends on two supply sources to the encephalon: the basilar and carotid systems, what indicates an important degree of evolutionary maturity. The absence of anomalies in this primate demonstrates evolutionary stability.Keywords: encephalon, carotid system, cerebral arteries, neotropical primate Cebus apella sp.

Estudamos em trinta espécimes do primata Cebus apella sp. (Linnaeus, 1766) o sistema carótico do encéfalo em animais coletados dentro dos parâmetros internacionais de bioética e bem estar animal. O material teve o sistema arterial perfundido (água a 40 ºC), injetado com látex corado (Neoprene 450, Dupont® do Brasil e Sulvinil® Corante, Glassurit), fixado em solução aquosa de Formaldeído (10%) dissecado sob lupa (RASOR û II û 20) para sistematização dos vasos. O sistema carotico é composto pela porção intracraniana e intradural dos seguimentos dependentes das artérias carótidas internas esquerda e direita, as artérias carótidas do encéfalo (ace) e seus ramos de divisões látero-mediais e ântero-mediais: as artérias cerebrais médias acm e rostrais (acr), comunicantes caudais e artérias corioídeas Está interligado, através das artérias comunicantes caudais, ao sistema vértebro-basilar (100%). A ace termina trifurcando-se (50%), ou bifurcando-se (50%) em arranjos vasculares que envolvem as acm e acr, acc e artéria corioídea. A acm é o ramo mais estável deste circuito e a acr após vascularizar os bulbos olfatórios (93,3%) anastomosa-se com a artéria contralateral formando a artéria inter-hemisférica que conecta rostralmente os leitos sanguíneos do circuito arterial da base do encéfalo. Pode-se considerar que o Cebus apella sp. depende de duas fontes de suprimento para o encéfalo: os sistemas basilar e carotídico, isto indica um grau elevado de maturidade evolutiva. A ausência de anomalias demonstra neste primata estabilidade evolutiva.