Bilateral Variation of the Vertebral Artery: Report of a Case and its Clinical Implication / Variación Bilateral de la Arteria Vertebral; Reporte de un Caso y su Implicancia Clínica

SUMMARY: There are many reports on anatomical variations of the vertebral arteries, which may be related to origin, trajectory, caliber, and side. Bilateral variations are less frequent, however, and less common are bilateral variants that differ from each other. The aim of this work was to report the presence of a bilateral variation of the vertebral artery and its functional and clinical implications. Dissection of a female cadaver, fixed in 10 % buffered formaldehyde, which had not undergone any previous surgeries in the study area and had anatomical variations in both vertebral arteries. In each one, follow-up was done from its origin to its end, determining its trajectory, diameters, branching, and anatomical relations. A left vertebral artery was found, starting in the aortic arch and making a sinuous trajectory of 4 curvatures to enter the transverse foramen of C4. The right vertebral artery began as the first branch of the subclavian artery. Its initial trajectory was rectilinear, followed by a right concave curve, a 360° loop that included a second ascending curve, and ended straight before entering the transverse foramen of C6. The coexistence of bilateral variations in the vertebral arteries is possible. This atypical situation can potentially generate vascular and neurological pathologies, but with different symptoms and causes. Knowing these variations and deliberately searching for them will enable the specialist to make a suitable differential diagnosis.

Existen múltiples reportes sobre variaciones anatómicas de las arterias vertebrales, las que se pueden relacionar con origen, trayecto, calibre y lateralidad. Sin embargo, las variaciones bilaterales son menos frecuentes, y menos común es que las variantes bilaterales sean diferentes entre ellas. El objetivo de este trabajo fue reportar la presencia de una variación bilateral de la arteria vertebral y su implicancia funcional y clínica. Disección en un cadáver de sexo femenino, fijado en formaldehido tamponado al 10 %, el cual no presentaba intervenciones quirúrgicas previas en la región de estudio y que tenía variaciones anatómicas en ambas arterias vertebrales. En cada una se realizó seguimiento desde su origen hasta su terminación, pudiendo determinar su trayecto, diámetros, ramificaciones y relaciones anatómicas. Se encontró una arteria vertebral izquierda originada en el arco aórtico, que realizaba un trayecto sinuoso de 4 curvaturas e ingresaba al foramen transverso de C4. La arteria vertebral derecha se originaba como primera rama de la arteria subclavia. Su trayecto inicial era rectilíneo seguido por una curva de concavidad derecha, un loop (giro) de 360° que incluía una segunda curva ascendente y terminaba en dirección recta antes de ingresar al foramen transverso de C6. La coexistencia de variaciones bilaterales en las arterias vertebrales es posible. Esta situación atípica, potencialmente puede generar en la persona patologías neurológicas de origen vascular, pero con sintomatología y causas diferentes. Conocer estas variaciones y realizar una búsqueda intencionada de ellas permitirá el especialista realizar un adecuado diagnóstico diferencial.

The carotid and vertebral arteries discovery ­ initial findings / A descoberta das artérias carótidas e vertebrais ­ achados iniciais

The studies on the vascular system, including the cervicocephalic arteries (carotid and vertebral arteries), present a long trajectory, having their deep roots in the far past, considering the Western authors, having as representatives the Greek sages Alcmaeon, Diogenes, Hippocrates, Aristoteles, Rufus, and Galenus. They produced pivotal knowledge dissecting mainly cadavers of animals, and established solid bases for the later generations of scholars. The information assembled from these six authors makes it possible to build a quite clear picture of the vascular system, here specifically focused on the cervicocephalic arteries, and mainly of the extracranial segments. Thus, the carotid system became fairly well identified, origin, course, and name, as well as the origin of the still unnamed arteries running through the orifices of the transversal processes of the cervical vertebrae, and entering into the cranium. Almost all that was then known about human anatomy, since this period, and then throughout the Middle Ages, was extrapolated from animal dissections. This state of affairs was maintained until the 14th century, when human corpses dissections were again allowed.

Os estudos do sistema vascular, incluindo as artérias cervicocefálicas (artérias carótidas e vertebrais), apresentam um longo percurso, tendo suas raízes profundas no passado distante, considerando os autores ocidentais, tendo como representantes os doutos gregos Alcméon, Diógenes, Hipócrates, Aristóteles, Rufus e Galenus. Eles produziram conhecimento pivotal, dissecando principalmente cadáveres de animais e estabelecendo bases sólidas para as gerações futuras de estudiosos. A informação reunida desses seis autores permite construir um quadro bastante claro do sistema vascular, aqui focado especificamente nas artérias cervicocefálicas e principalmente nos seus segmentos extracranianos. Assim, o sistema carotídeo ficou bastante bem identificado, origem, trajeto e nome, assim como a origem das ainda não nomeadas artérias que percorrem os orifícios dos processos transversos das vértebras cervicais e entrando no crânio. Quase tudo que era conhecido sobre anatomia humana, desde esse período, e depois ao longo da Idade Média, foi extrapolado a partir de dissecções de animais. Esse estado de coisas foi mantido até o século 14, quando a dissecção de cadáveres humanos foi novamente permitida.

Traumatic Dissection of Arterial Cervical Vessels: Report of Two Cases and Literature Review

Even though traumatic dissection of cervical arterial vessels is themajor cause of stroke among adults, it is still an underdiagnosed disease in neurosurgical emergencies, since most patients do not have or present subtle clinical signs in the acute phase. The authors report two interesting cases of cervical artery dissection with different traumatic mechanisms and present a broad literature review about this subject.

Safety ranges in V3 segment of the vertebral artery for surgical procedures at the craniocervical junction / Rangos de seguridad en el segmento V3 de la arteria vertebral para procedimientos quirúrgicos en la unión craneocervical

The aim of this study was to establish safety ranges for the third vertebral artery segment (V3) for craneocervical procedures. Injury to V3 represents a potentially catastrophic complication. Its tortuous path and complex relationship with neighboring structures, increasing the risk. Ten male adult cadavers (20 vertebral arteries) with arterial infiltration of red latex were studied. The length, angles and anatomical measurements were obtained between the selected surgical landmarks and the portions of V3 segment. The horizontal portion has a length of 32.7 ± 3.6 mm with an angulation of 115.1 ± 8.3 degrees. The mean distances of the horizontal portion were: from the midline to the V3 groove of C1 posterior arch (24.7 ± 6.3 mm); from C1 pars interarticularis to the V3 distal loop of V3 (8.9 ± 1.4 mm). The vertical portion has a length 32.5 ± 5.6 mm with an angulation of the proximal loop of 113.6 ± 5.8 degrees. The mean distances between the C2 spinous process to the medial surface of the distal loop (43.8 ± 4.2 mm); from the C1-C2 joint to the V3 vertical portion (9.5 ± 1.5 mm); from C2 pars interarticularis to V3 in the C2 transverse foramen (6.5 ± 3.4 mm); from C2 pars interarticularis to V3 in the C1 transverse foramen (17.5 ± 4.5 mm). We reported four potential sites where V3 can be injured during four different surgical procedures: exposure of the posterior arch of C1, and pars interarticularis of C1 in the horizontal portion and exposure of the C1C2 joint, and placement of C1-C2 transarticular screws one in the vertical portion. We provide measurements of redundancy and safety ranges to reduce the risk of injury to the V3 segment during craniocervical surgical procedures.

El objetivo de este estudio fue establecer rangos de seguridad en el tercer segmento de arteria vertebral (V3) para cirugías de la región craneocervicales. La lesión de V3 representa una complicación potencialmente catastrófica. Su tortuoso trayecto y compleja relación con las estructuras aledañas, aumenta el riesgo. Se estudiaron diez cadáveres adultos masculinos (20 arterias vertebrales) con infiltración arterial de látex rojo. La longitud, ángulos y medidas anatómicas se obtuvieron respecto a los puntos de referencia quirúrgicos y las porciones del segmento V3. La porción horizontal tiene una longitud de 32,7 ± 3,6 mm con una angulación de 115,1 ± 8,3 grados. Las distancias medias de la porción horizontal fueron: desde la línea media hasta el surco V3 del arco posterior C1 (24,7 ± 6,3 mm); desde C1 pars interarticularis hasta el bucle distal V3 de V3 (8,9 ± 1,4 mm). La parte vertical tiene una longitud de 32,5 ± 5,6 mm con una angulación del bucle proximal de 113,6 ± 5,8 grados. Las distancias medias entre el proceso espinoso C2 y la superficie medial del bucle distal (43,8 ± 4,2 mm); desde la unión C1-C2 hasta la porción vertical V3 (9,5 ± 1,5 mm); de C2 pars interarticularis a V3 en el foramen transversal C2 (6,5 ± 3,4 mm); de C2 pars interarticularis a V3 en el foramen transversal C1 (17,5 ± 4,5 mm). Informamos cuatro sitios potenciales donde la V3 puede lesionarse durante cuatro procedimientos quirúrgicos diferentes: exposición del arco posterior de C1 y pars interarticularis de C1 en la porción horizontal y exposición de la articulación C1-C2, y colocación de C1-C2 Tornillos transarticulares uno en la porción vertical. Proporcionamos mediciones de los rangos de redundancia y seguridad para reducir el riesgo de lesiones en el segmento V3 durante procedimientos quirúrgicos craneocervicales.

The foramen transversarium of typical and atypical cervical vertebrae: morphology and morphometry / El foramen transverso de vértebras cervicales típicas y atípicas: morfología y morfometría

The seven cervical vertebrae found in the human body are classified into typical and atypical vertebrae. Their transverse processes contain foramen transversarium (FT) and traditionally there is one foramen present on each side, of similar size. However, variations of this foramen regarding its shape, size, number, laterality, location and osteometric characteristics have been documented in the literature. This morphological and morphometric study was conducted on 126 cervical vertebrae (82 typical and 44 atypical) obtained from the osteological bank at the University of Kwa-Zulu Natal to produce a database which may serve as a useful guideline to medical personnel. There were variations observed regarding shape, number of FT, laterality and position, which have not previously been reported. The most types of variations were evident in the typical cervical vertebrae, then secondly, the seventh cervical vertebrae. The axis vertebrae did not display any accessory FT or variations.

Las siete vértebras cervicales que se encuentran en el cuerpo humano se clasifican como vértebras típicas y atípicas. Sus procesos transversos presentan un foramen transverso (FT) y normalmente este foramen es de tamaño similar en cada lado. Sin embargo, se han reportado en la literatura variaciones de este foramen, con respecto a su forma, tamaño, número, lateralidad, ubicación y características osteométricas. Este estudio morfológico y morfométrico se realizó en 126 vértebras cervicales (82 típicas y 44 atípicas) obtenidas del banco de Osteología de la Universidad de Kwa-Zulu Natal, para producir una base de datos que pueda servir como una guía útil para el personal médico. Se observaron variaciones con respecto a la forma, el número de FT, la lateralidad y la posición, que no se habían reportado anteriormente. La mayoría de los tipos de variaciones eran evidentes en las vértebras cervicales típicas y en segundo lugar en las séptimas vértebras cervicales. Los axis no mostraron ningún FT accesorio o variaciones.

Geometric features of vertebrobasilar arterial system in adult black Kenyans / Características geométricas del sistema arterial vertebrobasilar en kenianos negros adultos

Geometric features of vertebrobasilar system influence occurrence of posterior circulation atherosclerosis, aneurysms, stroke and neuroradiological procedures. These features show ethnic variation, but data from black Africans in Sub Saharan Africa are scarce. This study aimed to describe geometric features of vertebrobasilar system in a black Kenyan population. It was a descriptive cadaveric study at Department of Human Anatomy, University of Nairobi. One hundred and seventy three formalin-fixed adult brains of individuals (99 male; 74 female; Age range 20 - 79) who had died of non cerebrovascular causes were studied. Level and angle of confluence of vertebral artery; diameter, length and bifurcation angles of basilar artery were measured. Data were analysed by SPSS version 21 for windows. The student t - test was used to determine the sex differences at 95 % confidence interval. Data are presented in macrographs, tables and bar charts. Confluence of vertebral arteries occurred at the sulcus bulbopontinus in 79.8 %; rostral to it in 11.5 % and caudal to it in 8.7 % of cases. Mean angle of vertebral artery confluence was 46.7º and 68.9º in males and females respectively (p£0.042). Mean length of the basilar artery was 26.8 mm; 26.3 mm in males and 27.1 mm in females (p=0.465). Mean diameter was 3.52 mm; 3.32 mm in males and 3.72 mm in females (p=0.002). The mean angle of basilar artery bifurcation was 120.3º ± 15.2; 99.3º ± 32.9 in males and 140.3º ± 16.1 in females (p=0.024). It was wider than 90º in 82.9 % of males and 95.9 % females (p=0.032). In 85 (49.1 %) it was wider than 120º. The vertebrobasilar system in the Kenyan population has geometric features that constitute risk factors for atherosclerosis. These features display sex dimorphism which may explain differences in prevalence of atherosclerosis and aneurysms. Neurosurgeons and neurologists should be aware of these differences. Individuals with risk prone geometric features should be followed up for atherosclerosis.

Las características geométricas del sistema vertebrobasilar influyen en la aparición de aterosclerosis en la circulación posterior, aneurismas, apoplejía, detectados durante procedimientos neurorradiológicos. Estas características muestran variación étnica, pero los datos de los africanos negros en el África Subsahariana son escasos. Este estudio tuvo como objetivo describir las características geométricas del sistema vertebrobasilar en una población negra de Kenia. Fue un estudio descriptivo cadavérico en el Departamento de Anatomía Humana de la Universidad de Nairobi. Se estudiaron 173 cerebros adultos (99 varones, 74 mujeres, rango de edad 20-79), fijados en formalina, de individuos que habían fallecido por causas no cerebrovasculares. Se midieron el nivel y ángulo de confluencia de la arteria vertebral, diámetro, longitud y bifurcación de la arteria basilar. Los datos fueron analizados por SPSS versión 21 para Windows. La prueba t de Student se utilizó para determinar las diferencias de sexo con un intervalo de confianza del 95 %. Los datos se presentan en macrografías, tablas y gráficos de barras. La confluencia de las arterias vertebrales se produjo en el surco bulbopontino en el 79,8 %; rostral al surco en 11,5 % y caudal al surco en 8,7 % de los casos. El ángulo medio de la confluencia de la arteria vertebral fue 46,70 y 68,90 en hombres y mujeres, respectivamente (p£0,042). La longitud media de la arteria basilar fue de 26,8 mm; 26,3 mm en hombres y 27,1 mm en mujeres (p=0,465). El diámetro promedio fue de 3,52 mm; 3,32 mm en hombres y 3,72 mm en mujeres (p=0,002). El ángulo medio de la bifurcación de la arteria basilar fue de 120,30 ± 15,2; 99.30 ± 32,9 en hombres y 140,30 ± 16,1en mujeres (p=0,024). Era más amplio que 90º. En un 82,9 % de los hombres y 95,9 % de las mujeres (p=0,032) se observó un ángulo más amplio que 90°. En 85 (49,1 %) fue más amplio que 120°. El sistema vertebrobasilar en la población de Kenia tiene características geométricas que constituyen factores de riesgo para la aterosclerosis. Estas características muestran dimorfismo sexual que puede explicar las diferencias en la prevalencia de aterosclerosis y aneurismas. Los neurocirujanos y los neurólogos deben tener en cuenta estas diferencias. Las personas con características geométricas propensas al riesgo deben ser seguidas por aterosclerosis.

Anatomical variations of the foramen transversarium in cervical vertebrae / Variaciones anatómicas del foramen transverso en vértebras cervicales

The cervical vertebrae are recognized mainly by the presence of the foramen transversarium, which is crossed by the vertebral artery and vein, accompanied by sympathetic fibers. The main objective of this study was to observe and describe the anatomy and variations in the foramen transversarium. 121 cervical vertebrae were analyzed, including the macroscopic characteristics, shape and diameter and presence of the foramen transversarium, as well as the accessory foramen transversarium. All cervical vertebrae presented the foramen transversarium, with a mean diameter of 5.60 mm and a mean diameter of 4.40 mm on the right and 5.92 mm - 5.56 mm on the left, respectively. With regard to shape classification according to Taitz et al. (1978), 90.08 % presented the same shape on both sides, and 9.91 % had different shapes. The presentation of the different shapes was as follows: shape 1 41.32 %; shape 2 4.13 %; shape 3 18.8 %; shape 4 14.04 %; and shape 5 12.39 %. Regarding the presence of accessory foramen transversarium, 17.35 % of the vertebrae presented it, 66.6 % unilateral, 57.14 % on the right side and 42.85 % on the left side. Osteophytes, were presented in 5.7 %. The anatomical knowledge of these variations is useful for spine surgeons in preoperative planning and for preventing vertebral vessel and sympathetic nerve injuries during cervical surgical approaches.

Las vértebras cervicales son reconocidas principalmente por la presencia del foramen transverso (FT), por el cual transita la arteria y vena vertebral además de fibras simpáticas. Las variaciones en el FT pueden estar asociadas con una alteración en el calibre y el curso de la arteria vertebral. El objetivo del presente estudio fue observar y describir la anatomía así como las variaciones en el FT. Fueron analizadas 121 vértebras cervicales, en las cuales el FT fue observado macroscópicamente de manera bilateral así como el foramen transverso accesorio (FTA) en las que se encontrara presente. La forma y diámetros máximo y mínimo del FT fue medido de manera bilateral con ayuda de un cáliper digital. De 121 vértebras cervicales, la totalidad presentaron FT con diámetros máximo y mínimo derecho de 5,60 y 4,40 mm respectivamente y de 5,92 y 5,56 mm máximo y mínimo del lado izquierdo. Con respecto a la clasificación de forma de Taitz et al. (1978) el 90,08 % presentó la misma forma de manera bilateral y un 9,91% formas distintas. La forma 1 se presentó en un 41,32 %, la 2 en un 4,13 %, forma 3 18,8 %, 4 14,04 % y 5 en 12,39 %. Con respecto a la presencia de FTA, un 17,35 % lo presentó, siendo 66,6 % unilaterales, un 57,14 % derecho y 42,85 % izquierdo. La anatomía y variaciones en el FT y la arteria vertebral y los componentes nerviosos están interrelacionados. Su conocimiento morfológico es clínicamente importante, ya que el curso de la arteria vertebral puede distorsionarse en tales situaciones. Por lo que es importante a la hora de adoptar medidas cautelares para salvaguardar la arteria vertebral en las cirugías de columna cervical.

Ramos colaterais do Arco aórtico do preá (Galea spixii Wagler, 1831) / Collateral branches of the aortic arch of galea (Galea spixii Wagler, 1831)

O preá é um roedor típico da caatinga pertencente à família Caviidae. Considerando a inexistência de dados sobre o arco aórtico do preá, foi realizado este estudo tendo como objetivo descrever os ramos colaterais do arco aórtico neste cavídeo, e dessa forma, contribuir com dados para biologia da espécie. Foram utilizados vinte preás machos provenientes de estudos anteriores e encontravam-se armazenados em freezer no Centro de Multiplicação de Animais Silvestres (CEMAS/UFERSA). Os animais foram descongelados, a cavidade torácica foi aberta, a aorta canulada e o sistema vascular lavado com solução salina e em seguida, injetado látex Neoprene corado com pigmento vermelho, amarelo ou branco. Posteriormente, os animais foram fixados em formol e depois de 72 horas, dissecados e analisados, sendo obtidos desenhos esquemáticos e os exemplares mais representativos fotografados. O arco aórtico do preá emitiu como ramos colaterais, o tronco braquiocefálico e a artéria subclávia esquerda. O tronco braquiocefálico originou na maioria das peças estudadas, a artéria carótida comum esquerda e o tronco braquiocarotídeo, do qual surgem as artérias subclávia direita e carótida comum direita. As artérias subclávias direita e esquerda em todos os animais estudados emitiram a artéria vertebral, a artéria torácica interna, a artéria cervical superficial, o tronco costocervical e a artéria axilar. O padrão da formação do arco aórtico do preá assemelhou-se ao observado em outros roedores, tais como no mocó, no porquinho-da-índia e na chinchila...

Galea spixii is a typical rodent of the caatinga belonging to the Caviidae family. Considering the lack of data on the aortic arch of the galea, this study aimed to describe the collateral branches of the aortic arch in this specie and to contributes to knowledge of its biology. Twenty males from previous studies were used which had been stored in a freezer at Multiplication Center of Wild Animals (CEMAS/UFERSA). The animals were thawed, the thoracic cavity was opened and the aorta cannulated vasculature was washed with saline and then injected with Neoprene latex colored with red pigment, yellow or white. Subsequently, the animals were fixed in formalin and after 72 hours dissected and analyzed, to obtain schematic drawings and the most representative samples were photographed. The cavy aortic arch issued as collateral branches, the brachiocephalic trunk and the left subclavian artery. The brachiocephalic trunk afforded in most of the specimens the left common carotid artery and the brachiocarotid trunk, where the right subclavian and right common carotid arteries arise. The right and left subclavian arteries in all animals studied issued the vertebral artery, internal thoracic artery, superficial cervical artery costocervical trunk and axillary artery. The pattern of formation of the aortic arch of galea was similar to that observed in other rodents, such as the kerodon, the guinea pig and chinchilla....

Sistemática para el estudio Doppler de carótidas / Systematic assessment in carotid doppler ultrasound

La exploración de los ejes carotideo y vertebral resulta sencilla técnicamente, con un aprendizaje relativamente rápido para el que inicia la actividad, especialmente si se establecen protocolos de exámenes estandarizados y fácilmente reproducibles. El objetivo de la sistematización en los servicios de Doppler vascular es que los exámenes realizados por distintos operadores sean similares en cuanto a la técnica y la terminología del informe; a nivel docente la sistematización ofrece al neófito una metodología clara a seguir con el fin de completar las evaluaciones y solidificar el proceso de aprendizaje.

The far-lateral craniotomy: tips and tricks / A craniotomia extremo-lateral: dicas e truques

This article intends to describe in a didactical and practical manner the suboccipital far-lateral craniotomy. This is then basically a descriptive text, divided according to the main stages involved in this procedure, and that describes with details how the authors currently perform this craniotomy.

O presente artigo visa descrever de forma didática e prática a realização da craniotomia suboccipital extremo-lateral. Trata-se, portanto, de um texto fundamentalmente descritivo, dividido conforme as principais etapas da realização dessa craniotomia, e que descreve com detalhes a técnica com que o presente grupo de autores evolutivamente veio a realizá-la.

Evaluation of the vertebral artery by 3D digital subtraction angiography / Evaluación de la arteria vertebral mediante angiografía por sustracción digital 3D

The objective of the present study is to determine origin, entry level to the transverse foramen and diameter according to sex and side through 3D angiographic images of seventy-nine vertebral arteries obtained using DSA imaging method. During radiological evaluation, axial, coronal and sagittal images of the artery were used. Data of our study was uploaded to SPSS 14.0 program and significance test and Mann Whitney-U test of the difference between two means were used to evaluate the data. While 76 of the vertebral arteries (96.2%) were originating from the subclavian artery, 3 of them (3.8%) were directly originating from aortic arch. In 67 of 76 the vertebral arteries originating from the subclavian artery were entering through C6, 6 through C7, 2 through C5 and one through C4 transverse foramen. It was seen that one of 3 the vertebral artery originating from aortic arch was entering through C6, one through C7 and the other through C4 transverse foramen. While the mean diameter of the vertebral artery was 3.88±0.71 mm at the right side (3.99 mm in men, 3.66 mm in women), the mean diameter at the left side was 4.15±1.05 mm (4.23 mm in men, 4.06 mm in women).

El objetivo fue determinar el origen, nivel de entrada y diámetro del foramen transverso, en función del sexo y lado sobre 79 arterias vertebrales a través de imágenes angiográficas 3D utilizando el método de formación de imágenes DSA. Durante la evaluación radiológica, se utilizaron imágenes axiales, coronales y sagitales de la arteria. Los datos se procesaron en el programa SPSS 14.0 con las pruebas U de Mann Whitney y de significancia para evaluar la diferencia entre los datos. Mientras que 76 de las arterias vertebrales (96,2%) se originaron de la arteria subclavia, 3 de ellas (3,8%) lo hicieron directamente desde el arco aórtico. En 67 de 76 arterias vertebrales, se observó el origin en la arteria subclavia a través de C6; 6 a través de C7, 2 a través de C5 y una a través del foramen transverso en C4. El diámetro medio de la arteria vertebral fue 3,88±0,71 mm en el lado derecho (3,99 mm en hombres y 3,66 mm en mujeres) y en el lado izquierdo fue 4,15±1,05 mm (4,23 mm en hombres y 4,06 mm en hombres).

Expresión morfológica de la arteria basilar: un estudio con material de autopsia de individuos colombianos / Morphological expression of the basilar artery: a study with colombian population's autopsy material

La arteria basilar (AB) presenta una expresión variable, la cual es determinante en la etiología de eventos clínicos que comprometen el tallo cerebral. El propósito de este trabajo fue determinar la expresión morfológica de la AB en una muestra de población colombiana. Fueron estudiados 100 tallos cerebrales de individuos a quienes se les practicó autopsia en el Institutode Medicina Legal de Bucaramanga. El sistema vertebro-basilar fue perfundido con resina sintética y evaluado los calibres, trayectorias, niveles de origen y finalización de la AB. La AB presentó trayectoria rectilínea en 68 por ciento, desviación a la derecha en 12 por ciento, sinuosa en 10 por ciento y desviación a la izquierda en 10 por ciento. La longitud total de la AB fue 30,2 mm DE 4,07 y la longitud con relación al origen de la arteria Cerebelar superior fue 28,1 mm DE 3,84. Los calibres proximal y distal de la AB fueron 3,96 mm DE 0,48 mm y 3,7 mm DE 0,58 respectivamente. Con relación a las arterias de origen de la AB, se observó hipoplasia ( 2 mm) de la arteria vertebral derecha en el 8 por ciento y de la arteria vertebral izquierda en el 11 por ciento (P = 0,30). Se observó el origen de la AB a tres niveles del surco pontomedular: a nivel en el 43 por ciento, por arriba de este en el 30 por ciento y por debajo de este surco en 27 por ciento de los casos. Las trayectorias sinuosas y desviadas de la AB observadas y la presencia de hipoplasias de la arteria vertebral son ligeramente superiores a los señalados en estudios previos, mientras que su longitud se ubica en un rango medio y su calibre es ligeramente inferior a lo señalado en la literatura.

The basilar artery (BA) has a variable expression which is determinant in the etiology of clinical events that compromise the brain stem. The purpose of this study was to determine the morphological expression of BA in a Colombian population sample. We studied 100 brainstems of individuals which underwent an autopsy at the Instituto de Medicina Legal of Bucaramanga. The vertebra basilar system was perfused with synthetic resin and its calibers, paths, levels of origin and end of the BA were evaluated. The BA presented a rectilinear trajectory in 68 percent, deviation to the right in 12 percent, sinuous in 10 percent and deviation to the left in 10 percent. The total length of the BA was 30.2 mm SD 4.07, its length in relation to the origin of the superior cerebellar artery was 28.1 mm SD 3.84. The proximal and distal caliber of the BA were 3.96 mm SD 0.48 mm and 3.7 mm SD 0.58 respectively. In relation to the origin arteries of the AB, hypoplasia was observed ( 2 mm) of the right vertebral artery in 8 percent and the left vertebral artery in 11 percent (P = 0.30). The origin of BA was observed at different spontomedullary groove levels: at level in 43 percent, above it in 30 percent and below it in 27 percent of the cases. The sinuous and diverted paths from the BA observed and the presence of vertebral artery hypoplasia are slightly higher than those reported in previous studies, while its length is at medium range and its caliber is slightly lower than reported in the literature.

Arteria vertebral izquierda aberrante / Aberrant left vertebral artery

Se presenta una variación anatómica de la arteria vertebral izquierda, detectada en un cadáver utilizado para docencia en el Departamento de Anatomía de la Escuela de Medicina de la Pontificia Universidad Católica de Chile. En el mediastino superior del cadáver mencionado, se pudo apreciar que el arco aórtico da origen, de derecha a izquierda, a las siguientes ramas: arteria braquiocefálica, arteria carótida común izquierda, arteria vertebral izquierda aberrante y, finalmente, la arteria subclavia izquierda. La arteria vertebral izquierda aberrante se origina en la parte más alta del arco aórtico, presentando en este punto un diámetro de 4 mm; luego asciende a la izquierda de la carótida común ipsilateral y por sobre la cara anterolateral de la columna vertebral, tomando contacto con ramos cardíacos del tronco simpático cervical. Luego de un trayecto de 95 mm, ocupando el mediastino superior y la raíz del cuello, se hace profunda entrando en el foramen transverso de la 6 vértebra cervical, donde su calibre se ha reducido a 2,65 mm. En el presente trabajo, se discute la evolución que presentan las arterias intersegmentarias dorsales cervicales en la antímera izquierda que permite explicar esta variación anatómica.

An anatomical variation of the left vertebral artery, detected in a cadaver used for teaching purposes in the Department of Anatomy, School of Medicine, Catholic University of Chile is presented. In this case, the aortic arch gives rise, from right to left, to the following branches: the brachiocephalic artery, the left common carotid artery, the aberrant vertebral left artery and, finally, the left subclavian artery. The aberrant left vertebral artery originates from the top of the aortic arch, presenting here a diameter of 4 mm, then ascends to the left of the common carotid ipsilateral, over the anterolateral aspect of the spine, making contact with cardiac branches of the cervical sympathetic trunk. After ascending 95 mm, occupying the upper mediastinum and the root of the neck, the artery enters the transverse foramen of the 6th cervical vertebra, where its diameter was reduced to 2.65 mm. In this paper we discuss the development of the cervical dorsal intersegmental arteries in the left antimera, process that could explain this anatomical variation.

Rare variation in the right vertebral artery

The variations of vertebral artery are important with regard to their potential clinical impact .The study reports the variation of course of right vertebral artery in male cadaver. The vertebral arteries arise from the superioposterior aspect of the first part of subclavian artery. The vessel takes a vertical course to enter into the transverse foramen of sixth cervical vertebra. Right vertebral artery in its course in the neck ascends between the carotid sheath and prevertebral fascia. But in this case, right vertebral artery at level of C3 pierced the prevertebral fascia to reach the transverse foramen of C3 .The length of this part is longer than normal size, but its lumen was normal. In international literature, the incidence of vertebral artery passing through C3 transverse foramen is seen in approximately 0.2% of the studied population. No anthropometric parameter has shown this case in Iran

Anomalous origin of right vertebral artery from right external carotid artery

A 50 years old male was admitted with sub-arachnoid haemorrhage. Angiographic examination revealed an abnormal origin of the right vertebral artery from the right external carotid artery. Multiple variations in the origin of right vertebral artery have been reported in literatures. Anomalous origin of the right vertebral artery from the right external carotid artery has not been reported earlier

Anatomia do sulco da artéria vertebral / Vertebral artery groove anatomy

INTRODUÇÃO: Diversas técnicas cirúrgicas têm sido realizadas na região craniocervical devido a diversas patologias. Durante o acesso cirúrgico a essa região existe um risco potencial de lesão iatrogênica da artéria vertebral, relacionado ao acesso lateral amplo e à avaliação inadequada da anatomia local. Variações no trajeto da artéria vertebral ocasionam maior risco de lesão vascular. O estudo pré-operatório por imagem da anatomia da artéria vertebral e do seu sulco tem sido realizado para aumentar a segurança cirúrgica. OBJETIVO: Estudar a morfometria da artéria vertebral no atlas através da tomografia computadorizada do sulco da artéria vertebral (SAV) em 30 atlas isolados de cadáveres. MATERIAIS E MÉTODOS: O SAV e suas relações com a linha média foram avaliados através de oito medidas lineares e duas angulares, bilateralmente. A média, valor máximo e mínimo, e desvio padrão foram calculados para cada parâmetro. RESULTADOS: O SAV apresentou uma maior largura e maior espessura do lado esquerdo (p<0,05) CONCLUSÃO: os nossos dados sugerem que a dissecção posterior e superior do arco posterior devem permanecer a uma distância lateral de 11,2mm e 7,4mm da linha média para que haja segurança no procedimento.

INTRODUCTION: Several surgical techniques have been carried through in the skull-cervical region due to various pathologies. During the surgical access to this region, a potential risk of iatrogenic injury of the vertebral artery exists, related to extended lateral access and the inadequate evaluation of the local anatomy. Variations in the groove of the vertebral artery lead to a greater risk of vascular injury during surgery. Preoperative image study of the vertebral artery anatomy and its groove has been realized to enhance surgical safety. OBJECTIVE: to study the morphometry of atlas vertebral artery on computed tomography scan images of the vertebral artery groove (VAG) in 30 dry atlas. METHODS: VAG and its relationship with the midline were evaluated through eight linear and two angular measures, bilaterally. The average, maximum and minimum values, and standard deviation were calculated for each parameter. RESULTS: VAG has shown to be wider and thicker on the left side (p<0,05). CONCLUSION: our data suggest that the posterior and superior dissection of the posterior arch must be made at lateral distance of 11,2mm and 7,4mm to the midline in order to provide safety during the procedure.

Microsurgical anatomy of the posterior circulation.

CONTEXT: The microsurgical anatomy of the posterior circulation is very complex and variable. Surgical approaches to this area are considered risky due to the presence of the various important blood vessels and neural structures. AIMS: To document the microsurgical anatomy of the posterior circulation along with variations in the Indian population. MATERIALS AND METHODS: The authors studied 25 cadaveric brain specimens. Microsurgical dissection was carried out from the vertebral arteries to the basilar artery and its branches, the basilar artery bifurcation, posterior cerebral artery and its various branches. Measurements of the outer diameters of the vertebral artery, basilar artery and posterior cerebral artery and their lengths were taken. RESULTS: The mean diameter of the vertebral artery was 3.4 mm on the left and 2.9 mm on the right. The diameter of the basilar artery varied from 3-7 mm (mean of 4.3 mm). The length varied from 24-35 mm (mean of 24.9 mm). The basilar artery gave off paramedian and circumferential perforating arteries. The origin of the anterior inferior cerebellar artery (AICA) varied from 0-21 mm (mean 10.0 mm) from the vertebrobasilar junction. The diameter of the AICA varied from being hypoplastic i.e., CONCLUSIONS: The authors have documented the various anomalies as well as the differences of the anatomy in this area in the Indian population as compared to the Western literature.

Estudo anatômico do trajeto da artéria vertebral na coluna cervical inferior humana / Anatomical study of the vertebral artery path in human lower cervical spine

O aumento da utilização de novas técnicas e materiais de síntese para o tratamento cirúrgico de afecções da coluna cervical baixa foi acompanhado da crescente preocupação em relação às complicações que podem ocorrer. A técnica de fixação transpedicular, amplamente utilizada para os outros níveis da coluna vertebral, quando realizada na coluna cervical, apesar de conferir maior estabilidade quando comparada a outras técnicas, pode cursar com complicações graves como lesão da artéria vertebral, lesão de raiz nervosa, além de lesão da articulação facetária. A vértebra C7, no entanto, é considerada mais segura para a realização de tal procedimento, já que, na grande maioria das pessoas, segundo os estudos anatômicos disponíveis, esta não possui a artéria vertebral dentro de seu forame transverso, pois este vaso irá penetrar tal estrutura apenas na vértebra C6. Como hoje existem apenas estudos de imagem para avaliação do trajeto desta artéria e suas variações anatômicas, realizamos este estudo anatômico dissecando 40 artérias vertebrais de cadáveres para avaliar a incidência das variações anatômicas. Encontramos 3 casos onde a artéria vertebral penetrou o forame transverso já em C7 (7,5 por cento), o que aumentaria o risco de uma técnica transpedicular neste nível. O restante das peças anatômicas possuíam anatomia habitual.

The increasing use of new techniques and materials for surgical treatment of lower cervical spine conditions has come along with an increasing concern regarding potential complications that might occur. The transpedicular fixation technique, frequently used in other spine levels, is used on the cervical spine, while providing more stability than other techniques, it may cause serious complications such as vertebral artery injury, nervous root injury, or facet joint injuries. However, the C7 vertebra is considered safer for performing this procedure, since, in the vast majority of people, according to available anatomical studies, does not have a vertebral artery passing through its cross-sectional foramen, because that vessel is inserted into such structure only on C6 vertebra. As there are only imaging studies available today for assessing the path of this artery and its anatomical variables, we conducted this anatomical study by dissecting 40 cadaver's vertebral arteries in order to assess the incidence of anatomical variations. We found 3 cases where the vertebral artery penetrated into cross-sectional foramen at C7 (7.5 percent), a fact that enhances the risk of an undesired injury with a transpedicular technique at this level. The other remaining specimens showed a usual anatomy.

Right vertebral artery: anomalous prevertebral course and distribution

Vertebral artery [VA] is the largest branch of the first part of the subclavian artery and the chief source of blood supply to brainstem, cerebellum, occipital lobe of cerebrum and posterior cranial fossa. Anomalous origin, course and / or branching pattern of VA may lead to disturbance in vertebro-basilar hemodynamics, risking cerebro-vascular insufficiency. A unique case of right VA having usual origin, but anomalous course and branching pattern in its prevertebral segment is described. Moreover the right thyrocervical trunk was absent in present case and inferior thyroid artery branched off the variant VA. The ligation of such vertebral artery may cause a compromise to thyroid in addition to posterior cranial fossa blood supply. The information about its course is crucial during diagnostic investigations and surgical procedures in the head and neck region