A frequência da artéria calosomarginal foi estudada em 52 cérebros humanos, adultos e de ambos os sexos. Neste estudo foram considerados a origem e os padrões de ramificação da artéria calosomarginal. Com bases no trabalho de Watts23 em primatas subhumanos, foi proposta uma hipótese do significado evolutivo da artéria calosomarginal.

The neuroanatomic study of the callosomarginal artery was performed bv simple and careful dissection in 52 human brains. The observation was made with stereoscopic magnifying glass. The results were the following: the callosomarginal artery was present in 36.6% (19/52) of the cases on the right hemisphere and 29%(15/52) on the left hemisphere; unilateral absence on those hemispheres was of 17.3%(9/52) and 25.0%(13/52), respectively; bilateral absence was of 46.1% (24/52). The register of the presence or absence of the artery was based on proposed criteria by Moscow and col.14. With regard to phyllogenetic signification one has considered the hypothesis that the development of the callosomarginal artery possibly was closely related with a structural and physiological expansion of the neocortex in man.

Estudo neuroanatômico da artéria orbitofrontal, considerando frequência, origem e distribuição, foi realizado em 50 encéfalos humanos, dissecados sob lupa estereoscópica. Os resultados alcançados contribuem para caracterizar este ramo da artéria cerebral anterior como entidade anatômica bem definida. Do ponto de vista filogenético, foi considerada a hipótese de homologia entre a artéria orbitofrontal e os ramos orbitário posterior e orbitário anterior dos primatas sub-humanos.

The neuroanatomic study of the orbitofrontal branch of the anterior cerebral artery was performed by simple and careful dissection in 50 human brains. The observation was carried out with stereoscopic magnifying glass. The results with regard to frequency and origin of the artery were the following: the orbitofrontal artery was present in 90% (45/50) of the cases on the right hemisphere and 92% (46/50) on the left hemisphere; in 26 cases (52%) on the right side and 34 cases (68%) on the opposite side, the artery arose between anterior communicating and frontopolar arteries; in 19 cases (38%) on the right side and 12 cases (24%) on the left side the vessel was not the classical first branch of the postcommunical segment of the anterior cerebral artery, it arose between the Heubner artery and the frontopolar artery. With regard at filogenetic signification of the orbitofrontal artery it has been formulated the hypothesis that the artery is homologous to posterior and anterior orbital branches of the anterior cerebral artery described by Watts in sub-human primates.

A freqüência e os padrões de ramificação da artéria mediana do corpo caloso foram determinados em 130 encéfalos humanos adultos, de nordestinos brasileiros, com o auxílio de lupa estereoscópica. A artéria esteve presente em 89,2(116/130) dos casos, sendo que ela constituiu um vaso calibroso em 20% (26/130) dos encéfalos examinados. Em todos os exemplares, a artéria mediana do corpo caloso, calibrosa ou não, sempre originou ramos bilaterais para ambos os hemisférios, inexistindo os tipos uni-hemisférios exclusivos. Foi notada a grande semelhança entre o padrão bi-hemisférico típico e os padrões da artéria cerebral anterior ímpar dos animais inferiores, sem contudo ser possível estabelecer relação de identidade entre os dois vasos. Outrossim foi formulada uma hipótese segundo a qual a artéria mediana do corpo caloso teria evoluido a partir da fusão dos ramos da artéria anterior ímpar, destinados ao suprimento do ramo caloso.

The neuroanatomic study of the median artery of the corpus callosum was performed by simple and careful dissection in 130 adult brains from northeasterner brazilians. The observation was realized with stereoscopic magnifying glass. The median artery of the corpus callosum was present in the 89,2% (116/ 130) of the cases. The artery exibited a gross caliber in 20% (26/130) of the specimens with the following patterns: a) in twelve brains (six on the right side and six on the left side) the median artery of the corpus callosum displaied a "predominant" unihemispheric pattern with regard to the distribution of their branches, and supplied the territory of the pericallosal artery of the correspondent side. The term "predominant" was used considering that in all the cases the artery supplied branches to the medial surfaces of both the cerebral hemispheres; b) in ten examples the median artery of the corpus callosum was a single trunk which then passed into the longitudinal cerebral fissure, and as an unpaired artery it supplied branches to the medial surfaces of both hemispheres; c) finally, in four cases, the median artery of the corpus callosum, at the level of the rostrum of the corpus callosum originated the two pericallosal arteries. With regard at filogenetic origin of the median artery of the corpus callosum it has been formulated the hypothesis that the artery possibly was originated by fusion of the callosal branches of the unpaired anterior cerebral artery of lower forms.

O presente estudo teve como objetivo estabelecer a frequência de anastomoses potenciais na metade posterior do círculo arterial do cérebro em 87 encéfalos de nordestinos brasileiros, falecidos sem manifestação neurológica aparente. O padrão fetal do segmento inicial da artéria cerebral posterior (ramo comunicante posterior) ocorreu em 46% (40/87) dos casos. A frequência com relação ao lado foi a seguinte: 21,8% (19/87) no lado direito, 13,8% (12/87) no lado esquerdo e 10,4% (9/87) bilateral. Anastomoses potenciais bilaterais e unilaterais, ao nível dos ramos comunicantes posteriores com padrão fetal ou grosso calibre (Padget, 1948 3), estiveram presentes em 71,2% (62/87) dos círculos arteriais; nos 25 casos restantes (28,8%) os ramos comunicantes apresentaram, nos dois lados, calibre muito pequeno. As várias alternativas de anastomoses potenciais entre os sistemas carotídeo e vertebrobasilar, ao nível da porção posterior do círculo arterial do cérebro, são identificadas com as suas respectivas frequências.

This neuroanatomic study has been performed to establish the frequency of potenciais anastomosis in the posterior portion of the cerebral arterial circle in 87 brains from northeasterner brazilians without any aparent clinical manifestations of neural dysfunction. The fetal pattern of the posterior communicating branch was present in the 46% (40/87) of the cases. The frequency with regard to side was the following: 21,8% (19/87) on the right side; 13,8% (12/87) on the left side and 10,4% (9/87) bilateral. The bilateral and unilateral potenciais anastomosis at level of the posterior communicating branches, with fetal pattern or with gross caliber (Padget, 19483), were present in the 71,2% (62/87) of the arterial circles. The bilateral potenciais anastomosis were formed by two posterior communicating branches with fetal pattern in the 10,4% (9/87) of the cases, by two of those vessels of gross caliber in the 11,5% (10/8/) of the circles, and by one fetal posterior communicating branch, and one contralateral posterior communicating branch of gross caliber in the 13,8% (12/87) of the cases. Unilateral potenciais anastomosis constituted by fetal posterior communicating branch (21,8%) or by posterior communicating branch with gross caliber (13,8%) ocurred in the 35,6% (31/87) of the arterial circles.