Left anterior cerebral artery arising from a right internal carotid artery: a rare case of carotid-anterior cerebral artery anastomosis.

Carotid-anterior cerebral artery anastomosis (carotid-ACA anastomosis) is described as infrequent vascular connections between the pre-ophthalmic segment of the internal carotid artery (ICA) and the A1 segment of the anterior cerebral artery (ACA). The embryological origin of these variant is still unclear and they are often associated to other vascular anomalies of the circle of Willis, as well as to the presence of aneurysms. Carotid-ACA anastomosis is often right-sided although left and bilateral cases have also been described. We report a rare case by MR angiography of a carotid-ACA anastomosis in which the abnormal vessel arises from the right ICA and takes an infraoptic course to join the A2 segment of the contralateral ACA, making this vascular anomaly function as a 'left ACA with an origin at the right ICA'. The A1 segment of the left ACA is absent and both A2 segments of the ACAs present fenestration. To our knowledge, no similar cases have been reported in English literature so far.

Persistent trigeminal artery: a cross-sectional study based on over 3 years conventional angiography, CT angiography and MR angiography images.

PURPOSE: The trigeminal artery is one of the four primitive anastomosis established between the internal carotid artery and the vertebrobasilar system that regresses at the sixth week of embryonic development. Its persistence in adult life (PTA) is usually found incidentally. The aim of this study is to determine its prevalence, main characteristics and clinical significance. METHODS: A cross-sectional study was performed over the last 3 years, 2012-2014, to analyze images performed on conventional angiography, CT angiography and MR angiography of patients who attended the Neuroradiology Department of the Hospital Universitario Doce de Octubre in Madrid, Spain, to control their underlying pathology. RESULTS: Nine cases of PTA were found (prevalence 0.37 %, two men, seven women; three right, six left; age range 13-88 years). Eight PTA emerged from the cavernous ICA and one from the petrous segment. Six cases were lateral or petrosal type and one was medial or sphenoidal type. The whole PTAs anastomosed the BA, six at the middle third and three at the distal third. Weon et al.'s type 3 was predominant. CVD incidence was 55.6 % and aneurysm incidence was 22 %. CONCLUSIONS: PTA prevalence was similar to those previously reported, being commonly left-sided, Salas et al.'s lateral or petrosal type, Weon et al.'s type 3 and with no gender predominance. CVD and aneurysms incidence in the presence of a PTA were higher than in general population. Its anatomical relations make it essential to consider its presence and directional blood flow when planning endovascular and neurosurgical treatments.

Thomas Willis, a pioneer in translational research in anatomy (on the 350th anniversary of Cerebri anatome).

The year 2014 marked the 350th anniversary of the publication in London of Cerebri anatome, a ground-breaking work of neuroscience heavily influenced by the political and cultural context of Baroque Europe and mid-17th century England. This article aims to review the work of the English physician and anatomist Thomas Willis, specifically with regard to the contents of his Cerebri anatome. Willis's academic and professional career was influenced by the turbulent period of the English Civil War during which he studied medicine. Willis went from chemistry to dissection arguably because of his need to justify the body-brain-soul relationship. As a result, he became a fellow of a select club of eminent experimentalists, and afterward was a Fellow of the Royal Society. Later on, he went to London, leaving the academic life to dedicate himself fully to the profession of medicine. As a physician, Willis did not base his practice on aphorisms but on a 'bench to bedside' approach to medicine, while studying neuroanatomy--covering embryology, comparative anatomy and pathological anatomy--as a basis for the comprehension of neurological pathology. He developed innovative anatomical methods for the preservation and dissection of the brain, injection of coloured substances and illustration of his findings. In Cerebri anatome, Willis recognized the cerebral cortex as the substrate of cognition. He also claimed that the painful stimuli came from the meninges, but not from the brain itself. He explained for the first time the pathological and functional meaning of the brain's circular arterial anastomosis, which is named after him. He also specified some features of the cranial origin of the sympathetic nerves and coined the term 'neurologie'. Cerebri anatome marked the transition between the mediaeval and modern notions of brain function, and thus it is considered a cornerstone of clinical and comparative anatomy of the nervous system. The new contributions and methods employed by Willis justify his place as a father of neurology and a pioneer of translational research.