Introduction: Galen of Pergamon stands in history as one of the first to acknowledge the importance of the brain as the hegemonikon or regent part of the body. Despite the limitations of Galen’s anatomical technique he was able to lay the foundation of vascular neuroanatomy and neurosurgery. This study reviews the literature of Galenic understanding of anatomy and theorised function of neurovascular structures.

Methods: The published works of Galen were consulted to critically review his anatomical methodology in dissection as well as his understanding neurovascular structure and function. These works included “On Anatomical Procedures”, “On the Doctrines of Hippocrates and Plato”, and “de Usu Partium”. These sources were supplemented with available modern and ancient literature to critically appraise its understanding of Galen.

Results: Galen’s methods, recorded in “On Anatomic Procedures” involved a combination of dissection and vivisection of animal subjects. Central to the Galenic understanding of neurovascular structures and function appears to be both the retiform plexus and the choroid plexuses. The retiform plexus a vascular network present only in non-primate mammals is described by Galen as a “fisherman’s net” structure of fine arterial supply closely associated with the pituitary infundibulum and floor of the third ventricle. Despite this anatomical error, Galen is able to provide a highly detailed account of the blood supply of the choroid plexuses and theorise their role in CSF production. In addition to anatomical dissection, Galen conducted a series of vascular ligation experiments of the internal carotid artery and theorised the presence of additional sources of vascular supply, the later termed Circle of Willis.

Conclusions: Although his methods used had clear limitations, Galen was able to come to an understanding of cerebrovascular structures that was to remain the foundation for generations to come and the origin of our modern anatomical understanding.

Patient Care: Understanding of surgical history provides its practitioners with a different contextual view of surgical practice and its evolution over time. This project also demonstrates the human ability to create and answer research questions which may guide modern research techniques.

Learning Objectives: By reading this poster participants should be able to: (1) Understand the foundation of cerebrovascular neurosurgery through the role of Galen (2) To gain an appreciation of critical appraisal of Galenic and other ancient works both through his contemporaries and also by modern standards (3) To establish a historical timeline of neurosurgical practices

References: Ancient Sources: Galen, "De Usu Respirationis" in Galen: On Respiration and the Arteries , eds. D. Furley & J.S. Wilkie, Princeton: Princeton University Press, pp. 194. Galen, On the doctrines of Hippocrates and Plato, ed. P. De Lacy (trans.). 1978-1984, Berlin: Akademie-Verlag. Galen, De usu partium. Helmreich G. (trans.) 1968. Amsterdam: A. M. Hakkert. Galen , On Anatomical Procedures. Singer, C. (trans.). 1956. London: Oxford University Press. Galen, On Anatomical Procedures: The Later Books. Duckworth, W.L.H. (trans.).Cambridge: Cambridge University Press. Modern Sources: DeGutierrez-Mahoney, C.G. & Schechter, M.M. 1972, "They myth of the rete mirabile in man", Neuroradiology, vol. 4, pp. 141-158. Harris, C.R.S. 1973, The heart and the vascular system in ancient Greek medicine, from Alcmaeon to Galen, Oxford: Clarendon Press. Rocca, J. 2003, Galen on the Brain: Anatomical Knowledge and Physiological Speculation in the Second Century A.D. Boston: Brill. Rocca, J. 1998, "Galen and Greek Neuroscience (Notes Towards a Preliminary Survey)", Early Science and Medicine, vol. 3, no. 3, pp. 216-240.