Journal of Perinatology (2020) 40:688 https://doi.org/10.1038/s41372-020-0610-8 CORRESPONDENCE Contributions of Ibn Alnafis to the correct understanding of the circulation Ahmed Osman 1 Received: 31 December 2019 / Revised: 28 January 2020 / Accepted: 4 February 2020 / Published online: 12 February 2020 © Springer Nature America, Inc. 2020 To the Editor: I read with great interest the elegant review of the history of ductus arteriosus presented by Raju [1]. However, some additional clarification may further our understanding of the progress towards a correct understanding of the circu- lation, from Claudius Galen (130—200 CE) to Andreas Vesalius (1514–1564). Many physicians and scientists— who were not facing allegations of heresy—made sig- nificant contributions to medicine, including challenging Galen’s doctrine of the circulation in the Middle Ages [2]. Ibn Alnafis (1210–1288 AD) stands out among those scholars as the first to describe the pulmonary circulation and introduce the concept of coronary circulation [3]. Ibn Alnafis wrote in his book: Sharah Al Tashreeh Al Qanon (Commentary on anatomy of the Canon of Avicenna): “The blood from the right chamber of the heart must arrive to the left chamber, however, there is no direct pathway between the two sides. The thick septum of the heart is not perfo- rated and has no visible pores as some people thought (referring to Avicenna) or invisible pores (in reference to Galen). The blood from the right chamber must flow through the vena arteriosa (pulmonary artery) to the lungs, spread through its substance, be mingled with air while in the lungs, pass through the arteria venosa (pulmonary vein) to reach the left chamber of the heart to form the vital spirit…” [4]. Andrea Alpagus (1450–1522), a professor of medicine at Padua University who spent many years in Syria, translated Ibn Alnafis’s writings into Latin. This translation was printed in Italy in 1547. Michael Servetus (1511–1553) published his second revised issue of “Christianismi Res- titutio” in 1553 where he included a description similar to that of Ibn Alnafis. Although he didn’t make reference to Ibn Alnafis, it is very likely he was influenced by him [5]. Two other University of Padua professors, Realdo Colombo (1516–1559) and Andrea Vesaluis (1514–1564), subse- quently described the same pulmonary circulations in their respective books [5]. Compliance with ethical standards Conflict of interest The author declares that he has no conflict of interest. Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. References 1. Raju TN. From Galen to Gross and beyond: a brief history of the enigmatic patent ductus arteriosus. J Perinatol. 2019;39:1442–8. 2. Ranhel AS, Mesquita ET. The middle ages contributions to cardi- ovascular medicine. Braz J cardiovascular Surg. 2016;31:163–70. 3. Aird WC. Discovery of the cardiovascular system: from Galen to William Harvey. J Thrombosis Haemost. 2011;9:118–29. 4. Numan MT. Ibn Al Nafis: his seminal contributions to Cardiology. Pediatr Cardiol 2014;35:1088–90. 5. Abdel-Halim RE. The missing link in the history of circulation. Neonatology 2011;99:311. * Ahmed Osman ahmed.osman@nationwidechildrens.org 1 Department of Pediatrics, The Ohio State University and Nationwide Children’s Hospital, Columbus, OH, USA 1234567890();,: 1234567890();,: