Herophilus , a Greek anatomist, born at Chalcedon in Bithynia, flourished about 300 B. 0. He lived at Alexandria, where he acquired great reputation both as a teacher and practitioner. He is generally thought to have been the first who actually studied and taught anatomy from the dissection of human bodies; and he no doubt practised this method to a far greater extent than had previously been done. His investigations in human anatomy were marked by so much originality and exactness, that a large number of the anatomical names now in use date from him. He first distinguished the nerves from the tendons, with which they had previously been confounded, and showed that they originate from the brain. He recognized the principal membranes of the brain and the eyeballs, and gave them their names of arachnoid, retina, etc. The confluence of the great longitudinal and lateral sinuses of the brain is still called the torcular Herophili; and the first division of the small intestine retains the designation, duodenum, which he gave to it.

He is also said to have examined to some extent the internal organs, for the purpose of investigating the nature and cause of the disease which produced death; thus laying the foundation of the science of pathological anatomy, the study of which was recommenced by Morgagni, 2,000 years later. The original works of Herophilus have long been lost, with the exception of a few fragments, and are now known mainly through quotations by Galen and others.