History of anatomy

The history of anatomy as a science extends from the earliest examinations of sacrificial victims to the sophisticated analyses of the body performed by modern scientists. It has been characterized, over time, by a continually developing understanding of the functions of organs and structures in the body. Methods have also advanced dramatically, advancing from examination of animals through dissection of cadavers to technologically complex techniques developed in the 20th century.

Egypt
The study of anatomy begins at least as early as 1600 BCE, the date of the ancient Egyptian Edwin Smith papyrus. This treatise shows that the heart, its vessels, liver, spleen, kidneys, uterus and bladder were recognized, and that the blood vessels were known to come from the heart. Other vessels are described, some carrying air, some mucus, and two to the right ear are said to carry the "breath of life", while two to the left ear the "breath of death". The Ebers papyrus (c. 1550 BCE) features a treatise on the heart. It notes that the heart is the center of the blood supply, with vessels attached for every member of the body. The Egyptians seem to have known little about the function of the kidneys and made the heart the meeting point of a number of vessels which carried all the fluids of the body – blood, tears, urine and sperm. .

Greece
The earliest medical scientist of whose works any great part survives today is Hippocrates, a Greek physician active in the late 5th and early 4th centuries BCE (460 - 377 BCE). His work demonstrates a basic understanding of musculoskeletal structure, and the beginnings of understanding of the function of certain organs, such as the kidneys. Much of his work, however, and much of that of his students and followers later, relies on speculation rather than empirical observation of the body.

In the 4th century BCE, Aristotle and several contemporaries produced a more empirically founded system, based on dissection of animals. Works produced around this time are the first to identify the difference between arteries and veins, and the relations between organs are described more accurately than in previous works.

The first use of human cadavers for anatomical research occurred later in the 4th century BCE when Herophilos and Erasistratus performed dissections of cadavers in Alexandria under the auspices of the Ptolemaic dynasty. Herophilos in particular developed a body of anatomical knowledge much more informed by the actual structure of the human body than previous works had been.

Galen
The final major anatomist of ancient times was Galen, active in the 2nd century. He compiled much of the knowledge obtained by previous writers, and furthered the inquiry into the function of organs by performing vivisection on animals. His collection of drawings, based mostly on dog anatomy, became the anatomy textbook for 1500 years. The original text is long gone, and his work was only known to the Renaissance doctors through the careful custody of Arabic medicine. Hampered by similar religious restrictions as anatomists for centuries after him, Galen assumed that anatomical structures in dogs were the same as for humans.

Medieval to early modern anatomy
Little progress was made in anatomy for some time after the fall of the Roman empire. Although Arab scientists contributed heavily to medieval learning and culture, taboos against handling corpses limited their contributions to anatomical research. The first major development in anatomy after Galen occurred at Bologna in the 14th to 16th centuries, where a series of authors dissected cadavers and contributed to the accurate description of organs and the identification of their functions. Prominent among these anatomists were Mondino de Liuzzi and Alessandro Achillini.

The first challenges to Galen also occurred in the 16th century. Thanks to the printing press, all over Europe a collective effort proceeded to distill the original Galen from the various, mostly Arab, added texts. Vesalius was the first to publish a treatise, De humani corporis fabrica, that challenged him "drawing for drawing" travelling all the way from Leuven to Padua for permission to dissect victims from the gallows without fear of persecution. His drawings are triumphant descriptions of the, sometimes major, discrepancies between dogs and humans, showing superb drawing ability. Many later anatomists challenged Galen in their texts, though Galen reigned supreme for another century.

A succession of researchers proceeded to refine the body of anatomical knowledge, giving their names to a number of anatomical structures along the way. The 16th and 17th centuries also witnessed significant advances in the understanding of the circulatory system, as the purpose of valves in veins was identified, the left-to-right ventricle flow of blood through the circulatory system was described, and the hepatic veins were identified as a separate portion of the circulatory system. The lymphatic system was also identified as a separate system at this time.

17th and 18th century anatomy
The study of anatomy flourished in the 17th and 18th centuries. The advent of the printing press facillitated the exchange of ideas. Because the study of anatomy concerned observation and drawings, the popularity of the anatomist was equal to the quality of his drawing talents, and one need not be an expert in Latin to take part. Many famous artists studied anatomy, attended dissections, and published drawings for money, from Michelangelo to Rembrandt. For the first time, prominent universities could teach something about anatomy through drawings, rather than relying on knowledge of Latin. The only impediment was a possible reprimand from the Church, which frightened several anatomists of that time from performing dissections on their own kind. Though a very fruitful period for the sciences, the Renaissance could be dangerous, as seen in the case of Galileo. Some scientists were scared enough to keep moving from city to city. Descartes is a prime example. Only certified anatomists were allowed to perform dissections, and sometimes then only yearly. These dissections were sponsored by the city councilors and often charged an admission fee, rather like a circus act for scholars. Many European cities, such as Amsterdam, London, Copenhagen, Padua, and Paris, all had Royal anatomists (or some such office) tied to local government. Indeed, Nicolaes Tulp was Mayor of Amsterdam for three terms. Though it was a risky business to perform dissections, and unpredictable depending on the availability of fresh bodies, attending dissections was perfectly legal. Many anatomy students traveled around Europe from dissection to dissection during the course of their study - they had to go where a fresh body was available (eg after a hanging) because before refrigeration, a body would decay rapidly and become unsuitable for examination.

Many Europeans interested in the study of anatomy traveled to Italy, then the center of anatomy. Only in Italy could certain important research methods be used, such as dissections on women. M. R. Columbus and Gabriele Falloppio were pupils of Vesalius, the 16th century anatomist. Columbus, as his immediate successor in Padua, and afterwards professor at Rome, distinguished himself by rectifying and improving the anatomy of the bones, by giving correct accounts of the shape and cavities of the heart, of the pulmonary artery and aorta and their valves, and tracing the course of the blood from the right to the left side of the heart, by a good description of the brain and its vessels, and by correct understanding of the internal ear, and the first good account of the ventricles of the larynx. Osteology at nearly the same time found an assiduous cultivator in Giovanni Filippo Ingrassias.

19th century anatomy
During the 19th century, anatomists largely finalised and systematised the descriptive human anatomy of the previous century. The discipline also progressed to establish growing sources of knowledge in histology and developmental biology, not only of humans but also of animals. Extensive research was conducted in more areas of anatomy. England was particularly important in this research. Demand for cadavers grew so great there that body-snatching and even murder came into use as a means of obtaining them. In response, parliament passed the Anatomy Act 1832, which finally provided for an adequate and legitimate supply of corpses. The relaxed restrictions on dissection provided a suitable environment for Gray's Anatomy, a text that was a collective effort and became widely popular. Now seen as unwieldy, Gray's Anatomy was born out of a need to create a single volume on anatomy for the traveling doctor.

Modern anatomy
Anatomical research in the past hundred years has taken advantage of technological developments and growing understanding of sciences such as evolutionary and molecular biology to create a thorough understanding of the body's organs and structures. Disciplines such as endocrinology have explained the purpose of glands that anatomists previously could not explain; medical devices such as MRI machines and CAT scanners have enabled researchers to study the organs of living people or of dead ones. Progress today in anatomy is centered in the field of molecular biology, as the macroscopic aspects of the field have now been catalogued and addressed.