Progress in Understanding Human Anatomy

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Progress in Understanding Human Anatomy

Overview

The great European Renaissance, or revival of thinking, had a major impact on the study of human anatomy. The development of medicine established by the Greeks and Romans, and imbued with a spirit of inquiry, had long served as the unchallenged standard of medical practice and belief. During the Middle Ages knowledge of the human body was enveloped with ignorance and superstition. A religious and cultural taboo against human dissection limited anatomical knowledge to what could be gleaned from the study of animal specimens.

All of this changed with the development of universities in Italy. Responding to the need of the times to understand the causes of death, anatomists began to challenge ancient traditions by performing dissections of the human body. They were aided by an unusual group of professionals, artists who sought to understand the nature of the body to perfect their craft. Another great invention, printing, enabled duplication of the text, and wood engraving enabled drawings and illustrations to help people understand anatomy.

One of the first great anatomists was Andreas Vesalius (1514-1564), who had an amazing impact because he made anatomy acceptable and questioned long held traditions of the past. As anatomy developed in the great universities beginning in Bologna, others began a study in earnest. Antonio Benivieni (1440?-1502) dissected cadavers to study disease and the cause of death, and his findings were published in 1507.

A professor, Johannes Dryander (1500-1560), made the first illustrations directly from cadavers and published these in 1537. By the middle of the sixteenth century public dissections became a matter of curiosity among the populace in general. Many of these were done in the town square and drew crowds from miles around. Heironymus Fabricius (1583-1619) worked on the Aristotle Project, which sought not only knowledge of structure, but also comparative understanding of anatomy.

By the end of the period, and moving into the 1700s, the state of anatomy had so changed that it could hardly be compared to the simple beginnings in the mid-fifteenth century.

Background

Gross anatomy is the term used to describe a systematic knowledge of the structure of the body. From the earliest times several things prevented organized investigation of both human and animal bodies. Social ideas against touching and cutting a dead body developed. Tampering with the body was believed to be tampering with the soul. Religious beliefs became enveloped with myth about anatomy. For example, the belief prevailed that men had one less rib than women, as set forth in the biblical story of the creation in Genesis, when God took a rib to made Eve.

Aristotle (384-322 b.c.) applied logical and rational thinking to biology, and his precepts of anatomy and physiology were based on animal observation. Empedocles (490?-430 b.c.) of Sicily was the first to introduce the theory of the four humors, which influenced medical thought for 2,000 years. It was believed that when the humors were out of balance, the person was sick. Hippocrates (460?-377? b.c.) adopted these ideas for use in clinical medicine. Within this theory of knowledge, anatomy is not considered useful and is subordinate to practice. Galen (130?-200?), in the same tradition, prided himself on being a fine clinician and adapted his knowledge from the study of apes, pigs, sheep, goats, and even an elephant's heart—but not humans. He knew much about the skeletal anatomy, but human dissection was out of the question. Galen drew on his knowledge of animal anatomy, combined with Hippocratic medicine and Platonic reasoning, to establish a hold on thinking for hundreds of years.

Mondino di Luzzi (1275-1326) was a professor of anatomy at Bologna who first introduced dissections of humans instead of pigs. He wrote the first textbook on anatomy, which remained popular for two centuries and emerged in a 79-page printed version in 1515.

Human dissection began toward the end of the thirteenth century at the University of Bologna. Although frowned upon by the Church and tradition, dissection became a necessity to find out causes of death. The great universities supported the dissections, which extended to Padua, Florence, Pisa, and Venice. Anatomy was still influenced by Galen, and the efforts at illustration were initially to support his beliefs.

During the fifteenth century a great change occurred in the general culture, inspired by the rediscovery of Greek work. The Renaissance of learning that exploded in the sixteenth century included the development of anatomy.

Impact

The influence of Leonardo da Vinci (1452-1519) on anatomy was not felt by his contemporaries in the medical community, but he did establish a pattern for medical artists that began slowly to expand through Italy first, then to other areas. His notebooks included methods for the study of the arm and forehand, motor muscles of the hands and wings, and actions of the muscles in breathing. Da Vinci led a group of painters, philosophers, and poets to commend the beauty of the human form. Their emblem became the Vetruvian man, the human form superimposed on the cosmos. This interest in the human body led naturally into interest in its physical structure and workings.

Da Vinci spent hours in his basement dissecting and studying corpses. He created about 750 anatomical drawings, and in 1489 planned an anatomical atlas of the stages of man from the womb to the tomb, although this was never completed. Some of the drawings of early anatomists indicated exposure to da Vinci.

With interest in everything Greek, the first anatomy text was written by Allessandro Benedeti (d. 1512) who lived 16 years in Greece, then came to Padua in 1490 as a professor of anatomy. The discovery of Galen's On Anatomical Procedures showed how to carry out a dissection. Galen had encouraged people to find out for themselves about anatomy. The only flaw was that he used animals not humans.

Enthusiastic about the work of Galen, Vesalius took up the challenge to examine anatomy firsthand and, as a result, became one of Galen's great critics. Born in Brussels, Belgium, Vesalius studied under Jacob Sylvius, Galen's great champion. In later years, Sylvius would become Vesalius's adversary due to Vesalius's criticism of Galen, and even called him a mad man. When war in 1533 forced Vesalius to flee Paris, he went to Louvain, where he introduced human dissection. At the time, criminals were left on a gibbet (the place of hanging) for public scorn. Vesalius secretly stole these bodies, smuggled their bones home, and reconstructed the skeleton.

In 1537 he went to Padua, a great institution for dissecting, although it was not mandatory for physicians. In 1538 he designed for his students Six Anatomical Pictures, a treatise still influenced by Galen's legacy. But as he found out more about anatomy, it became more unsettling. He began to challenge Galen and came to the conclusion that human anatomy must be learned through dissections. Dead bodies, not dead language, were the key to learning.

To do this, he got a huge supply of dead bodies of executed criminals and began his great masterpiece De humani corporis fabrica (On the Structure of the Human Body). He took the book to Basel where it was published in 1543. This book was a great turning point in medicine, for it promoted the understanding of the structures of the human body. At the time the artwork was thought to be done by the famous Italian painter Titian, but was later attributed to one of his assistants, a Dutch artist named Jan Stephen van Calcar (1499-1546). The poses are astounding, showing a body without skin standing or posing in front of landscapes of various kinds. Vesalius showed the human body was the key to medical knowledge.

Another aspect of anatomy emerged from the work of Antonio Benivieni, that of pathological anatomy, or autopsy, to find the cause of disease. A native of Florence, Benivieni studied medicine at Pisa and became a respected physician in his city. While practicing, he became convinced that autopsy was the only way to discover causes of disease. He observed gallstones, cancer of the stomach, peritonitis, and many other conditions. He published several books that were lost at the time, but were later found and published. His The Hidden Causes of Disease presented a new method of thinking in medical science—that of the discovery of cause of death by autopsy.

Heironymus Fabricius became a professor at Padua in 1565. He was not only interested in anatomical structure, but also comparative approach. He stressed three aspects of anatomy: description, action, and use of body parts. His most significant work on the valves of the veins laid the foundation for William Harvey (1578-1657) to develop this theory of blood circulation.

An interesting trend also developed in anatomy—that of public dissections. Because of plagues and other diseases, people became very curious about how these were transmitted and about the body in general. Public dissections became quite a spectacle.

In the 1520s anatomical drawings and texts increased in number, whetting further interest and curiosity. Johannes Dryander, a professor at Marburg, Germany, carried out the first public dissection. Dryander also created a trend in anatomy—specializing on one part. He wrote a treatise detailing the anatomy of the head. Rolfinck, also in Germany, continued the trend of public dissection into the 1600s.

Later anatomists specialized in the study of body parts. Bartolomeo Eustachio (1500-1574) produced a detailed study of the kidney and ear. He criticized Vesalius for studying the kidneys of a dog instead of those of a human, and dog's ears instead of man's. A structure of the ear, the Eustachian tube, is named for him.

Most scientists recognize Vesalius's 1543 publication as the beginning of the renaissance in medicine and anatomical inquiry. The anatomists opened the floodgate of medicine. Their interest in the structure of the human body naturally led to studies of how these structures function. Human physiology would soon develop.

EVELYN B. KELLY