Galen

Galen was born around 129 in Pergamon, a city in western Asia Minor (in present-day Türkiye). His father was an architect and scholar, and Galen is said to have studied philosophy and mathematics from childhood before beginning his medical studies at about sixteen. After studying in leading centers of learning such as Pergamon, Smyrna, and Alexandria, he returned to his hometown and was appointed as a physician to gladiators. His daily experience observing and treating the varied injuries sustained in gladiatorial combat is said to have laid the foundation for his practical knowledge of anatomy.

He moved to Rome around 162, where he gained renown and served as a court physician to Emperor Marcus Aurelius and his son Commodus. He wrote hundreds of works in Greek, a substantial number of which survive today. His death is generally dated to around 216, though scholars' views differ somewhat.

At the time, human dissection was strictly prohibited in Roman society. Galen sought to uncover the structure of the human body by dissecting animals such as pigs, goats, and Barbary macaques and conducting experiments on living animals. His major areas of research included the following.

• Nerve function: He demonstrated experimentally that tying off or cutting the nerves leading to a pig's larynx caused it to lose its voice. He also cut the spinal cord at different segments to identify which parts of the body became paralyzed.
• Blood in the vessels: Through animal experiments, he demonstrated that arteries contain flowing blood rather than air.
• Antagonistic relationships between muscles: He described how muscles pull on bones to move joints, and how muscles that contract to produce movement in one direction are paired with muscles that act in the opposite direction.
• Classification of cranial nerves: He classified and organized the nerves extending from the brain into seven pairs.

The humoral theory that Galen systematized is also an essential part of medical history. Building on the teachings of Hippocrates, he held that the body contains four humors—blood, phlegm, yellow bile, and black bile—and that the balance among them determines health and disease. Although this explanation is not accepted in modern medicine, it had a profound influence for centuries in its attempt to understand an individual's temperament and overall bodily condition as an integrated whole.

Because he relied primarily on observations from animal dissections, many of his descriptions did not match human anatomy. He believed that blood was continually produced in the liver and consumed in peripheral tissues, and that invisible, tiny pores in the septum of the heart allowed blood to pass through. These errors were corrected through Andreas Vesalius's *On the Fabric of the Human Body*, published in 1543 and based on human dissection, and William Harvey's discovery of blood circulation in 1628. Even so, Galen retains a prominent place in medical history: one scholar's observations and experiments remained the medical standard for more than a thousand years.

Galen valued preventive care to maintain health as well as the treatment of disease. In works such as *On the Preservation of Health*, he addressed specific guidelines for exercise, diet, sleep, bathing, and massage. He also wrote a work recommending physical exercise using a small ball, *On Exercise with a Small Ball*. Particularly notable is his distinction between friction treatments used to prepare the body before exercise and those used to ease fatigue afterward. This is why his writings are often cited in discussions of the historical origins of manual therapies and bodily care before and after exercise. However, the intensity and methods of massage described in these texts were written from the perspective of ancient medicine, so they are better understood as historical records of a long tradition of bodily care rather than applied directly in practice.

In Galen's time, treating the body directly with the hands was one of a physician's important duties. Today's manual therapy, osteopathy, and modern hands-on therapies that work with fascia are not directly connected to ancient medical practice, but the basic premise—that precise hands-on work requires a thorough understanding of the body's structure—remains unchanged. In this sense, the practice of understanding muscles and nerves and caring for the body on the basis of anatomical knowledge connects with a long-standing tradition that began with Galen's observations.