Hippocrates, Galen, and the Uses of Trepanation in the Ancient Classical World

Symeon Missios, M.D.


Neurosurg Focus. 2007;23(1):E11 

In This Article

Galen and the Teaching of Trepanation

Six centuries after the birth of Hippocrates, the evolution of ancient medicine and neurosurgery reached another milestone with the studies and writings of Galen of Pergamon (AD 129-200; Fig. 3). Galen, whose name in Greek (Γαλην´ος) means "peaceful," was born in the city of Pergamon in Asia Minor (now Turkey). His father, Aelius Nicon, was an architect and a scholar, with interests in mathematics, astronomy, philosophy, and Greek literature. Galen grew up in an environment of intellectual stimulation and strong scholarly tradition, at a time when the Hellenic element was becoming increasingly strong within the Roman world and Greek aspects of learning and the Greek language were being used more extensively.[22]

Figure 3.

Galen. Lithograph by Pierre Roche Vigneron (Paris: Lith de Gregoire et Deneux, ca. 1865). Courtesy of the US National Library of Medicine.

Figure 4.

Photograph of the first page of Synopsis de Pulsibus (Venice, ca. 1550), the Greek manuscript of Galen's treatise on the pulse, interleaved with a Latin translation. Courtesy of the US National Library of Medicine.

According to legend, the gods instructed Nicon to urge his son to study medicine, and for 4 years Galen studied at the Aesculapion of Pergamon, a sanctuary to the god of healing and a site where medical knowledge and religious activities, healing, and superstition blended.[24] After his father's death in 150 AD, Galen traveled to Smyrna, Corinth, and Alexandria. He spent 4 years at the Alexandrian school of medicine, where he studied anatomy and physiology and was exposed to the tradition of Herophilus and Erasistratus. He returned to Pergamon in 157 AD, at the age of 28, and began to practice medicine as a physician appointed to the gladiators. The gladiators' injuries provided Galen with ample opportunities to expand his knowledge of anatomy, physiology, and treatment, to gain valuable practical experience in trauma, and thereby to produce some of his most original work.

In 163 AD, Galen moved to Rome, where his work, anatomical studies, passion for knowledge, and success as a physician quickly distinguished him from the established authority of Roman physicians. In 168 AD, Galen joined the emperor Marcus Aurelius, and in 169 AD he was appointed personal physician to Commodus, the emperor's son. Under the protection of the Roman Empire, Galen continued his studies, teachings, and writings. In 191 AD, a fire destroyed important parts of Galen's work, but he was not dissuaded, and he spent the next few years of his life, until his death in 200 AD, continuing his medical research and writings and producing major works.[25]

The Works and Philosophy of Galen

Galen's works included over 500 lectures, books, and treatises, written in Attic Greek and totaling more than 4 million words.[8,24,28] Unfortunately, due to the fire of 191, only a sample has survived across the centuries. His works encompass every aspect of medicine and describe important advances in anatomy, physiology, and treatment. His contribution to our knowledge of the nervous system, neuroanatomy, and neurosurgery is vast. Galen described the corpus callosum, ventricular system, fornix, tectum, pineal and pituitary glands, and the cranial nerves.[8,24,27] He identified the recurrent laryngeal nerve in animals and recognized its association with voice changes.[8] He recognized that spinal trauma can affect the use of limbs and described the peripheral nervous system and its relationship to the spinal cord. Studies of the ventricular system allowed him to recognize and describe the symptoms and signs of hydrocephalus.[8,23,30] He improved the technique of trepanation and defined its use, which became more widespread. Galen's work, based on the foundations of the Hippocratic corpus, collected all preceding medical knowledge, developed it, expanded on it, and shaped the practice of medicine for the centuries to come.

The quest for intellectual supremacy within a rigid system of logic, reason, and experience dominates Galen's teachings. Galen never disputed the works of Hippocrates and was respectful of the legacy of the knowledge passed on by his predecessors, yet he admitted that they were at

times obscure and that the knowledge should be used as a foundation for future scientific discovery only.[24] Galen was exposed to various medical sects and was intolerant of several of his colleagues because of their ignorance and superficial knowledge of medicine.[5] Galen advocated philosophical training for all physicians and the use of proven principles and logical progression in the gain of new medical knowledge, the same way a mathematician uses proven theorems to advance his field. Through his experiments and dissections, Galen sought to demonstrate the workings of the human body in an indisputable and undeniable way. He stressed the importance of anatomical knowledge for practicing surgeons:[2]


If a man is ignorant of the position of a vital nerve, muscle, artery or important vein, he is more likely to maim his patients or to destroy rather than save life. [30]

Galen's work on both the science and the philosophy of medicine ushered medicine and neurosurgery through the classical period, and his writings served as the basis of knowledge regarding the nervous system through the Renaissance until the end of the 16th century.

Galen's Teaching on Trepanation

Galen lived in an era when trepanation was better known and more accepted by the practicing physicians as well as the public. He advocated use of the procedure for relief of intracranial pressure and drainage of phlegmatous lesions.[22] Galen was aware of and accepted Hippocrates' description of head trauma and the classification of the five different types of head injuries. The treatise On Injuriesof the Head is mentioned in three of the surviving works of Galen: De methodo medendi libri, In Hippocratislibrum de officina medici commentarii, and In Hippocratislibrum primum epidemiarum.[24] The traditional teaching of protecting the meninges persists, and Galen describes the importance of safeguarding the dura and protecting its integrity. Galen's works describe the technique and tools of trepanation and the use of the procedure for both clinical and research purposes.[22]

Trepanation is used in clinical practice for the relief of intracranial hematomas in the case of head trauma, as well as the drainage of "phlegmatous" lesions of the head.[22] Its use is also expanded to include the repair of depressed skull fractures. The patients typically sat up in order to allow blood to drain and to prevent obstruction of the surgical field, which was important in a time without suction and proper lighting. Hemostasis was an important issue, particularly because the scalp is so well vascularized. The incision was intended to suppurate, drain, and then heal slowly, and the wound was designed to be left open and heal by secondary intention and never by tight packing.[1]

Several substances were applied to scalp incisions and trepanation wounds for both hemostatic and medicinal purposes. Most of these substances acted as chemical irritants, and their application created a local inflammatory reaction and osteitis, which can be identified on skull remains as erosion of the bone along the trepanation site. Nevertheless, sometimes application of these chemical irritants also served an antiseptic purpose because they impeded bacterial growth as well.[1] Hippocrates advised application of a "jet-black ointment" of unknown consistency, followed by application of an oil-smeared linen rag and then linen soaked in cataplasm (a boiled mixture of flour and vinegar) in wounds in which the degree of bone damage cannot be determined. Galen described application of mixtures of vinegar, honey, and sea salt in rain water as well as ointments, which included medicinal plant extracts, pigeon blood, and black coral powder.[13]

The danger of injury to the meninges from free bone fragments is identified, and trepanation and wound exploration and removal of bony fragments become the treatment for such injuries. Galen advises all physicians to apply their knowledge and practice their surgical skills first on animals. For surgical practice, he recommends using heads of animals that are most similar to humans, such as apes, and for the study of anatomy, animals with large brains and easily identifiable structures, such as oxen.[22,24] He discusses the importance of minimizing blood loss and protecting the dura, and he states that the only way to gain proficiency is through knowledge of anatomy, repetition, experimentation, and practice. Galen's descriptions of the procedure reveal that he had extensive personal experience and was highly skilled in its practice. He was familiar with the dangers associated with the procedure and the effects of too much pressure on the exposed brain. In Delocis affectis he states:


If one presses too hard while treating the fractured bones of the skull by trepanation, the patients immediately lose all sensation and becomes motionless. [22,24]

And in De placitis Hippocratis et Platonis:


For when we chisel out the fragments of bone we are compelled for safety to put underneath the so-called protectors of the meninx, and if these are pressed too heavily on the brain, the effect is to render the person senseless as well as incapable of all voluntary motion. [24]

The effect of such an injury is, however, often attributed not to brain parenchymal damage, but to pressure on the ventricular system, an assumption Galen made based on his vivisection experience.[24,30]

Galen himself performed numerous dissections and often employed trepanation for research purposes during his vivisections and study of the brain in vivo. In his work OnAnatomical Procedures he describes one of his vivisections:


Insert a hook into the dura mater and draw it upwards. Then first cut through the piece of it that has been raised, so that it may not make contact with the part of the brain lying underneath it. . . . Should the dissection be thus performed, then after you have laid open the brain and divested it of the dura mater, you can first of all press down upon the brain on each one of its four ventricles, and observe what derangements have afflicted the animal. . . . And when one presses down upon that ventricle which is found in the part of the brain lying at the nape of the neck, then the animal falls into a very heavy and pronounced stupor. . . . And if the incision should have been imposed upon the fourth . . .ventricle then the animal seldom returns to its natural condition. [4,23,27]

Comparing the effects of different ventricular lesions, he states that

incising the posterior ventricle harms the animal the most, and next after that the middle ventricle. Incising each of the anterior ventricles causes a less serious injury, but of greater degree in older animals, a lesser degree in the young.[22,27]

He accurately observes that compression of the brain and the ventricles leads to mental status changes and stupor, which are reversible with time, and that injuring the ventricles, particularly the fourth ventricle ("the posterior ventricle"), leads to more severe and irreversible mental status depression and coma.

Tools of Trepanation

In Galen's time, many more instruments had been added to the physicians' armamentarium, and the technique of trepanation had become more sophisticated. Galen describes the use of various trepans, some of which are guarded drills designed to minimize the danger of dural injury. The "crown trephine" (χοινικ´ις) lacked a guard and was used for removing bone and gaining intracranial access. The "drill trepan" (τρ´υπανον) was used in a technique of making multiple perforations on the bone in a circumferential fashion in order to facilitate bone removal. A guarded drill version of that instrument was also used and was termed the abaptiston (αβ´απτιστον). The guarding mechanism often involved a way to set the length of the drill prior to the procedure. Galen also describes the use of the meningophylax (ìηνιγγοφ´υλαξ), the "dural protector," a flat piece of metal that was passed through fracture fissures under the bone and over the dura and served as another layer of protection.[18,22] Specifically for the repair of skull fractures, Galen preferred using a chisel to remove the bone around the fracture and recommends against the use of a trepan, which he considers a practice of the "ancients."


All kinds of fractures of the skull are treated by chiseling out the fractured parts, cutting clear round the fracture with the chisel. The ancients used to cut them out with circular trephines which they rotated, later head augurs were employed, which gave starting points for the chisels. For the moderns the chisels alluded to above suffice. [6,30]

Galen's Study of Hydrocephalus

Galen was a pioneer in the study of hydrocephalus. He described cases of the condition, classified different types of hydrocephalus according to the anatomical compartments he considered affected, and offered recommendations for surgical treatment. In his work Introductio seuMedicus he writes:


There are four kinds of hydrocephalus, one between the brain and the meninges, one between the membranes and the bone, one between the bone and the pericranium and one between the bone and the skin. In the skin occur favus (a dermatophyte skin infection), wens (sebaceous cysts), and on the outside, baldness. For favus or wens we make either a straight or curved incision on the surface, and pull out the sac with the fingers and remove them with the fluid contained in them. Hydrocephalus under the skin and pericranium we empty by two or three incisions. Those beneath the bone we chisel out. Those between the meninges and the brain do not admit treatment. [6,30]

A case that illustrates the use of trepanation for the treatment of hydrocephalus involves the 1995 discovery on the site of the ancient town of Fidenae (along the suburbs of Rome) of the skeleton of a child who had hydrocephalus described by Mariani-Constantini et al.[13] The cranium had been well preserved and bore the mark of a 5 x 3 5–cm trepanation orifice along the frontoparietal region. There was evidence that a blunt surgical instrument was used, most likely a chisel, and the borders of the orifice displayed the evidence of osteitis following the procedure.[13] Further analysis of the skull and the location of indentations and vascular grooves suggests evidence of chronic shift of the intracranial contents, probably the result of a supratentorial mass. Most likely the child was afflicted by a brain tumor, which led to hydrocephalus and the development of macrocephalic features. The trepanation would have been performed in order to relieve symptoms associated with the increased intracranial pressure. The skull markings indicate that the procedure was done while the child was alive and that the child lived for a few weeks after the procedure.[13]


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