Works of François Xavier Bichat

Marie François Xavier Bichat (14 November 1771 – 22 July 1802) is known as the father of histology. In a few years of vigorous research following the French Revolution, François Xavier Bichat, a young genius from Lyons working in Paris, attempted to define the properties of life by exploring aspects of existence that disappeared with death.

His methods were both anatomical (he adopted the notion of tissues as anatomical structures and used surgical methods) and philosophical (he classified life functions into two types: animal and organic).

For Bichat, chemistry possesses its simple bodies, which by various combinations, form compound bodies; likewise anatomy has its simple tissues, which by combining compose the organs.

Bichat’s central theoretical innovation, set forth in his 1800 Treatise on Membranes, was the substitution of the membrane unit in the analysis of health and disease.

Building on the tradition of pathological anatomy established by Giovanni Battista Morgagni, Bichat insisted that diseases could not correctly identified as diseases of specific organs, but as diseases of specific tissues.

Two years later after publication of Treatise on Membranes he produced General Anatomy Applied to Physiology and Medicine.
Works of François Xavier Bichat

Mondino de Luzzi

The dissection of human corpses had only taken place in Alexandria, and even then its practice was brief, perhaps lasting no more than a hundred years.

Mondino de Luzzi (1275-1326), usually known by his Latin name of Mundinus, must be given the credit of reviving the study of the anatomy of the human body by systematic dissection, which had remained dormant for some 1500 years since the days of the great Alexandrian anatomists, Erasistratus and Herophilus.

Born and educated in the northern Italian city of Bologna, famous for its university, Mundinus receiving his medical degree in 1290 and becoming Professor of both Anatomy and Surgery at the university, joint chair which became traditional and which persisted for the next two centuries at this and other Italian university. He lived at a time when the taboos surrounding human dissection were beginning to weaken.

Mundinus distinguished himself by his systematic work in anatomy and by the fact that he carried out the dissection himself rather than allowing someone else to do them for him as was to become the usual practice.

His anatomical Anathomia, written in 1326, is a landmark on the history of anatomy. In content it is akin to modern manuals of dissection, and it became the most popular anatomical treatise of the fourteenth, fifteenth and early sixteenth centuries; it passed through about thirty printed editions and was still in use even after the works of the Renaissance anatomist began to appear.
Mondino de Luzzi

Andreas Vesalius: modern founder of anatomy

The human anatomy references used by doctors through the year AD 1500 were actually based mostly on animal studies, more myth and error than truth.

Andreas Vesalius (1514-1564) was the first to insist on dissections, on exact physiological experiment and direct observation.

Vesalius discovered many errors in Galen’s work and revealed his evidence to discredit Galen and to show that Galen’s description of curved human thighbones, heart chambers, segmented breast bones, etc, better matched the anatomy of apes than humans.

Vesalius dissected the cadavers himself. This contravened the usual procedure, on which the professor read from a Galenic text while the body was opened by a menial or prosector. Vesalius began to employ drawings to clarify the various structures of the body.

Vesalius detailed more than 200 discrepancies between actual human and Galen’s descriptions, Time after time, Vesalius showed that what every doctor and surgeon in Europe relied on fit better with apes, dogs, and sheep than human body.

Vesalius De Humani Corporis Fabrica was completed and published his magnificent anatomy book in 1542.

Ultimately the scientific study of anatomy became accepted as the avenue of increasing the knowledge of this discipline and the practice of medicine.

With the rise of modern science, the approach that Vesalius pioneered became the standard for medicine. Physicians followed him into the body dissecting it as a way of understanding how it worked.
Andreas Vesalius: modern founder of anatomy

Circle of Willis

In 1664 the British scientist Thomas Willis (1621-1675) described in his treatise about a circle of arteries at the base of the brain that act as a traffic for the blood flowing to the head.

Willis landmark text, Cerebri Anatome, 1664, was reproduced many times and developed into a pocket-sized standard textbook for medical students.

The circle of Willis provides a potential diversion for collateral blood supply following the occlusion of one major cranial arteries feeding, into it.

Because of Willis’s thorough illustrations and explanation of this structure, it is known today as the circle of Willis.

Scientists had observed this circle as early as the 16th century, but it was Thomas Willis, Sedleian Professor of Natural Philosophy at Oxford, who first noted it importance in directing the flow of blood. He was aware of this feature and asked his friend Christopher Wren, the architect of Canterbury Cathedral, to illustrate the arterial circle which he did masterfully.

Wren had for the first time injected fluid into the vessels of an animal while being architect for King Charles II, for whom he built St. Paul’s Cathedral in London and 53 other churches.
Circle of Willis 

History of physiology

The term ‘physiology’ to represent ‘the science of the functions of the human body in good health’ seems to have been used for the first time in 1542 by Jean Fernel in his work: De naturali parte medicinae.

The physiology of respiration was developed by the studies of John Mayow (1643-1670), who proved that when blood is aerated, it changes appearance and that breathing is an exchange of gases. Oxygen was discovered in the eighteenth century by Joseph Priestly and Antoine-Laurent Lavoisier. Soon it was generally accepted that all animal life required oxygen.

Physiological research in the early nineteenth century continued to focus on anatomical structure to locate the site of biological processes and elucidate their nature.

William Harvey’s experiment proof of the circulation of the blood, founded physiology as a science and have it a method. The doctrine of the circulation is the fundamental conception of physiology.

By the time anatomy became essential to medical education, physiologists were well placed to profit; however, virtually all medical anatomy was done on cadavers.

Physiology a distinct utilizing chemical, physical and anatomical method began to develop in the 19th century. Claude Bernard in France; Johannes Muller in Germany; and Sir Michael Foster in England may be numbered among the founders of physiology as it now is known.
History of physiology

Retinal anatomy

The retina was first described by Herophilus of Chalcedon around 300 BC. It was named by Rufos of Ephesus (c, 110 AD) and appeared to early anatomists as a surrounding net which supported the vitreous.

Herophilus of Chalcedon was one of only two scientists (the other one being Erasistratus of Ceos) to perform systematic scientific dissections of human cadavers. The sensitive layer at the back of the eye seemed to him rather like a spider’s web. Hence he named it the amphiblestroides, the Latin translation of which is ‘retina’.

Though Galen noted structural similarities to the brain, he was unable to provide further understanding regarding its function.

For Galen, the crystalline lens was the ‘receptive organ’ of the eye, while the retina was an organ of nutrition and conveyors of visual spirits to and from the lens.

Galen emphasized the similarities between the retina and the brain and maintained that the retina and optic nerves were really displaced parts of the brain.

Apparently, William Briggs in 1685 first illustrated the fibrous nature of the retina. Briggs trained as a physicist and wrote several texts on the anatomy of the eye.

It was Johannes Kepler who first suggested that the retina served as the eye’s primary photoreceptor tissue. By using alcohol fixation, Treviranus in 1835 performed the first detailed microscopic retinal studies.

A better understanding of the structure of the retina came after 1840 the year in which Adolph Hannover began to use chromic acid to harden tissue, in order to slice thinner sections.

He then described the receptors as facing away from the vitreous chamber and identified and numbered the principle layers of the retina.

Only with the subsequent development of electron microscopy, trypsin digest, clinical fluorescein angiography, and optical coherence tomography have scientists been able to understand the retinal’s cellular connections, ultra-structure and retinal vasculature, as well as correlate anatomical and clinical findings.
Retinal anatomy

Erasistratus of Ceos (325 BC – 250 BC)

Erasistratus was a Greek physician in Alexandria who helped establish the foundations for the scientific study of anatomy and physiology. Erasistratus was the son of Cretoxene, sister of the physician Medias and Cleombrotus.

It has been held that Erasistratus lived in Alexandria and the he practiced medicine there in the third century BC about 400 years before Galen. His works are lost for fragments quoted by other writers,

Erasistratus made numerous physiological and anatomical discoveries, perhaps using – like his contemporary Herophilus – an exceptional combination of human and animal dissection to explore the structure and workings of the human body.

Among his achievements, two in particular won high praise from later authors. First he described the heart valves, noting the irreversibility of the flow through the valves and detailing the heart’s pumping action. He supplied an excellent description of the bicuspid and tricuspid valves and their function in determining one-way flow through the heart.

Second, his account of the brain includes descriptions of its four ventricles, the convolution of the cerebrum and the cerebellum and the origin of the nervous system in the brain.

Erasistratus believed that all tissue in the body contains veins arteries and nerves and these vessels serve as channels by which various substances fundamental to the functioning of the body conducted to its various organs.

Erasistratus rejected the widespread Hippocratic theory of humoral medicine. Instead, he attributed disease to ‘plethora’ an excess of blood that produces inflammation and blocks the flow of pneuma.
Erasistratus of Ceos (325 BC – 250 BC)

Father of Anatomy – Herophilus of Chalcedon (335-280 BC)

Often called the father of anatomy. Herophilus of Chalcedon was a well respected physicians and teacher of medicine in Alexandria.

Herophilus was born at Chalcedon, Greek city on the Propontus, nearly opposite to Byzantium.

Herophilus received his early training as physician from Chrysippus, a widely known Stoie philosopher, who had taught at the school of Cnidus and had also written on medical topics.

Herophilus showed a decided learning toward the study of anatomy. He was the pupil of Praxagoras of Cos. He was an original investigator and the first of the Hippocratic school to distinguish himself as an anatomist.

Herophilus lived during a period in Greek medical history when human dissection was allowed, and he greatly advanced the study of scientific anatomy through his extensive dissections of human cadavers.

He experimented on living animals and even on condemned criminals placed at his disposal in the prisons.

Some of the books written by Herophilus have been used for several centuries but only a few fragments from his texts have survived.

He had a good picture of the nervous system, including the connection between the brain, spinal cord and nerves.

He argued that the brain was the center of the nervous system, rejecting Aristotle’s claim that the heart was the seat of intelligence.
Father of Anatomy – Herophilus of Chalcedon (335-280 BC)

Medieval Treatises on the Body

Medieval Treatises on the Body
In the thirteenth and fourteenth centuries, art and anatomy both experienced an awakening, fostered by legislative changes the decline of religious teaching and reactions to criminal violence or epidemic diseases.

Municipalities, especially in Italy, were pressured to permit dissection in order to determine cause of death in cases of murder of other unusual situations.

The rise of secular universities also contributed to the increase of dissection. In Christian tradition, the body was linked to sin and the temporal existence of the profane world.

Learning about its inner workings was not only unnecessary but it could jeopardize salvation, because the literal interpretation of Scripture anticipated the resurrection of the soul within an intact body.

As a result, the church did not condone dissection. Images of anatomic from the medieval period emphasize the barbarity of the act. Sometimes, the pope granted special dispensations for certain medical schools, such as Montpellier in southern France, but the subjects were executed criminals – or, on rape occasions, living criminals, who may have been sentenced to death by vivisection.

Legal dissections were ritualized and infrequent – once or twice a ear, for example; in some places, only once every five years. The professor sat high above the scene reading from a Latin edition of Galen.

The demonstrators were often illiterate barbers, who dissected in conjunction with lesson.

As a result, the words of Galen could persist unchallenged. Differences between the cadaver and a Galenic ideal were explained by the imperfection of the (usually criminal) mortal.
Medieval Treatises on the Body

Galen on Herophilus

Galen on Herophilus
Herophilus ‘attained the highest degree of accuracy in things which became known by dissection and he obtained the greater part of his knowledge, not like the majority from irrational animals, but from human beings themselves.’ – by Galen

Galen was born in 129 AD in Pergamum, on the Aegean coasts of modern Turkey, but he lived much of his live in Rome. He deplored the laws that forbade human dissection: at least three of his many treatise were devoted to human anatomy, ostensibly as understood by the Alexandrians.

He received medical training in Smyma and Alexandria.

Galen served as a physician to the gladiators, and he may have taken advantage of gaping wounds to observe internal structure.

A great experimenter, he dissected animals, both living and dead, his preferred subjects being a pig and the rhesus monkey.

He extrapolated from animals to humans and devised elaborate theories concerning anatomical strictures, the motion of blood, and the origin and sustenance of life.

Galen’s genius was evident in the physiological experiments he conducted on animals. The work On the Use of the Parts of the Human Body comprised seventeen books concerning this topic. To study the function of the kidneys in producing urine, he tied the ureters and observed the swelling of the kidneys.

Some observations were accurate for animals but missed their marked when applied or humans, for example, he ascribed five lobes to the liver and a vascular network in the brain called the rete mirable.

Galen’s writings are authoritative and bragging, and his teleological perspective allowed him to conceive of all structures as having been created for a purpose.

His immediate successors may have carried out some human dissection, but anatomies became rare and ritualized exercise for endorsing Galen’s authority, not for seeking truth.

Galen spent the rest of his life at the Court writing an enormous corpus of medical works until his death in 201 AD.
Galen on Herophilus

Dissection and Anatomical ideas

Dissection and Anatomical ideas
The elaborate burial practices of the ancient Egyptians provided frequent opportunities for the observation of body parts.

Embalmers were adept at situating and extracting organs through tiny holes and slits in the body.

Egyptian graphic art may have been stylized, but the statuary reveals a sensitive appreciation of surface and underlying structure. Unlike the embalmers and artist, however the physicians do not appear to have used anatomy.

Our knowledge of ancient Egyptian medicine is based on a few surface papyri. Egyptian explanations of disease seem to have emphasized physiology, on which breath was the essence of life.

Blood vessels were hypothesized rather than known, and only a few organs were connected with specific functions. Some organs were associated with certain deities and used as hieroglyphics.

For instance, a stylized uterus, or sa, represented the goddess of childbirth. Because this symbol was bicornuate (had two horns), scholars think that the model may have been animal rather than human.

Ancient Greek sculpture reflects a preoccupation with the accurate portrayal of surface anatomy, with attention to the underlying muscles and bones.

Votive offerings left at temples by sick people hoping for cures were fashioned from clay or stone to resemble afflicted body parts – uterus, breasts, bladder and limbs – sometimes with anatomical derangements such as varicose veins.

Despite these artistic influences and their skill in observation, Greek doctors were not especially interested in anatomy. Dissection of human bodies was forbidden, and funeral practices centered on cremation.

Given the laws and funeral customs, few opportunities arose for examination of internal structure of humans. Exceptions are found in Hippocratic treaties on fractures and dislocation, which reveal extensive knowledge of bone and joints.

Illustration is essential to the teaching of anatomy, and the ban on dissection did not extend to animals. The fourth century BC philosopher and biologist Aristotle, appears to have used large diagrams when he taught the comparative anatomy of animals.

After about 300 BC the Greek city of Alexandra permitted dissection of the bodies of criminals, alive or dead. These public demonstration were designed to horrify as much as instruct.

That the practice was reserved for criminals indicates the social ambivalence regarding dissection, which could be seem as a desecration.

Two Alexandrians, Herophilus and Erasistratus, describe minute structures, including lymph lacteals, the meninges and vascular structures such as s torcular herophili.
Dissection and Anatomical ideas

Anatomy in Medicine

Anatomy in Medicine
Anatomy is the study of the structure of the body. Today it seems integral to the study of medicine but structured explanations of disease were long considered secondary to those of function.

The word ‘anatomy’ is derived from the Greek word –dissection. It still implies cutting, but also structure (morphology) – the shape, size and relationships of body parts, It is also metaphor for the analysis of any problem.

Medicine is the study of disease and its treatments, its understand disease doctors focus on abnormalities of structure and function, which are the objects of the complimentary disciplines of anatomy and physiology.

Traditionally these two domains have competed for curriculum time, laboratory space and pride of place in the minds of practitioners.

Of course considerable overlap takes place between structure and function; a broken leg does not work very well; neither does a heart with a hole in its septum.

Medical cultures that emphasized the study of anatomy peaked centuries ago, in Alexandria, then decline, peaked again during the Renaissance then declined and peaked again in the last century.

The present form of medical education still reflects this most recent heyday but the perceived centrality of anatomy in modern medicine may on the wane again.
Anatomy in Medicine