Episode 34: The Physical

 in Podcasts  tagged auenbrugger / corvisart / ebm / history / Laennec / medieval / physical exam / piorry / uroscopy by

The physical exam has become a ritual of the modern doctor’s appointment, with pokes, prods, and strange tools. How did this become a normal thing to do? In this episode, I’ll discuss how the physical exam went from the medieval examination of a flask of urine to basically what we have today in just a few decades in early 19th century France, and how the exam is still developing in the 21st century. Plus, a brand new #AdamAnswers about why Americans insist on using the Hermes’ Staff as a symbol for medicine. All this and more in episode 34 of Bedside Rounds, a tiny podcast about fascinating stories in clinical medicine!

 

Sources:

  • Antic T, DeMay RM. “The fascinating history of urine examination,” Journal of the American Society of Cytopathology (2014) 3, 103e107
  • Ghasemzadeh N and Zafari AM, “A Journey into the History of the Arterial Pulse,” Cardiology Research and Practice Volume 2011 (2011).
  • McGee S, Evidence Based Physical Diagnosis 4th edition. Amazon link: https://www.amazon.com/Evidence-Based-Physical-Diagnosis-Steven-McGee/dp/0323392768
  • Nicolson M, Commentary: Nicholas Jewson and the disappearance of the sick man from medical cosmology, 1770–1870. Int J Epidemiol 2009;38:622–33)
  • Jewson ND. The disappearance of the sick-man from medical cosmology, 1770–1870, Sociology , 1976, vol. 10 (pg. 225-44)
  • Robertson WE. Physical diagnosis from the time of Rontgen. Ann Med Hist. 1934;6:255–63
  • Rodgers MM, “Piorry on Pleximetry and Auscultation,” Boston Med Surg J 1852; 46:151-152
  • Tan SY and Hu M, “Josef Leopold Auenbrugger (1722 – 1809): father of percussion. Singapore Med J 2004 Vol 45(3):103
  • Walker HK, “The Origins of the History and Physical Examination,” Clinical Methods: The History, Physical, and Laboratory Examinations.Boston: Butterworths; 1990.
  • Wallis F, Signs and Senses: Diagnosis and Prognosis in Early Medieval Pulse and Urine Texts. Social History of Medicine Vol. 13 No. 2 pp. 265-278.
  • Wilcox RA et al, “The Symbol of Modern Medicine: Why One Snake Is More Than Two,” Ann Intern Med. 2003;138:673-677.
  • Verghese et al, A History of Physical Examination Texts and the Conception of Bedside Diagnosis.
  • Voswinkel P, From uroscopy to urinalysis. Clinica Chimica Acta 297 (2000) 5–16

Transcript

This is Adam Rodman, and you’re listening to Bedside Rounds, a tiny podcast about fascinating stories in clinical medicine. This episode is called The Physical. One of the more bewildering and ritualized aspects of a modern trip to a doctor is the physical exam. You can be poked and prodded with bizarre instruments, or they can be invasive and uncomfortable. These days, an exam is more likely to be brief and perfunctory, the fleeting placement of a stethoscope on your chest. But medicine — and our society — has a love affair with the physical; so much so that we call the annual trip to the doctor not only a “visit”, but a physical. 

 

But the physical exam that we know and love developed over just a few short decades in France at the turn of the 19th century — from medieval to modern in just a few decades. In this episode, we’re going to talk about how the physical exam developed, what it replaced, and how we’re still dealing with those implications today.

 

The idea of a history and physical is ancient of course. For example, “On Regimen in Acute Diseases,” Hippocrates exhorts his learners:

 

One should pay attention to the first day the patient felt weak; one should inquire why and when it began. These are the key points to keep in mind. After these questions have been cautiously considered, one should ask the patient how his head feels, or if he has any pain or if he feels heavy. … In regard to the chest, one should ask the patient if he has pain there and if he has a slight cough, with pain in the abdomen when he coughs

 

This is remarkably modern advice, and I’d hope would be heeded by any medical student today. Hippocrates is stressing the importance of asking symptoms — that is, the patient’s experience of the disease, and putting them together in a story. I’d contrast this with signs — looking for supposedly objective evidence of disease on a patient’s body.

 

This seems straightforward, but we have to keep in mind that the ancients had a different notion of disease than we do. In Episode 32 I spoke about the development of Humoral theory — the idea that the body is made up of four constituent fluids, blood, phlegm, black bile, and yellow bile, and the idea that disease comes from imbalances in these fluids, or dyscrasias. A history could be very helpful in uncovering these imbalances — was the climate too cold? To much red meat in the diet? Maybe you lived on the first floor, or too close to a swamp? But you can see the problem when it comes to the exam. Disease is caused by imbalances in these fundamental fluids — but they lie deep inside the body and out of sight. How can you see that?

 

Sometimes, of course, you could. From the Edwin Smith papyrus, a remarkable document from ancient Egypt, we have detailed descriptions of trauma, and the first physical description of cancer. Hippocrates himself has two signs named after him that we still use today — Hippocratic fingers, or clubbing — a broad fingernail deformity that is linked to cardiac and pulmonary disease, as well as the “Hippocratic Face” — the sunken temples, bulging eyes, and leaden expression seen in wasting disorders, that the Hippocratics said portends death. 

 

But ultimately physical signs that you could see on the body were in the minority. Because in order to determine the balances of the fluids inside the body, the best way was to study fluid outside the body. And there were two main ways to do this.

 

The first was feeling the pulse. From the time of Hippocrates onwards, evaluation of the radial pulse in the wrist has been a standard part of the physical exam. It was thought that the arteries contained pneuma — the air of life, that was then carried to the rest of the body. The word artery actually comes from the Greek word for “air”.  By carefully observing the pattern of this pneuma, an astute physician could peek into the dyscrasias of the body. This had become increasingly complicated by the time of Avicenna in the 11th century: he divides every pulse into eight different categories, each with two or three dimensions. And there were some great observations there — Maimonides, for example, writes that “the pulse which is very abnormal and totally irregular” points a signs of underlying illness, correctly identifying what was likely atrial fibrillation a thousand years ago.

 

The second method of peeking inside the body was uroscopy — observation of the urine. The Greeks had understand that urine was a byproduct of pepsis, usually translated as concoction — the usually healthy breakdown of the four humors. By observing these breakdown products, we could hopefully figure out underlying imbalances in the humors. By the middle ages, a doctor would examine urine in a long flask called a matula. He’d look for sediment, odor — but most of all for color. With the invention of the printing press, prints with different color hues explaining uroscopy were widely disseminated. This was so associated with physicians that the matula became the de facto symbol of doctors in this period, much as how the stethoscope is treated today. Examination of the urine even stretched into the occult — there were doctors who read prophecies in the matula.  I’ve posted some fascinating prints on Twitter of doctors with matulae, and some of the color guides that physicians would have used.

 

So the pre-modern physical exam largely consisted on evaluating the pulse and urine to try and discern hidden causes of disease — that is, imbalances in the humors. How did physicians use this information?  The historian Faith Wallis went through all the medical manuscripts at an Italian Monastery in Monte Cassino, including a fascinating handbook called “How you should visit the patient.” Her major argument is that the medieval physical exam was prognostic in character — and not diagnostic. It was primarily helpful for figuring out how the patient was going to do, rather than figuring out an underlying cause. 

 

I’ve called this a medieval physical exam — but it lasted well into what we call the modern era. Case reports in the 19th century had detailed descriptions of pulse, and a major medical textbook in 1747 described the 35 different urine qualities. Black urine in particular was of especial interest to early modern doctors, since it seemed to suggest the existence of the mysterious black bile. Apparently, as late as 1810, medical examinees in Germany would be expected to be familiar with the “Woman of Thasos,” who was described in the Hippocratic corpus some 2000 years before as having black urine. 

 

So how did this all change? Remarkably, the shift was quite rapid — we went from matula and lengthy paeans on pulse to a remarkably modern exam in the period of only a couple decades, and the implications of this shift have stuck with us ever since. And the reason why is due to a small group of doctors practising in Paris at the cusp of the 19th century. 

 

But the true birth of the physical exam actually starts decades earlier, in the 1750s in Vienna. Josef Leopold Auenbrugger was a young physician volunteering in the Spanish Military Hospital in Vienna. His wards were full of patients with pulmonary tuberculosis. Following the tradition of the day, he would perform autopsies after his patients died, and he noticed that many of them had a considerable amount of fluid in the lung. Auenbrugger became obsessed with discovering this fluid when patients were still alive. The musically inclined physician thought back to how his father, an innkeeper, had checked wine levels by tapping on casks, and he surmised he could do the same for the human chest. He devised a series of experiments by which he injected water into cadavers and then percussed — tapped with his fingers — to determine the location of the fluid. He then set to using this method of sick patients and then noting his accuracy on autopsy. In 1761, he published his findings in a short paper called simply “Inventum Novum” — New Discovery — where he describes his method — but also predicts a new type of physical exam where not only can the physician for the first time see inside the human body but, “perhaps, also, the same observation and experience may lead to the discovery of other truths … in the diagnosis, prognosis, and cure of thoracic affectations.”

 

It’s a remarkable paper, even more remarkable for how short it is. Auenbrugger realizes that the physical exam can actually diagnose specific disease in specific organs — and not just help elucidate hidden causes. He’s predicting the development of physical diagnosis, not just an exam. So why do we have the French School, and not the Viennese?

 

Unfortunately, it’s because his paper fell on deaf ears. His idea — that you could tell about the inside of a living person from exam only — was so controversial he was forced to resign his post at the Military Hospital, and he was rejected by his mentor. Nothing would come of his discovery for another 50 years.

 

Until, in Paris, where another young doctor Jean-Nicholas Corvisart rediscovered Auenbrugger’s work. Like Auenbrugger, Corvisart was a bit of an iconoclast. His father wouldn’t support his studies in medicine, so he took a job as a male nurse at the Hotel-Dieu in Paris to cover his studies. He graduated as the youngest in his class, but “first in scholarship.” He was going to be the director of the new Necker hospital — but Madame Necker basically fired him after he refused to wear the powdered wig that his role would require. And to think I feel like a rebel when I don’t wear a necktie or white coat… He managed an appointment at Charity Hospital, where he was renowned for his bedside teaching — and a new focus on examining the patient with a key to seeing what was going on inside. One of his preferred methods was called “immediate auscultation” — placement of the ear on the chest wall of the patient, often covered by a thin cloth for sanitary reasons. But  Auenbrugger’s percussion was his greatest passion. He received a copy of “New Discovery” and enthusiastically set about developing and teaching the skill to his trainees. Finally, in 1808 he republished Auebrugger’s work with his own observations in his tome called “The Hollow Cavities Resounded”. It’s actually an awesome name, because it comes from the scene in Virgil’s Aeneid where the doomed Lacoon tries to convince the Trojans that the horse is a trap by throwing his spear so the Trojans could hear the echoes inside. It’s a great analogy analogy, Auenbrugger was ignored just like Lacoon was — though at least he wasn’t dragged to his death by a sea serpent. 

 

Corvisart — who was by this time Napoleon’s personal physician — made the reputation of percussion and the idea of physical diagnosis pretty much overnight. Auenbrugger actually lived to see this — he died at age 87, a year after Corvisart published his book, and though it’s unclear how aware he was of what was going on in France, I’d like to think that the jolly old man was aware he had been vindicated in the end. In any event, Corisart’s students would go on to further develop the physical exam by making detailed observations of patients when they were alive, and then performing autopsies when they died to link these signs to disease in the body.

 

Corvisart’s two most prominent students were Piorry and Laennec. Piorry first, since his influence has faded in the 20th century. So as the story goes, Piorry was a itchy man, and one day while he was scratching himself, he noticed the characteristic noise of nails on skin. He then scratched a coin, and noted how it was louder and made a different character. He realized that he could use this principle to “hear” inside the human body, through different densities of tissue. He invented a tool he called a “pleximeter” — a small ivory plate that he would strike with his fingers, and later a small hammer. He would use this to map out patient’s organs in crayons — showing enlarged spleens, livers, and hearts — and his patient’s torsos apparently looked like geographic maps. He was held in quite renown — there’s a story that he visited the Royal Palace to have an audience with the King, but he was told the King wasn’t in the reception room. Piorry then percussed the closed door with his pleximeter and diagnosed the presence of the King in the reception chamber! That’s kind of obnoxious, go I get why the King was ignoring him.

 

Rene Laennec, on the other hand, is still remembered today. He’s now tied with Jenner for the award for doctors I like to blab about — he was featured back in episode 9 about his invention of the stethoscope, and more recently in episode 29 on Mahler and cardiac auscultation. So I encourage you to listen to both those episodes for more Laennec. He, of course, invented the stethoscope — following Corvisart’s model, he would place his head directly on the chest, but when confronted with a buxom young woman, he demurred and rolled a quire of paper as a tube to listen to her heart. An experienced carpenter, he returned home and started to experiment with wooden tubes until he perfected his “cylinder”. 

 

But, as I’m sure you’re getting from this, it’s not just the invention of the stethoscope, or percussion, or the pleximeter that made the physical exam. It was a dedication — an obsession really — to linking these signs to diseases in the body. And Laennec was certainly obsessed. His biographer went over his schedule: he would awake at 7:30 in AM and take consultations while he was still dressing and eating breakfast. He’d skip lunch and round constantly until 5:30 PM at Necker Hospital, which in post-revolutionary France no longer required powdered wigs. He’d eat dinner, and then return to the hospital until 10 PM, rounding again. On every patient, he’d make detailed observations of their lung and heart sounds. And when those patients died — which they often did — he’d perform the autopsy himself, linking his exam findings to pathology in their chests. In 1819, he published “On Mediate Auscultation” where he described his methods, and introduced a number of terms for lung sounds we still use today — rales and rhonchi, egophany, crepitations or crackles. With every copy of his book you’d get a stethoscope, handmade by Laennec himself. By the time of his death — unfortunately from tuberculosis in 1826, probably every stethoscope in the world was handmade by Laennec. 

 

This collection of bedside teaching, examination, and autopsy that arose in Paris around Corvisart was called the French School and became incredibly influential. Doctors from all over the world flocked to the city to study their methods, and took them back to their home countries. The impacts of the French school are still with us today.

 

But before I talked too much about that, I want to talk about the Great Man Theory and medicine. And that’s basically that doctors love the Great Man Theory. Historians may have moved on, but we have not. There are a number of reasons for this — medicine has a natural bias towards the individual patient, but I think mostly because culturally our training naturally places us in a hierarchy underneath a Great Man (or Woman). Conference rooms in medical schools are not adorned with scientific discoveries, or pictures of patients, or even of doctors caring for patients, but the portraits of “Great men” (and women for the more modern ones) stretching back hundreds of years. William Osler sums this up nicely: in Aequanimitas, he wrote, “It helps a man immensely to be a bit of a hero-worshipper, and the stories of the lives of the masters of medicine do much to stimulate our ambition and rouse our sympathies.”

 

I know I just spoke for, like, 10 minutes about the contributions of three “Great Men,” but believe it or not, I don’t agree with Osler. First of all, because history is far more complicated than that — we can’t separate individuals from the cultural, societal and economic trends that surround them. But in the case of medicine especially, I think that the supposed virtues of individual physicians and their great discoveries and accomplishments blinds us to the messy and zigzagging path we’ve had to take to advance science and to help our patients. I mean, one of the major reasons I love doing this podcast is to talk about that process by which we’ve created modern medicine — and how all of us are still in the middle of that process.

 

My point is, the development of the French School didn’t happen in a vacuum. Paris peri-revolution was the site of innovations in numerous fields — physics, chemistry, philosophy, economics. And major advances in human dissection were necessary for Auenbrugger and Corvisart to even have the idea of performing autopsies. The modern idea of the hospital — a place of healing and teaching, separate from just a hospice that would be a final step before death —  was necessary. And even more importantly, the beginnings of industrialization that would bring poor peasants to the city — where they could become ill with diseases of proximity like tuberculosis and crowd the hospitals — was necessary. In a very real way, it was the suffering and deaths of our patients in large numbers that lead these doctors to develop the idea of the physical exam. 

 

By 1850 or so, France was no longer the center of the medical world — Germany would lead the way in medical innovation, but the French School had left its mark. Physicians the world over poured themselves into developing ways of seeing inside the human body. Vital signs were developed for the first time with the development of clinical thermometry, which I talked about in the #AdamAnswers of last episodes. Entirely new fields were developed based on observation, like dermatology, as we realized that the skin could give us important information about diseases inside the body. New tools were added — the ophthalmoscope, the syphingomanometer or blood pressure cuff, and the reflex hammer, which was initially a repurposed pleximetry hammer, believe it or not. And new medical signs were invented and added to the physicians repertoire. 

 

This new field of physical diagnosis had real effects of patients — and it wasn’t always good. A major limitation of the French School, of course, was that doctors became very good at diagnosing and classifying disease while patients were still living. They were no better at treating them, however, and the old standbys — purgatives, laxatives, and bloodletting — remained the standard of care. 

 

But more important, there were very real effects on the doctor-patient relationship. Much has been written about the disappearance of the sick man from the medical cosmology during this period. In traditional Western medicine, dating back to the Hippocratic tradition, the patient’s experience had mattered the most. But now this knowledge was something available only to the doctor — it might be present on the patient’s body, but they had no active part in it. And patients went from being essentially patrons who sought out physicians on equal ground, to objects for learning, both in life, and then in death. And naturally, the burden on patients fell not on rich, white male patients, but on the poor, the female, the ethnic minorities.

 

So by the turn of the 20th century physical diagnosis was at its height. Teachers like William Osler were legendary at physical examination — with the listen of a stethoscope or the tap of a finger, they could diagnose fluid in the belly, a pneumonia in the lungs, or damaged heart valves. Every part of the body would be examined for subtle signs of disease.  Like Osler wrote, “One finger in the throat and one in the rectum makes a good diagnostician.” And increasingly, there were effective treatments for these diseases that doctors would uncover. The exam became associated not with detached doctors in overcrowded tuberculosis hospitals, but modern medicine itself. 

 

And basically since the halcyon days of the early 20th century, the physical exam has been in decline ever since. The big cause? Remember that the power of the physical exam — or, really, more specifically physical diagnosis — is that it allows doctors to better identify disease inside the human body. And just around the turn of the 20th century, doctors started developing better technological methods to see inside the body. The most literal, of course, was the X-ray, invented by Wilhelm Roentgen in 1896. By 1910, chest x-rays had become commonplace and now the pneumonia that could be heard on exam was visible for all to see — including the patient. And in 1903 Willem Einthoven invented the electrocardiogram, which showed the subtleties of the heart’s function on a strip of paper. Laboratory medicine as well was allowing doctors to objectively measure the blood’s constituents and chemistry — instead of humors, we could check the hemoglobin, lactic acid, or the concentration of sodium. All of these methods became increasingly sophisticated throughout the 20th and 21st centuries. Now in my armamentarium, I can look at the echoes of blood vessels to find clots, directly visualize the arteries of the heart with dye, and use the magnetic resonance of water in the brain to localize strokes. 

 

The power of the exam had been its ability to reveal disease inside the body, and now doctors had a panoply of new ways to do that. Abraham Verghese, the physical exam maven, and his colleagues have performed a review of the major physical diagnosis textbooks of the 20th century, which shows, very rapidly, how the use of the physical exam changed. In the first half of the 20th century, “physical diagnosis” was not considered any different than medical diagnosis — tests like pulmonary auscultation would be listed along with a chest x-ray. But by the 1950s, the “physical exam” — basically in the form we all recognize today — had been completely separated from the rest of medical diagnosis. And it was increasingly taught as an end to itself — the exam that all physicians have to do to their patients, and not specifically as part of diagnosis of a disease. This is essentially how I was taught the exam in medical school; to listen carefully to the lungs in eight different places on the chest, to methodically tap out the liver and the spleen in a way that would make Piorry proud, and to dutifully check every cranial nerve and large muscle group — all in every patient, regardless of their complaint. 

 

It some ways, it shouldn’t be surprising that doctors started to abandon the physical exam. The stresses of our modern medical system — especially in America — led to even less time at the bedside, and a “proper” physical exam takes a considerable amount of time. The development of EMR has led to the “iPatient” as Verghese calls it — a tendency to view information in the computer — laboratory results, imaging studies, and old records — as the patient themselves, instead of, you know, actually talking to your patient. And I think doctors have had a sneaking suspicion that the physical exam probably doesn’t work as well as we’ve been taught.

 

Which is why it’s appropriate that the physical exam is entering a new era — the evidence-based physical exam. Starting in the 90s, doctors actually started to look at how well the physical exam allowed us to detect disease. Take the humble Homans’ sign, for example. John Homans was a surgeon looking for an effective way to identify blood clots in the leg in an era before ultrasound. He found that if you dorsiflexed the foot — imagine walking on your heels — and you had pain behind the knee, you were more likely to have a blood clot in your leg. This has been taught to generations of medical students, again, including myself. But when it was finally studied, we discovered that the test was essentially useless — both for ruling out and ruling in a blood clot. 

 

Similar studies have been done with basically every physical exam sign — the essential textbook is Steven McGee’s Evidence-Based Physical Diagnosis, now in its fourth edition. I have a well-worn copy of the third edition at home and vouch for it being amazing.

 

So what are we to make of the physical exam today? I’m schizophrenic when it comes to the exam. On the one hand, clinicians like Verghese argue that the laying on of hands brings us back to the bedside and helps build up the doctor-patient relationship. But I don’t really agree with this medical exam Kabuki. There was such a thing as a “doctor-patient” relationship long before the physical exam existed, and it’s arguable that the development of the exam actually helped to damage this relationship. I mean, I completely agree that being at the bedside makes the patient-doctor relationship, but it’s through a genuine human connection that we do this. We gain no extra points by pretending to listen to the heart while quickly placing the stethoscope on four different points on the chest (and don’t be fooled — you can get get basically zero information by listening so quickly). We’re also a bit guilty of “hero worship” when we talk about the great physical exam skills of the doctors we’re emulating. Disease presented far more dramatically before the mid 20th century — all of the French School were working with end-stage tuberculosis, for example, and prior to antibiotics, rheumatic fever would have made heart murmurs far more common — and more dramatic.

 

On the other hand — I love the physical exam, and I’ve found it really useful, especially when I’ve worked in Botswana. I get a palpable thrill when I’ve diagnosed tricuspid regurgitation through CV fusion — giant waves in the neck veins, also called Lancisi’s sign, or when I feel a patient’s fingernails and feel the transverse ridge of Beau’s lines and ask, “What happened three weeks ago?” And I still use the exam on a regular basis to treat patients — especially when I’m treating heart failure. I even have some of my own physical exam findings that I excitedly tell my residents — my favorite is cracked and grown out fingernail polish on an older lady who insists that she’s doing very well at home, and would just like to be discharged. I’ve noticed that it suggests someone who has been very independent, but on whom illness has taken a bigger toll than they’d like to admit.  At the same time, I find it unhelpful to listen to my patients’ chests, hearts, and abdomen’s daily, especially if they don’t have any complaints in those organs.

 

So we’re veering dangerously deep into my opinions, as someone who loves both the exam, and being at the bedside. I think it’s very pertinent that McGee named his book “Evidence-Based Physical Diagnosis” and not physical exam. Because I think the best way to view the exam is not as something that we just do, but as a test we use to help diagnose a disease, and track its responsiveness to our treatments. We shouldn’t do it just because — because it’s been taught, because it builds a medical relationship. It’s a tool in our armamentarium; sometimes very effective, sometimes not so much. Now we have modern biostatistical tests like sensitivity, specificity, and likelihood ratios, to help us better evaluate exam procedures — but fundamentally I think that Auenbrugger, Corvisart, Piorry, and Laennec would find this view very familiar. 

 

Okay, that’s it for the show — but wait! It’s time for a #AdamAnswers! 

 

#AdamAnswers is our segment where I answer your burning questions about medicine, no matter what they are. This month’s is from Zao Naegele via facebook, who asks, “Why is Hermes’ staff confused as the symbol for medicine?”

 

Great question Zao! I’m gonna pull a little bit of a Dan Brown novel and go into some, uh, symbolology, or whatever he called the field that’s actually called “semiotics”.  So Hermes’ staff is called the Caduceus. You’ve all seen it — it’s two snakes coiled around a winged staff. The “symbol for medicine,” as you allude to, is the Rod of Asclepius — a single snake around a wooden pole. A picture is worth a thousand words, so check out my Twitter for a comparison. In the United States at least, both of these are commonly used to symbolize medicine, though doctors’ societies almost always use the Rod of Asclepius. So how did this happen?

 

In the time of the ancients through roughly, oh, 500 CE or so, the major symbol of the medical field was Asclepius’ rod. Asclepius was a semi-mythic Greek healer, worshipped as the son of Apollo. The Hippocratic school — and therefore, the idea of a physician — grew out of his priesthood. In fact, the Hippocratic oath starts, “I swear by Apollo, and by Asclepius, Hygeia, and Panacea and all the gods and goddesses, making them my witnesses”. So why a rod with a snake? The most popular story was that Asclepius was treating a man who had been struck dead by Zeus with a thunderbolt. Unbeknownst to him, a venomous snake entered the room, which surprised Asclepius who killed it with a whack of his staff. But then a second serpent arrived and placed healing herbs in the mouth of the dead snake, who came back to life and smartly slithered away. Asclepius realized this was a message from the gods, and used the same herbs to heal his patient. Mercury’s caduceus, on the other hand, was clearly identified with commerce.

 

So what happened? Most importantly, Christianity happened. Early Christians and the Catholic Church were not interested in propagating the symbols of pagan gods, especially those with the symbol of a snake, which was associated with Satan. The doctor examining his urine specimen in the matula became the primary symbol of medicine, as I talked about earlier. But in the 17th century, with renewed interest in the Classics, the weakening of the Catholic church, and the association with the Greeks with the new field of science, these old pagan gods — Asclepius, Hygaeia, and Panacea became popular again, though as symbols and not products of worship. And along with Asclepius the god, his rod again became a potent symbol of medicine, utilized in very much the same fashion — in arts, in textbooks, on medals.

 

So how did the Caduceus become seen as a symbol of medicine in the United States? You’ll note that I keep saying in the U.S., because this is pretty much only an issue here and Canada. And the answer is, essentially, by mistake. The most accepted theory is that the Caduceus had become the symbol of a number of European publishers, especially John Churchill in London, who supplied many of the medical textbooks to the United States. He chose — appropriately — the Caduceus, with two snakes labeled “Medicine” and “Literature”, with the imprint “An Unbreakable Bond Unites” below. 

 

In the U.S., this printer’s mark was mistaken as a symbol of medicine by some publishers, who used the Caduceus in their own textbooks. But there’s no sense that it was overshadowing the actual Rod of Asclepius until, well, basically 1902. In this year, Captain Frederick Reynolds of the U.S. Army Medical Corps successfully changed the seal from the Rod of Asclepius to the Caduceus. From his correspondence, it’s clear that he did not realize any symbolic difference between the two, and thought that the Caduceus was simply a more attractive version of the rod. From the army, it spread broadly throughout the country until post-WWI, when it was the dominant symbol of medicine in North America. But in the 20s onward, medical societies started to correct their errors; the American Medical Association, for example, changed its logo from the Caduceus to the Rod in the 1930s. 

 

But the confusion has stuck, and even though most professional societies now use Asclepius’ rod appropriately, you’ll find the Caduceus all over the place. Including in the future — don’t worry, I don’t know this off the top of my head — but in Star Trek Star Fleet doctors like McCoy and Crusher still use the Caduceus. If the Federation can’t get it right, I don’t think any of us will.

 

Okay, Zao, I’m done playing a symbologist. It wasn’t as exciting as chasing down stolen antimatter from CERN –#spoileralert. But I hope you enjoyed the trip.

 

And for you dear listener, there are so many great questions you could be asking RIGHT NOW. Will you have a go at it? So please, send me whatever burning medical questions you have on Twitter or Facebook.

 

So that’s it for the show! And that was a doozy. This is just the first of three — well, two and a half — episodes on the physical exam. I’m sure you can tell, I love the physical exam, even though I think many of the ways modern doctors use it are kind of silly. I’ve talked about this book twice so far, but for any medical students or residents listening, get your hands on a copy of Steven McGee’s Evidence based Physical Diagnosis; I’ll have a link in the shownotes. It doesn’t tell you HOW to do exams — you can use youtube for that, or whatever other resource you want. Even a textbook! But it tells you WHY you do each physical exam maneuver, and which ones actually work. I put a lot of work into this one — believe it or not, I’ve got way more stuff that I DIDN’T put into the episode. So let me know what you think — and as always, I love feedback!

 

You can find all our episodes on the website at www.bedside-rounds.org. I’m also on Apple Podcasts, Stitcher, Spotify, iiHeartRadio, or the podcast retrieval method of your choice. I’m on facebook at /BedsideRounds, and on Twitter @AdamRodmanMD, where I tweet mostly about medical history and evidence based medicine. Come say hi!

 

All of the sources — and there are a lot of them this time — are in the shownotes.

 

And finally, while I am actually a doctor and I don’t just play one on the internet, this podcast is intended to be purely for entertainment and informational purposes, and should not be construed as medical advice. If you have any medical concerns, please see your primary care provider.