Tag Archives: Human Anatomy

April 19, 1895 (a Friday)

Anatomical regions of the human body.

The Basle Nomina Anatomica (BNA) was published in Latin after its unanimous approval on this date at the IX Congress of the Anatomische Gesellschaft in Basel, Switzerland.

In the late nineteenth century some 50,000 terms for various human body parts had been in use. The same structures were described by different names, depending (among other things) on the anatomist’s school and national tradition. Vernacular translations of Latin and Greek, as well as various eponymous terms, were barriers to effective international communication. There was disagreement and confusion among anatomists regarding anatomical terminology. Work on a new international system of anatomical terminology had begun in 1887 and culminated with publication of the BNA. It reduced the number of anatomical terms from 50,000 down to 5,528.

April 10, 1901 (a Wednesday)

On this date, Duncan MacDougall, MD, performed his first experiment to test a hypothesis, to wit, “If personal continuity after the event of death is a fact, if the psychic functions continue to exist as a separate individuality after the death of brain and body, then it must exist as a substantial material entity.” This implies that this entity should have mass, so MacDougall asked himself, “Why not weigh on accurate scales a man at the very moment of death?”

The following is an extract of a letter written by Dr. MacDougall to a Richard Hodgson, MD and dated 10 November 1901, describing MacDougall’s first experiment. The letter was published in May 1907, along with a report of his subsequent experiments, in the Journal of the American Society for Psychical Research:

duncan_macdougall_1907_-_21pp_page_13-14

Interestingly, in a commentary published with the report, the editor of the Journal wrote that he “does not share the hopes which many entertain regarding the possibility of ‘weighing a soul,’ but this does not preclude his [MacDougall's] recognition of the value of experiment, whatever its outcome. The main point is to have a definite conclusion established, whether it be negative or affirmative.”

According to The New York Times, MacDougall was a “reputable physician” and “at the head of a Research Society which for six years has been experimenting in this field.”

References:

April 1, 1578

William Harvey

On this date, the English physician and scientist William Harvey was born. He is credited with being the first in the Western world to describe correctly and in exact detail the systemic circulation and properties of blood being pumped around the body by the heart. Harvey published his discovery in a treatise entitled Exercitatio Anatomica de Motu Cordis et Sanguinis in Animalibus (On the Motion of the Heart and Blood in Animals) in 1628. Brief, well argued, and clearly written, De Motu Cordis is very probably the one and only great classic of Western science written before 1800 that is still widely read today. His discovery was dramatically confirmed later in the seventeenth century by microscopist Marcello Malpighi’s discovery of capillaries.

Functional knowledge of the heart and the circulation had remained almost at a standstill ever since the time of the Greco-Roman physician Galen – 1,400 years earlier. With Harvey, life began to receive mechanistic explanation. The essential idea of mechanistic explanation is that “natural” events have “natural” causes and can be explained by cause-and-effect relationships that do not involve special action of supernatural agency. This is fundamental to modern science.

Title page of *De Motu Cordis*

Just as important was Harvey’s methodology. De Motu Cordis quickly became understood as a rejection of traditional methods. It was viewed as challenging the traditional system of deductive reasoning via syllogisms, instead advocating experimentation and sensory experience. The empirical methodology observable in Harvey’s work is now the acknowledged scientific method and has been universally adopted across all science and medicine.

Harvey clearly understood the implications of his work, for he wrote at the opening of Chapter VIII (“Of the abundance of blood passing through the heart out of the veins into the arteries, and of the circular motion of the blood”), in which he demolishes the core of the Galenic model:

Thus far I have spoken of the passage of the blood from the veins into the arteries….But what remains to be said upon the quantity and source of the blood which thus passes, is of a character so novel and unheard-of that I not only fear injury to myself from the envy of a few, but I tremble lest I have mankind at large for my enemies, so much has wont and custom become second nature. Doctrine once sown strikes deep its root, and respect for antiquity influences all men. Still, the die is cast, and my trust is in my love of truth and the candor of cultivated minds.

He also left a message in De Motu Cordis that is as true today as it was 500 years ago:

True philosophers, who are only eager for truth and knowledge, never regard themselves as already so thoroughly informed, [so that they do not] welcome information from whomsoever and from wheresoever it may come; nor are they so narrow-minded as to imagine any of the arts or sciences transmitted to us by the ancients, in such a state of forwardness or completeness that nothing is left for the ingenuity or industry of others. On the contrary, very many maintain that all we know is still infinitely less than all that remains unknown. [Nor] do philosophers pin their faith to others’ precepts in such [ways] as they lose their liberty, and cease to give credence to the conclusions of their proper senses. Neither do they swear such fealty to their mistress Antiquity, that they openly, and in sight of all, deny and desert their friend, Truth. [emphasis added]

In Exercitationes de Generatione Animalium (On the Generation of Animals) in 1651, Harvey was extremely skeptical of spontaneous generation and proposed that every living animal originally comes from an egg, introducing the oft-quoted phrase “ex ova omnia” (all [life] from eggs). [However, Harvey did not completely reject spontaneous generation.] His experiments with chick embryos supported the theory of epigenesis, which states that organisms develop from substances in the egg that differentiate during embryonic development.  This was in conflict with the now-descredited preformationist view that perfect miniature versions of offspring exist in the gametes and grow during development.  [Please note that the term 'epigenesis' carries different meanings. Here, it used used in the older sense, as a theory of animal and plant development. In more modern times, it refers to mechanisms by which gene regulation over generations is controlled by elements other than DNA.]

References:

  • Schultz, S.G., “William Harvey and the circulation of the blood: The birth of a scientific revolution and modern physiology,” News in Physiological Sciences 17: 175-180 (Oct 2002).

January 20, 1862 (a Monday)

In medical knowledge, Egypt leaves the rest of the world behind.

The Odyssey, Book 4 by Homer

Zen stones

The Edwin Smith Papyrus

On this date, in the city of Luxor, Egypt, the American Egyptologist Edwin Smith made an important historical discovery when he bought an ancient papyrus from a dealer named Mustapha Aga. After Smith died in 1906, his daughter, Leonora Smith, gave the papyrus to The New York Historical Society. In 1920, James Henry Breasted, founder of the Oriental Institute of Chicago, was asked to translate the papyrus. Finally, in 1930, Dr. Breasted published the English translation for The New York Historical Society (University of Chicago Press). The papyrus now resides at The New York Academy of Medicine, where it has been since December 2, 1948.

The Edwin Smith Papyrus is the first known medical document dating from the 17th century B.C.E. However, it is thought to have been based on earlier documents, possibly by the 27th century B.C.E. medical writer and architect Imhotep, among others, since the papyrus appears to be a compilation of work based on the writing of multiple authors. This would make it the oldest of all known medical papyri. According to Breasted, the papyrus is a copy of an ancient composite manuscript which contained, in addition to the original author’s text, a commentary added a few hundred years later in the form of 69 explanatory notes (glosses). The treatise contains 48 systematically arranged case histories, beginning with injuries of the head and proceeding downward to the thorax and spine, where the document unfortunately breaks off. These cases are typical rather than individual, and each presentation of a case is divided into title, examination, diagnosis, and treatment. The treatment of these injuries is rational and chiefly surgical; there is resort to magic in only one case out of the 48 cases preserved. The Edwin Smith Papyrus is of special interest to the anatomist because it describes the sulci and gyri on the surface of the brain, the meninges (coverings of the brain), and the cerebrospinal fluid for the first time in recorded history.

September 13, 1848 (a Wednesday)

Phineas Gage skull diagram 1868 (left) and skull (right).

Phineas Gage (1823-1860) is one of the earliest documented cases of severe brain injury. He is the index case of an individual who suffered major personality changes after brain trauma. As such, Gage is a legend in the annals of neurology, which is largely based on the study of brain-damaged patients.

On this date, 25-year-old Phineas Gage and his crew were working on the Rutland and Burlington Railroad near Cavendish, Vermont. Gage was preparing for an explosion by compacting a bore with explosive powder using a tamping iron. While he was doing this, a spark from the tamping iron ignited the powder, causing the iron to be propelled at high speed straight through his skull. It entered under the left cheek bone and exited through the top of the head, and was later recovered some 30 yards from the site of the accident.

Gage recovered almost entirely from his physical disabilities, except for loss of sight in one eye. It is surprising, of course, that Gage survived such a traumatic event at all, but more surprising is the fact that his personality was completely changed as a result of the accident. Gage’s doctor describes how “the equilibrium or balance, so to speak, between his intellectual faculty and animal propensities” had been destroyed. The changes became apparent as soon as the acute phase of brain injury subsided. He was now “fitful, irreverent, indulging at times in the grossest profanity which was not previously his custom, manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times perniciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged than they are abandoned. . . .” .

These new personality traits contrasted sharply with the “temperate habits” and “considerable energy of character” Phineas Gage was known to have possessed before the accident. Previously, he had “a well balanced mind and was looked upon by those who knew him as a shrewd, small businessman, very energetic and persistent in executing all his plans of action.” So radical was the change in him that friends and acquaintances could hardly recognize the man. They noted sadly that he was “no longer Gage.”  In fact, he was so different that his employers had to let him go shortly after he returned to work. The problem was not lack of physical ability or skill – it was his new character.

References:

  • Damasio, Antonio R. Descartes Error: Emotion, Reason and the Human Brain, New York: Avon, 1994.

September 8, 1504

Plaster cast of original statue of 'David', by Michelangelo, Florence, Italy, 1501-4. Cast by unknown maker, Florence, Italy, about 1857.

Plaster cast of original statue of ‘David’, by Michelangelo, Florence, Italy, 1501-4. Cast by unknown maker, Florence, Italy, about 1857.

On this date, the original statue of David by Michelangelo was unveiled in Florence, Italy.

Interestingly, a replica of the statue of Michelangelo’s ‘David’ was originally presented to Queen Victoria by the Grand Duke of Tuscany in 1857, but was immediately given by the queen to the South Kensington Museum (now the V&A). The story goes that on her first encounter with the cast of ‘David’ at the Museum, Queen Victoria was so shocked by the nudity that a proportionally accurate fig leaf was commissioned. It was then kept in readiness for any royal visits, when it was hung on the figure using two strategically placed hooks. In a photograph of the Art Museum taken around 1857-9 the figure of David is shown wearing a fig leaf. The fig leaf is likely to have been made by the Anglo-Italian firm D. Brucciani & Co., based in London.

Male nudity was then a contentious issue. A letter sent to the Museum in 1903 by a Mr Dobson complained about the statuary displayed: ‘One can hardly designate these figures as “art” !: if it is, it is a very objectionable form of art.’

In relation to Mr Dobson’s complaint, the then director Caspar Purdon Clarke noted: ‘The antique casts gallery has been very much used by private lady teachers for the instruction of young girl students and none of them has ever complained even indirectly’ (museum papers, 1903).

Tin fig leaves had been used during the early years of the Museum on other nude male statuary, but later authorities at South Kensington were dismissive of objections. Nowadays, the fig leaf is no longer displayed on the David. Instead, it is housed in its own case on the back of the plinth of the figure.

Hopefully, that’s where it will remain.

Location of the Mind Remains a Mystery

ResearchBlogging.orgWhere does the mind reside? It’s a question that has occupied the best brains for thousands of years, including the Buddha’s.

Recent advances in functional magnetic resonance neuroimaging, a technique that measures brain activity in the hope of finding correlations between mental functions and specific regions of the brain, have led to a wealth of studies that map particular functions onto regions. Self-awareness is defined as being aware of oneself, including one’s traits, feelings, and behaviors. Previous neuroimaging studies had suggested that self-awareness (SA), which is central to human consciousness, depends critically on specific brain regions, namely the insular cortex, the anterior cingulate cortex (ACC), and the medial prefrontal cortex (mPFC). This proposal predicts that damage to these regions should disrupt or even abolish SA — an afflicted individual should be like a zombie, according to David Rudrauf, a neurologist at the University of Iowa in Iowa City.

University of Iowa researchers studied the brain of a patient with damage to three regions long considered integral to self-awareness — left to right, the insular cortex, anterior cingulate cortex, and medial prefrontal cortex. Image credit: UI Department of Neurology.

So when Rudrauf and his team heard about patient R, they immediately thought he could help set the record straight. Patient R is a 57-year-old man whose brain was damaged in 1980 following a severe episode of herpes simplex encephalitis. His brain damage is bilateral, more extensive on the right, and encompasses the target regions mentioned above: the insular cortex, the ACC, and the mPFC. Rudrauf et al reasoned that if any of the structures that are damaged in this patient are indeed critical for the different aspects of SA implicated by the hypothesis described above — i.e., insula, ACC, mPFC — the patient should show clear disruptions of the corresponding functions. Conversely, if these structures are not critical, R should show largely preserved SA.

In fact, R displays a strong concept of selfhood. Rudrauf’s team confirmed this by checking whether he could recognize himself in photographs and by performing the tickle test — based on the observation that you can’t tickle yourself. They concluded that many aspects of R‘s self-awareness remained unaffected. “Having interacted with him it was clear from the get go that there was no way that [the theories based on neuroimaging] could be true,” says Rudrauf. R also has an IQ within the normal range, although he does have severe amnesia, which prevents him from learning new information, and he struggles with social interaction.

The UI researchers estimate that R has ten percent of tissue remaining in his insula and one percent of tissue remaining in his anterior cingulate cortex. Some had seized upon the presence of tissue to question whether those regions were in fact being used for self-awareness. But neuroimaging results presented in the current study reveal that R’s remaining tissue is highly abnormal and largely disconnected from the rest of the brain.

The authors of the report conclude that:

R is a conscious, self-aware, and sentient human being despite the widespread destruction of cortical regions purported to play a critical role in SA, namely the insula, anterior cingulate cortex, and medial prefrontal cortex.

“Self-awareness corresponds to a brain process that cannot be localized to a single region of the brain,” says Rudrauf. “In all likelihood, self-awareness emerges from much more distributed interactions among networks of brain regions.”

Patient R demonstrates that the mind remains as elusive as ever.

References:

  • Philippi CL, Feinstein JS, Khalsa SS, Damasio A, Tranel D, & et al. (2012). Preserved Self-Awareness following Extensive Bilateral Brain Damage to the Insula, Anterior Cingulate, and Medial Prefrontal Cortices Plos ONE, 7 (8) DOI: 10.1371/journal.pone.0038413

Literary Announcement!

FireworksI am pleased to announce the publication of the second edition of my book entitled Understanding Human Anatomy through Evolution! It is an excellent book, if I do say so myself. I even have an endorsement from the gentleman below, whom you may recognize!untitled-2