Archive for the ‘Anatomy’ Category

I’ve previously written about the benefits of squatting for ailments of the gastrointestinal tract, specifically diverticulitis and hemorrhoids.  Some argue that squatting to defecate can prevent all manner of illness and while there are some clinical conditions I’d like to explore further in the squatting-in-the-bathroom paradigm, today I want to write about something quite different.


I finished my Obstetrics and Gynecology clerkship 5 weeks ago. I did my clerkship at a large, and rather posh, private hospital that is affiliated with my medical school.  There are some great doctors there, but I was sometimes aghast at the rather aggressive approach to delivery that many took.  The cesarean section rate for the last year was 47%, well above the national average of 33%, and most labors were artificially augmented.  I did not witness a single VBAC (Vaginal Birth After Cesarean), and was told that only one of the house attendings would perform them.


On the first day of my clerkship, I asked the clerkship director if women delivered in a variety of positions or if they were restricted to delivering in lithotomy (what many today think of as the “traditional” birthing position with the mother on her back with her feet in stirrups).  The director seems to be a rather progressive woman (she is the driving force pushing the hospital to become a “baby-friendly hospital”) and she gave me a rather knowing look and said “I know what you’re getting at, but unfortunately everyone here delivers lying down”.


Indeed, as I went through my rotation, all the vaginal deliveries I saw were done in the semi-reclined position that is common in western hospitals.  This is not universally true.  When I ask my family physician (who actually delivers babies- quite a rarity in this day and age) what position her patients delivered in, she immediately responded “whatever position they’re most comfortable in!”, a response I have heard from a few other MDs as well as many midwives and labor coaches.


Birth is, of course, a risky thing… Death in childbirth was historically a significant cause of mortality, and the rates are still high in some countries.  I think it’s important to recognize that birth is still a risky endeavor, and while pregnancy and labor is a normal human experience, it is one that comes with real dangers. Nonetheless, just because historic rates of maternal demise were much higher than they are today does not mean we should not cast an eye to historic practices when thinking about birth.  As I’ve argued before, I think modern medicine (in obstetrics and in most fields) could greatly benefit from casting an eye to evolution and our ancestors to further improve our current medical system by combining ancestral and evolutionary knowledge with modern technology and science.


I planned to write a significant argument for the consideration of “non-traditional” (though they are, in fact, traditional) positions for laboring, but then I came across a book from 1883 that said it all already. The book, entitled Labor Among Primitive Peoples (with the subtitle Showing the development of the obstetric science of today from the natural and instinctive customs of all races, civilized and savage, past and present.) by George Julius Engelmann MD, is available in it’s entirety thanks to the power of Google Books.


This book is fascinating, and at many times frightening (more on that later), but I found the “Posture in Labor” chapter of particular interest for this post.  There, the author divides the positions into 3 main categories: Perpendicular (including standing, partially suspended, and suspended), Inclined (including sitting erect, squatting “as in defecation”, kneeling, and semi-recumbent), and horizontal (on the back, side, or chest and stomach (!)). He also goes through the then common birthing practices of countries in Europe, Asia, Africa, North America, Central and South America, and Australia and the surrounding islands [1].


Curious?- here are some highlights from the book, but I highly recommend you take a scroll through the book to at least see the illustrations!


The squatting position of the Tonkowas- a Native American group indigenous to present-day Oklahoma and Texas.

The squatting position of the Tonkowas- a Native American group indigenous to present-day Oklahoma and Texas.


The squatting tradition of the Pawnee Native Americans- the laboring mother squats with her back to a female assistant while someone (in this case a shaman) assists with the delivery. This position (with an assistant acting as a back support) was apparently popular in many cultures around the world.

The squatting tradition of the Pawnee Native Americans- the laboring mother squats with her back to a female assistant while someone (in this case a shaman) assists with the delivery. This position (with an assistant acting as a back support) was apparently popular in many cultures around the world.



If you’re curious (as I was) this is what a “suspended” birth looks like, here you go.

If you’re curious (as I was) about what a “suspended” birth looks like, here you go.


There is plenty to be said on each of the positions mentioned, but for the sake of this post I will focus on what the author says on squatting.  He states that squatting


is hardly to be defined with exactness, yet we may, in a general way, consider all postures as squatting which resemble that assumed in defecation. Though apparently inconvenient, and repugnant to the refined woman, this position is certainly the most natural one for expulsion from the abdominal or pelvic viscera, and will certainly, in many cases, facilitate labor. (72)


He documents the experience of another physicians, saying:


“… he tells me of attending a lady of good position in society in two labors. ‘In her first labor, delivery was retarded without apparent cause. There was nothing like impaction, or inertia, yet the head did not advance. At every pain she made violent efforts, and would bring her chest forward. I had determined to use the forceps, but just then, in one of the violent pains, she raised herself up in bed and assumed a squatting position, when the most magic effect was produced. It seemed to aid in completing delivery in the most remarkable manner, as the head advanced rapidly, and she soon expelled the child by what appeared to be one prolonged attack of pain. In subsequent parturition, labor appeared extremely painful and retarded in the same manner; I allowed her to take the same position as I had remembered her former labor, and she was delivered at once squatting.” (73)


Information on traditional birthing positions can also be wrought from the Old Testament. The King James translation of Exodus 1-16 says “When ye do the office of a midwife to the Hebrew women, and see them upon the stools…”. However there is some scholarly debate about the translation of the word “stools”, as a more accurate translation might actually be “stones”.  You might wonder what stones have to do with birthing, until you see this depiction of a popular Persian birthing position.


If you’re curious (as I was) this is what a “suspended” birth looks like, here you go.

If you’re curious (as I was) this is what a “suspended” birth looks like, here you go.


A friend recently shared a video of women delivering in the squatting position.  I post this video with the STRONGEST OF WARNINGS. I warn (only slightly jokingly) that that which is seen, cannot be unseen*. Proceed at your own risk! Birth is magical (though not mysterious), but some people find the imagery rather disturbing.


With that warning in place, I present the following video:



Those that have seen (or perhaps experienced) birth in the modern conventional position will probably agree that these women make labor look somewhat easy…


It’s also interesting to explore the delivery position of some of our closest living ancestors.  It appears that chimpanzees naturally deliver in a squatting position (with a similar “occiput anterior” presentation).



One of the most basic elements of obstetrics that we learn in medical school is the “7 cardinal movements” of delivery. Medical student must know these movements- engagement, descent, flexion, rotation, external rotation, and expulsion- and on the labor and delivery floors we are expected to participate in and assist with deliveries.  I remember watching many of my classmates “air-deliver” babies- going through the maneuvers of “catching” (a much more honest term than “delivering”) a baby, as we discussed these cardinal movements. While I understand that it is important to know these normal movements, the idea that a physician actually guides these movements is laughable. Truly, in most deliveries, our hands are there to catch and support. In fact, they are likely only necessary because of the position that we have developed for women to deliver.  In this youtube video explaining the 7 cardinal movements, the doctors hands only show up once the head is expulsed so that the baby’s head does not rest on the perineum. Indeed, “protect the perineum” is the mantra chanted to med students and novice doctors learning to deliver babies in a reclining position.  In the squatting position, gravity protects the perineum.


Support is needed because of maternal positioning, not intrinsic necessity.

Support is needed because of maternal positioning, not intrinsic necessity.


Gravity isn’t the only reason to consider delivering in a squatting position. I’ve heard it said (though haven’t found a reliable source) that squatting not only increases a woman’s ability to push (allowing her to better utilize her abdominal muscles), but also helps the pelvis open wider for delivery (due to the pull of abducting muscles).  In this position, and with the aid of gravity, it seems (and again I’ve heard it suggested) there is a lower risk of a perineal tear, something that I saw all too frequently during my Ob clerkship.


Squatting is by no means a perfect solution to birthing.  According to at least one study conducted in Nepal, squatting deliveries (along with multiparity and early age of first birth) are associated with an increased risk of pelvic organ prolapse later in life [2].  Also, opting for a squatting delivery removes the option of an epidural for pain control. An epidural causes a loss of sensation below the level of anesthesia, thus making walking (and squatting) impossible.


Squatting is not the only traditional (though now it would be classified as “non-traditional”) birthing position that women can consider.  I whole-heartedly appreciate my family physician who encourages women to find a position that is most-comfortable for them.  Hands-and-knees (exactly what it sounds like), has actually been studied in the first stage of labors for mothers whose babies are delivering in the occiput-posterior position.  While the study was small, the findings were encouraging [3].


Sometimes when I talk about evolutionary and ancestral medicine people assume that I am anti-modern medicine.  I am not. In childbirth in particular, modern advances in general health, pre-natal care, diagnostics, medicine, and surgery have saved countless lives. I am, however, in favor of assessing (and re-assessing) our beliefs (new and old) about how to best obtain and preserve health.


I find Dr. Engelmann’s book fascinating, and while there are elements that are rather disconcerting (the traditions of male and female circumcision, a surgery performed on men to decrease fertility, and the tradition in one culture of removing one testicle to prevent the conception of twins to name a few), I find his observations and his humble admissions (as well as his love of commas) lovely.  His conclusions are well worth reading (emphasis mine):


Abler obstetricians than myself have undoubtedly understood the movements of women, and the positions which they assumed in the agony of the expulsive pains. As regards myself, I must candidly confess this was not the case; and it was not until I had undertaken this work, and had begun to study the positions assumed by savage and civilized people during labor, that I began to understand that there was a method in the instinctive movements of women in the last stage of labor. I had seen them toss about and sought to quiet them; I bade them have patience and lie still upon their backs; but, since entering upon this study, I have learned to look upon their movements in a very different light. I have watched them with interest and profit, and believe that I have learned to understand them. It has often appeared to me, as I sat watching a tedious labor case, how unnatural was the ordinary obstetric position for the parturient woman; the child is forced, I may say, upwards through the pelvic canal in the face of gravity, which acts in the intervals between the pains, and permits the presenting part of the child to sink back again, down the inclined canal. If we look upon the structure of the pelvis, more especially the direction of the pelvic canal and its axis, if we take into consideration the assistance which may be rendered by gravity, and, above all, by the abdominal muscles, the present obstetric position seems indeed a peculiar one.


The contractions of the previously inactive and rested abdominal muscles are a powerful adjunct to the tired uterine fibre, in the last prolonged and decisive expulsory effort, and in the dorsal decubitus they are somewhat hampered; they act to the best advantage in the inclined positions, semi-recumbent, kneeling, or squatting. We know that the squatting position is the one naturally assumed if an effort is required to expel the contents of the pelvic viscera; we, moreover, all know how difficult, even impossible, it is for many to perform those functions recumbent in bed, and mainly because they have-not sufficient control of the abdominal muscles in that position. Much more is this the case in the expulsion of the child; but the recumbent position is sanctioned by custom; it is pointed out as apparently convenient; it is imperatively demanded by prudery; and by a false modesty which hides from view the patient’s body beneath the bed clothes; and above all it is dictated by modern laws of obstetrics, the justice of which I have never dared question; we have all been taught their correctness, and we all thoughtlessly follow their dictates. There is no reason for assuming this position, though we are taught it; it is not reason, or obstetric science, but obstetric fashion which guides us,- guides us through our patients; and blindly do we, like all fashion’s votaries, follow in the wake. (140-141)


Obstetrics is a specialty where many do not want to question the norm. Indeed, fear of litigation generally pushes physicians to be overly aggressive in managing labor and quick to opt for cesarean delivery. Randomized controlled studies that push the boundaries of modern “obstetric fashion” are unlikely to be performed for fear of litigation, but observation of mothers who choose to deliver in various positions as well as consideration of ancestral practices can potentially help drive modern medicine to a higher standard.



The “progression” of the obstetrical chair. The first stool is not unlike some modern  birthing stools, while the final incarnation is not too far displaced from the modern delivery-room bed.

The “progression” of the obstetrical chair. The first stool is not unlike some modern birthing stools, while the final incarnation is not too far displaced from the modern delivery-room bed.


*A brief story from when I was on an Emergency Medical Services elective.  The ambulance I was on was called to back up another team that had gone to attend at precipitous delivery. When we arrived, it became apparent that we were not there to assist the patient (it was her fourteenth (!!!) delivery), but rather to make sure that the EMT who had just witnessed his first delivery did not pass out.  He had a very pale and shocked look to him, and he just stared at us blankly as we helped the mother with her new child. After a couple minutes, he looked at us and asked “does the mental image ever go away?”. He later admitted that he didn’t want to sleep with his girlfriend for at least two weeks… I believe this is what a good male friend of mine describes as figuring out the difference between “medical vagina and sexy vagina”. 


1.            Engelmann, G.J., Labor Among Primitive Peoples. Second ed. 1883, St Louis: J.H. Chambers and Co.

2.            Lien, Y.S., G.D. Chen, and S.C. Ng, Prevalence of and risk factors for pelvic organ prolapse and lower urinary tract symptoms among women in rural Nepal. Int J Gynaecol Obstet, 2012. 119(2): p. 185-8.

3.            Stremler, R., E. Hodnett, P. Petryshen, B. Stevens, J. Weston, and A.R. Willan, Randomized controlled trial of hands-and-knees positioning for occipitoposterior position in labor. Birth, 2005. 32(4): p. 243-51.


And finally, for your viewing pleasure, this classic:


Read Full Post »

‘Tis the season for cheesy cards, overpriced restaurant dinners, flowers, chocolates, jewelry, and stuffed animals.  I’ll admit that I’ve never been a huge fan of Valentine’s Day.  We started off on the wrong foot, with those awkward grade-school valentine exchanges, and I’ve never seen eye-to-eye with Valentine’s day over the crass-consumerism that seems part-and-parcel with this holiday.  That, and even in my most desperate days I could never understood the gustatory appeal of candy hearts.


This year, instead of doing my best to ignore the day, I thought I’d have a little fun. I’ve said it before and I’ll say it again: evolution is everywhere. This is never more true than in the bedroom!


Snuggling, cuddling, spooning… name your term.  


Why do humans like to cuddle?  There are a number of arguments that can be made for snuggling.  Physical contact in the form of massage increases levels of the “love” hormone oxytocin [1] and decreases cortisol [2] (though some of the data on massage is fuzzy, perhaps because massage, especially in a research setting, can be a rather impersonal experience in comparison to cuddling).  More frequent hugs increase oxytocin levels and lead to lower blood pressure and heart rate in premenopausal women [3]. An interventional trial that looked at the effects of “warm touch” (including hand-holding, hugs, and “cuddling up”) in married couples showed an increase in salivary oxytocin (in husbands and wives) and a decrease in systolic BP (in husbands only) in the treatment group [4].


Increased oxytocin seems to enhance the effects of social support on stress responses [5].  Oxytocin also plays a role in the early stages of romantic attachment, and encourages pair-bonding (and parental attachment) [6]. But oxytocin isn’t the only compound that is altered by cuddling-up or that affects the way we feel about other people. There is also evidence that touch alters the release of endorphins[7], and that neuropeptides may play a role in the beneficial nature of physical touch [8].


On a day like Valentine’s Day, which purports to revolve around the concept of love (and chocolate sales), the arguments that physical contact reduces stress and increases the hormone associated with pair-bonding are probably king.  Recently  (and I did warn you I’m a bit cynical about this holiday), I’ve been wondering if there is something a little more… “anatomically practical” about cuddling.


Why you (men) shouldn’t “hit it and quit it”.


Anyone that has spent anytime thinking about human pair bonding has spent time thinking about short-term vs. long-term interests when it comes to the mating game. Yes, humans are predisposed to long-term bonding, but that doesn’t mean that there isn’t a significant role of short-term mating in human procreation (perhaps not as much now, thanks to social norms and the potential for paternity tests, but sources frequently cite that ~10% of children aren’t actually the offspring of the father that raises them, though a more thorough investigation shows that the rate is probably closer to 3% [9].).  As an aside, while on my EMS elective I was repeatedly subjected to the Maury Povich show and it’s ilk while hanging out at headquarters (the lounge TV was usually blaring in the background). I doubt that Frederick Sanger imagined how his great discovery of DNA sequencing would be used when he developed the method in 1975 (for which he later won a Nobel prize in Chemistry- his second). “You are NOT the father!!!” But I digress…


Different species have various ways of decreasing paternity uncertainty.  Some animals- canines for example- have a very… awkward (maybe I’m being anthropomorphic, I apologize) way of increasing the likelihood of paternity. After the completion of mating, the male doesn’t leave the female’s side. He can’t. Seriously. He is physically attached.


Dog mating is significantly different from that of humans. When the dog’s penis is first inserted into the vagina it isn’t actually erect and is only able to penetrate thanks to the penis bone, also known as the baculum. After insertion, the penis swells and the bulbus glandis at the base of the penis literally locks the penis in place, preventing the removal of the penis. This is known as “knotting” or “tying”.  This cumbersome position usually lasts 5-20 minutes after ejaculation.


At least one book on dog genetics says that this process seems “quite irrational”, but the authors submit that it “must serve a purpose as it has remained despite apparent drawbacks, such as vulnerability to attacks during the act.” [10]. I doubt I’m the first to suggest that the advantage of this prolonged intimacy is an increase in certainty of paternity.  It seems rather obvious that this method of copulation gives the lucky suitor’s sperm time to gain advantage in the race to fertilization, before another competitor’s sperm can enter the race.


Fortunately, humans have not evolved this mechanism of assuring paternity. Instead, I’d argue that post-coital snuggling can offer some of the advantages of canine-coupling.


Some people might think that humans are above such an animalistic tendency. If a man doesn’t stick around long enough to ensure that his sperm have time to reach their destination, would another man’s actually get the chance?


Well maybe…  It has actually been argued that the human penis is evolutionarily shaped (literally) to help a man get his semen where it needs to be, even if it didn’t actually get there first.  In the article “The human penis as a semen displacement device*”, researchers argue that the shape of the human penis is “designed” to remove semen from the vagina during sex, clearing the way for new semen to be deposited in the most advantageous location (increasing the likelihood of paternity) [11].  This strengthens the argument that if you’re a man, and you want to ensure paternity, it’s probably best you hang around to make sure your sperm doesn’t have any competition in reaching it’s goal.


So there you have it, the “principle into practice evolutionary argument for snuggling”.  Sure, in the modern world men may not WANT paternity with every sexual encounter, but that doesn’t mean that the evolutionary mechanisms and behavioral predispositions aren’t already in place to improve paternity-certainty.  On a day like Valentine’s day, you might rather focus on how cuddling increases oxytocin, leading to emotional bonding.  Just remember that snuggling also physically bonds you, and that may not be such a bad thing…


*This paper wins the award for most giggle-worthy methods. Some of the lines could be right at home at #overlyhonestmethods. E.g.: “… this recipe was judged by three sexually experienced males to best approximate the viscosity and texture of human seminal fluid.”



1.            Morhenn, V., L.E. Beavin, and P.J. Zak, Massage increases oxytocin and reduces adrenocorticotropin hormone in humans. Altern Ther Health Med, 2012. 18(6): p. 11-8.

2.            Rapaport, M.H., P. Schettler, and C. Bresee, A preliminary study of the effects of repeated massage on hypothalamic-pituitary-adrenal and immune function in healthy individuals: a study of mechanisms of action and dosage. J Altern Complement Med, 2012. 18(8): p. 789-97.

3.            Light, K.C., K.M. Grewen, and J.A. Amico, More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women. Biol Psychol, 2005. 69(1): p. 5-21.

4.            Holt-Lunstad, J., W.A. Birmingham, and K.C. Light, Influence of a “warm touch” support enhancement intervention among married couples on ambulatory blood pressure, oxytocin, alpha amylase, and cortisol. Psychosom Med, 2008. 70(9): p. 976-85.

5.            Heinrichs, M., T. Baumgartner, C. Kirschbaum, and U. Ehlert, Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress. Biol Psychiatry, 2003. 54(12): p. 1389-98.

6.            Schneiderman, I., O. Zagoory-Sharon, J.F. Leckman, and R. Feldman, Oxytocin during the initial stages of romantic attachment: relations to couples’ interactive reciprocity. Psychoneuroendocrinology, 2012. 37(8): p. 1277-85.

7.            Keverne, E.B., N.D. Martensz, and B. Tuite, Beta-endorphin concentrations in cerebrospinal fluid of monkeys are influenced by grooming relationships. Psychoneuroendocrinology, 1989. 14(1-2): p. 155-61.

8.            Dunbar, R.I., The social role of touch in humans and primates: behavioural function and neurobiological mechanisms. Neurosci Biobehav Rev, 2010. 34(2): p. 260-8.

9.            Anderson, K.G., How Well Does Paternity Confidence Match Actual Paternity. Current Anthropology, 2006. 47(3): p. 513-520.

10.            Ruvinsky, A. and J. Sampson, The Genetics of the Dog. http://www.google.com/books?id=bgZwjdB4xgEC&source=gbs_navlinks_s ed. 2001: Google Books.

11.            Gallup, G.G., R.L. Burch, M.L. Zappieri, R.A. Parvez, M.L. Stockwell, and J.A. Davis, The human penis as a semen displacement device. Evolution and Human Behavior, 2003. 24: p. 277-289.

Read Full Post »

Many people get their start in the ancestral health/evolutionary wellness world through food.  Be it “paleo” or “primal” (or perhaps the ever practical advice of Dr. Emily Deans: “Don’t eat like a Jerk”), most people start this journey with food, and then start to apply the evolutionary mindset to other aspects of life. Once the logic of “eating evolutionarily” sets in (and once you realize how good you look and feel while doing it), you might start to apply the evolutionary approach to other aspects of your life.

Once you’ve been at this long enough, you start to think about the evolutionary aspects of everything- food, movement, socialization, sex, sun, stress, and sleep (so many s’s!)- but it seems that the two that most frequently go together are food and feet.  The exact timeframe may vary, but there’s usually not a huge gap between someone adopting a “primal” or “paleo” diet, and someone purchasing their first pair of Vibram Five Fingers– and so your migration to the fringe begins…

The jump from an evolutionary approach to food to barefoot running is an appropriate one.  The evolution of the foot (and our ability to run) is often traced to the human ability to run down prey, and thus the evolutionary argument that meat is an important part of an appropriate human diet. From an evolutionary health perspective, the argument that “these feet were made for moving” (without the help of massive rocker-bottom shoes) just starts to make sense, and might just prevent (or explain) injury.

If you’re not familiar with the arguments for a barefoot approach (or if you are, but haven’t seen this video), I highly recommend the following brief video, made to accompany this paper [1], in the eminent journal Nature*.

It certainly makes sense that a forefoot foot strike pattern inline with our evolutionary “design” might be protective against running-induced injury.  Indeed, a small retrospective study that was published this July showed exactly that.  In cross-country runners, those with a forefoot foot strike had significantly less repetitive stress injuries than their rearfoot-striking counterparts [2].

Embracing the barefoot message does not mean you have to embrace actually going barefoot.  You can see from the VFF link above that there are options for those who want the barefoot experience without the unpleasant effects of doggie-doo.  For those worried about being labeled part of the monkey-foot army, have no fear- there are minimalist options out there that are relatively indistinguishable from *regular* footwear.

In the last few years there’s been an explosion of minimalist or “barefoot” shoes. Those in the market can chose from a number of mainstream or more esoteric brands.  From New Balance Minimus Zeroes and Merrel Gloves to Vivobarefoot and some of the Inov-8 options, there are many options for the barefoot enthusiast to try.

I’ve gone through a number of pairs of VFF at this point, with the rather simple KSOs being my style of choice.  I’ve endured the occasional joshing from friends and entertained many questions from strangers out on trails, and am generally enthusiastic about VFFs, but they’re definitely not a “stealth” minimalist shoe.  On the other hand, the Vivobarefoot sneakers that I wear in the hospital look like totally normal sneakers. [I’ll admit my favorite hospital “outfit” is the 4 S’s- Scrubs, Sneakers, Sweatshirt, and Stethoscope]

I’m not here to write a review of the Vivos I’ve been wearing (though they’ve been great for me). My advice for anyone looking to explore minimalist shoes is to go to a store and try on the different options. I know some people love the Merrel line, but they’re definitely too narrow in the arch area for me (they leave me feeling like I’m in shoes with big arch support).  I want to try the NB Mimimus Zeroes (the newest NB “barefoot” option with no heel drop) before I purchase my next pair of sneakers.

Shopping for a new pair of sneakers is definitely on my mind, as I’ve recently realized that my original pair of Vivos is on the way out. They’re had a good run, but some of the luggs are now totally worn down, and the sole is starting to erode too. I hadn’t noticed in the way they wore, but when I flipped them over I was initially surprised to see where there was wear.

Ever since I was a kid I’ve been “hard” on sneakers. I’ve worn through the soles of many shoes (and stomped down the back of many an unlaced sneaker- much to my parents chagrin). In the past, I’ve always noticed that it was the heels of my sneakers’ soles that went first.  With my Vivobarefoots, the wear is only prominent at the ball of my feet. I dug up an old pair of sneakers (not worn out, as I switched over to minimalist options before these were done) and you can clearly see that the greatest wear is in the heel areas. Yes- there is some wear in the toes, but not much. For contrast, look at my ailing Vivos.

The different wear patterns in my last pair of normal Merrels and my minimalist Vivobarefoots.

For me, this is pretty convincing evidence that minimalist shoes do, in fact, encourage the midfoot strike that is desired by those that go barefoot. That’s not to say that minimalist shoes are a cure-all for heel striking. You can check out this video from the 2011 NYC barefoot run to see the variety of footfall patterns- many of those with minimalist shoes have a different footfall from the truly barefoot, with a couple examples of heel-striking in minimalist shoes… ouch!

Some technical difficulties aside, minimalist shoes are definitely a step in the right direction (pun intended?) for those wishing to get a more “evolutionarily appropriate” footfall, without going truly barefoot (or for those who might like to go barefoot, but are constrained by social norms (or hospital policy!))

Lunch/sun break on a sunny day on my surgery clerkship.

Usual disclaimers apply- minimalist shoes are not for everyone. Getting accustomed to minimalist shoes can take time. Consult a medical professional before starting any exercise regime. Go in search of the Wizard of Oz (NOT DOCTOR OZ!) if you are in need of your own brain.

*For those keen on reading more about evolutionary medicine, Daniel Lieberman published an article on evolutionary medicine and barefoot running in April [3].

1.         Lieberman, D.E., M. Venkadesan, W.A. Werbel, A.I. Daoud, S. D’Andrea, I.S. Davis, R.O. Mang’eni, and Y. Pitsiladis, Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature, 2010. 463(7280): p. 531-5.

2.         Daoud, A.I., G.J. Geissler, F. Wang, J. Saretsky, Y.A. Daoud, and D.E. Lieberman, Foot strike and injury rates in endurance runners: a retrospective study. Med Sci Sports Exerc, 2012. 44(7): p. 1325-34.

3.         Lieberman, D.E., What we can learn about running from barefoot running: an evolutionary medical perspective. Exerc Sport Sci Rev, 2012. 40(2): p. 63-72.

Read Full Post »

If you’re just reading my blog for the first time, I’d recommend you go back and read the last two posts where I talk about the fallacy of the appendix as a vestigial organ and how and why this organ sometimes goes off the tracks in our modern environment.


In this final installment on the appendix, I’d like to explore how we can take what we know about the appendix, consider it in an evolutionary light, and think about the practical implication of this knowledge. As discussed in my first post, it has been proposed that the appendix evolved as a safe house for the commensal microbiota that live in our gut. This safe house is useful in undeveloped communities where enteric pathogens are common, but is probably not so important (or may actually be problematic) in today’s hygienic world. A recent paper, however, challenges the idea that the appendix is no longer useful in our modern world.


Clostridium difficile (or as it’s referred to on the floor ‘C. diff.’) is an unpleasant little bacterium that causes a condition known as pseudomembranous colitis. Many people carry around some C. diff, but an overgrowth can occur after a course of antibiotics kills off other bacteria or after infection with a particularly nasty strain of C. diff. In these situations, serious colitis can occur. Infection with this bacterium can cause anything from mild diarrhea to fulminant colitis with shock and death. C. diff is the most common form of hospital-acquired diarrhea in acute care settings, and the prevalence is increasing due to the emergence of particularly virulent strains. Unfortunately, once you’ve acquired C. diff, you’re significantly more likely to contract it again- with 20% of people getting a recurrence. Do you see where this is going? As my previous post suggested, the appendix is probably helpful in developing countries with widespread food and water-borne GI infections, but not so useful in the developed world where these things are less common. But what about in the hospital, where rates of infection are unfortunately rather high?


In those that have been infected with C. diff, it appears that having an appendix is significantly protective against having a recurrence [1]. This protection could be conferred by two potential mechanisms (or a combination). The GALT tissue may provoke the appropriate immune response, and/or, the normal microbiota that were kept safe in the appendix can repopulate the gut, protecting it from a recurrence. I’m not quite sure how to apply option (a) to a practical approach right now, but I think option (b) offers some interesting ideas. Full warning- this is about to get a little gross…


The standard treatment for C. diff is a course of serious antibiotics (the fact that C. diff overgrowth is frequently caused by antibiotics sometimes seems to be lost in the mix). One of my fellow med students informed me recently that there’s a brand spanking new antibiotic on the market that is specifically geared towards preventing the recurrence of C. diff, (Fidamoxicin, trade name Dificid) but I’m not familiar with that treatment. What I am familiar with, however, are fecal transplants.


Fecal transplants (bacteriotherapy sounds so much less… gross), are exactly what they sound like. You take the feces from a healthy donor, test them for all types of nasty pathogens, and then implant them in your sick recipient. I had been informed by an infectious disease doc that the preferred route of entry was a nasogastric tube, but recent studies seem to imply that transplantations via colonoscopy are very effective [2] (and I don’t know about you, but for this particular procedure, going ‘up the out-hole’ seems a whole lot more appealing that going ‘down the in-hole’). In either case, the large intestines are first flushed with an isotonic solution and then the donor material is transplanted. This procedure seems to be very effective in treating and preventing a recurrence of C. diff, though it has yet to become a common or generally accepted practice (they don’t do it at my medical school for example). The obvious advantage of this procedure is that it inoculates the gut with a population of healthy/normal bacteria after an infection (and probably some antibiotics) that has knocked down (or out) the native flora. Additionally, in a world with progressively fewer and fewer effective antibiotics, it offers a therapeutic option that does not rely on pharmaceuticals. The obvious disadvantages are the gross factor and the pressing question of ‘who is the donor’ (for the record- they usually look to your spouse if you have one). Also, the procedure remains rather expensive because of the expense of testing samples and the nature of the procedure, however efforts to streamline the process appear effective [3]. Also- if you happen to be going in for a procedure that will see your native flora eradicated, you can actually save your own sample for an autologous transplantation at a later date.


Fecal transplants seems to be an interesting and appropriate treatment after C. diff overgrowth, and could also be beneficial in other GI conditions that are caused by dysbiosis. There’s definitely reason to think it might also be useful for treating a number of gut conditions such as Crohn’s disease, ulcerative colitis, irritable bowel, and maybe even systemic problems such as allergies and auto-immune conditions [4]. These are all things that warrant more research.


But how does this all tie back to the appendix?


Principle into practice. If we believe that the appendix acts as a safe house for commensal micro biota that are capable of repopulating the gut when needed, we should take special consideration for those that have had their appendix removed. While I tend to think that fecal transplants could be an appropriate therapy for most people as therapy for a C. diff overgrowth, it might be an exceptionally good choice for those without an appendix who do not have a reservoir of healthy bacteria to repopulate the gut after C. diff is eliminated. Furthermore, while I’m uncertain how effective supplemental and dietary probiotics are, it would seem reasonable to encourage those without an appendix (I think it is reasonable to encourage everyone to eat these things, but I think special recommendations should be given to those without an appendix) to eat fermented foods rich in microbiota after episodes of diarrhea. Additionally- the incorporation of dietary prebiotics to encourage the growth of commensal bacteria is probably also a reasonable recommendation. If nothing else, I would suggest that these considerations warrant further thought and potentially some research.


It’s also interesting to consider the potential role of the appendix in inflammatory conditions that appear to have an immune component such as ulcerative colitis. It seems that a misfunctioning appendix may play a role in the etiology of these disorders. While removal of the appendix might not be ideal, if it offers a mechanism by which to control these otherwise rather devastating conditions, it should not be overlooked. In these conditions, I would approach appendectomy as a procedure of last resort, but if normal gut function cannot be achieved by normalization of gut flora through other methods, it might appear to be a reasonable approach.


Finally- while the appendix appears to be a highly specialized organ, with important and interesting functions, acute appendicitis is a very serious and life-threatening condition. Appendectomy has been the gold-standard treatment for appendicitis for years, however recent research suggests that medical-management (antibiotics) may be effective for some patients [5]. Medical management of this condition represents a serious shift in the approach to treating appendicitis. It also offers an opportunity to save an organ whose importance and function we are only just starting to understand. Again- appendicitis is a life-threatening condition, and not treating it is not an option (if you suspect a problem- get to an emergency room ASAP), but the understanding that this organ plays a real and important role in human physiology suggests that if we can save the organ, perhaps we should (this is in contrast to current trend of ‘if in doubt, take it out’).


Understanding that the appendix is a specialized organ that has evolved to play a role in maintaining the gut micro flora is an important development in the study of normal and disturbed gut function. The realization that the appendix acts as a safe house for normal gut flora that can repopulate the gut after disease offers insight into how we might preferentially treat those who lack an appendix after episodes of gut dysbiosis. Furthermore, studying the role of the appendix in maintaining and regulating the actions of the immune system in the gut may offer important insights into understanding and then hopefully treating, immune-based gut conditions. How we might study this, however, is a story for another day. Until then- I hope you’ve enjoyed these musings on the appendix- thinking about the little organ in principle and in practice



1.         Im, G.Y., R.J. Modayil, C.T. Lin, S.J. Geier, D.S. Katz, M. Feuerman, and J.H. Grendell, The appendix may protect against Clostridium difficile recurrence. Clin Gastroenterol Hepatol, 2011. 9(12): p. 1072-7.

2.         Mattila, E., R. Uusitalo-Seppala, M. Wuorela, L. Lehtola, H. Nurmi, M. Ristikankare, V. Moilanen, K. Salminen, M. Seppala, P.S. Mattila, V.J. Anttila, and P. Arkkila, Fecal Transplantation, Through Colonoscopy, Is Effective Therapy for Recurrent Clostridium difficile Infection. Gastroenterology, 2012. 142(3): p. 490-6.

3.         Hamilton, M.J., A.R. Weingarden, M.J. Sadowsky, and A. Khoruts, Standardized Frozen Preparation for Transplantation of Fecal Microbiota for Recurrent Clostridium difficile Infection. Am J Gastroenterol, 2012

4.         Borody, T.J. and A. Khoruts, Fecal microbiota transplantation and emerging applications. Nat Rev Gastroenterol Hepatol, 2011. 9(2): p. 88-96.

5.         Liu, K. and L. Fogg, Use of antibiotics alone for treatment of uncomplicated acute appendicitis: a systematic review and meta-analysis. Surgery, 2011. 150(4): p. 673-83.



Read Full Post »

I hope that my last post persuaded you that the appendix is not the pathetic remains of our forbearers’ large cecum, but is in fact a nifty piece of anatomy that maintains a safe house for the normal micro flora of our gut (If you’re interested in gut micro flora, Melissa wrote a great post here). While this little organ seems to work well in developing countries where there are frequent outbreaks of enteric pathogens and minimal hygiene, something seems to have gone awry in the developing world. While appendicitis is exceedingly rare in developing countries, it has been reported that up to 6% of the population in industrialized countries develop appendicitis necessitating appendectomy [1]. Why has our bacterial safe house turned into a ticking time bomb?

As early as 1505, Leonardo da Vinci identified the appendix and recognized that it sometimes became inflamed and burst. Much of his medical knowledge was lost, and it wasn’t recognized again until 1705 when the (then very young) father of clinical case reports, Giovanni Battista Morgagni, dissected a man who had died of appendicitis and subsequent peritonitis. That case actually revolutionized the understanding of medicine, with Morgagni and his mentor Valsalva recognizing that a specific disease was caused by a specific condition in a specific part of the body. This showed that illness was not caused by an imbalance of humors or a generalized malaise, but rather a specific cause. This one case led Morgagni and Valsalva to perform autopsies on all their deceased patients, and their detailed notes of over 700 cases were analyzed and published in the book On the Seats and Causes of Disease as Indicated by Anatomy. This book, and the idea that disease is caused by specific disorders, revolutionized medicine.

While appendicitis was one of the first diseases for which the anatomical source was recognized, we still don’t clearly understand why the condition occurs. It is generally believed that appendicitis occurs when the appendix is obstructed (by obstruction of the opening into the cecum by feces or swelling of the appendix due to proliferation of the tissue of the appendix itself), and the mucinous products of the appendix build up, leading to increased pressure and eventually tissue death. This dead tissue encourages bacterial proliferation (and we’re no longer talking about the friendly house-keeping type). Acute appendicitis is a medical emergency, and one that must be diagnosed and handled quickly. The removal of an inflamed, but intact, appendix is a much easier and neater procedure than trying to manage the aftermath of a ruptured appendix and subsequent peritonitis. If you think you might have appendicitis- get thee to the emergency department!

But why has appendicitis become so common? Appendectomy is sometimes referred to as ‘bread and butter’ for a general surgeon, but in developing countries this condition is almost unheard of. The rate of appendicitis is reported to be about 35-fold higher in the United States than in areas of African unaffected by modern health care and sanitation. Additionally, as communities adopt Western sanitation and hygiene practices, the rate of appendicitis increases [2]. Could appendicitis be another result of the “hygiene hypothesis”- the idea that modern medicine and sanitation can lead to an under-stimulated and over-active immune system?

As discussed in my first post, the appendix is associated with a large amount of gut-associated lymphoid tissue (GALT). While I pointed out that the appendix does secrete some substances that actively encourage the formation of biofilms for friendly bacteria, GALT also plays a role in the more typically recognized ‘keep the bad guys out’ aspect of the immune system. It’s that part of the system that tends to go awry with our modern hygienic world. Our immune system evolved to handle and control a number of different pathogens, including unfriendly bacteria and parasites. In the absence of pathogens, however, the system can go amiss The immune system is primed and looking for a fight, and if nothing appropriate comes along to take a beating, the immune system can start getting self-destructive, going after the body in which it is housed. It’s a classic case of ‘idle hands’ (or an active teenager with no good way to get the energy out!). This may well play a role in the prevalence of appendicitis in the developed world: overactive GALT tissue causes the appendix to swell, plugging the appendix, stopping the secretions from exiting into the cecum, and leading to increased pressure and subsequent necrosis and disease. (This is the condition that tends to occur in young people. In older people, appendicitis tends to be caused by the physical blockage of the appendix by a coprolith).

So is that it? In the past, and in the developing world, the appendix operated as a safe house for commensal bacteria. In the modern/hygienic world the appendix isn’t really needed, and can in fact get a bit out of whack because it doesn’t have anything to direct it’s immune-related functions towards. It definitely seems as though this might be the case, and unfortunately the problem appears to extend beyond the appendix. It turns out that an overactive appendix may also play a role in ulcerative colitis- an inflammatory condition of the large intestine. In some people with ulcerative colitis, an appendectomy improves the symptoms of ulcerative colitis, and in others it can completely cure the condition. The intended purpose of the appendix may shed light on why this pathology occurs. First- in a hyper-immune state, the appendix may house bacteria that the immune system aberrantly attacks. Alternatively (or additionally), the GALT tissue may drive the gut into a hyper-immune state. In either case- understanding the evolutionary purpose of the appendix can help understand and treat the conditions that occur in our modern hygienic world. Furthermore, it offers evidence that we should think about the impact of our uber-hygienic world, and consider how we might best handle the mismatch between our immune system that evolved to keep us safe in a dirty world and our modern clean environment.

(If you’re looking for a scholarly discussion of this topic, I highly recommend The cecal appendix: one more immune component with a function disturbed by post-industrial culture [2].)

1.            Bollinger, R.R., A.S. Barbas, E.L. Bush, S.S. Lin, and W. Parker, Biofilms in the normal human large bowel: fact rather than fiction. Gut, 2007. 56(10): p. 1481-2.

2.            Laurin, M., M.L. Everett, and W. Parker, The cecal appendix: one more immune component with a function disturbed by post-industrial culture. Anat Rec (Hoboken), 2011. 294(4): p. 567-79.

Read Full Post »

As my last post may have suggested, I’ve recently been taking a deeper look at the large intestine – specifically the appendix. The appendix is a small, intestinal, diverticulum (basically a little pouch) that protrudes off the cecum (the first part of the large intestine, itself a little pouch- though much bigger than the appendix). You may have heard (and indeed, at the time of writing, Wikipedia has it written) that the appendix is a vestigial structure- a now useless remnant of something that was useful to our ancestors. Darwin actually helped propagate this belief, theorizing that the appendix was a shrunken remnant of a larger cecum. Furthermore, the relatively common and apparently benign surgical removal of the appendix, the procedure known as appendectomy, seems to support the idea that the appendix is of no particular use to humans today.

But is it?

There is an increasing body of information supporting the idea that the appendix is not a vestigial structure and that it has a specific role in human health. This might get a bit lengthy, so I will approach this topic in stages- probably culminating in a few posts.

First things first- is the appendix really vestigial? As I mentioned above, Darwin believed that the appendix was vestigial. He came to this idea because of the (erroneous) belief that hominids were the only primates to possess an appendix. Other primates that eat vast quantities of leaves and fibrous material that needs to be fermented by gut microflora, have large cecums where fermentation can occur. Humans, who don’t rely on copious vegetation for nutrition, only have a small cecum. It was thus hypothesized that the appendix was the shrunken remains of our forbearers’ large cecum. What Darwin was missing, however, was the fact that a number of species, including many primates, have large cecums and ALSO have an appendix. Hmm…

Another clue that the appendix is not simply the excess baggage of our herbivorous forbearers is that according to phylogenetic analysis, the appendix has actually arisen at least twice, independently, in evolutionary history. Such research also suggests that the appendix has been maintained in mammalian evolution for 80 million years [1]. To have evolved twice, independently, and to have been maintained for 80+ million years, suggests the appendix is not a useless remnant.

If the appendix is not vestigial, what is its function?

The dual evolution of the appendix, and the occurrence of an appendix in species with large cecums suggests that the organ plays an important role in normal physiology. Anatomically, the appendix is found at the end of the cecum, in a rather secluded corner of the intestines (if you can imagine such a thing). While the length of the appendix varies greatly from human to human, the diameter remains relatively constant. Another constant is the appendix’s association with a large amount of immune tissue known as GALT (gut-associated lymphoid tissue). While most people tend to think of immune tissue as ‘bacteria-fighting’ stuff, it turns out that some immune tissue produces substances (such as secretory IgA and mucin) that actually support bacterial growth, specifically the growth of biofilms.

Biofilms have been the focus of quite a bit of research recently, and usually not in a good way. Because people tend to think of biofilms (literally aggregates of bacteria embedded in self-produced slime) as pathogenic and problematic conglomerates, the focus of most research has been how best to disrupt and destroy them. It’s not entirely unwarranted either, Biofilms tend to be associated with unpleasant conditions, such as infections of medical implants and dental plaque. However, biofilms of commenselate bacteria (the ones we evolved with, on our skin and in our gut) are a way of safeguarding good bacteria.

When this is all put together, it appears that the appendix, with its relatively constant diameter and with the secreted products of GALT, is well adapted to facilitate and maintain communities of mutualistic intestinal flora [2]. It has thus been theorized that the appendix can act as a source of normal microbiota that can inoculate the gut when needed.

Why would your gut need to be inoculated with normal microbiota? Isn’t that what’s already in your gut?

It has been suggested [2, 3] that the appendix acts as a ‘safe house’ for resident microbiota when a GI infection occurs. When disease-causing bacteria are flushed from the intestines by diarrhea, the normal bacteria are eliminated as well. The appendix safe-guards a population of the normal bacteria that can then repopulate the large intestine after the diarrhea has passed. This function may not seem too important today in the developed world, where we enjoy relatively good hygiene and relatively low levels of epidemic diarrhea, but in the not too distant past and in populations that still suffer from diseases such as cholera, the appendix likely plays an important role in recovering from diarrheal diseases.

While the appendix offers benefits if you live in a developing country, it is less important (though not entirely so- I’ll get to that later) in developed countries with modern hygiene practices such as water treatment and sewage systems. In fact, in the developed world, the appendix has become a bit of a liability, with a surprisingly large portion of the population developing appendicitis at some point during their life. In my next post I’ll discuss the appendix in disease and health, and probably wax poetic about how we should consider this interesting little organ in our modern environment.

1.            Smith, H.F., R.E. Fisher, M.L. Everett, A.D. Thomas, R.R. Bollinger, and W. Parker, Comparative anatomy and phylogenetic distribution of the mammalian cecal appendix. J Evol Biol, 2009. 22(10): p. 1984-99.

2.            Bollinger, R.R., A.S. Barbas, E.L. Bush, S.S. Lin, and W. Parker, Biofilms in the normal human large bowel: fact rather than fiction. Gut, 2007. 56(10): p. 1481-2.

3.            Laurin, M., M.L. Everett, and W. Parker, The cecal appendix: one more immune component with a function disturbed by post-industrial culture. Anat Rec (Hoboken), 2011. 294(4): p. 567-79.

Read Full Post »

I’m in the process of writing a post, but came across this paper that is too good not to share. In 1912, the Scottish anthropologist and anatomist Arthur Keith published the paper The Functional Nature of the Caecum and Appendix in the British Medical Journal (full text available to all- nerds and medical historians rejoice!).  This article discusses some intricacies of the cecum and appendix, but his conclusions will sound familiar to anyone familiar with the paleo approach.

The author points out that there was a growing opinion (in the early 1900s) that the large intestine had become (at least in humans) useless and dangerous! Indeed, in the popular 1903 book The Nature of Man, the author claims “It is no longer rash to say that not only the rudimentary appendix and the caecum, but the whole of the large intestine are superfluous, and that their removal would be attended with happy results”. Part of the argument of this time was that the modern diet no longer needed bacterial action for full digestion, making the large bowel superfluous.  Not only was the large intestine useless, but it was also possibly dangerous (being termed by one surgeon a “cesspool”).

Arthur Keith, however, offered another approach: “in place of appealing to surgery to adapt our digestive tract to our present dietary, it seems possible that we may discover a diet which is suited to our present digestive tract”.

The concluding paragraphs ring true 100 years after they were written:

When we think of how the diet of highly civilized races has changed-in quality, quantity, and character-in comparatively recent times, one must marvel that our organization, which was evolved to deal with a more primitive and more precarious supply of food, has accommodated itself to modern conditions so well as it has. We know that beyond the neolithic period, when cereals began to be cultivated, some six thousand years ago, there lies a vast hinterland of rude human existence, when man must have lived on the natural products of the country. With the discovery of fire and of the artificial preparation of food (we know that man had discovered the use of fire before the end of the Pleistocene period) the task of the alimentary system must have been greatly altered. The greatest changes, however, are those of more recent centuries- the concentrated nature of food, its plentiful supply, its highly artificial character. When we come to realize how slowly evolutionary processes have affected man’s body in past times, we can hardly expect our internal digestive system to adapt itself to the rapid pace demanded by the ever-accumulating resources of civilization.

Thus an impartial survey of the evidence at present at the disposal of the anatomists indicates very plainly that we cannot hope to prevent or cure the ailments to which the great bowel is liable so long as we regard it as a hopelessly injurious or useless structure. On the other hand, if we regard it as having all the anatomical appearances of a useful structure, our outlook becomes hopeful if we can only discover what its uses are. If we only knew how to keep it suitably and profitably employed by altering our diet to meet its requirements, it will, we have every reason to think, serve us and future generations just as well as it answered the digestive needs of primitive and successful races in the past.

Yeah- what he said!

Read Full Post »