Prehistoric vs. Modern Man: When did our Back Start to Hurt so Bad?

Paleopathology: Musculoskeletal Disease in Early Man
The Paleo Diet might be healthy, but the Paleo Life was hard!

​Low back pain is a common - essentially universal - problem for modern men and women.  Even though we continually improve our tools, our work environments, our recreation, we still encounter back and neck pain problems that interfere with or even curtail our normal daily activities.
 
So back pain problems must have been even worse for our ancestors, right?

It's not so clear-cut.  Although they are widespread among modern man, arthritis and back problems were not a common affliction among our ancient ancestors, at least not to the extent they would talk about them much.
 
While we do have extensive medical treatises and descriptions of illness and injury dating back to the hieroglyphics and Egyptian times, there is very little written about arthritis in early literature: Egyptian papyrus manuscripts (the Edwin Smith papyrus) discussed a wide variety of illnesses and injuries, but did not address the problems of joint disease at all. 

Disorders of infection, and skin lesions, and deformity were discussed, but the only discussion of spinal disease alluded to the care of someone who falls from height and injures his back, and can no longer move his legs or control his bladder; that patient cannot be helped and will, the manuscript tells us, soon die.  

And that was pretty much the standard of diagnosis and treatment up until the later decades of the 1800's.  Low back pain?  When you devoted your life to hard labor and warfare it had to be an issue, but, I guess, when you're building pyramids for a living you don't mention it.

It is difficult to find, among all the human archeological or fossil evidence, many specimens with typical knee or hip degenerative joint disease of even a moderate degree.  Why is it that a disease process so prevalent today would be so hard to find in material just a few hundred years old - a blink of an eye in evolutionary time? 
 
Is osteoarthritis, as we know it today, kind of a new disease to man? Is it truly a byproduct of civilization, reflecting changes in diet or environment, or alterations in activity patterns? 
 
The fossil remains of our predecessors suggest an interesting answer to these questions, and may provide insight into the evolution of bone and joint disease in modern mankind.
 

Iron Age pelvis following a severe injury which fractured and displaced the pelvic ring and sacroiliac joint and fractured the left hip socket. This sort of injury is seen in patients who've been hit by a car and are often fatal today. But this pelvis has healed!

​Paleopathology is the scientific study of disease processes - pathology - of the past, defined as "the science of the diseases which can be demonstrated in the human and animal remains of ancient times". 
 
The importance of paleopathology lies in the ability to carefully examine the physical remnants of ancestors or ancestral species, and to determine not only how these animals or individuals functioned normally, but also the diseases which they faced and the way they responded and adapted to them.
 
The Ancient Fossil Record is all about bones:
Evidence of disease has been found in the fossil remains of dinosaurs and early mammals predating the appearance of man by 100's of millions of years.  

Paleontologists have found many examples of dinosaur bones showing spinal disc degeneration and spontaneous fusion similar to the severe disc disease we see today.

​Since bone is the only tissue remaining in most of these specimens, very little can be said about diseases of the blood or visceral organs unless that disease also had an effect on the bone.  For instance, we do know that bacteria and parasitic organisms were around and probably caused infections in pre-historic times much as they do now, but the only evidence we have of those infectious diseases comes from the rare examples where bone was involved.
 
Mummies, on the other hand: 
Mummification - either accidental or intentional - does provide an opportunity to study soft tissue disorders, infections by bacteria and parasites, and toxicology in ancient man

This preColumbian miner was mummified by the natural chemicals found in the cave where he died.

Although we are most familiar with mummification as it was practiced in ancient Egypt, mummification can occur naturally in any perpetually arid or frozen environment.  Well preserved mummies have been found in the Peruvian Andes, the Arctic, Siberia, and in the drier climates of the Mediterranean, North Africa, Australia and Japan.  Chemical preservation has produced mummies in pre-Columbian salt and copper mines of South America, and has resulted in a series of remarkable "Bog bodies" in Northern European peat bogs. 
 
The Tollund man is one of several bodies recovered from the peat bogs of northern Europe that demonstrated such startling preservation of the body's soft tissues - including features such as eye color and finger print pattern - that local police were summoned to the discovery, even more than 2,000 years after death.

The Tolund Man bog body was startlingly well preserved, an effect of the peat swamp he was deposited in after what is thought to be ritual execution or sacrifice.

​The maintenance of the soft tissues in Egyptian mummies is often remarkable. The diffuse rash seen on the face, torso and thighs of Pharaoh Ramses V, and on other mummies of the period, is highly suggestive for smallpox.  Histological examination confirmed the diagnosis.  The quality of histologic material after mummification can permit sophisticated analysis, and DNA analysis now opens the door to far more sophisticated study and pathological diagnosis.  

​Implications:
The fossil record of disease has historical and clinical importance, providing information about the types of diseases present prior to careful written accounting, and the spread of disease among peoples and populations who may not have had the capacity or time to write. 
 
For example: scholars argued for years that the hookworm, an intestinal parasite, was introduced into American native populations by infected African slaves brought to South America by the Spanish.  For years there was no physical or descriptive evidence to suggest that hookworm had ever existed in the New World prior to the arrival of the Europeans.  In 1960, however, while studying intestinal specimens from a 500 year old, pre-Columbian mummy found in Peru, researchers found well preserved examples of the parasites still attached to the intestinal wall.  

​Scanning Electron Microscopy showed details of the worms' head and buccal cavity, allowing conclusive identification of both the species and variety, proving that this parasite was established in America long before the arrival of the Spanish.
 
Musculoskeletal Paleopathology: 
What, then, were the predominant forms of musculoskeletal disease among our ancient ancestors? 
 
Deformity was a common cause of dysfunction in ancient man.  

​The deformed foot of the Egyptian Pharaoh Siptah, once described as an example of club foot, appears to modern observers to more closely mirror the residual deformity caused by polio. X-rays of Siptah's foot show a specific deformity classic for paralysis and not clubfoot, and the limb is shortened, a combination commonly seen with polio. 
 
On the other hand, examples of true, untreated clubfoot have been found in both Egypt and Europe, were illustrated in Egyptian writing, and seen in archeological specimens.  One European specimen from the Bronze Age demonstrates the dramatic inward rotational deformity of the mid-foot, (adduction), and rolling-in of the heel (inversion) so severe that the foot was actually inverted - upside down -  to the point that this Bronze age man could only walk on what should have been the top of his foot.

But walk he did, evidenced by the extensive calluses and bone spurs that formed on the dorsal surface of those bones.
 
Systemic disorders or infections that left their mark on bone are also apparent among the fossilized and preserved remains of early man.  Examples of leprosy have been found in ancient Egyptian material and throughout Europe.  Specimens exhibiting signs of syphilitic infection are quite common in Native American remains of both North and South America, but have never been found in Egyptian material. 

​Tuberculosis, common around the globe today, was common then too. And since it did attack the bones - and the spine - quite frequently, we see it clearly in the archaeological record.

European spine with osteomyelitis due to tuberculosis causing severe bone destruction and deformity.

​What of the other common diseases of bones and joints we treat today, particularly those leading to degenerative joint disease and degenerative disc disease?
 
First of all, disease processes linked in any way to aging are significantly more common in our modern population than they would be in any period in the past.  We should expect significant differences in the incidence of most common cancers, chronic disease, and osteoarthritis relative to today's populations.  To be blunt, people didn't used to live that long!
 
The average age at death in Bronze and Iron Age man was approximately 25-35 years, depending on where you looked.  In some ancient cemeteries as many as 50% of all bodies are of infants and small children, which brings the averages way down, but even among those that made it to adulthood, longevity was not promised.

Graphic illustration showing average age of people throughout history and prehistory, at the time of death. Age at death of prehistoric men and women is based on skeletal examination of fossil remains throughout the world and recovered subjects from European burial sites.

​Prior to the 1700's, people just did not live very long.  Going back 3,000-4,000 years, even among the Pharaohs -who were the best fed, most carefully protected individuals in the relatively advanced land of Egypt - the chances of long life were slim.  Of 26 royal mummies studied at the British Museum, only 10 had lived to the age of forty, and only 2 had lived beyond fifty. 
 
King Thutmose I, acclaimed as a great military leader, greatly expanded the territories and influence of Egypt through victories over both the Nubian and Syrian nations.  He sired three princes and a princess during his reign as Pharaoh and established a successful dynasty. 

​Yet x-rays of the Pharaoh's mummy revealed open growth-plates in the proximal humerus, distal femur, and proximal tibias, and no degenerative joint changes in any joint.  The fossil record shows us that, despite all of his accomplishments, Thutmose I was dead before he reached the age of 21 years!.

X-ray of knees of Pharaoh Thutmose showing clearly seen growth lines, which typically disappear at the end of adolescence or early adulthood

 
Only recently did man start living beyond his sixth decade with any frequency.  Prior to the 1700's, the odds of living to the age of 40 had not changed much in about 200,000 years - and they were universally poor.  In the last 300 years, however, mans' longevity has increased significantly, and continues to increase to this time.

Graph depicting the percentage of people that survive birth living to a given age. For instance, among older humans, only 5%, roughly, of individuals would live to be 60 years of age, compared to modern mankind, where more than 15% will live beyond 80!

This dramatic improvement in individual survival has had an effect on the types of diseases we see in mankind.  In comparing a modern population - with an expected survival into the 70's and 80's - to an ancient population where only 5% of the people survived past age 40 - three predictions might be made:

• First, we can predict that diseases that don't start until adulthood but then progress throughout life will appear more common and far more severe in modern populations.  These conditions will be present among ancient peoples, but less frequently and only in their mildest forms.  Think arthritis.

• Second, we can predict that some diseases that typically occur as a result of some repetitive insult or toxic exposure will be rare in ancient populations, and others very common.  Diseases that require a threshold of exposures or trauma, such as carcinogen exposure, may not reach that threshold in the ancient population, but will become increasingly common in modern populations depending on age.  On the other hand, unprotected exposure to things we now avoid might lead to more common disease findings.  We see this in mummies around the world where dust and sand inhalation has resulted is a frequent finding of silicosis, a disease of the lungs we still see, but less frequently, today.

​

• Finally, we can predict that diseases that typically occur only with advanced age will be rare or unseen in ancient populations despite being common or ubiquitous in modern elderly populations, showing a significant difference in incidence when the two groups are compared, unless matched for age. Think of our most common cancers and osteoporosis.

 ​As an example of the first principle, consider osteoarthritis.  We know that degenerative joint disease is rarely present in people before 30 years of age, unless associated with a traumatic injury of the joint, and that clinically significant knee or hip degeneration rarely occurs before the age of 40.  This means that, even though the degenerative process was ongoing, only 5% Bronze or Iron age men would be likely to develop clinical osteoarthritis prior to their death, unless associated with some other pathology.
 
Causes of early, advanced degenerative joint disease in pre-historic men would be similar to the what we see among young patients today, occurring as a result of aseptic necrosis, or pediatric disorders like Perthes disease, slipped capital femoral epiphysis, and congenital dislocation or dysplasia of the hip.  

​These entities affected young individuals then as now, and produced crippling joint disease among the generations that came before corrective orthopaedics.  In fact, many archeological specimens presented in scientific texts as examples of "osteoarthritis" do show deformities more suggestive of acetabular dysplasia or slipped capital femoral epiphysis than of typical osteoarthritis.
 
End stage degenerative disc disease, the type we see after 15 - 20 years of symptoms, is very rare in Bronze Age populations.  What is seen is a high incidence of mild to moderate vertebral spurring, suggesting that the same degenerative processes were ongoing, but never got too severe.  Primitive man rarely lived long enough to "wear out" his vertebrae, though the rigors of his lifestyle frequently left a mark on his spine.
 
The leading cause of joint destruction in prehistoric populations was trauma.  This represents the second prediction above:
 
Anyone who accumulates sufficient exposures (trauma) can develop the disease, but if you don't live very long you need to experience a large dose early on to manifest the clinical disease.  Meaning, prehistoric man would develop joint disease after major traumatic events, but rarely "got enough steps in" to generate serious osteoarthritic degeneration.

X-ray showing common findings of degenerative joint disease seen today, present in an Egyptian mummy

To make matters even tougher, prehistoric man had to survive his fractures, and avoid starvation, in order to live long enough to develop even acute post-traumatic arthrosis.  There are examples of prehistoric poly-trauma, but they aren't common, and degenerative joint disease is seen in the survivors of these injuries.
 
One very old example of an individual surviving multiple injuries long enough to develop secondary degeneration is of a Neanderthal skeleton from an Iranian cave site discovered in the 1950's.  "Shanidar 1" was apparently a rare survivor of major trauma.  

Picture of skull of Shanidar 1, a 50,000 year old Neanderthal who survived skull fracture, amputation of an arm and injuries to knees, ankles and feet, that would have left him nearly defenseless and unable to hunt or protect himself.

​Standing about 5'6" tall, Shanidar 1 lived approx. 50,000 years ago, and probably lived to an age of 40 years.  Years before he died, Shanidar 1 sustained at least one, and more likely a series of serious musculoskeletal injuries.  At one point, probably a decade before he died, he sustained a severe crushing injury to his right arm and leg.

Remnants of the shattered and amputated humerus, an infected clavicle and fractured scapula of Shanidar 1. Trinkaus, E.: The Shanidar Neanderthals. Academic Press, New York, 1983

​Fossil remains show that he suffered an amputation of the right arm through the distal humerus, fractures of the clavicle, scapula, and right knee, and a crush injury to the foot.  He also sustained, perhaps at a different time, a crushing blow to the left side of his head which may have blinded him in the left eye. 

Picture of eroded and possibly infected femur Shanidar 1.

​Any time prior to the advent of antibiotics and modern medical care this combination of these injuries could have proved fatal.
​
Nonetheless, Shanidar 1's amputation healed, he survived the chronic osteomyelitis of the open clavicle fracture and severe post-traumatic degenerative joint disease of the knee and ankle.  The extent of bony healing and the degree of joint degeneration suggest that he lived for many years after his injury.

Arthritic joints of the foot and a long-healed fracture of the fifth metatarsal bone showing an older injury of the foot of Shanidar 1 that had healed completely.

​Considering the violent and uncertain environment in which he lived it is impossible that he could have survived without extensive support from members of his tribe.
 
Septic arthritis was likely a cause of degenerative joint disease in prehistoric man, but acute sepsis in these people was probably routinely lethal.  Those dying soon after the onset of their osteomyelitis or septic arthritis would leave no bony evidence of their disease.  Chronic infection and obvious joint destruction would be more likely to occur in those suffering from tuberculous disease.  And we do know that was a thing!
 
There are many drawings and sculptures in both Old and New World antiquities illustrating the common features of tuberculosis.  There is excellent evidence that tuberculosis was prevalent in both hemispheres in pre-Columbian times. The mummy of an Egyptian high priest demonstrates the classic findings of tuberculosis of the thoracic spine recognized by physicians over the past centuries.

Picture of spine and pelvis of tuberculosis victim showing vertebral destruction (Pott's deformity) and cavity in the pelvic wing due to a large psoas muscle abscess.

​A marked kyphosis and a large psoas abscess are clinically apparent in this mummy.  The severe kyphosis commonly caused by tuberculosis could produce paraplegia, a fatal condition in ancient times.
 
Finally, in considering diseases that only appear with advanced age, the age differences in modern and ancient populations greatly affect the perceived prevalence of some disorders.  Cancer would be an example of this third principle.  The tumors that commonly produce skeletal destruction in modern man most often arise in primary cancers of the organs, and only attack the skeletal structures if the patient survives long enough to develop metastases. 

​This would include most metastatic neoplasms, which make up 95% of all skeletal lesions we deal with today.  These tumors generally don't emerge until the fifth and sixth decade of life - or later - and probably had little impact upon prehistoric man and very little effect on his skeleton.  For this reason, we see a disproportionately large number of primary tumors - tumors of youth and young adulthood - predominating in archaeological material.

An enormous destructive lesion was found in the lower extremity of an Iron Age saxon youth buried in an English cemetery. A radiograph through a peripheral portion of the lesion showed a classic "sunburst" of ossifying soft tissue similar to that seen in advanced osteosarcoma today.

Ancient man didn't have a predisposition to these primary tumors compared to metastatic tumors, s/he just lived long enough to get the one type, but rarely long enough to get the other.
 
Post-menopausal osteoporosis would be another example of this third condition.  This malady is ubiquitous in our modern society with millions of elderly members, but would be exceptionally rare in a population where less than 5% of people survived their fifth decade.  For this reason osteoporosis is a disease entity that is not mentioned in texts on paleopathology, and the sequelae of osteoporosis - hip fractures, thoracic compression fractures - have not been reported.
 
It is apparent that many of the disorders which afflict man today have been present for thousands of years, little changed from the diseases represented in our earliest fossil material.  

Trauma, infection, neoplasia, endocrinopathies, and congenital and acquired deformities are all represented in the fossil and prehistoric record.  However, the disease profile of ancient society differs from that of modern society in significant ways.  Specifically, three disease processes are underrepresented in early populations when compared to modern society:
 
1.         Slowly progressive diseases of adulthood, requiring years to reach a level of significant severity.
 
2.         Diseases occurring in advanced age because of repeated exposure to trauma or stimuli.
 
3.         Diseases associated with age related hormonal or physical changes.
 
Hence, degenerative joint and spinal disease occurred in primitive man primarily because of a single traumatic or infectious insult which altered the mechanics or health of the joint, not because of cumulative micro-trauma, progressive degeneration, or genetic predisposition.
 
It is likely that the environmental and pathologic conditions responsible for orthopaedic disease have existed relatively unchanged for eons.  It's likely, in fact that modern humans face consistently lighter strains and loads than our predecessors (fewer bears to fight, no pyramids to build). And, we haven't seen a change in the virulence of a pathogen, or an altered susceptibility or response to disease of the host.  (Tuberculosis still does what tuberculosis has always done if we don't treat it).

​What has changed is this:

The prolonged life span of contemporary man has produced a previously unseen developmental phase in our life-cycle, within which new responses to chronic disease are necessary.  And, while we are getting better at treating problems in this new phase of life, we haven't been at it that long and we are still working out alot of kinks!
 
Conclusion:

​The primary cause of symptomatic joint and back degeneration throughout the early history of man was most likely trauma, less frequently sepsis, and rarely, primary osteoarthritis.  Congenital and acquired deformities, aseptic necrosis, and pediatric conditions such as congenital dysplasia, slipped capital femoral epiphysis, or Legg-Calve-Perthes disease may have played a relatively greater role in this much younger population, as they occur in a younger age group and are not lethal conditions.  Sepsis, though common, probably killed so many of its victims that degenerative disease due to chronic infectious arthritis would be uncommon. 

In most cases, then, degenerative joint disease in ancient man was the result of an acute injury, not a response to chronic wear and tear.  And it's also likely that few people of ancient times - Neanderthal through the middle ages - would survive long after an injury like that without considerable social support.  Even then, few people lived long enough or comfortably enough to call an arthritic hip or aching back their biggest problem and that likely explains why we read so little about those problems in our oldest literature or see them in the fossil record!

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