Christopher David Czaplicki. 21st Century Anthropology: A Reference Handbook. Editor: H James Birx. Volume 1. Thousand Oaks, CA: Sage Reference, 2010.
Paleopathology, an application of biological anthropology, offers us an interesting perspective into the lives of the ancients. When skeletal remains are all that are left from many ancient civilizations, paleopathologists rely on strict skeletal analysis to offer insight into ancient civilizations. Combining scientific inquiry with educated reasoning can give anthropologists an idea of the daily activities of individuals; their diet, health, and environment; and even more, specifically, the cause of death of each individual. This can offer anthropologists insight not only into the prevalence and evolution of a disease in a past civilization but also into what trends to expect from the same or similar diseases today. While paleopathology can focus on more recent cases from a forensic anthropological standpoint, most paleopathologists focus more specifically on what can be learned from the remains of individuals long gone. Often, these remains consist almost entirely of bone. However, in more unique cases, such as with “Ötzi the Iceman,” tissue structure remained incredibly preserved over thousands of years (Fowler, 2000). This allowed anthropologists astonishing insights into human life in the Copper, or Chalcolithic Age.
Paleopathology started as a subspecialty with the emergence of archaeology. However, in the beginning, most archaeologists were concerned with artifacts instead of skeletal remains, since the latter seemed to have little monetary value compared to golden relicts. On the few occasions that attention was paid to human remains, usually only the skull was studied (Waldron, 2001). A series of measurements, known as cranial fixation, were taken while the postcranial skeleton drew little attention from even the most senior of archaeologists, who were after greater riches (Jarcho, 1966). At roughly the same time, paleopathology was being looked at from another front: medicine. As the United States continued to move westward in the middle to late 1800s, doctors began to take interest in the skeletal remains of Native Americans. One of the first studies, published in 1876, looked at the prevalence of syphilis in Native American skulls (Jones, 1876). Little advances were made into the field of paleopathology until the first decade of the 1900s, when archaeologists began excavating Egyptian temples. Under the direction of George Reisner, over 6,000 bodies were examined although the pathological findings were not well reported (Waldron, 2000). Again, the field seemed to fade into obscurity for several decades until the emergence of Calvin Wells, one of the most respected and imaginative paleopathologists in history. With a strong passion and enthusiasm for the field, he drew on his medical training to work with archaeologists to study the history of human disease. His book Bones, Bodies and Disease (Wells, 1964) was a landmark publication in the field and advanced the field of paleopathology to the level it is today.
To detect the subtle signs of illness in skeletal remains, paleopathologists must receive extensive training to master this art form. During undergraduate studies, most receive a broad background in anthropology overall, taking classes in biological anthropology, cultural anthropology, archaeology, and linguistics (Klepinger, 2006). Alternatively, paleopathologists may graduate with a bachelor’s degree in the sciences, with a heavy emphasis on anatomy and the human body. They should have knowledge of the basic sciences and mathematics. Some may include medical training in their studies, as paleopathology is a survey of the history of disease. Many then go on to pursue a master’s degree as well as a doctorate in biological anthropology, with a strong emphasis on the human skeleton, osteopathy, and the skeletal record. Unfortunately, there are currently no regulations in place on the practice of paleopathology and forensic science. Thus, quality control is an issue as amateur sleuths, with inadequate training, can attempt to interpret skeletal remains.
Paleopathology can be broken into several general components: arthropathy, infection, oral pathology, trauma, and tumors (Aufderheide & Rodríguez-Martín, 1998). Arthropathy, or disease of the joints, includes some of the more common findings of paleopathology, including simple arthritis and gout. Serious infections can often leave their mark on bones, especially debilitating chronic diseases, such as syphilis and tuberculosis. Oral pathology, which examines diseases of the oral and maxillofacial regions, may offer insights into not only dental practices and oral health but also diet. Trauma is one of the most obvious abnormalities in bone to identify, even to an untrained observer. Fractures and breaks can be examined, and paleopathologists are often able to determine if the individual lived beyond the initial injury based on bone-healing patterns. Lastly, tumors, or neoplastic osteosarcomas, may not be as obvious as some may be led to believe. Although obvious outgrowths may be observed in the bone itself, many times these tumors can be subtle, remodeling the internal bone structure before the cancer metastases to different parts of the body.
From a pathological perspective, changes in the joints appear to be most common when analyzing fossil skeletons (Waldron, 2001). While this can include many rare and unusual disorders, most paleopathologists are more familiar with common ailments, including osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, and gout.
Osteoarthritis is a very common disorder in the living (Resnick, 1981). Many of the joints in our body are bathed in synovial fluid, including joints of the knee, hands, toes, and neck. This fluid acts as a lubricant for the constant pressures placed on the ends of our bones with each movement. Many of our bones also have a layer of cartilage on their ends, also acting as a shock absorber. This cartilage may degenerate from the normal wear and tear through time, and is replaced by less plastic bone in an effort for the joint to repair itself. This new bone, forming on the ends of the bones, is known as an eburnation and is the classic indication of this illness when examining fossil skeletons. This can cause pain and inflammation in the effected joint, making every movement very painful. However, although this disease may actually be pathologically present in many individuals, some are completely unaware of its presence and have little or no pain.
Rheumatoid arthritis, similar to osteoarthritis, involves destruction of the articular cartilage (Abdel-Nasser, Rasker, & Valkenburg, 1997). This occurs from an autoimmune response in which the body produces antibodies against the synovial membrane enclosing the joint. This inflammation of the membrane spreads to the cartilage and bone, causing deformities and, in some cases, fusing the two bones. Paleopathologists can distinguish rheumatoid arthritis from osteoarthritis by the lack of new bone formation during the degenerative process. This can often be difficult, however, as arthritic bones tend to be fragile and damage easily during excavation or from erosion over time. Therefore, care must be taken to be sure the degenerations observed are truly from rheumatoid arthritis and not simply erosions of points of entry from blood vessels and nerves. New techniques in radiography have been helpful in confirming this diagnosis. Since this disorder targets the synovial membrane, the joint margins are affected first, then rheumatoid arthritis invades the rest of the joint surface. If radiographic studies show the joint surface has degenerated but not the joint margins, then paleopathologists can conclusively say that the skeleton did not suffer from rheumatoid arthritis.
Ankylosing spondylitis, unlike the previous two joint diseases, affects the spinal column as opposed to the synovial joints of the body (Waldron, 2001). This disease presents with a fusion of the spinal column, starting at the sacrum and moving slowly upward toward the cervical vertebrae. In this disorder, which has been linked with a genetic abnormality, no vertebrae are skipped in the disease’s progression, helping to distinguish it from other spinal fusion disorders, such as reactive arthropathy. Due to the gross morphological changes to the spinal column, and even to the rib cage in some cases, paleopathologists can easily arrive at this diagnosis. Needless to say, this disease is extremely debilitating to those persons who are afflicted.
Gout is an extremely common disease in which uric acid crystals are deposited in the joints, leading to painful inflammation in the affected areas (Ball, 1971). If this becomes a chronic problem, the deposits may become large tophi, leading to erosions in the joint. This disease is most commonly presented in the joint between the phalange of the large toe and the first metatarsal. Paleopathologists can diagnose gout with the use of X-ray imaging, which will show asymmetrical degenerations in only a single area of the skeleton, with no osteoporosis associated as with other joint diseases.
As most diseases directly affect body tissue, which is rarely if ever preserved, the signs of an infectious disease may not be apparent to a paleopathologist (Waldron, 2001). Relative to the overwhelming number of potential infections, very few present themselves in the bone. Aside from very rare diseases, such as Proteus syndrome, several widespread diseases do in fact make their mark on the bone: tuberculosis, leprosy, and syphilis.
Up until the creation of streptomycin, tuberculosis was one of the deadliest diseases known to man. Caused by Mycobacterium tuberculosis, tuberculosis is an airborne illness characterized by primary lesions in the lung (Bauman, 2009). After the initial infection, the Mycobacterium may lie dormant for many years within a lesion in the lung tissue, with the patient being relatively asymptomatic. This period, which is variable among patients, will end when the lesion ruptures, releasing the bacteria back into the lung tissue. The bacteria will continue to spread throughout the body, most notably in areas of the chest, lymph nodes, and skeleton. If the infection reaches the bone, then degeneration of the tissue is observed, most commonly in the spine and hands. In the hands, a condition known as tuberculosis dactylitis is observed, characterized by extreme inflammation in the fingers. In the spine, the anterior portion of the vertebral column is destroyed, creating a distinct angulation known as Pott’s disease. If the disease continues to progress, then this angulation may ultimately lead to a complete collapse of the spine. It is this dramatic change to the spine that paleopathologists rely on to make the diagnosis of tuberculosis. However, since the prevalence of this gross anatomical change is much lower than the overall prevalence of the disease, paleopathologists are looking for new techniques in order to identify tuberculosis in skeletal remains. One such technique is the extraction of ancient DNA, or aDNA, from M. tuberculosis remains within the skeleton (Taylor, Goyal, Legge, Shaw, & Young, 1999). This DNA can be replicated, using the polymerase chain reaction, and analyzed to confirm the presence of the disease. An even more inventive technique is the extraction of mycolic acids from skeletal remains, which make up the outer layer of the bacteria (Donaghue, Spigelman, Zias, Gernaey-Child, & Minnikin, 1998).
Of the infectious diseases studied by paleopathologists, none have had such a profound clinical impact as the study ofleprosy (Møller-Christensen, 1965). Caused by Mycobacterium leprae, the bacteria initially infect the peripheral nerves (Bauman, 2009). If the immune system cannot overcome this initial infection, then the disease may progress systemically, affecting bones throughout the body, especially the hands, feet, and skull. In both the hands and feet, the phalanges are absorbed. In the skull, the anterior nasal spine is also absorbed, creating a round, wide opening for the nose. The front teeth are also absorbed. These distinct changes in the skull are known as facies leprosa (Møller-Christensen, 1965) and are telltale signs for any paleopathologist looking to make this diagnosis. Study of the remains of skeletons with leprosy paired with the remains of skeletons with tuberculosis can help to explain the history of these two diseases in humankind. Since both diseases are caused by a strain of Mycobacterium, partial immunity from one disease occurs when infected with the other. Since the incidence of leprosy seemed to suddenly decline in Europe at around the same time the incidence of tuberculosis rose, paleopathologists hypothesize that the emergence of tuberculosis created immunity to leprosy throughout the population. However, extensive studies must continue to estimate the true prevalence of the diseases at that time in order to support this theory.
The disease syphilis, caused by Treponema pallidum, has several distinct stages of progression (Bauman, 2009). Transmitted sexually, the primary infection of syphilis is characterized by chancres, or sores, in the genitalia, or occasionally, other areas of the body. This may occur after a short incubation period following the initial exposure. Secondary syphilis, which usually begins several months after the primary period, is characterized by more numerous and painful lesions that occur in moist areas of the body, as well as in the palms of hands and on the soles of feet. It is at this stage when the host is most contagious. From secondary syphilis, the patient may enter a latent stage in which there are no signs or symptoms of the disease despite its presence in the body. The bacteria can remain dormant in this stage for many years, and some patients never progress to tertiary syphilis, the final and most debilitating stage. In tertiary syphilis, granulomas, or inflammatory balls created as an immune response, occur throughout the body in an attempt to destroy the bacteria. Since these granulomas, also known as gummas, can occur in any tissue, any organ system can be affected. Thus, a variety of symptoms are observed in patients at this stage. From a pale-opathologic perspective, gross anatomical changes to the bone are the most profound changes. Erosion and healing of the skull is cyclic as the disease progresses, creating what is known as caries sicca (Hackett, 1976). Bone depositions can also occur extracranially, especially on the anterior surface of the tibia. In some cases, especially in infants, the deposition is so severe in this area that it is known as sabre tibia (Waldron, 2001).
Trauma, or body-altering physical injuries, can often have very distinct presentations in skeletal remains (Waldron, 2001). Fractures and breaks can be identified with relative ease by even the most inexperienced pale-opathologists. These fractures can be further analyzed to see if they resulted in death or if the specimen received medical attention based on the presence or absence of healing patterns. When observing fractures, there are many different types based on the style of break and how the bones interact with the surrounding tissues.
One of the most common type of fracture is, unsurprisingly, named the simple fracture (Müller, Nazarian, Koch, Schatzker, & Heim, 1994). In this fracture, the surrounding tissue may be damaged; however, the skin is not broken, giving it the additional name of closed fracture. Due to these criteria, paleopathologists can only suspect this type of fracture with little to no bone displacement, such as with small hairline or incomplete fractures where the bone ends never separate. The alternate type of fracture, where there is enough displacement to break the skin, is known as a compound, or open fracture. These are much more susceptible to infection, since the exposed bone ends may come into contact with pathogens in the environment.
Within these broader fracture types, there are many other fracture types, usually related to how the bone broke (Müller et al., 1994). For example, a transverse fracture refers to the angle of the breakage in relation to the axis of the long bone: 90 degrees. Similarly, an oblique fracture is a fracture that occurs diagonally in relation to the axis of the long bone. Different types of forces also result in different types of fractures. For example, stress fractures are caused due to repeated stress on the bone and not necessarily from acute trauma. This type is common in the feet of long distance runners, which are constantly feeling the forces of stress between the body and the pavement. Another type is adepression fracture in which the outer layer of the bone, the cortex, is driven into the inner bone and underlying tissue. Since most long bones cleanly break with enough force, depression fractures are most commonly seen with fractures of the skull. Another notable fracture type, which is only seen in immature bones, is the greenstick fracture, in which only the outer cortex of the bone is fractured while the inner, immature bone bends.
While healing rates can be highly variable throughout the different bone types and different patient ages, healing does take place in well-defined stages, which can help paleopathologists determine how long, after the initial injury, the patient survived (Waldron, 2001). Within the first 4 to 8 weeks, union between the fragments usually takes place, holding the two together. During this time period, it is very important that the two ends be aligned anatomically correct to ensure proper healing. If this is not established, especially in the long bones of the limbs, then a patient will likely experience an extreme deficit in limb functionality. After this period of union, it will usually take an additional 4 to 6 weeks until the bone can support the weight, or handle the forces it once could. Interestingly, many studies of skeletal remains with severe breaks have found the bone to be properly aligned, leading pale-opathologists to believe that even the earliest civilizations knew the importance of proper alignment in the healing process (Waldron, 2001).
While many types of trauma observed in past civilizations are acute injuries, such as fractures, there are also many documented instances of ritualistic trauma. One such type is trephination, in which a hole is drilled into the skull with a specific instrument designed specifically for that purpose (Margetts, 1967). Similar to burr holes performed by surgeons to release cranial pressure during hemorrhaging, it is believed that trephination may have been performed on individuals with chronic headaches and brain injuries. However, unlike burr holes, which are based on science and performed in an effort to relieve cranial pressure, trephination was performed in hopes of releasing the evil spirits from the body of the patient, thereby, hoping to cure them. The paleopathologist generally has no trouble identifying trephinations in skeletal remains, which often have more clean-cut holes relative to depression fractures. Often, there are signs of healing, indicating that this procedure, if not successful, was at least not immediately fatal.
Another ritualistic trauma performed is artificial cranial deformation, which can include the flattening or the elongating of the skull. Paleopathologists have dated skulls with these abnormalities to 45000 BCE (Trinkaus, 1982). It is believed that these abnormalities are related to either a social class or to very specific groups or clans, as with the ancient Mayans. Since the sutures between cranial bones do not fuse during youth, intentional deformation begins early in life (Tubbs, Salter, & Oakes, 2006). It was often achieved by tying stones or boards to the head with a great deal of pressure, forcing the bone to slowly remodel itself over many years.
In modern medicine, it is difficult to find a dirtier word than tumor or cancer. This group of diseases has sidestepped the best efforts of countless scientists as the battle against cancer continues. A tumor, or neoplasm, is a mass of cells, dividing uncontrollably due to faulty genetics or molecular cues gone wrong. This rapid cellular division can cause an accumulation of mutations, spreading and changing faster than modern medicine can keep up with. While this certainly is not true of all cancer types, as great strides have been made against breast cancer, cervical cancer, and prostate cancer, many other cancer types still have scientists scratching their heads in dismay. While relatively rare compared to other cancers (roughly 200 deaths a year), primary bone tumors generally occur in areas of the bone still undergoing division, such as the growth plate of the long bones (Waldron, 2001). Since bone growth ends in adulthood, primary bone tumors, such as osteosarcomas, generally occur only in children under 20 years of age. These can be difficult to initially diagnose, which is the very key in successful treatment. Usually, osteosarcomas are not detected until metastasis to other regions, resulting in more distinct symptoms. From a paleopathology perspective, little information can be found on osteosarcomas throughout time due to their extreme rarity even today.
Secondary bone tumors are much more common and occur from the metastasis of cancer from other regions of the body. These secondary tumors can present themselves anywhere, although they are most common in the spine, pelvis, femur, and skull (Waldron, 2001). In this type of cancer, malignant tissue invades the bone, replacing the normal bone tissue with the rapidly dividing malignant tissue. Therefore, in examining fossil skeletons, a variably shaped hole marks the site of tumor invasion, which is quite distinct in appearance compared with other holes such as those caused by bullets. Since the tissue decomposed long ago, paleopathologists can only guess the type of cancer the individual suffered from, except in one unique cancer type.
Unlike other secondary tumors from other cancer metastases, prostate cancer invasion actually causes deposition of bone instead of degeneration. It is believed that similar proteins, activated in both prostate cancer cells and normal bone stromal cells, activate osteoblasts to begin bone deposition (Koeneman, Yeung, & Chung, 1999). While this interaction still isn’t entirely clear, the results are striking for any paleopathologist to observe, with prominent neoplasms on the bone surface.
Built to withstand the constant mechanical and chemicals stresses of a typical human lifetime, it is no wonder that teeth can remain remarkably intact over thousands of years. Generally, being the only piece of skeletal remains that has come into direct and constant contact with the environment, teeth can provide paleopathologists with quite a bit of evidence on the lifestyle and activities in the daily living of an individual (Klepinger, 2006). With fairly standard growth rates for younger skeletons, anthropologists can gain a rough idea of the age of the skeleton when they passed. While this may be important for statistical studies, paleopathologists are most interested in the diseases that have affected the teeth through time.
Cavities are a nuisance that a good portion of the population has experienced at one point in their lives. With an increase of acidic beverages and sweets in our diet, fluoride is removed from the teeth, causing weakness and demineralization of the teeth. This breakdown, coupled with acid production by bacteria in the oral cavity, causes the formation of dental caries, or cavities. These decompositions can be quite apparent in the dental record of our ancestors as the lesions form deep between the teeth. In more dramatic cases, the cavities may have advanced all the way into the root of the tooth, which, if allowed to continue to spread, can even cause an infection in the maxillary sinus. If an infection occurs at this level, gross anatomical changes are apparent in the teeth as well as small changes within the sinus that can be viewed with fiber optics (Waldron, 2001). It is interesting to note that the prevalence of cavities in the dental record increases with the amount of sugar introduced into the diet at the time (Moore & Corbett, 1971, 1973, 1975).
While cavities may be somewhat rarer in more dated specimens, an oral calculus is relatively more common. These are formed by the mineralization of the teeth, leaving deposits on the teeth (subgingival) or gums (supragingival). Since mineralization forming calculi are directly opposite of the demineralization of cavities, it is no wonder that the two seem to exist in inverse proportions in the fossil record (Waldron, 2001). Studies on these calculi have shown bacterial presence within the calculi, along with the remnants of any other debris that may have been in the oral cavity (Dobney & Brothwell, 1986). Whether this can include food remnants, offering insight into the individual’s diet, is the subject of further research.
Periodontal disease, associated with poor oral hygiene, is characterized by bone loss around the teeth due to a high level of bacteria in plaque. This decay can be horizontal and occur across all levels or vertical, occurring at each individual tooth at varying rates (Rogers, 2008). If the decay reaches a certain point, then the individual will begin to lose teeth, which is quite evident in the fossil record. This can easily be distinguished from any teeth lost after death due to the presence of new bone growth around the tooth socket in an attempt at repair. It is important to note that all tooth loss is not necessarily from periodontal disease but can also be caused by trauma, scurvy, leprosy, or other illnesses. Thus, care must be taken to closely examine the surrounding bone structure for degeneration before a correct diagnosis can be made.
In September 1991, two German tourists, Helmut and Erica Simon, were hiking along the Italian-Austrian border on a Similaun mountain when they came across a corpse sticking out from the snow (Fowler, 2000). He was crudely removed, the excavation team not realizing he was more then a stray backpacker caught in bad weather. Causing quite a bit of damage during the process of excavation, including damage to the hip and limbs, the mysterious man was brought to an Austrian morgue. Because of suspicion over the ancient-looking objects found with the corpse, including a copper axe, unfinished bow and arrows, and a stone knife, archaeologist Konrad Spindler was called to examine the body. It didn’t take long for the archaeologist to confirm that this was no ordinary corpse.
Dated to be from 3300 BCE (or roughly 5,300 years old), Ötzi the Iceman is one of the oldest specimens ever recovered with tissue structure still intact (Fowler, 2000). This has allowed scientists, anthropologists, and paleopathologists a unique opportunity to look at not only skeletal remains but also organ and tissue remains. Attributed to the cold glacier environment, Ötzi is remarkably preserved, an almost completely unheard of phenomenon in the archaeological realm; he was lying completely safe in a shallow trench as the ancient glacier moved over his frozen body. This relatively unchanging condition of Ötzi’s icy tomb has allowed DNA and histological analyses, giving paleopathologists a very detailed overview of his health.
Due to the importance of this archaeological find, painstaking care was taken to ensure Ötzi’s preservation (Fowler, 2000). This made research rather difficult, as Ötzi must be kept in a constant state of humidity and temperature, mimicking the conditions he spent the last 5,300 years in. Thus, paleopathologists, who normally rely on skeletal interpretations, had to rely on X-rays and other diagnostic tests to discover Ötzi’s ailments. Strictly from a paleopathological standpoint, Ötzi was not in the best of health when he died. X-rays of Ötzi’s chest revealed broken ribs, with both complete fractures and hairline cracks. Doctors closely examined the films and reported no signs of healing around the bones. Due to Ötzi’s semidehydrated state, they could not detect the normal inflammatory response associated with breaks that occur right at death. Thus, doctors could not ascertain whether these fractures occurred at death or over the next 5,300 years. Doctors also noted several healed fractures on the left side of Ötzi’s rib cage, perfectly aligned, which he had probably lived with for some time.
Also, thanks to the dehydrated state of Ötzi’s remains, computerized tomography (CT) scans had limited use in analyzing his corpse (Fowler, 2000). Many of Ötzi’s internal organs were dried and shriveled, showing up as nothing more than wisps on CT films. Even the brain was nothing more than a fragile ball, bouncing around inside the cranium. However, CT scans did provide researchers a good idea of the age of Ötzi when he died. Due to the slow rate of fusion of the cranial-plate sutures, researchers noticed that, while these sutures were closed, they were still slightly visible, leading them to believe Ötzi was between 25 and 30 years of age. The aorta could also still be analyzed on CT films and showed some signs of arteriosclerosis—surprising for a man of his young age. The use of CT scans also revealed some arthropathies, most notably osteoarthritis. While this was again a surprising find for his age, researchers believe it was the difficult lifestyle of the Iceman that seemed to hasten the onset of these degenerative diseases.
Since full autopsies would have completely jeopardized the longevity of Ötzi’s preservation, tissue samples were carefully taken to be analyzed. Extractions from his gastrointestinal tract found the presence of Trichuris trichiura, a type of whipworm (Dickson, Oeggl, & Handly, 2003). Although Ötzi showed none of these signs, severe infections of this parasite can result in diarrhea, blood loss, and even rectal prolapse. Ötzi also had 3 Beau’s lines on his one remaining fingernail, an indication of three recent illnesses at least 6 months before death. It is believed that Beau’s lines form after cellular division stops in the nail bed, creating distinct horizontal lines across the nail. This can be caused by systemic illnesses, such as infections, poison ingestions, and severe traumas resulting in shock.
While most paleopathologists deal with cases that are no longer of any forensic significance, Ötzi again provided a new challenge in determining the cause of death. Many initially assumed he froze to death in the cold glacial region, exhausted and looking for refuge from the inhospitable environment. In fact, researchers published a report in Science that, although speculative, made more sense of death by freezing (Seidler, 1992). Konrad Spindler had another theory. In 1993, he proposed that Ötzi may have actually been fleeing for his life. Based on the unfinished condition of his weapons and the signs of injury throughout his body, Spindler believed that Ötzi may have been fleeing his village from a massacre, which was documented as common in the Copper Age (Spindler, 1994). However, many felt that this story was stretched so that Spindler could reach higher sales for his Iceman book, which was to be released that year. Because of this, for many years, his theory was dismissed by his peers, despite being very well liked in the “popular imagination” (Fowler, 2000). However, a high resolution CT scan in 2001 revealed an arrowhead lodged in his shoulder (Dickson et al., 2003). Now realizing foul play was a legitimate factor, anthropologists took a closer look at the body, finding more and more signs of trauma in the hands, wrist, chest, and head, all of which showed no signs of healing. While it is possible that he bled to death from the arrowhead lodged in his shoulder, most anthropologists have now come to the conclusion that he was killed from a blow to the head, whether by an attacker or by falling from blood loss.
When people think of mummies, many think of the cloth-wrapped mummies of Egypt, which have long been of interest to archaeologists and anthropologists. Part of a very unique culture and way of life, Egyptian mummies and tombs have been studied and researched a great deal since the early 1900s. However, mummies as a class have a much broader definition that includes many other specimens found outside of Egypt. The process of mummification “involves the transformation of once-living body or tissue into a state of arrested decay” (Aufderheide, 2003, p. 41). Thus, by this basic definition, we can broaden our view of mummies beyond Egypt, and in fact, mummies have been found throughout Europe in Spain, France, Germany, Austria, Italy (including the Iceman); throughout South America in Peru, Chile, and Argentina; throughout Africa and Asia; and even in the United States. Because the mummies found in each individual region have their own unique properties and cultural relevance, these are of much more interest to the cultural anthropologists, while pale-opathologists are much more interested in the diseases that plagued these individuals.
To understand how paleopathologists study mummies, it is important to first understand how they are preserved. Decomposition occurs in several phases (Aufderheide, 2003). The first is the release of normally regulated digestive enzymes within the cells, which begin non-specifically digesting cellular structures. Bacteria then begin to further digest body tissues, aided by larger organisms, such as maggots and scavengers. Thus, mummification must somehow block these processes in order to preserve the integrity of the body. Since enzymes must operate in an aqueous environment, the drying out of a body, or desiccation, is one of the most common methods employed in the mummification process. This, unsurprisingly, occurs in dry arid regions, such as the deserts of Egypt, the Gobi desert of Mongolia, and the dry regions of Peru and Chile. This is not to say that heat is the only method employed when drying a body. Freeze-drying techniques used by mountainous peoples, such as the Incas of the Andes (Schobinger, 1991), are also used. With this technique, water slowly leaves frozen body tissue via sublimation, a process in which the ice passes directly to water vapor, bypassing the liquid phase. The Iceman was so well preserved by this method. These cold temperatures can also block enzymatic action, which requires a narrow optimal temperature range for functioning. Most bacteria can only thrive in a narrow temperature range, and thus, frozen specimens tend to be very well preserved. A third method, although less common, uses honey or other concentrated solutions to coat the body. Due to osmosis, the water will leave the body to enter the more concentrated solution. Furthermore, honey has been found to have antimicrobial properties, furthering the preservation of a body (Aufderheide, 2003). Heavy metals, such as arsenic, copper, mercury, and lead, can also block the activity of many of these enzymes by binding them and changing their structure, thereby rendering them useless. An example of this is the “Copper Man” mummy from CE 1000, found in a copper mine in Northern Chile (Bird, 1979). This mummy is remarkably intact, which many attribute to the copper found throughout the viscera. However, many point to the dry conditions of the mine and region as the true reason for his excellent condition (Preston, 1980).
The dry conditions of these tissues have given pale-opathologists difficulty in diagnosing any illness beyond the skeletal structure, which is otherwise usually still quite reliable. Many organs are desiccated or degenerated to a point beyond recognition, and even the anatomical position is not an entirely reliable marker in organ identification (Aufderheide, 2003). Despite these limitations, many techniques used in autopsies of the recently deceased can be employed in the study of mummies. For example, mummies can be systematically dissected; this enables examining of overall morphological changes to various organs, looking for any telltale signs of disease. Histological sections for microscopic analysis can also be taken, employing a variety of stains to analyze various cellular structures. In mummies, where structural integrity must be absolutely preserved and dissection is not an option, radiographic methods may be employed. While this may include simple X-rays to look at bone changes, CT scans can also be used to create three-dimensional reconstructions. Magnetic resonance imagings (MRIs) are rarely used as the desiccated remains do not respond well to this imaging technique thereby providing little additional resolution over cheaper and faster CT scans. Endoscopy, in which a flexible camera is sent into the body for pictures of biopsy retrieval, is also used in the study of mummy pathology. This is again used to preserve the integrity of the remains, limiting gross mutilation while still allowing researchers to take samples of various organs for histological or chemical analysis, which can include DNA composition and amino acid racemization.
Due to the mummification process, gross anatomical changes in the organs are not reliable markers of disease. Histological techniques are a paleopathologist’s best chance at identifying an infectious disease in mummies (Aufderheide, 2003). For example, tissue samples from the spinal cord may show dried pus and the presence of small bacilli, leading many to the diagnosis of meningitis. Similar samples can show a myriad of other infectious diseases throughout the body, including trachoma in the eye, caused by Chlamydia trachomatis; Mucocutaneous leishmaniasis, a parasitic infection of the mucous membranes; myocardial infections; and various pulmonary infections. Paleopathologists must also rely on histological techniques when identifying neoplasms. Again, since gross anatomical changes of various organs cannot be markers for disease, histological sections must be examined for the presence of cancerous cells, which have a characteristic appearance in comparison with normal differentiated cells. DNA analysis for the presence of genetic abnormalities is also slowly starting to come into use and is certainly an area of further research. For example, Huntington’s chorea, a neurodegenerative disorder that is inherited in a dominant fashion, would only be able to be detected by these means, as the brain is almost always atrophied beyond normal analytical means.
Areas for Further Research
With the possibility of the discovery of significant archaeological finds on any given day, paleopathologists will certainly have ample specimens to analyze for years to come. This can include unique case studies like Ötzi the Iceman, Egyptian kings, or the bog people. Alternatively, paleopathologists can concentrate on more “normal” findings, providing a much better picture of the daily activities of an ancient population. It was earlier discussed that epidemiological studies must continue looking at the incidence of leprosy and tuberculosis over time. These studies can and have been applied to the incidence of any of the aforementioned diseases, and this is always an area that can be expanded on as more skeletal fossils are recovered from the fossil record.
One of the most exciting new areas in paleopathological research is the emergence of a chemical analysis of skeletal remains. Many papers have already been written that looked at the presence of heavy metals, most notably lead, in skeletal remains (Waldron, 1983). The composition of other elements can also be examined, although they must be present in high enough quantities in the diet and bone (Ezzo, 1994). As technology advances, new extraction techniques will be employed, allowing pale-opathologists access to proteins in the fossilized bone for analysis. For example, if paleopathologists can find molecular factors for a disease, such as the rheumatoid factor, then they can confidently make the diagnosis for this illness and many others.
With the completion of the human genome project, the ability to extract aDNA has even more relevance than ever. Although using aDNA as a focus for experiments does pose a challenge due to the general poor quality of most samples and large missing segments, it does show a great deal of potential for future research (Cano, 1996). By examining very specific gene fragments, researchers can watch the evolution on a genotypic level of our own species over time in the fossil record. Gene studies can also be made to look at migration patterns, as highly conserved genes unique to individual populations are tracked over time in the fossil record. Never before have paleopathologists had access to such detailed information, and the potential in this new field is quite limitless as technology continues to advance in genetics.
The field of paleopathology will continue to provide answers for anthropologists, while introducing even more questions about our past. As new technologies are used in the interpretation of skeletal remains, we can expect to gain a great deal of insight about not only the diseases that affected us but also the story of our species and our evolution over time. But why search for the answers to these questions? The famed paleopathologist Calvin Wells (1964) put it well when he said,
Disease and injury mirror more faithfully the haps and mishaps imposed by the vagaries of life and struggle to survive. If we seek the genetic affinities of an individual or group, details of normal anatomy and physiology are usually our most rewarding study; for the more intimate knowledge of how people have responded to the aggression of their environment pathology is a surer guide … The intricate relationship between a people’s way of life and the diseases they endure is the chief reason for the study of paleopathology. (pp. 17-18)