new world cranial deformation practices: historical implications for pathophysiology of cognitive...

NEW WORLD CRANIAL DEFORMATION PRACTICES:HISTORICAL IMPLICATIONS FOR PATHOPHYSIOLOGYOF COGNITIVE IMPAIRMENT INDEFORMATIONAL PLAGIOCEPHALY

INTRODUCTION: Throughout history, prehistoric and even some contemporary civ-ilizations have practiced various forms of intentional and unintentional cranial defor-mation. Plagiocephaly can be the result of craniosynostosis, infant positioning, orother unintentional or intentional deformation.MATERIALS: We reviewed the medical and anthropological literature and utilized theanthropological collections of Arizona State University and the San Diego Museumof Man for evidence of cranial deformation and its possible physiological and cogni-tive side effects. Evidence of cranial shaping was also sought among art or stone workfrom representative cultures.RESULTS: The anthropological record and literature attest to the presence of much moresevere forms of deformation than that seen as a result of contemporary infant position-ing. Despite this evidence, there is no anthropological evidence as to the possible cog-nitive effects that such deformation may have, although some evidence is reviewed thatsuggests a possible physiological mechanism for the same.CONCLUSION: Because we can only view these cultures through the relics of time, anyconclusions one might draw from the anthropological and historical record regardingthe cognitive effects of head deformation can only be inferred through generalizedobservations and are tenuous. Nevertheless, there does not seem to be any obviousevidence of negative effect on the societies that have practiced even very severe formsof intentional cranial deformation (e.g., the Olmec and Maya). On the other hand, thephysical anthropology and the contemporary developmental literature suggest possi-ble mechanisms for such an effect.

KEY WORDS: Cognitive impairment, Cranial deformation, Craniosynostosis, Neurosurgical history,Plagiocephaly

Neurosurgery 60:1137–1147, 2007 DOI: 10.1227/01.NEU.0000255462.99516.B0 www.neurosurgery-online.com

NEUROSURGERY VOLUME 60 | NUMBER 6 | JUNE 2007 | 1137

LEGACY

Gregory P. Lekovic, M.D.,Ph.D., J.D.Division of Neurological Surgery,Barrow Neurological Institute,St. Joseph’s Hospital and Medical Center,Phoenix, Arizona

Brenda J. Baker, Ph.D.Department of Anthropology,Center for Bioarchaeological Research,School of Human Evolution and Social Change,Arizona State University,Tempe, Arizona

Jill M. Lekovic, M.D.Department of Pediatrics,St. Joseph’s Hospital and Medical Center,Phoenix, Arizona

Mark C. Preul, M.D.Division of Neurological Surgery,Barrow Neurological Institute,St. Joseph’s Hospital and Medical Center,Phoenix, Arizona

Reprint requests:Mark C. Preul, M.D.,c/o Neurosurgery Research,Barrow Neurological Institute,350 W. Thomas Road,Phoenix, AZ 85013.Email: [email protected]

Received, September 14, 2006.

Accepted, January 31, 2007.

Plagiocephaly can be caused by craniosyn-ostosis or deformation and has been asso-ciated with impaired cognition (22–26).

This issue has become more pressing becausethe incidence of deformational plagiocephalyhas increased since the American Academy ofPediatrics adopted the Back to Sleep campaign(50). However, whether or not plagiocephalyper se plays a causative role in such impair-ment remains controversial. To gain perspec-tive on this issue, we examined the historicaland archeological records of cultures that rou-tinely practiced severe forms of cranial defor-mation. These practices created deformational

plagiocephaly that was far more acute thanwhat is typically encountered by practitionersof pediatric neurosurgery today. Clearly, theeffects of these practices on cognition can onlybe surmised. Nonetheless, such a survey mayoffer insights relevant to the current concernsabout positional plagiocephaly.

We examined human skeletal remains fromthe collections of Arizona State University andthe San Diego Museum of Man and reviewedthe anthropological literature on the inten-tional deformational practices among prehis-toric Native Americans to examine whether ornot the possible effects on cognition could be

inferred from the anthropological record. Several reviewsdescribe the general practices of intentional cranial deformationin many parts of the world (5, 19–21, 38, 51). None, however,concentrate on its possible effects on cognition. Currentthought on the treatment of head deformation in pediatricsand neurosurgery is a convenient context for this historicalexamination. It is impossible to assess the cognitive abilities ofindividuals or groups in cultures that once practiced cranialdeformation. However, their remains, coupled with culturalevidence, may suggest implications relevant to the contempo-rary debate on the effect of positional deformational plagio-cephaly on cognition.

MATERIALS AND METHODS

The anthropological, neurosurgical, and pediatric literatureon cranial deformation was reviewed, specifically from readilyavailable New World cultural evidence. Representative exam-ples of cranial deformation in archaeological collections ofhuman skeletal remains, mainly from ancient cultures of theSouthwest United States, from the School of Human Evolutionand Social Change at Arizona State University in Phoenix andfrom the San Diego Museum of Man were used to demonstratetypes of alteration in past peoples and for purposes of illustra-tion. Evidence of cranial shaping was sought among art orstone work from representative ancient cultures of the NewWorld, including the Maya, Olmec, and Inca, and variousancient Indian cultures of North America.

The Problem: Does Deformational PlagiocephalyCause Cognitive Impairment?

Interestingly, the debate about the impact of artificial headshaping on cranial and brain development and cognitionintrigued even some of the most prominent of mid-19th cen-tury neuroscientists such as Rudolf Virchow and Pierre-PaulBroca (16). Likewise, in the late 1950s, nearly the same discus-sions on potential impacts of cranial deformation were takingplace at the Johns Hopkins Hospital between George Ander-son, then assistant professor of pediatrics, Earl Walker, chief ofneurosurgery, and the noted anthropologist, anatomist, andscientist, Ashley Montagu. Their discussions and letters docu-ment interest in better treatment for plagiocephaly or othermalformations of the cranium, and were related to a largeNational Institute of Neurological Disease and Blindness “col-laborative project into identifying the etiology of neurologicaldisease and defect in children” (44).

The Back to Sleep recommendation of the National Instituteof Child Health and Human Development and the AmericanAcademy of Pediatrics was adopted in 1992. This campaignwas an attempt to reduce the incidence of sudden infant deathsyndrome, which has been linked in epidemiological studies toinfants sleeping in the prone position. Since the adoption ofthe campaign, the rate of sudden infant death syndrome hasdropped by an impressive 40%. However, an unintended con-sequence has been an increase in the incidence of plagio-

cephaly attributable to infant head positioning (3, 50). In acommunity-based practice environment, for example, morethan 15% of patients measured prospectively showed evidenceof at least mild positional deformation, whereas 1.5% had asevere deformity associated with concomitant facial and cra-nial base deformation (32).

Recognizing that a supine sleep position may contribute todeformational plagiocephaly, the American Academy ofPediatrics Task Force on Infant Sleep Position and SuddenDeath Syndrome recommended “tummy time” (i.e., pronepositioning when awake and observed) for infants to promoteupper shoulder girdle strength and to avoid plagiocephaly. TheTask Force also recommended alternating head position weeklyto prevent children from developing a preference for one sideover the other (26).

Recently, the use of dynamic orthotic cranioplasty has gar-nered publicity as an alternative treatment to changing infanthead position. In uncontrolled studies, the apparatus restorednormal head shape better than standard repositioning tech-niques (26). Whether or not the mildly superior performanceof orthotic cranioplasty over repositioning justifies theexpense of the orthosis depends partially on the indicationsfor treatment.

Supine-sleeping infants were found to have gross motormilestones later than prone-sleeping children (15). This differ-ence has been attributed to relative weakness in upper shoul-der girdle strength among infants sleeping supine and disap-pears after 18 months of age (14). Overall, these initialconcerns that supine sleeping may be associated with adversedevelopmental effects have received little support. However,several studies have provided evidence of adverse cognitiveeffects from plagiocephaly caused by positional occipitaldeformation. Indeed, increases in the incidence of learningdisabilities among patients with persistent deformational pla-giocephaly may be comparable to those found in patients withcraniosynostosis. Miller and Clarren (35) found that the rate oflearning disabilities among 63 patients with persistent defor-mational plagiocephaly was 39.7% compared with 7.7% of thesiblings of affected children who served as controls. Parentswere interviewed about their child’s school performance andparticipation in an early intervention program, special educa-tion classes, or other special aid. Compared with the controls,significantly more children with deformational plagiocephalyrequired such services.

Among 35 patients ranging from 4 to 48 months of age withpure deformational plagiocephaly (i.e., excluding patientswith any diagnosis of genetic disorder, prematurity, or syn-drome), Habal et al. (28) found a 51% incidence of languagedelays or disorders. Between 1997 and 1999, Panchal et al.(43) used the Bayley Scales of Infant Development to assess42 consecutive infants with deformational plagiocephaly.These infants had a significantly elevated incidence of severedevelopmental delay (8.7%).

Differences in auditory-evoked responses predictive of latercognitive functioning have been studied in infants with plagio-cephaly (9, 36). Balan et al. (4) evaluated auditory-evoked

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potentials in 15 patients with plagiocephaly, including 10 withpositional plagiocephaly, two with lambdoid synostosis, andthree with anterior plagiocephaly. Irrespective of the cause ofplagiocephaly, these infants had smaller amplitude P150 andN250 responses than normal controls. The findings support acommon etiology of cognitive impairment in craniosynostosisand deformational plagiocephaly.

The causal relationship between head deformation andadverse cognitive sequelae is, however, difficult to establishbecause many comorbid conditions may predispose a child todevelop deformational plagiocephaly. Hypotonic children,such as those with mental retardation, chromosomal abnor-malities, and cerebral palsy, or children with torticollis, are atrisk for deformational plagiocephaly because they develop apreference for one head position over the other. Still, a strongcircumstantial argument can be made against the likelihood ofdeformational plagiocephaly, per se, having a significanteffect on children’s cognitive development, namely that headdeformation, whether unintentional or by design, is a wide-spread cultural phenomenon among prehistoric and indige-nous peoples.

Anthropological and Historical Contextsof Deformational Plagiocephaly

Cranial deformation practices, whether intentional or unin-tentional, have been a common feature in many ancient soci-eties. Indeed, in many parts of the world such practices con-tinue today.

Unintentional Cranial DeformationUnintentional shaping of an infant’s cranium is the conse-

quence of habitual positioning. Many historic and prehistoricNative American groups, particularly in the Southwest andPlains, used cradleboards to contain an infant while it was car-ried or sleeping, or while the mother was engaged in otheractivities. The use of cradleboards flattens the occiput, muchlike the deformation seen in contemporary American infantswho are habitually placed on their backs to sleep (Fig. 1A). Asin contemporary infants, the deformation was often asymmet-rical as a result of an infant’s preference for looking toward oneside or another (Fig. 1B).

Positional plagiocephaly is common in prehistoric South-western skeletal samples and extends across a considerablelength of time. Cradleboards have been found from the Basket-maker II period (c. 100 BC–AD 400). Occipital deformation wasalso common in the Adena and Hopewell people and at someMississippian and protohistoric sites in the Southeast andMidwest (40). These people, however, did not use a writtenlanguage. Thus, the learning disorders thought by some (4, 28,50) to be associated with deformational plagiocephaly mayhave been too subtle to be recognized by people in societies inwhich cranial deformation was common.

Intentional Cranial Deformation: “Headshaping”Intentional shaping of infants’ heads, resulting in more

extreme deformation of the cranium than cradleboarding, was

also widely practiced in the past and continues today.Dingwall’s (16) 1931 book, Artificial Cranial Deformation: AContribution to the Study of Ethnic Mutilations, remainsunequaled for its breadth and detail of the topic, surveyingthe history of the practice around the world. Gerszten andGerszten (20) and Goodrich and Tutino (21) reviewed infor-mation on intentional cranial deformation as it relates to thehistory of neurosurgery and to the development of craniofa-cial surgery from various parts of the world. Anatomists andothers (17, 27, 29, 34, 47) have been fascinated with artificialcranial deformation even before the birth of physical anthro-pology as a formal discipline, as exemplified by works likeSamuel Morton’s (37) Crania Americana; or a Comparative Viewof the Skulls of Various Aboriginal Nations of North and SouthAmerica, published in 1839. This volume contains 72 plates,principally of skulls from North and South America and theCaribbean. Extreme examples are best known from theNorthwest Coast, Peruvian cultures, and the ancient Olmec,Toltec and Maya in Mesoamerica. Intentional deformationwas also common in the southwestern and southeasternUnited States (12, 40, 48). Known European cases date fromthe Neolithic period, and have been found in Britain (7),among the Huns of eastern and central Europe (49), and inancient Cyprus (33). In antiquity, head shaping was practicedon every inhabited continent, with evidence from Iraq as earlyas 45,000 BC (42) and in fossilized remains of early Homo sapi-ens from Australia (2).

Devices used to shape heads include cloth bindingswrapped around the infant’s head, anteroposterior compres-sion via boards or stones bound together and placed aroundthe head, and cradleboard attachments that compress the fore-head. In some cultures, mothers molded and squeezed theheads of their infants between their hands while nursing,changing them from breast to breast so that a desired symmet-rical appearance could be obtained (16). Most cultures usedcranial modification as a marker of ethnic identity or social sta-tus. It was also done to appear ferocious in battle and for cul-tural or racial imitation. Deformation and sex also correlate,


IMPLICATIONS OF CRANIAL DEFORMATION PRACTICES

FIGURE 1. Example of unintentional cranial deformation among theSouthwest Native Americans. Lateral (A) and basilar (B) views withoccipital flattening caused by cradleboarding showing plagiocephaly sim-ilar to the positional plagiocephaly that results from positioning infantssupine. Photographs courtesy of Charles Merbs, Ph.D., with permission.

BA

FIGURE 2. A, carved jade figurine of a seated Olmec ruler in a ritual posedisplaying a cone-like cranial shaping, Mexico state of Puebla, San MartínTexmelucan, Highland Olmec culture, c. 900–500 BC. Photograph cour-tesy of the Dallas Museum of Art, with permission. B, ceramic figurineshowing cranial deformation in Olmec artwork. Note the lateral concaveshaping. Photograph courtesy of Jorge Pérez de Lara, with permission.Frontal (C) and side (D) views of a skull from Morton’s Crania Amer-icana showing a deformation common to the Natchez tribe of the south-central United States, which was similar to that of the Olmec. The Natchezmay have had origins in or close associations with cultures in Mexico.From, Morton SG: Crania Americana; or a Comparative View of theSkulls of Various Aboriginal Nations of North and South America.Philadelphia, J Dodson, 1839 (37).

with males usually exhibiting a more extreme appearance,although in a few cultures, females were more likely to showsuch deformation (16, 19, 21, 49).

In Mesoamerica, early Olmec (1400 BC–400 AD) figurineshave a characteristic elongated head (Fig. 2). Such cranialdeformations are thought to have been common throughoutthe Olmec civilization. The Olmecs, the forerunners of civi-lizations in Mexico, are considered to be a dynamic culturewith mathematics, a calendar, a well-developed system ofwriting, art, farming, and relatively large-scale engineeringprojects (11, 39, 54).

As many as 90% of Mayan skeletal remains exhibit evidenceof intentional, decorative, or cosmetic cranial deformation prac-tices (48). Patterns of deformation varied according to geo-graphical regions and periods. However, the prevalence of cra-nial deformation remained constant throughout the Preclassicaland Postclassical periods of Mayan civilization (100 BC–1521AD), during which time there was a stable progression ofMayan arts and sciences.

Unlike the unintentional cranial deformation that occurred asa consequence of cradleboarding, deformation in Mayan craniais much more severe. Our ability to conclude that deforma-tional plagiocephaly did not adversely affect the cognition ofNative Americans who practiced cradleboarding is hamperedby the absence of a written language. Mayan culture, however,did practice writing. Presumably, adverse effects of head shap-ing among the literate elite would have been obvious to others,as cognitive impairment would have hampered reading andwriting capabilities (Fig. 3).

Although it is impossible to assess the effects of Mayan cra-nial deformational practices on cognition, the anatomic andarchaeological records provide a circumstantial argumentagainst a negative consequence (Fig. 4). It is logical to assumethat cultures would associate changes in cognition or deleteri-ous effects on a child’s health with severe head shaping. Suchpractices would likely have died out quickly, especially amongthe Mayans or Peruvians, for example, where severe inten-tional head shaping was comparatively widespread. Never-theless, the practice seems to have been most common amongruling, religious, or elite classes. The consequential cognitivesequelae of severe cranial deformation may have been cultur-ally accepted and identified with these social classes of uniquestanding, and thus continued. Or, perhaps the sequelae werenot behaviorly obvious. Among anthropologists of the early tomid-19th century, it was thought that the skulls of ancientPeruvians were naturally elongated with retreating foreheads.

The idea of the Peruvian skull as being naturally ‘flathead’ . . . was discussed in the report of the Council ofthe American Antiquarian Association in 1855. . . . It isnot difficult to understand why the earlier inquirersfailed to grasp the fact of Peruvian artificial deforma-tion. The custom was so widespread, and the siteswhich attracted early attention provided such a massof specimens, that the theory that such conformationswere natural was easy of acceptance (16).

Among 500 skulls unearthed from Peru (ancient Inca) in themid-19th century housed in Paris and another similar number inthe University Museum at Rome, only 10% did not show extraor-dinary skull deformations (16). Furthermore, 19th century studiesfrom France on living subjects found no evidence of brain injuryor cognitive impairment associated with severe head shaping (52).

Impact of Deformation on Cranial Growthand Development

In the anthropological literature, the application of devices toshape the head have usually been interpreted to act “primarily


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A B

DC

FIGURE 4. A and B, detail of Mayan stone pan-els found in Palenque's Temple XIX, carved inthe early 8th century AD. The images show KingAhkal Mo' Nahb III (K'inich Ahkal Mo' Nahb),who was born on September 16, 678 and died afterAugust 22, 731; he was grandson of the famousMayan king, K'inich Hanab Pakal. Note theoblique tabular cranial shaping in which the fore-head becomes slanted and elongated. Also, AhkalMo' Nahb is typically depicted with what appearsto be a nose-forehead prosthetic that accentuatedthe angle of cranial shaping. The curved line of thenose represents the true profile, and the prostheticis seen above the nose. Photographs courtesy ofJorge Pérez de Lara, with permission.

on the outer table and secondarily on cerebrally influencedregions” (1). Cheverud et al. (10) performed finite-element scal-ing on samples of deformed skulls from Peru and theNorthwest Coast Salish to investigate the effects of fronto-occip-ital shaping. They found that physical reshaping of the neuro-cranial vault results in a series of compensatory bony changesrequired for normal neural growth, so that the size of the neu-rocranial vault remains the same. In this case, the compensatorygrowth involved the mediolateral aspect of the cranium. Thus,a 5% decrease in the anteroposterior dimensions of the face cor-responded to a 5% increase in the width of the cranial base.

The relationship between cerebrally derived pressure on thecranial vault and sutural fusion, as evidenced by the tendencyto promote premature sutural fusion in shunted hydro-cephalus, has led some to posit a causal relationship between



FIGURE 3. A, Mayan codex ves-sel from the Middle Classic Period(AD 400–600) depicting the elon-gated head of the Maize God beingborn from a seed. B and C, two ofa set of three Yaxchilan limestonelintels, Numbers 24 and 26, (LateC la s s i c Mayan Per i od , AD600–900), each of which formedthe ceiling of a deep doorway toone of the Yaxchilan temple’s threeseparate rooms. As worshipersentered, they looked up to see thescene overhead. The lintels werecommissioned by Lady Xoc andfeature her performing crucialduties during the reign of her hus-band. The stonework shows theflattening of the forehead and elon-gated, conical head of a famous Mayan king and queen. In royal Mayancourts, women filled important civic and religious roles denied them inmany Mesoamerican cultures. On the first of these lintels (B), Lintel 24,commemorating a blood-letting rite in AD 709, Shield Jaguar stands hold-ing a flaming torch with Lady Xoc kneeling in front of him. As she runsa rope studded with thorns or spines through her tongue, spots of bloodcollect on the paper in the basket in front of her. In Lintel 26 (C), commem-orating a ritual in AD 725, Lady Xoc hands a jaguar helmet to ShieldJaguar, securing his place in the line of kings, or perhaps on his way to bat-tle. Photographs courtesy of Jorge Pérez de Lara, with permission.

A B A

B

C

externally applied forces and sutural fusion. Graham et al.(22–26) and Koskinen-Moffett et al. (31) have argued that per-sistent deformation in utero may promote premature fusion.According to this view, deformational plagiocephaly exists ona continuum with synostosis per se. Although this hypothesisis widely cited, experimental models of sutural constraint inrabbits and sheep have failed to demonstrate such an associa-tion (6, 18). The persistence of sutures in mechanicallydeformed skulls is evident in the anthropological literature.

Several anthropological studies have focused on the impactof artificial cranial deformation on sutural complexity. Anincrease in the frequency of wormian bones (sutural ossicles) inthe lambdoidal suture has been suggested (16, 41, 45, 46).Pucciarelli (45) concluded that higher frequencies of wormianbones were found in experimentally deformed rat crania andthat such experimental deformation may be an extrageneticexpression of wormian bones. He inferred that this evidencemay be relevant to studies on racial differences based on dis-continuous cranial traits (16, 46). Konigsberg et al. (30), how-ever, found that the frequency of coronal ossicles increasesregardless of the type of deformation. They observed that ossi-cles typically occur near the position of pads or a wrappingdevice. Their study suggests that biomechanical forces operat-ing on the skull as it is shaped promote compensatory growthat the sutures where force is applied. This idea is supported byKonigsberg et al.’s (30) statement that nonmetric traits thatdevelop prenatally are unaffected by deformation.

White (53) found a strong association between sagittal synos-tosis and lambdoidal wormian bones among Mayans atLamanai, Belize. The high frequency of synostosis in unde-formed skulls suggested an underlying heritability. However,the increased frequency of wormian bones in individuals withfronto-occipital deformation reinforces the importance ofsutural development in maintaining overall skull size.Environmental factors seem to affect posterior sutures morethan anterior sutures, perhaps a result of the rapid growth ofthe posterior cranium immediately after birth (41). However,none of these studies demonstrated a significant increase insutural fusion in deformed skulls, irrespective of the extent ofdeformation.

Investigating endocranial vascular changes related to bothsynostosis and artificial cranial deformation, O’Loughlin (41)found significant alterations in the patterns of venous sinusdrainage between normal, synostosed, and deformed skulls.Both artificial deformation and craniosynostosis alteredendocranial vasculature, but the patterns differed. Venous sinusimpressions are shallower under the areas of greatest deforma-tional stress; those further away from the stress show compen-satory enlargement. In synostosis, however, the sinuses arewider and deeper under the fused sutures. Moreover, 71% ofoccipitally deformed skulls demonstrated enlarged occipitaland marginal sinus impressions, and the frequency of left trans-verse sinus dominance increased in right-sided asymmetricallydeformed skulls. This finding demonstrates both developmen-tal plasticity of venous outflow channels and also testifies to theability of external compressive forces to affect them. It could be

the basis for a pathophysiological mechanism common to bothcraniosynostosis and external deformation, namely, regionalvenous outflow obstruction and subsequent consequentialincreases in local intracranial pressure.

Using silicone casts in rats, Burrows et al. (8) comparedthe changes in endocranial vascular channels in experimen-tal conditions of immobilization and synostosis. The dimen-sions of the posterior dural venous sinus were significantlyreduced in synostosed rats compared with normal or immo-bilized rats. They concluded that the endocranial events weresecondary phenomena that reflected regionally alteredsutural dynamics, including increased intracranial pressure,local reductions in intracranial pressure, or accumulations ofcerebrovascular fluid.

Imaging studies seem to point toward a decrease in cerebralglucose metabolism in the occipital cortex in children with syn-ostosis. Using positron emission tomographic imaging of chil-dren with single suture synostosis (metopic, coronal, or sagit-tal), David et al (13) showed regionally variable signals forglucose metabolism, whereas there was a consistent decrease inthe posterior occipital region, the area of visual developmentand visual spatial coordination. After surgical release of thesuture, there were significant increases in maximal and averageglucose metabolism in the occipital cortex. None of these stud-ies has focused on cognition or been able to link events sur-rounding cranial or brain malformation or vascular alterationto effects on cognition.

Anthropological Literature on Cognitive AbilityAlthough Dingwall’s (16) compendium is rich in detail on

the scope and means of cranial deformation (especially forNew World cultures), there are only minor relevant com-ments associating it with cognitive ability one way or theother; indeed, this was not the object of the work. Dingwall,in referring to extant cultures of which he had direct contactstated, “It does not seem that the practice of head deforma-tion among the North West Coast tribes affects their mentalfaculties” (16). In his 1839 Crania Americana: Or a ComparativeView of the Skulls of Various Aboriginal Nations of North andSouth America, Morton (37) described the devices used forshaping heads in detail. Despite the deformation, he notedthat “the absolute internal capacity of the skull is not dimin-ished, and, strange as it may seem, the intellectual facultiessuffer nothing” (37). He cited journals of travelers to thearea to support this contention. Nineteenth-centuryAmerican explorers, including Lewis and Clark, describedthe extreme cranial deformations of Native Americans in theColumbia River Basin. While visiting the Chinook, Dingwallnoted that both sexes had their heads “flattened in a mostdisgusting manner” (16), whereas other explorers tended todiscount the deformations as hidden by the hair. However,the explorer J.K. Townsend, in his 1839 “Narrative of a jour-ney across the Rocky Mountains to the Columbia River,”recounts the observation of a young child from whom thedeforming apparatus had just been removed. The entirefrontal region was flattened, causing an enormous projection


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behind, and the child’s protruding eyes were inflamed, anddiscolored as were the surrounding orbital areas. However,the child seemed to behave and react normally to its motherand others (16).

“Collectively known at the time as ‘Flatheads,’ these groupspracticed parallelofronto-occipital deformation by a board orbindings placed across the infant’s forehead while it was posi-tioned in a cradleboard (Fig. 5). Lewis and Clark are quoted asfinding these people “inquisitive and loquacious, with under-standings by no means deficient in acuteness, and with veryretentive memories.…Every thing they see excites their atten-tion and inquiries…all our inquiries they answered with greatintelligence…they are keen, acute and intelligent” (37). Mortonhad occasion to meet one “full-blood Chenouk” whose “headwas as much distorted by mechanical compression as any skullof his tribe in my possession, and presented the very counter-part to the Kalapooyah figured on the annexed plate” (Fig. 5)(37). According to Morton, who gained the young man’s con-sent to measure his skull, “he appeared to me to possess moremental acuteness than any Indian I had seen” (37).

Although later derided for many of his racial categorizationsand conclusions based on cranial measurements and phreno-logical observations of various cultures, Morton’s informationon cranial shaping among American continent peoples wasunsurpassed in its day and remains a unique primary source ofinformation on cranial deformation. He collected ancient skullsfrom North, Central, and South America, along with othersfrom various extant tribes in the continent. He also interviewedmany explorers of these regions and was familiar with writingsfrom the age of the Spanish conquistadors.

In fact, a central theme of Morton’s work is that he could findno evidence of cognitive deficits among peoples practicingsevere cranial deformation. He theorized similar means bywhich the tribes on the Columbia river, ancient inhabitants ofVenezuela, the Charibs of the Antilles, some tribes of Peruvians,and other peoples of North and Central America had foreheads“compressed by art, the back and lateral parts of the craniumbecome proportionately expanded, in order to make room forthe brain that has been displaced from the anterior chamber.…”(37). Furthermore, Morton wrote that many ancient Peruvians’heads were “as remarkable for their narrowness as for theirlength” (37). He continued,

when nature has denied an imaginary grace, art iscalled in to supply the deficiency; and even wherethere has been no such deficiency, human vanityprompts to extravagance.…It would be natural tosuppose that a people with heads so small andbadly formed would occupy the lowest place in thescale of human intelligence. Such, however, was notthe case…

as Morton quotes accounts of Conquistadors who describedthe fabulous architectural structures of pre-Incan and Incancivilization (37). Morton criticized others for their primitiveview of the Inca:



FIGURE 5. A, frontispiece of Morton’s Crania Americana. B, skull of a“Kalapooyah Indian,” a living counterpart to which Morton encounteredamong the Chinook who “appeared to . . . possess more mental acutenessthan any Indian [he] had seen” (37). As documented by plates in CraniaAmericana, other tribes on the Columbia River that practiced cranial defor-mation included the Chinook, Cowalitsk, and Killemook. From, MortonSG: Crania Americana; or a Comparative View of the Skulls of VariousAboriginal Nations of North and South America. Philadelphia, J Dodson,1839 (37).

A

B

FIGURE 6. A, a Chinook cradleboard that Morton acquired from a friend.The neck of the child rested on the ridge to the right of the board (D). C isa grass pad that was drawn over the child’s forehead. The other partsmarked D were for straps to keep the child’s body in place. The body restedon a mat of soft grass. E is a support for the cradle or a step to raise the cra-dle head up in the air for easier lifting. According to Morton, childrenreportedly remained in such a cradle from 4 to 8 months, “or until thesutures of the skull have in some manner united, and the bone becomessolid and firm” (37). Morton wrote that “…so highly is this deformity val-ued among the Columbia River tribes, that their slaves (who are for themost part derived from the adjacent tribes) are not allowed to practiceit.…[The] absolute internal capacity of the skull is not diminished, and,strange as it may seem, the intellectual facilities suffer nothing. The latterfact is proved by the concurrent testimony of all travelers who have writ-ten on the subject” (37). From, Morton SG: Crania Americana; or aComparative View of the Skulls of Various Aboriginal Nations ofNorth and South America. Philadelphia, J Dodson, 1839 (37). B, illus-tration of a Chinook mother with an infant in the head molding apparatus.Dingwall writes, “The old Spanish Franciscan Diego de Landa who dealtwith the Maya… and who was Bishop of Merida about 1572, describedhow the natives of his day deformed the heads of their children. …Scarcelyfour or five days after birth the child was stretched out upon a sort of lit-tle bed made of reeds or strips of other material, and then the head wasplaced between a couple of boards, one at the back and one at the front.These were then pressed together and fastened. For days at a time thechild was thus left in suffering…and sometimes so much pain was causedthat the children died, [or] had openings behind the ears, a condition ofthings which…was not uncommon” (16). From, Dingwall EJ: ArtificialCranial Deformation: A Contribution to the Study of EthnicMutilations. London, John Bales, Sons & Danielson Ltd., 1931 (16).

Thus the seemingly superhuman efforts of the Egyp-tians are at least equaled by those of the Peruvians.…apeople destitute of horses, oxen, or any beast of bur-den except the feeble lama; and yet they have leftmonuments which sufficiently attest their great inge-nuity and indomitable perseverance.…The arts of thepresent day, with all the refinements of successivegenerations of ingenious minds, would perhaps beinadequate to achieve those remarkable ends whichare common in the monuments of Peru (Fig. 6) (37).

Morton also discussed Incas in the province of Chicuito whomolded their children’s heads “for the purpose of increasingthe ferocity of countenance in war…and adding to the healthand strength of the body” (37). For one Peruvian tribe, “alltheir attention is bestowed on preserving a firm texture of thebody, and on flattening the forehead and hinder part of thehead [in an upward direction] with a view of resembling…thefull moon, and of becoming the strongest and most valiant peo-ple in the world” (37). The Inca Huyna Capac, through a pas-sage from Garcilaso de la Vega in Morton’s work, mentioned aculture that he conquered that achieved a remarkable appear-ance with severe cranial deformation: “ …they deform theheads of their children by placing, at birth, a small board on theforehead and another on the occiput, and drawing them tighterday by day until the child has attained the age of four or fiveyears. By this process the head becomes broad from side toside, and narrow from back to front. Not satisfied with thisdeformity they shave the hair from the top of the head, and thenape of the neck, letting it grow on the sides only; and this notbeing combed or arranged, but rude and entangled, adds to thehideousness of their physiognomy” (37).

As among the Maya, Morton noted “the custom of moldingthe cranium into artificial forms is of great antiquity and preva-lence in Peru.” (37) In fact, it was so common that in 1585, theEcclesiastical Court of Lima forbade parents, under specifiedpenalties, “to compress or distort the heads of their children inthe various modes which were in vogue even at that lateperiod” (37).

More recently, Ortner (42) stated that, the complications ofcranial deformation are mainly cosmetic, while noting thatcompression could disrupt normal growth at the cranialsutures and give rise to minor abnormalities. Citing Moss’s1958 study indicating that the magnitude of growth is notreduced, Ortner concluded that “the practice probably did notproduce any serious health problems” (42).

In most societies in which intentional cranial deformation ispracticed, deformed crania are typically associated with peopleof high status. Therefore, it seems unlikely that significant cog-nitive impairment results from such shaping (Fig. 7). That farmore extreme intentional cranial deformation than that foundin modern American children has been practiced across cul-tures for long periods suggests that such adverse cognitiveeffects are unlikely. In his letter to George Anderson, AshleyMontagu replied,


LEKOVIC ET AL.

A

B

All the evidence we have indicates that no form ofhead binding has any untoward effect upon thegrowth of either the brain or the development of themind.…My experience with artificially deformed cra-nia strongly suggests that no alterations are producedexcept 1) alteration in the form of the bones and 2)pressure may approximate the squama temporalistoward the frontal bone, or rather, the other wayround, if the pressure is occipito-frontal, or merelyfrontal. The sutures remain unaffected, that is to say,there is no premature synostosis, and this is animportant point because it enables one to distinguishbetween those pathological cases in which there hasbeen premature synostosis of endogenous originfrom those cases which, as in artificial cranial defor-mation, are of exogenous origin. I have never heardof a case of artificially produced microcephaly as aresult of artificial cranial deformation. Anything canhappen, but I think it extremely unlikely that such aresult is likely to follow upon any of the large vari-eties of artificial cranial deformation. What some-times happens is that the visceral layer of the duramater tends to adhere to the cranial layer, and thatthe arachnoid may also be involved, and sometimes,also, the pia, in forming adhesions to the inner tableof the skull. This is particularly the case in frontalforms of deformation. In such forms of deformationan exophthalmos is produced by the pressure-in cer-tain parts considered muy simpatico!” [sic] (44)

CONCLUSION

The anthropological record supports endocranial effects ofhead deformation in situations that parallel those of the posi-tional plagiocephaly that has followed the adoption of theBack to Sleep campaign. However, the overwhelming preva-lence of head shaping in ancient cultures seems to argueagainst cranial shaping exerting a significant adverse effect oncognition. Across history, cranial deformation has been muchmore severe than that currently encountered by neurosur-geons. Yet many cultures, including most of their populationsor at least their leading citizens, have practiced incredibleskull deformation, while still achieving marked cultural pro-gression (e.g., producing architecturally complicated struc-tures, systems of calendars, mathematics, and materials work-manship). Such cultural progression would likely have beenprecluded if cognitive deficits had been widespread amongthose of high status, much less across most of their popula-tions. Some cultures, such as the Maya, achieved high levelsof scientific and artistic sophistication despite their wide-spread practice of extreme forms of head shaping. Even if thearcheological record reflects only a small subset of the Maya,such as the elites, those people presumably responsible foradvancing and maintaining Maya culture, it would be logicalto assume that at least gross deleterious effects would benoted rapidly and the practice halted. Nevertheless, some

form of cognitive effect (e.g., a “learning disability”) cannot bediscounted entirely. However, the observations of cranialdeformation with proptosis by Ashley Montagu and J.K.Townsend imply significant increases in intracranial pressurein these individuals. Around-the-head, or band-type, defor-mation procedures would seem to be more serious in notallowing the head to expand in compensatory ways. Overtime, such procedures would cause brain injury with associ-ated intellectual deterioration. The translation to a popula-tion scale may be that a cognitive effect, although not obvious,could be serious enough and culturally widespread so as tointerfere with the ability of a culture to respond to certainchallenges. The collapse of the southern Mayan cultureremains enigmatic, attributed to warfare, invasion, migration,disease, over-farming, social class struggle, economic collapse,religious change, and climactic alteration. It is intriguing,however, to postulate whether or not neurological effects fromartificial head deformation contributed to the scenario of cul-tural demise. Unfortunately, the record of severe head shapingfound in some of the most notable ancient cultures in the NewWorld does not lend itself to a direct demonstration of theeffects of cranial deformation on cognition. There is simply noway to test cognition in cultures that precede us by centuries.As Ashley Montagu stated, the mystery is likely to go on as“unfortunately microscopic examinations [on the brains underconditions of artificial cranial deformation] have seldom beendone.” If present, however, such a cognitive effect may havebeen adapted to or contributed to the perceived world orWeltanshauung of these peoples in an interesting and meaning-ful, or even culturally harmful, way. Perhaps, considering theevidence from past cultures that practiced severe skull defor-mation may help shed perspective on our own medicoculturalpractices by which we assess and treat deformational plagio-cephaly today.

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AcknowledgmentsGregory P. Lekovic, M.D., Ph.D., received the Vesalius Prize from the History of

Neurological Surgery Section of the American Association of Neurological Surgeonsfor this study, which was presented in part at the 73rd Annual Meeting of theAmerican Association of Neurological Surgeons in New Orleans April 16–21, 2005.

We thank Charles Merbs, Ph.D., for his photographs from the collections ofArizona State University and the Museum of Man, Jorge Perez de Lara for pho-tographs of Olmec and Mayan antiquities, and the Dallas Museum of Art, Dallas,TX, for the photograph of the Olmec figurine.

COMMENTS

The authors have performed a most interesting review of cranial defor-mation and its practice in ancient cultures. The report was originally

sparked by a series of recent publications that suggest there is a higherincidence of developmental delays in children with craniosynostosisand, more importantly, in the population of children with deformationalplagiocephaly. In reviewing some of the recent work on this subject, theincreasing numbers of children with developmental issues is somewhatalarming. Keeping that concept in mind, the authors were interested inwhether the practice of cranial deformation, intentionally performed inmost cases, caused a similar incidence of developmental delay. In a care-ful analysis of the early literature from explorers and conquistadors, itbecame clear that intentional cranial deformation apparently did notcause a higher incidence of developmental delay. The images the authorshave attached to the paper clearly point out some of the severe cranialdeformations that were obtained with these practices. I remember a lec-


LEKOVIC ET AL.

ture by William Feindel, MD, in which he advocated that the possibledemise of the Mayans during the late classic period (circa 800–900 A.D.)might be caused by overly severe intentional cranial deformation. Heargued that this practice, typically only allowed among the nobility,might have led to a higher incidence of epilepsy and developmentalissues. It’s a provocative thought, but no one has an answer; hence thespeculations are most interesting to read. The only question that remainsin my mind is the recent disturbing issues being raised regarding devel-opmental delays in children with deformational plagiocephaly. If this istrue, then we have a serious problem, because pediatric neurosurgeonsand neurologists are observing an epidemic of this disorder.

James T. GoodrichBronx, New York

This fascinating article is the product of a careful review of the scien-tific literature as well as the anthropological collections of two large

institutions to examine the evidence for any adverse consequences oncognition associated with the practice of intentional cranial deforma-tion. The authors focused their research on the practice in the Americas,although intentional cranial deformation occurred at different timesby different cultures on every inhabited continent. The question statedby the authors for this study is whether plagiocephaly resulting fromcraniosynostosis causes cognitive impairment. They surmise that, giventhe severity of the deformational plagiocephaly caused by intentionalcranial deformation, if the practice did not result in any cognitivedeficit, then the much “milder” cases of positional cranial moldingencountered by physicians today would be even less likely to result incognitive impairment.

The authors conclude from their investigation that there were likelyno adverse consequences on cognition associated with even the mostextreme forms of intentional cranial deformation as practiced in theAmericas. Otherwise, the practice would have likely not been sowidely practiced throughout human history. An important questionis, what were the origins of this mutilation that was practiced by cul-tures widely separated by time and space?

Enrique GersztenRichmond, Virginia

Peter C. GersztenPittsburgh, Pennsylvania

This article contains a fascinating description of historical cranial defor-mation along with a relevant discussion of contemporary thought on

positional plagiocephaly. As the authors note, the incidence of this con-dition is increasing, making current dialog regarding the topic particu-larly relevant. Although careful to point out the lack of any direct evi-dence relating intentional cranial deformation and cognition, the authors’consideration of the advancement and productivity of the historical civ-ilizations in which this practice was prevalent makes for an intriguingargument. Considering the growing number of children who are devel-oping plagiocephaly, along with their concerned parents, the historicalcontext presented here will make for interesting discussion.

Lissa C. BairdMichael L. LevySan Diego, California

In recent decades, paleoanthropology has undergone impressiveadvances from a merely descriptive and historical discipline to a

dynamic interpretation of the variability of the human cranium interms of the functional and structural relationship of its different com-ponents. The anatomical variations induced by volumetric changes ofthe brain are those that most attracted the scientists’ attention.

Consequently, the changing human cranial phenotype is presentlyinterpreted as an integrated functional structure rather than a sim-ple coexistence of different and variable features. Craniosynostosiscan be regarded as a kind of disorder that interrupts the harmony ofthe progressive change of the calvarium and face during humanevolution. The therapeutic efforts are indeed aimed at reestablishingan “ideal” phenotype, namely, the perfect shape of the face and thecranium.

Cranial molding, and in particular, positional posterior plagio-cephaly, represents an additional puzzling phenomenon for functionalcraniology, as the deformed calvarium seems to not be associated withsignificant functional disturbances. There are several examples of pop-ulations that seem to have associated artificially deformed craniumswith privilege. Although cumulative experience suggests minimal orabsent neurofunctional impact of molded craniums, the reason for suchan attitude continues to remain very intriguing. Lekovic et al. stimulatethe debate with this elegant and very exciting review that uses an orig-inal source of information to question the possible impacts of cranialmolding on neurodevelopment.

Concezio Di RoccoRome, Italy



new world cranial deformation practices: historical implications for pathophysiology of cognitive...

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