Knowledge of Skull Base Anatomy and Surgical Implications of Human Sacrifice Among Pre-Columbian Mesoamerican Cultures
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See the corresponding retraction, DOI: 10.3171/2018.5.FOCUS12120r, for full details. Neurosurg Focus 33 (2):E1, 2012 Knowledge of skull base anatomy and surgical implications of human sacrifice among pre-Columbian Mesoamerican cultures RAUL LOPEZ-SERNA, M.D.,1 JUAN LUIS GOMEZ-AMADOR, M.D.,1 JUAN BArgES-COLL, M.D.,1 NICASIO ArrIADA-MENDICOA, M.D.,1 SAMUEL ROMERO-VArgAS, M.D., M.SC.,2 MIGUEL RAMOS-PEEK, M.D.,1 MIGUEL ANGEL CELIS-LOPEZ, M.D.,1 ROGELIO REVUELTA-GUTIErrEZ, M.D.,1 AND LESLY PORTOCArrERO-ORTIZ, M.D., M.SC.3 1Department of Neurosurgery, Instituto Nacional de Neurologia y Neurocirugia “Manuel Velasco Suárez;” 2Department of Spine Surgery, Instituto Nacional de Rehabilitación; and 3Department of Neuroendocrinology, Instituto Nacional de Neurologia y Neurocirugia “Manuel Velasco Suárez,” Mexico City, Mexico Human sacrifice became a common cultural trait during the advanced phases of Mesoamerican civilizations. This phenomenon, influenced by complex religious beliefs, included several practices such as decapitation, cranial deformation, and the use of human cranial bones for skull mask manufacturing. Archaeological evidence suggests that all of these practices required specialized knowledge of skull base and upper cervical anatomy. The authors con- ducted a systematic search for information on skull base anatomical and surgical knowledge among Mesoamerican civilizations. A detailed exposition of these results is presented, along with some interesting information extracted from historical documents and pictorial codices to provide a better understanding of skull base surgical practices among these cultures. Paleoforensic evidence from the Great Temple of Tenochtitlan indicates that Aztec priests used a specialized decapitation technique, based on a deep anatomical knowledge. Trophy skulls were submitted through a stepwise technique for skull mask fabrication, based on skull base anatomical landmarks. Understanding pre-Columbian Mesoamerican religions can only be realized by considering them in their own time and according to their own perspective. Several contributions to medical practice might have arisen from anatomical knowledge emerging from human sacrifice and decapitation techniques. (http://thejns.org/doi/abs/10.3171/2012.6.FOCUS12120) KEY WORDS • skull base • forensic anthropology • funeral rites • shamanism EFORE the discovery of the Americas by Chris- the first agricultural settlements, several common social topher Columbus in 1492, the central region of and cultural features evolved among Mesoamerican soci- the continent, known as Mesoamerica (extend- eties, such as complex calendar and numeral systems, rich Bing from Central Mexico to Nicaragua), was inhabited and colorful mythological traditions, advanced astronom- by prosperous ancient civilizations that flourished before ical knowledge, and a distinct architectural style, whose the Spanish colonization that began in the 16th century.14 vestiges still remain. Human sacrifice became a common Pre-Columbian Mesoamerican societies (Olmecs, Ma- cultural trait during the advanced phases of Mesoameri- yans, Totonacs, Aztecs, and Mixtecs) shared not only can civilizations.5,12 This phenomenon, influenced by a geographical area but also several cultural traits.14 As complex religious beliefs, included several practices such early as 7000 to 6000 BC, they domesticated the wild teo- as decapitation,3,9,12 cranial deformation,20 and the use of sinte and gradually transformed it by selection of seeds human cranial bones for skull mask manufacturing.15 Ar- into the ancestor of modern maize. It became the major chaeological evidence suggests that all of these practices crop of Mesoamerican societies by the time of Spaniard required specialized knowledge of cranial, skull base, exploration.2,13,18 Improvement of agricultural techniques and upper cervical anatomy.10 In the context of a world of and domesticationRetracted of maize and other vegetables (beans, perpetual war among tribes and hand-to-hand combat,3 squash, and chilies), as well as the raising of turkeys and considerable surgical applications might have emerged the Mexican hairless dog (Xoloitzcuintli), caused a tran- from this anatomical knowledge, such as the use of gold sition from paleo-Indian hunter-gatherers (foragers) to and silver to perform cranioplasties, refined surgical tech- established agricultural villages.16 niques to treat combat wounds, and the development of During the centuries following the establishment of head protection devices.11 Neurosurg Focus / Volume 33 / August 2012 1 R. Lopez-Serna et al. Systematic Search temples dedicated to the gods Quetzalcoatl and Tezcatli- poca.6 The Great Temple of Tenochtitlan represented the We conducted a systematic search for information axis mundi of Aztec civilization, and most of the religious on skull base anatomical and surgical knowledge among practices were performed there (including decapitation); Mesomerican civilizations. For this purpose, we exam- thus it is not surprising that most of the Aztec osteologi- ined the collections of the Mexican National Institute of cal specimens come from this site, where they gradually Anthropology and History and the National Autonomous accumulated over a period between 1440 and 1502 AD.4 University of Mexico, as well as previous reports of os- teological and pictorial collections obtained from excava- tions at some major archeological sites. Knowledge of Skull Base Anatomy and the A detailed exposition of these results is presented, Practice of Human Sacrifice Among Aztecs along with some interesting information extracted from historical documents and pictorial codices, to provide the Fray Bernardino de Sahagun, known as one of the reader with some valuable information concerning the most important chroniclers of the 16th century, exten- existence of skull base surgical practices among these sively described the Aztec way of life in his 12-volume ancient cultures. Florentine Codex. From this written evidence, it is known that parents decided the future profession of their ba- The Aztecs and the Great City of Tenochtitlan bies immediately after birth. Future priests had to go to the Calmecac, where they received a rigorous education The Aztecs, also known as Mexicas, inhabited the based on a specific program. As suggested by chroniclers, land we now call the Valley of Mexico, where Mexico Aztec priests may have begun their training as early as 5 City is situated. The ancient city of Tenochtitlan—the years old, and they had to learn both theory and practice, Aztec’s capital, whose vestiges still remain next to Mex- such as the technique for human sacrifice and decapita- ico City’s Metropolitan Cathedral (Metropolitan Cathe- tion. The Aztec priests were experts on anatomy of in- dral of the Assumption of Mary of Mexico City)—was ternal and external anatomical structures and used spe- founded in 1323, on a little swampy islet in Lake Texcoco. cific names for brain (cuayolotl) and head (tzontecomatl). According to legend, this unexpected place was selected Furthermore, they distinguished the skull base and upper by Aztec religious leaders because it is where they saw a 6 cervical spine (cuitla) as an independent structure from golden eagle perched on a paddle cactus, eating a snake. the rest of the cranium (cuech) and spine (xo).7 Graphic representation of this legend is depicted on the Paleoforensic evidence from more than 1000 bone Mexican coat of arms, which can be seen on the white specimens found in 19 offerings from the Great Temple stripe of the Mexican flag. indicates that Aztec priests used a specialized and sys- Over the decades, the Aztec civilization formed a tematic decapitation technique, possibly based on a deep powerful warrior empire that expanded its political and knowledge of skull base anatomy.4 Some osseous marks economical hegemony beyond the Valley of Mexico. At show a recurrent pattern among different specimens and the maximal extent of the Aztec Empire, Tenochtitlan ex- correspond to cuts inflicted on the occipitocervical junc- tended its power as far as the shores of the Gulf of Mexico tion with fine tools, probably obsidian or quartz knives and Pacific Ocean.18 (tecpatl; Fig. 1 left).7 These V-shaped indentations, located Inspired by their religious beliefs, the Aztecs launched 9 periodical ritual battles against their enemies, which pro- over the upper cervical vertebrae and occipital condyles, vided them with victims for sacrifice. According to the might have followed a blunt dissection of the upper neck, Duran Codex, these battles, known as “flower wars,” were with the intention of damaging the upper spinal cord and instigated by the Aztec emperor Tlacaelel after a great lower medulla oblongata. All cases of decapitation were famine, in an attempt to please the gods and obey their performed with the individual lying on his or her back; wishes.5,11 after the victims were sacrificed, the priests decapitated them between the fifth and sixth cervical vertebrae (Fig. The Great Temple (Huey Teocalli) was the main reli- 10 gious building of Tenochtitlan. It was a twin temple dedi- 1 right). Trophy skulls had 3 possible uses: as an offering cated to 2 gods: Tlaloc, god of rain, and Huitzilopochtli, inside the temple, with the flesh intact; for public display god of war. According to Aztec tradition, the temple was on a skull rack (tzompantli); and for fabrication of orna- built on the exact site of the city’s stone foundation.9 Dur- mental masks (Fig. 2). ing the Spanish conquest of Tenochtitlan,