Digital imaging of bone and tooth modification.

Digital cameras are capable of producing images of cut marks and other three dimensional subjects comparable to those obtained from the scanning electron microscope (SEM). Until now, the SEM has offered unparalleled depth of field and surface rendition. SEM units are, however, expensive to acquire and maintain, and SEM image production is time-intensive. Furthermore, SEM images lack color and are often incapable of imaging bone modifications because of magnification and chamber size limitations. A digital imaging method for producing extremely high depth of field enlargements of three dimensional, sub-millimeter scale objects circumvents these problems. In our presentation we employ four case studies of hard tissue modification related to: (1) the origins of meat-eating in the human lineage; (2) evidence for cannibalistic behavior among Neanderthals; (3) pre-Columbian evidence of North American dentistry; and (4) the earliest evidence of cranial surgery in North America. Procedures for replica production, image-capture, and image enhancement are provided. The digital images produced are compared to those obtained with the SEM. Image processing software, a crucial component of this method, allows complete control of graphic data, making graphic fraud a larger threat than ever before. Issues in ethics stemming from the application of this technology to scientific analysis are considered.

Brief communication: prehistoric dentistry in the American southwest: a drilled canine from Sky Aerie, Colorado.

A prehistoric Native American mandible from a Fremont site (circa AD 1025) in Colorado has a conical pit in the worn occlusal surface of the lower right canine. Natural causes for this modification are ruled out by the presence of internal striae, a finding confirmed by experimental replication. The canine was artificially drilled before the individual's death and is associated with a periapical abscess. This is one of a very few examples of prehistoric dentistry in the world, and the first from the American Southwest.

Brief communication: earliest cranial surgery in North America.

The archaeological evidence of ancient cranial surgery is limited to cases of trepanation and cauterization. I report here on the only known case of cranial surgery in direct association with the osseous image of a non-trauma-induced soft tissue lesion (sinus pericranii). This case, from Alameda County, California (Late Middle Period, ca. 300-500 AD), is the earliest and only definitive evidence of invasive surgery from prehistoric North America. Because this individual presents the only bony evidence of cranial surgery other than trepanation or cauterization, it contributes substantially to our extremely limited understanding of medical practices in preliterate societies.

Craniofacial configuration and postcranial development of a hydrocephalic child (ca. 2500 B.C.-500 A.D.): with a review of cases and comment on diagnostic criteria.

Hydrocephalus is a severe disorder of the central nervous system characterized by absorption blockage of the cerebral spinal fluid (CSF). The archaeological record of the condition ranges in time from 10,000 B.C. to 1670 A.D. and consists of 30 possible cases worldwide. A review of this material reveals that diagnostic criteria which fully delineate the condition have not been established. Previously, no attempt has been made to differentiate the two major categories of hydrocephalus and their subgroupings, or to identify other conditions which might result in similar morphologies. A partial child's skeleton from the Middle Period (ca. 2500 B.C. to 500 A.D.) of Central California Prehistory is described in light of an extensive clinical literature. Examination of this individual reveals a unique craniofacial configuration and malformed postcrania. Bony criteria for a differential diagnosis of hydrocephalus are established and applied to this individual. Based on these criteria, the individual is diagnosed as having a chronic form of noncommunicating hydrocephalus. Blockage of the CSF pathway most likely occurred in the aqueduct of Sylvius with a partial occlusion of the foramen of Monro or a frontal cyst. In addition, femoral development is suggestive of partial paralysis.

Analysis of a microcephalic child from the late period (ca. 1100-1700 A.D.) of central California.

Microcephaly is a severe developmental abnormality which is induced either genetically or environmentally. The archaeological evidence for the occurrence of this abnormality is minimal. Out of six possible cases, only three have been published; all are adult and represented solely by cranial remains. The focus of the current study is the nearly complete skeleton of a 3-year-old child recovered during archaeological excavations in San Jose, California. The individual is compared to a sample of 184 California Indians, ranging from 0.5 to 5 years, which were also recovered from archaeological excavations. In order to determine if microcephaly was the only disorder represented, metrical comparisons of the skull and postcrania and gross morphological comparisons of endocranial casts were made. Based on these comparisons the individual was determined to have a cranial vault size comparable to 6-month-old infants (630 cc), a facial skeleton equivalent to the 9-month-old to 2-year-old age groups, and a reduced stature. Due to the mosaic nature of the skull, the observed morphology was interpreted in terms of functional cranial components. Severe malformation of the orbital aspect of the frontal lobes was found in conjunction with a significant reduction in size of the cerebral cortex and left temporal lobe. On the basis of this analysis, the individual was found to exhibit the total morphological pattern associated with microcephaly. A differential diagnosis of other possible genetic disorders is also presented.