variations in the atmosphere (temperature, hygrometry), potential sources of degradation. The second was sanitary, with respect to the hospital space and the scanner room. It was indeed imperative to avoid any risk of transmission of nosocomial infection via equipment used for patients who are sometimes immunocompromised. The use of such a container made it possible to eliminate the risks of contaminating the atmosphere with possible germs originating from the mummy, spores in particular. A protocol for cleaning and disinfecting the equipment was also deployed at the end of the procedure, following the recommendations of the Comité de lutte contre les infections nosocomiales (CLIN). The examination consisted of a multidetector scan7 of the whole body in standard resolution8, then a targeted scan of the teeth in high resolution9.
4.2.3. Protocol for experimental reproduction of trepanation
In order to study the operating mode of the perforation carried out at the back of the mummy’s skull, to estimate the drilling technique, the tools used and the duration of the operation, a protocol for experimental reproduction on an actual skull was developed (Bordeaux Forensic Odontology Laboratory). This protocol was based on the theory that an opening of the cranial cavity created by removing a bone-skin flap through successive and confluent micro-drilling was carried out (see method no. 3 of Lisowski (1967)). The use of flint points – created for this experiment – was the preferred option here with respect to the archaeological context of the Chachapoyas (Toyne 2015). Following CT imaging, segmentation and 3D surface reconstruction of the trepanation (Figure 4.4(a)), a resin duplicate was created by proto-typing (b) for the creation of a matrix (c), which was then positioned on an anatomical model to replicate the perforation (d).
Figure 4.4. Experimental reproduction protocol of the cranial trepanation of the mummy MNHN-HA-30187
COMMENT ON FIGURE 4.4. – (a) 3D surface reconstruction of the trepanation. (b) Resin duplicate. (c) Matrix for the reproduction of the peripheral perforations, 10 mm diameter (in red) or 70 mm diameter (in yellow). (d) Tracing of the matrix on the actual skull and production of flint points. Images and photos: © Dr. C. Bou
4.3. Results
The CT imaging of the mummy enable us to see all of the individual, generally and in detail, from all angles (Figure 4.5). Depending on the image processing, the skeleton or the soft tissue can be examined. These images complement surface observations and allow for an initial biological assessment.
4.3.1. Basic biological identity
Despite the small volume occupied by the mummy due to its constricted position, its size is comparable to that of an adult. This is confirmed by the scan data, which allows a detailed visualization of the bone and dental state of the subject (Figure 4.6). The individual shows complete maturation of the long bones (fused conjugation cartilages), closure of the spheno-occipital synostosis and complete calcification of the third molars, indicating an age of over 20 years. The symphyseal pubic articular surfaces are relatively difficult to study in 3D because of the presence of fibrous cartilage. However, a not completely fused nucleus on cross-sectional images (Figure 4.6(c)) suggests an age of less than 40 years (Suchey and Brooks 1986). This age category is consistent with low dental attrition, seen even on the first molar (Figure 4.6(e)).
Figure 4.5. Examples of images of the mummy obtained from CT imaging. (a) Views from above and below. (b) Left profile views, and sagittal sections progressively shifted to the right profile, according to the application of various color filters. Images: (a) © Dr. S. Mérigeaud MD/Tridilogy; (b) © Dr. C. Bou
CT images are consistent with the presence of a penis, but structures at this level are difficult to recognize. Coxal bone measurements allow for a “probabilistic sexual diagnosis” based on a known global sex reference corpus (Murail et al. 2005). Of the 10 coxal bone measurements proposed by the method, six10 could be taken from the scanned images, classifying this specimen as “male” with a probability of 0.99. The maximum length of the humerus (317 mm), tibia (371 mm) and femur (463 mm) were measured. Based on femur length, which is best correlated with overall stature, their height is between 1.71 and 1.75 m, according to regressions based on current populations (Trotter and Gleser 1958; Cleuvenot and Houët 1993).
4.3.2. Osteo-dental status
There are no acquired skeletal abnormalities. The bone is not altered and there is no sign of arthrosis. However, there is a congenital transitional anomaly of the lumbosacral spinal hinge, commonly seen in modern populations: a lumbarization of the first sacral vertebra (S1) giving the impression that there are six lumbar vertebrae instead of five (Figure 4.7). The osteodental pathologies detected through imaging are the three carious lesions present on the contact faces between the upper left first molar (distal face) and second molar (mesial face) (Figure 4.6(c)) and on the lower left third molar.
Figure 4.6. Osteo-dental condition of mummy MNHN-HA-30187
COMMENT ON FIGURE 4.6.– (a) General view of the skeleton in anterior view after CT image processing. (b) Axial section and (c) 3D virtual reconstruction of the articular surface of the symphysis pubis. (d) General view of the dental arches. (e) Photograph of the maxillary teeth. (f) Detailed CT section of the caries present on the upper left molars 1 and 2. Images a, f and e: © Dr. C. Bou; images b, c and d: © Dr. S. Mérigeaud MD/Tridilogy
4.3.3. Internal organs
The soft tissues are well preserved externally and internally, except for the brain which is not visible. Only the dura mater is present inside the skull and the spinal canal (Figure 4.8(a)). The soft parts of the face and neck are also present (soft palate, tongue, larynx) (Figure 4.8(b)). At the thoracic level, the trachea, lungs, heart and diaphragm are clearly visible (Figures 4.9(a) and (c)). The presence of mediastinal and pulmonary calcifications (Figure 4.9(d)) is suggestive of tuberculosis. It could also be granulomatosis. The abdomen and pelvis show visceral structures that are difficult to recognize (possible mesentery), apart from the liver and kidneys (Figures 4.9(e) and (f)), which are atrophic due to dehydration.
Figure 4.7. Coronal section and 3D reconstruction of the lumbosacral junction, showing the transitional anomaly. Images © Dr. S. Mérigeaud MD/Tridilogy
Figure 4.8. (a) Sagittal and (b) axial sections showing intracranial and intraspinal dural remains and preservation of oropharyngeal-laryngeal soft tissue. Images © Dr. S. Mérigeaud MD/Tridilogy
Figure 4.9. Chest CT images. (a) Coronal section of the trachea [tr.]. (b) Coronal section of the lungs [pm.]. (c) Sagittal section of the heart [co.].