Dental Paleobiology in a Juvenile Neanderthal (Combe-Grenal, Southwestern France).

Combe-Grenal site (Southwest France) was excavated by F. Bordes between 1953 and 1965. He found several human remains in Mousterian levels 60, 39, 35 and especially 25, corresponding to MIS 4 (~75-70/60 ky BP) and with Quina Mousterian lithics. One of the fossils found in level 25 is Combe-Grenal IV, consisting of a fragment of the left corpus of a juvenile mandible. This fragment displays initial juvenile periodontitis, and the two preserved teeth (LLP4 and LLM1) show moderate attrition and dental calculus. The SEM tartar analysis demonstrates the presence of cocci and filamentous types of bacteria, the former being more prevalent. This result is quite different from those obtained for the two adult Neanderthals Kebara 2 and Subalyuk 1, where more filamentous bacteria appear, especially in the Subalyuk 1 sample from Central Europe. These findings agree with the available biomedical data on periodontitis and tartar development in extant individuals, despite the different environmental conditions and diets documented by numerous archeological, taphonomical and geological data available on Neanderthals and present-day populations. New metagenomic analyses are extending this information, and despite the inherent difficulties, they will open important perspectives in studying this ancient human pathology.

Earliest cranio-encephalic trauma from the Levantine Middle Palaeolithic: 3D reappraisal of the Qafzeh 11 skull, consequences of pediatric brain damage on individual life condition and social care.

The Qafzeh site (Lower Galilee, Israel) has yielded the largest Levantine hominin collection from Middle Palaeolithic layers which were dated to circa 90-100 kyrs BP or to marine isotope stage 5b-c. Within the hominin sample, Qafzeh 11, circa 12-13 yrs old at death, presents a skull lesion previously attributed to a healed trauma. Three dimensional imaging methods allowed us to better explore this lesion which appeared as being a frontal bone depressed fracture, associated with brain damage. Furthermore the endocranial volume, smaller than expected for dental age, supports the hypothesis of a growth delay due to traumatic brain injury. This trauma did not affect the typical human brain morphology pattern of the right frontal and left occipital petalia. It is highly probable that this young individual suffered from personality and neurological troubles directly related to focal cerebral damage. Interestingly this young individual benefited of a unique funerary practice among the south-western Asian burials dated to Middle Palaeolithic.

Retromolar ridge in edentulous patients: clinical considerations.

PURPOSE: A removable denture base should cover the mandibular retromolar regions to provide proper basal seal and denture function in edentulous patients. The bony residual ridge form, attached muscles, and covering mucosa provide support, stability, and retention of the planned prosthesis. There is insufficient information regarding bone anatomy, mucosal tissues, and muscles in the retromolar region after tooth loss. The purpose of this study was to examine the tissue morphology in the mandibular retromolar area of edentulous subjects and report on the clinical inferences in prosthetic and implant dentistry. MATERIALS AND METHODS: Specimens included 75 edentulous and eight dentate dry mandibles examined by macroscopic observations and linear measurements for size determinants in the left and right retromolar regions. Buccolingual histological sections of the mandibular retromolar region from seven edentulous subjects were also examined. The specimens were from the Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University. RESULTS: The specimens evaluated in this study revealed that a bony retromolar ridge can be large, with adjacent muscles attached several millimeters below its edentulous bone crest, or small, with muscles attached to the buccal and lingual bone crests. In all examined jaws, bony mylohyoid ridges (MR) and buccal shelves with affixed muscle fibers were present regardless of the remaining mandibular bone form and size. CONCLUSIONS: The mylohyoid muscles attached to MRs and the buccinator muscles affixed to buccal bony shelves are some of the barriers to the chronic but limited bone resorption, following tooth loss, time of edentulism, systemic factors, and denture wear.

Orientation of the human sacrum: anthropological perspectives and methodological approaches.

Discovering the nature of sacral orientation is of considerable anthropological importance. Therefore, this study aims at presenting a new anthropologically based definition for sacral anatomical orientation (SAO) angle, establishing standards of SAO for human population; examining the relationship between pelvic incidence (PI) and SAO; and associating SAO with demographic parameters. The study population consisted of 424 adult and 14 sub-adult (13-18 years, for SAO only) pelvises. Sacral orientation was measured using two different definitions: a) SAO is the angle created between the intersection of a line running parallel to the superior surface of the sacrum and a line running between the anterior superior iliac spine (ASIS) and the anterior-superior edge of the symphysis pubis; b) PI is the angle created between the perpendicular to the sacral plate at its midpoint and the line connecting this point to the middle of the axis of the acetabulum. SAO was measured using a specially designed mechanical measurement tool and a 3D digitizer. PI was measured via the 3D digitizer. The methods developed by us for measuring SAO and PI in skeletal material are valid and reliable. SAO and PI measures were highly correlated (r = -0.824, P < 0.001). The average SAO was 49.01 degrees (SD = 10.16), and the average PI 54.08 degrees (SD = 12.64). SAO was independent of ethnicity and sex, yet age dependent. This study establishes a methodology for estimating SAO and PI in skeletal material and furnishes the anthropological milieu with base line data regarding these parameters. Future studies in human evolution can greatly benefit from this study.

Morphologic characteristics of bony edentulous jaws.

PURPOSE: The objective of this study was to examine bone tissue characteristics of edentulous arches and residual ridges in different regions of the human jaws. MATERIALS AND METHODS: For the study, 24 maxillary and 99 mandibular completely edentulous dry specimens were examined macroscopically and by linear and caliper measurements. Width and length of the edentulous arches were registered from the molar regions to the crest of the incisor zone. Residual ridges were quantified at the incisor, premolar, and molar regions. RESULTS: Arches and ridges varied in size and shape. A trabecular bone track was present at the edentulous surface. In the maxillary arch, trabecular tissue was external to the cortical palatal vault, and in the mandible, the trabecular bony stretch was inside the cortical plates along the entire edentulous surface of the jaw. Of the ridges, 38% were thin knife-edged. In the maxilla, bone resorption was centripetal, and the crest of the edentulous arch was external to the osseous base of the cranium. In the mandible, resorption was centrifugal, forming an edentulous crest lingual to the mental protuberance anteriorly and to the mandibular base posteriorly. This discrepancy produced a reverse horizontal overlap of the residual crests, where the edentulous maxilla was at the same level or internal to the facing edentulous mandible. CONCLUSIONS: This study, performed on 123 human edentulous dry bone specimens, indicates that the edentulous arch and the residual ridge take many forms. At the occlusal surface of the edentulous jaw a trabecular track is the remaining scar after tooth extraction. To accommodate an entire metal osseointegrated implant within the residual bone volume, crest reduction and bone grafts may be required as preprosthetic surgical measures. After tooth loss, maxillary resorption was centripetal and apical, whereas mandibular resorption was centrifugal and also apical, resulting in a reversed horizontal relationship in fully edentulous subjects.

Surgical anatomy of the cervical segment of the hypoglossal nerve.

The surgical anatomy of the extracranial segment of the hypoglossal nerve (HN) has been sparsely investigated in the literature. This article studies the course and anatomical and topographic relationships of the HN in 23 formalin fixed cadavers bilaterally dissected under a surgical microscope. The descriptive anatomy is presented with relevant clinical and surgical implications.

Middle ear pathology in ancient and modern populations: incudal osteoma.

CONCLUSIONS: Osteomas of the incus were found in surprisingly high numbers in ancient and modern populations. The coexistence of osteoma formation and unique vascularization on the medial surface of the incus alludes to a relationship between the two findings. OBJECTIVE: Osteomas involving the middle ear ossicles are rare. The aim of this study was to compare the incudal pathology of ancient and recent periods using the recent literature. MATERIAL AND METHODS: Pathologies encountered in 1170 human incudes belonging to different populations from ancient and recent periods were studied. Most of the ossicles were found in the middle ear of dry skulls or during dissection. The observations were done with a binocular microscope and a Nikon Profile Projector. RESULTS: A total of 47 incudes (4.01%) presented with a variety of pathologies, osteomas being found in 19 cases (1.62%). The osteomas were noted only on the medial surface of the incus. Other findings, including prominent erosions, multiple nutrient foramina and pitting, were also found on the medial side of the incus. The incidence of osteoma was found to be more common in ancient populations (1.88%) and most prevalent among Bedouins (4.55%).

Relatively well preserved DNA is present in the crystal aggregates of fossil bones.

DNA from fossil human bones could provide invaluable information about population migrations, genetic relations between different groups and the spread of diseases. The use of ancient DNA from bones to study the genetics of past populations is, however, very often compromised by the altered and degraded state of preservation of the extracted material. The universally observed postmortem degradation, together with the real possibility of contamination with modern human DNA, makes the acquisition of reliable data, from humans in particular, very difficult. We demonstrate that relatively well preserved DNA is occluded within clusters of intergrown bone crystals that are resistant to disaggregation by the strong oxidant NaOCl. We obtained reproducible authentic sequences from both modern and ancient animal bones, including humans, from DNA extracts of crystal aggregates. The treatment with NaOCl also minimizes the possibility of modern DNA contamination. We thus demonstrate the presence of a privileged niche within fossil bone, which contains DNA in a better state of preservation than the DNA present in the total bone. This counterintuitive approach to extracting relatively well preserved DNA from bones significantly improves the chances of obtaining authentic ancient DNA sequences, especially from human bones.