Israel Hershkovitz

Middle pleistocene dental remains from Qesem Cave (Israel)

This study presents a description and comparative analysis of Middle Pleistocene permanent and deciduous teeth from the site of Qesem Cave (Israel). All of the human fossils are assigned to the Acheulo-Yabrudian Cultural Complex (AYCC) of the late Lower Paleolithic. The Middle Pleistocene age of the Qesem teeth (400-200 ka) places them chronologically earlier than the bulk of fossil hominin specimens previously known from southwest Asia. Three permanent mandibular teeth (C(1) -P(4) ) were found in close proximity in the lower part of the stratigraphic sequence. The small metric dimensions of the crowns indicate a considerable degree of dental reduction although the roots are long and robust. In contrast, three isolated permanent maxillary teeth (I(2) , C(1) , and M(3) ) and two isolated deciduous teeth that were found within the upper part of the sequence are much larger and show some plesiomorphous traits similar to those of the Skhul/Qafzeh specimens. Although none of the Qesem teeth shows a suite of Neanderthal characters, a few traits may suggest some affinities with members of the Neanderthal evolutionary lineage. However, the balance of the evidence suggests a closer similarity with the Skhul/Qafzeh dental material, although many of these resemblances likely represent plesiomorphous features.

Why Do We Fail in Aging the Skull From the Sagittal Suture

The controversy over the reliability of ectocranial suture status (open vs. closed) as an age estimation stimulated the pursuit of Meindl and Lovejoys suggestion (Meindl and Lovejoy [1985] Am. J. Phys. Anthropol. 68:57-66) for large scale analysis. The extent of the sagittal suture closure was assessed in 3,636 skulls from the Hamann-Todd and Terry collections. The debate over whether cranial suture ossification represents a pathologic or an age-predictable pathologic process also stimulated a comparison with age and two stress markers, hyperostosis frontalis interna and tuberculosis. Sagittal suture closure was found to be age-independent and sexually biased. The wide confidence intervals (for age) appear to preclude meaningful application of suture status for age determination. No correlation was found with the tested biological stressors.

Man the Fat Hunter: The Demise of Homo erectus and the Emergence of a New Hominin Lineage in the Middle Pleistocene (ca. 400 kyr) Levant

The worldwide association of H. erectus with elephants is well documented and so is the preference of humans for fat as a source of energy. We show that rather than a matter of preference, H. erectus in the Levant was dependent on both elephants and fat for his survival. The disappearance of elephants from the Levant some 400 kyr ago coincides with the appearance of a new and innovative local cultural complex – the Levantine Acheulo-Yabrudian and, as is evident from teeth recently found in the Acheulo-Yabrudian 400-200 kyr site of Qesem Cave, the replacement of H. erectus by a new hominin. We employ a bio-energetic model to present a hypothesis that the disappearance of the elephants, which created a need to hunt an increased number of smaller and faster animals while maintaining an adequate fat content in the diet, was the evolutionary drive behind the emergence of the lighter, more agile, and cognitively capable hominins. Qesem Cave thus provides a rare opportunity to study the mechanisms that underlie the emergence of our post-erectus ancestors, the fat hunters.

Range of Joint Movement in Female Dancers and Nondancers Aged 8 to 16 Years Anatomical and Clinical Implications

Background Little data are available on changes that occur with age in joint range of motion in dancers and nondancers. Hypothesis In dancers, joint range of motion will increase with age, whereas it will decrease in nondancers, independent of the joint studied. Study Design Cross-sectional study; Level of evidence, 3. Methods The study population included 1320 female dancers, aged 8 to 16 years, who participated in different types of dancing classes (classical ballet, modern dance, jazz, etc) and 226 nondancers of similar age. Range of motion was measured for the hip, knee, ankle, foot, and spinal joints. Results The pattern of differences in range of motion with age varied in different joints and types of movement. (1) For combined ankle and foot plantar flexion (pointe), ankle plantar flexion, and hip external rotation, there was no change in range of motion in dancers, whereas range of motion diminished with age in the nondancers. (2) For ankle dorsiflexion, neither group showed any change with age, and range of motion was significantly greater in the nondancer group. (3) For knee flexion, hip flexion, and hip internal rotation, range of motion decreased with age in both groups. (4) For hip abduction, range of motion decreased with age in dancers and remained constant in the nondancers. (5) For hip extension, range of motion increased in both groups. (6) For lower back and hamstrings, range of motion increased among dancers with age and remained constant among nondancers. Conclusion Dancers and teachers should realize that passive joint range of motion is unlikely to improve with age. Therefore, the major goal of a dancing program should focus on exercises that retain the natural flexibility of the dancers’ joints rather than trying to improve them.

First rib metamorphosis : Its possible utility for Human age-at-death estimation

Human first ribs demonstrate predictable, sequential changes in shape, size, and texture with increasing age, and thus, can be used as an indicator of age at death. Metamorphosis of the first ribs head, tubercle, and costal face was documented in a cross-sectional sample of preadult and adult first ribs of known age at death from the Hamann-Todd skeletal collection (Cleveland Museum of Natural History, Cleveland, Ohio). Blind tests of the usefulness of the first rib as an age indicator were conducted, including tabulation of intraobserver and interobserver inaccuracies and biases. First rib age estimates show inaccuracies and biases by decade comparable to those generated by other aging techniques. Indeed, the first rib method is useful as an isolated age indicator. When used in conjunction with other age indicators, the first rib improves the quality of summary age assessments.

Facet tropism and interfacet shape in the thoracolumbar vertebrae: characterization and biomechanical interpretation.

Study Design. Thoracolumbar facet and interfacet linear dimensions were measured and analyzed. Objective. To characterize and analyze the thoracolumbar facet and interfacet size and shape in relation to gender, ethnic group, and age and to detect the extent of normal facet tropism along the thoracolumbar spine. Summary of Background Data. Knowledge on facet tropism and interfacet shape is limited in the literature as most data are based on 2-dimensional measurements, small samples, or isolated vertebrae. Methods. Facet shape as represented by width, length, width/length ratio and interfacet distances was obtained directly from dry vertebrae of 240 adult human spines. The specimen’s osteologic material is part of the Hamann-Todd Osteological Collection housed at the Cleveland Museum of Natural History, Cleveland, OH. A total of 4080 vertebrae (T1–L5) from the vertebral columns of individuals 20 to 80 years of age were measured, using a Microscribe 3-dimensional apparatus (Immersion Co., San Jose, CA). Data were recorded directly on computer software. Statistical analysis included paired t tests and ANOVA. Results. A significant correlation was found between all thoracolumbar facet dimensions and an individual’s height and weight. Facet tropism is a major characteristic of the thoracolumbar spine, the left being longer in the thorax while the right is longer in the lumbar. In general, facet size is age-independent and greater in males compared with females with a significant ethnic component. Facet length is similar for all thoracic vertebrae, whereas it sharply and continuously increases in the lumbar vertebrae. Facet dimension manifests a bipolar distribution along the thoracolumbar vertebrae. Width/length ratio indicates that facets are longer than wider for most verte-brae. The interarticular area manifests a marked inverted trapezoidal shape at T1–T2, a rectangular shape at T3–L3, and an ordinary trapezoidal shape at L4–L5. Conclusions. Facet tropism is a normal characteristic in humans, yet it varies along the thoracolumbar spine.

Paleopathology and the origin of agriculture in the Levant.

This study addresses changes in health which were consequential to the Neolithic transition in the southern Levant, judged on the basis of the study of specific and nonspecific stress indicators, trauma, and degenerative joint disease in 200 Natufian (hunter-gatherer) skeletons (10,500-8300 BC) and 205 Neolithic (agricultural) skeletons (8300-5500 BC) from the southern Levant. The comparison of the health profiles of pre-Neolithic (Natufian) and Neolithic populations reveals a higher prevalence of lesions indicative of infectious diseases among the Neolithic population, and an overall reduction in the prevalence of skull trauma among males. No change over time was observed in the prevalence of degenerative joint disease. These results indicate that in the southern Levant the Neolithic transition did not simply lead to an overall deterioration in health but rather resulted in a complex health profile which was shaped by 1) an increase exposure to disease agents, 2) changes in diet, 3) population aggregation in larger and denser settlements, 4) changes in activity patterns and the division of labor, and possibly 5) a higher resistant immunological system and response capacity to environmental aggressions (mainly infections).

Lumbar facet orientation in spondylolysis: a skeletal study.

Study Design. Orientation of the lumbar articular facets at the L1–L5 level was measured and analyzed. Objective. To characterize the relationship between lumbar facet orientation and isthmic spondylolysis. Summary of Background Data. Whereas many studies have explored the relationship between facet orientation in the transverse plane and various spinal pathologies, there is insufficient data regarding this relationship and isthmic spondylolysis. Methods. A 3-dimensional digitizer was used to measure the transverse orientation of the lumbar facet joints at the L1–L5 level in 115 male individuals with bilateral isthmic spondylolysis (at L5) and 120 age and sex-matched normal control subjects from the Hamann-Todd Human Osteological Collection (Cleveland Museum of Natural History, Cleveland, OH). Statistical analysis included paired t tests and analysis of variance. Results. In both isthmic spondylolysis and control groups, considerable shifts were noticed from sagittally oriented articular facets at L1 to frontally oriented facets at L5. The change in orientation was significantly greater (up to 13° at L4) in the isthmic spondylolysis group (right inferior facets). Three of the 4 articular facets of L5 (right and left inferior and right superior) were significantly more frontally oriented in isthmic spondylolysis compared to the control group. A greater tendency of asymmetry in facet orientation was noticed in the isthmic spondylolysis group. Conclusion. Individuals with more frontally oriented facets in the lower lumbar vertebrae incorporated with facet tropism are at a greater risk for developing isthmic spondylolysis at L5.

Schmorl’s nodes distribution in the human spine and its possible etiology

Although Schmorl’s nodes (SNs) are a common phenomenon in the normal adult population, their prevalence is controversial and etiology still debatable. The objective was to establish the spatial distribution of SNs along the spine in order to reveal its pathophysiology. In this study, we examined 240 human skeleton spines (T4-L5) (from the Hamann–Todd Osteological Collection) for the presence and location of SNs. To determine the exact position of SNs, each vertebral body surface was divided into 13 zones and 3 areas (anterior, middle, posterior). Our results show that SNs appeared more frequently in the T7-L1 region. The total number of SNs found in our sample was 511: 193 (37.7%) were located on the superior surface and 318 (62.3%) on the inferior surface of the vertebral body. SNs were more commonly found in the middle part of the vertebral body (63.7%). No association was found between the SNs location along the spine and gender, ethnicity and age. This study suggests that the frequency distribution of SNs varies with vertebra location and surface. The results do not lend support to the traumatic or disease explanation of the phenomenon. SNs occurrences are probably associated with the vertebra development process during early life, the nucleus pulposus pressing the weakest part of the end plate in addition to the various strains on the vertebrae and the intervertebral disc along the spine during spinal movements (especially torsional movements).

Ligamentum Flavum Thickness in Normal and Stenotic Lumbar Spines

Study Design. A descriptive computed tomography (CT) study of the ligamentum flavum (LF) thickness in individuals with normal and stenotic lumbar spines. Objective. To establish standards for normal and pathologic range of LF thickness and its asymmetry as indicated in CT images and to examine its association with vertebral body size, age, and gender. Summary of Background Data. LF lines a considerable part of the posterior and lateral walls of the spinal canal and is a major role contributor to spinal canal stenosis. Due to methodologic deficiencies (e.g., small sample size, lack of control for vertebral body size, gender, and age), the normal range of LF thickness is still controversial. Furthermore, data on important aspect of LF thickness such as left-right differences are missing. Methods. Two groups of individuals were studied. The first group included 65 individuals with lumbar spinal stenosis (LSS) (mean age: 66 ± 9.7 years) and the second, 150 individuals (mean age: 52 ± 19 years) without LSS-related symptoms. LF thickness was measured on CT images (Philips Brilliance 64), obtained from axial plane scan at the intervertebral disc level. Measurements were performed at the levels of L3–L4, L4–L5, and L5–S1. Analysis of variance and t test were carried out to evaluate the association between LF thickness and demographic factors. Results. Absolute and relative LF thickness were significantly greater in the LSS group at the levels of L3–L4 and L4–L5 on both sides, compared to control group (P < 0.05). LF thickness was independent of gender (absolute and relative thickness). Even though LF thickness at all levels significantly increases with age, significant changes after the age of 60 occurred only at L3–L4. Significant asymmetry in LF thickness was found at L3–L4 (2.9 ± 0.90 mm on the right vs. 2.76 ± 0.90 mm on the left) and L5–S1 (3.42 ± 1.1 mm on the right vs. 3.22 ± 1.22 mm on the left) (P < 0.05). Conclusion. LF thickness is an age-dependent and gender-independent phenomenon. LF is significantly thicker on the right side. The borderline between normal and pathologic LF thickness should not be set at 4 mm.