The postcranial dimensions of the La Chapelle-aux-saints 1 Neandertal

The La Chapelle-aux-Saints 1 Neandertal has figured prominently in considerations of Neandertal body size and proportions. In this context, a reassessment of its major long bones and a reassembly of its principal pelvic elements (sacrum and right ilium) was undertaken. There are secure measurements for its humeral and radial lengths and its femoral head diameter, but the femoral and tibial lengths were almost certainly greater than previous values. The resultant humeral, femoral and tibial lengths are similar to those of other male Neandertals, its femoral head diameter is among the largest known for Middle and Late Pleistocene humans, but its radial length is relatively short. The pelvic assembly provides modest bi-iliac and inlet transverse diameters compared with the few sufficiently complete and undistorted Middle and Late Pleistocene archaic human pelves, but its dimensions are similar to those of large male early modern humans.     

The anomalous archaic Homo femur from Berg Aukas, Namibia: a biomechanical assessment.

The probably Middle Pleistocene human femur from Berg Aukas, Namibia, when oriented anatomically and analyzed biomechanically, presents an unusual combination of morphological features compared to other Pleistocene Homo femora. Its midshaft diaphyseal shape is similar to most other archaic Homo, but its subtrochanteric shape aligns it most closely with earlier equatorial Homo femora. It has an unusually low neck shaft angle. Its relative femoral head size is matched only by Neandertals with stocky hyperarctic body proportions. Its diaphyseal robusticity is modest for a Neandertal, but reasonable compared to equatorial archaic Homo femora. Its gluteal tuberosity is relatively small. Given its derivation from a warm climatic region, it is best interpreted as having had relatively linear body proportions (affecting proximal diaphyseal proportions, shaft robusticity, and gluteal tuberosity size) combined with an elevated level of lower limb loading during development (affecting femoral head size and neck shaft angle).     

Brief Communication: Calculating hominin and nonhuman anthropoid femoral head diameter from acetabular size

Femoral head size provides important information on body size in extinct species. Although it is well‐known that femoral head size is correlated with acetabular size, the precision with which femoral head size can be estimated from acetabular size has not been quantified. The availability of accurate 3D surface models of fossil acetabular remains opens the possibility of obtaining accurate estimates of femoral head size from even fragmentary fossil remains [Hammond et al.,: Am J Phys Anthropol 150 (2013) 565–578]. Here we evaluate the relationship between spheres fit to surface models of the femoral head and acetabulum of a large sample of extant anthropoid primates. Sphere diameters are tightly correlated and scale isometrically. In spite of significant taxonomic and possibly functional differences in the relationship between femoral head size and acetabulum size, percent prediction errors of estimated femoral head size remain low regardless of the taxonomic composition of the reference sample. We provide estimates of femoral head size for a series of fossil hominins and monkeys. Am J Phys Anthropol 155:469–475, 2014. © 2014 Wiley Periodicals, Inc.     

Neandertal postcranial remains from the Sima de las Palomas del Cabezo Gordo, Murcia, southeastern Spain

The Sima de las Palomas, southeastern Spain, has yielded a series of Neandertal postcranial remains, including immature and mature isolated elements and the fragmentary partial skeleton of a young adult (Palomas 92). The remains largely conform to the general late archaic/Neandertal morphological pattern in terms of humeral diaphyseal shape, pectoralis major tuberosity size and pillar thickness, ulnar coronoid process height, manual middle phalangeal epiphyseal breadth, manual distal phalangeal tuberosity shape and breadth, femoral diaphyseal shape, and probably body proportions. Palomas 92 contrasts with the Neandertals in having variably gracile hand remains, a more sellar trapezial metacarpal 1 facet, more anteroposteriorly expanded mid-proximal femoral diaphysis, and less robust pedal proximal phalanges. The Palomas Neandertals contrast with more northern European Neandertals particularly in various reflections of overall body size.     

Body mass and stature estimation based on the first metatarsal in humans

Archaeological assemblages often lack the complete long bones needed to estimate stature and body mass. The most accurate estimates of body mass and stature are produced using femoral head diameter and femur length. Foot bones including the first metatarsal preserve relatively well in a range of archaeological contexts. In this article we present regression equations using the first metatarsal to estimate femoral head diameter, femoral length, and body mass in a diverse human sample. The skeletal sample comprised 87 individuals (Andamanese, Australasians, Africans, Native Americans, and British). Results show that all first metatarsal measurements correlate moderately to highly (r = 0.62-0.91) with femoral head diameter and length. The proximal articular dorsoplantar diameter is the best single measurement to predict both femoral dimensions. Percent standard errors of the estimate are below 5%. Equations using two metatarsal measurements show a small increase in accuracy. Direct estimations of body mass (calculated from measured femoral head diameter using previously published equations) have an error of just over 7%. No direct stature estimation equations were derived due to the varied linear body proportions represented in the sample. The equations were tested on a sample of 35 individuals from Christ Church Spitalfields. Percentage differences in estimated and measured femoral head diameter and length were less than 1%. This study demonstrates that it is feasible to use the first metatarsal in the estimation of body mass and stature. The equations presented here are particularly useful for assemblages where the long bones are either missing or fragmented, and enable estimation of these fundamental population parameters in poorly preserved assemblages.     

Epipaleolithic human appendicular remains from Ein Gev I,Israel

The Upper Paleolithic (Early Epipaleolithic/Kebaran; ∼ 19,000 cal BP) human skeleton, from Layer 3 of Ein Gev I on the western flanks of the Golan Heights adjacent to the Sea of Galilee, retains sufficient limb remains to permit assessment of its body size and proportions, as well as diaphyseal reflections of skeletal hypertrophy. The individual was of modest stature but average mass for a later Upper Paleolithic individual, providing it with the body mass-to-stature body proportions characteristic of later Upper Paleolithic and more recent circum-Mediterranean humans. The humeri exhibit unexceptional diaphyseal asymmetry and robustness for an Upper Paleolithic human, and the femur exhibits similar relative diaphyseal hypertrophy. The humeral midshafts are relatively round, but the femoral and tibial midshafts are pronounced anteroposteriorly. As such, Ein Gev 1 provides additional paleobiological data on the appendicular remains of these Southwest Asian humans prior to the increasing sedentism of the terminal Pleistocene.     

Neandertal knees: power lifters in the Pleistocene?

It has been proposed (Trinkaus, 1983 a; Miller & Gross, 1998) that the marked thickness of Neandertal patellae and/or the posterior displacement of their tibial condyles increased their relative M. quadriceps femoris moment arms, thereby making their legs powerful in extension. However, it is necessary to compare these reflections of muscle moment arm length to appropriate measures of the body weight moment arm and body mass estimates, both of which are influenced by ecogeographically determined body proportions. Reassessment of tibial condylar displacement and patellar thickness, as well as patellar height, relative to an appropriate measure of the moment arm for the baseline load on the knee (body weight), to that moment arm times estimated body mass, and to that moment arm times a skeletal reflection of body mass (femoral head diameter) rejects the hypothesis that the Neandertals had exceptionally powerful knee extension. Relative tibial condylar displacement remains above that of a modern industrial society sample, but similar to that of the Broken Hill tibia, Late Pleistocene early modern humans and a recent human nonindustrial sample. Relative patellar thickness is similar to that of early modern humans, who have relatively thick patellae compared to the late Holocene human samples. Consequently, once body proportions are taken into account, there is little difference between the Neandertals and other later Pleistocene humans in knee extensor mechanical advantage, and all of these fossil hominids are similar in the more important proximal tibial proportions to those of nonindustrial recent humans.     

Precision and accuracy of acetabular size measures in fragmentary hominin pelves obtained using sphere‐fitting techniques

Hip joint diameter is highly correlated with body size in primates and so can potentially provide important information about the biology of fossil hominins. However, quantifying hip joint size has been difficult or impossible for many important but fragmentary specimens. New three‐dimensional technologies can be used to digitally fit spheres to the acetabular lunate surface, potentially allowing hip joint diameter estimates for incomplete joint surfaces. Here we evaluate the reliability of sphere‐fitting to incomplete lunate surfaces in silico using three‐dimensional polygonal models of extant anthropoid hipbones. Measurement error in lunate sphere‐fitting was assessed at the individual observer level, as well as between observers. Prediction error was also established for acetabular sphere size estimates for smaller divisions of the lunate surface. Sphere‐fitting techniques were then applied to undistorted regions of lunate surface in Plio‐Pleistocene hominin pelves, with a range of diameters constructed from extant error estimates. The results of this study indicate that digital sphere‐fitting techniques are precise and that the lunate does not need to be completely preserved to accurately infer hip dimensions, although some aspects of joint size and morphology can influence sphere size estimates. Joint diameter is strongly predicted by spheres fit to the cranial and caudal halves of the lunate in all anthropoids. We present new hip joint size estimates for a number of fossil hominins, and outline additional applications for digital sphere‐fitting as a morphometric technique. Am J Phys Anthropol 150:565–578, 2013. © 2013 Wiley Periodicals, Inc.     

The effects of femoral head size on the deformation of ultrahigh molecular weight polyethylene acetabular cups

Late loosening of cemented acetabular cups is increasingly being recognized as a clinical problem. One of the factors which may contribute to loosening is high localized deformation and stress at the cement-bone interface, the magnitude of which depends on the size of the total hip replacement (THR) femoral head. The effects of varying the femoral head size, from 22 to 32 mm, on strain values measured on the surface of the cup were investigated using experimental stress analysis techniques. The largest absolute strains were recorded when loading with the 22 mm head size. Peak strain values decreased to a minimum with the 26 mm head size and increased steadily with head sizes beyond 26 mm. The selection of an acetabular cup size and corresponding femoral head size in a total hip arthroplasty should not be an arbitrary one, but should be based on scientific studies which indicate minimum states of stress within the cup and cement mantle, as well as clinical evidence that the combination of components shows a reduced incidence of failure. This study experimentally quantifies the states of stress on the surface of the acetabular cup and points to the possible existence of an optimum component size to minimize surface stress.     

Problematic sites of third body embedment in polyethylene for total hip wear acceleration

A computational model was developed to identify the sites of third body particle embedment in a total hip acetabular component surface that are most problematic in terms of roughening the overpassing regions of the femoral head counterface, leading in turn to most severely accelerated polyethylene wear. The analytical approach used was to calculate loci of acetabular sites that, during the gait cycle, overpass previously documented regions of kinetically most critical femoral head roughening. Instantaneous local contact stress and sliding distance were postulated as factors contributing to the severity of the femoral head scratching/roughening which would be expected, due to otherwise-similar particles embedded along each such acetabular overpass locus. The computational results showed that the location of debris embedment was a potent determinant of the amount of polyethylene wear acceleration expected. The data also showed that the supero-lateral aspect of the acetabular cup is consistently and by far the most problematic area for third body particle embedment.     

More than one way to be a giant: Convergence and disparity in the hip joints of saurischian dinosaurs

Saurischian dinosaurs evolved seven orders of magnitude in body mass, as well as a wide diversity of hip joint morphology and locomotor postures. The very largest saurischians possess incongruent bony hip joints, suggesting that large volumes of soft tissues mediated hip articulation. To understand the evolutionary trends and functional relationships between body size and hip anatomy of saurischians, we tested the relationships among discrete and continuous morphological characters using phylogenetically corrected regression. Giant theropods and sauropods convergently evolved highly cartilaginous hip joints by reducing supraacetabular ossifications, a condition unlike that in early dinosauromorphs. However, transitions in femoral and acetabular soft tissues indicate that large sauropods and theropods built their hip joints in fundamentally different ways. In sauropods, the femoral head possesses irregularly rugose subchondral surfaces for thick hyaline cartilage. Hip articulation was achieved primarily using the highly cartilaginous femoral head and the supraacetabular labrum on the acetabular ceiling. In contrast, theropods covered their femoral head and neck with thinner hyaline cartilage and maintained extensive articulation between the fibrocartilaginous femoral neck and the antitrochanter. These findings suggest that the hip joints of giant sauropods were built to sustain large compressive loads, whereas those of giant theropods experienced compression and shear forces.     

Patterns of humeral asymmetry among Late Pleistocene humans

Human humeral diaphyseal asymmetry in midshaft and mid-distal rigidity is assessed through the Late Pleistocene in samples of late archaic (Neandertal) and early modern humans. It is considered with respect to directionality (handedness), levels of asymmetry, body size and sexual differences. The overall Late Pleistocene sample indicates a right-handed preference in frequencies (right: 74.8%, left: 15.0%, ambiguous: 10.3%), which are similar to those of recent human samples. Average levels of humeral asymmetry are elevated relative to Holocene samples through all but the small Middle Paleolithic modern human and eastern Eurasian late Upper Paleolithic samples. Humeral asymmetry is especially high among the males relative to the females, and the possibility of a division of labor between uni-manual tasks (mostly male) and bi-manual tasks (mostly female) is considered. At the same time, there is a general pattern of increased asymmetry with larger body size, but it remains unclear to what extent it reflects body size versus sexual effects on bilateral humeral loading. There do not appear to have been substantial changes in humeral asymmetry through time, indicating a continuity of similar manual behavioral patterns through the Late Pleistocene, despite considerable changes in technology through the Late Pleistocene.     

Body size estimation of small‐bodied humans: Applicability of current methods

Body size (stature and mass) estimates are integral to understanding the lifeways of past populations.Body size estimation of an archaeological skeletal sample can be problematic when the body size or proportions of the population are distinctive. One such population is that of the Holocene Later Stone Age (LSA) of southern Africa, in which small stature (mean femoral length = 407 mm, n = 52) and narrow pelves (mean bi‐iliac breadth = 210 mm, n = 50) produce a distinctive adult body size/shape, making it difficult to identify appropriate body size estimation methods. Material culture, morphology, and culture history link the Later Stone Age people with the descendant population collectively known as the Khoe‐San. Stature estimates based on skeletal “anatomical” linear measures (the Fully method) and on long bone length are compared, along with body mass estimates derived from “morphometric” (bi‐iliac breath/stature) and “biomechanical” (femoral head diameter) methods, in a LSA adult skeletal sample (n = 52) from the from coastal and near‐coastal regions of South Africa. Indices of sexual dimorphism (ISD) for each method are compared with data from living populations. Fully anatomical stature is most congruent with Olivier's femur + tibia method, although both produce low ISD. McHenry's femoral head body mass formula produces estimates most consistent with the bi‐iliac breadth/staturemethod for the females, although the males display higher degrees of disagreement among methods. These results highlight the need for formulae derived from reference samples from a wider range of body sizes to improve the reliability of existing methods. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Hand to mouth in a neandertal: right-handedness in regourdou 1

We describe and analyze a Neandertal postcranial skeleton and dentition, which together show unambiguous signs of right-handedness. Asymmetries between the left and right upper arm in Regourdou 1 were identified nearly 20 years ago, then confirmed by more detailed analyses of the inner bone structure for the clavicle, humerus, radius and ulna. The total pattern of all bones in the shoulder and arm reveals that Regourdou 1 was a right-hander. Confirmatory evidence comes from the mandibular incisors, which display a distinct pattern of right oblique scratches, typical of right-handed manipulations performed at the front of the mouth. Regourdou's right handedness is consistent with the strong pattern of manual lateralization in Neandertals and further confirms a modern pattern of left brain dominance, presumably signally linguistic competence. These observations along with cultural, genetic and morphological evidence indicate language competence in Neandertals and their European precursors.     

Articular and diaphyseal remodeling of the proximal femur with changes in body mass in adults.

Proximal femoral dimensions were measured from radiographs of 80 living subjects whose current body weight and body weight at initial skeletal maturity (18 years) could be ascertained. Results generally support the hypothesis that articular size does not change in response to changes in mechanical loading (body weight) in adults, while diaphyseal cross-sectional size does. This can be explained by considering the different bone remodeling constraints characteristic of largely trabecular bone regions (articulations) and largely compact cortical bone regions (diaphyses). The femoral neck shows a pattern apparently intermediate between the two, consistent with its structure. When the additional statistical "noise" created by an essentially static femoral head size is accounted for, the present study supports other studies that have demonstrated rather marked positive allometry in femoral articular and shaft cross-sectional dimensions to body mass among adult humans. Body weight prediction equations developed from these data give reasonable results for modern U.S. samples, with average percent prediction errors of about 10%-16% for individual weights and about 2% for sample mean weights using the shaft dimension equations. When predicting body weight from femoral head size in earlier human samples, a downward correction factor of about 10% is suggested to account for the increased adiposity of very recent U.S. adults.     

Ontogenetic adaptation to bipedalism: age changes in femoral to humeral length and strength proportions in humans, with a comparison to baboons

The increase in lower/upper limb bone length and strength proportions in adult humans compared to most other anthropoid primates is commonly viewed as an adaptation to bipedalism. The ontogenetic development of femoral to humeral proportions is examined here using a longitudinal sample of 20 individuals measured radiographically at semiannual or annual intervals from 6 months of age to late adolescence (a subset of the Denver Growth Study sample). Anthropometric data (body weights, muscle breadths) were also available at each examination age. Results show that while femoral/humeral length proportions close to those of adults are already present in human infants, characteristically human femoral/humeral diaphyseal strength proportions only develop after the adoption of bipedalism at about 1 year of age. A rapid increase in femoral/humeral strength occurs between 1 and 3 years, followed by a slow increase until mid-late adolescence, when adult proportions are reached. When age changes in material properties are factored in, femoral strength shows an almost constant relationship to body size (body mass.bone length) after 5 years of age, while humeral strength shows a progressive decline relative to body size. Femoral/humeral length proportions increase slightly throughout growth, with no apparent change in growth trajectory at the initiation of walking, and with a small decline in late adolescence due to later growth in length of the humerus. A sex difference in femoral/humeral strength proportions (females greater) but not length proportions, develops early in childhood. Thus, growth trajectories in length and strength proportions are largely independent, with strength proportions more responsive to actual changes in mechanical loading. A cross-sectional ontogenetic sample of baboons (n=30) illustrates contrasting patterns of growth, with much smaller age changes in proportions, particularly strength proportions, although there is some indication of an adaptation to altered limb loadings early in baboon development.     

Allometry of head and body size in Holocene foragers of the South African Cape

Opportunities to assess morphological allometry in small-bodied human populations are rare. The foragers of the Later Stone Age of the South African Cape are characteristically small-bodied. Previous studies have shown that during the period of ca. 3500 to 2000 years BP (uncalibrated (14) C dates), the regional population shows transient reduced stature, body mass, and cranial size, a pattern that has been tentatively tied to demographic pressure on resources. This study examines the relationships among cranial size (centroid size) and body size (femoral length, femoral head diameter, and bi-iliac breadth) during the second half of the Holocene (N = 62). Reduced major axis regression indicates negative allometry of cranial centroid size with body size. Residuals (from ordinary least squares regression of cranial centroid size on body size) are regressed on radiocarbon date to examine temporal changes in the relationship between cranial and body size. Cranial and pelvic sizes are most conserved through time, while more ancient skeletons possess shorter femora and smaller femoral heads. The relationship between cranial centroid size and femoral length shows larger and more variable residuals at more recent dates, indicating a greater or more variable disassociation between cranial size and stature relative to more ancient skeletons. A similar, but nonsignificant relationship exists between cranial size and bi-iliac breadth. These results provide insights into the use of aspects of body size and proportionality in the assessment of health in past populations.     

A 42-year-old patient presenting with femoral head migration after hemiarthroplasty performed 22 years earlier: a case report

Introduction

Treatment of femoral neck fractures in young adults may require total hip arthroplasty or hip hemiarthroplasty using a bipolar cup. The latter can, however, result in migration of the femoral head and poor long-term results.

Case presentation

We report a case of femoral head migration after hemiarthroplasty performed for femoral neck fracture that had occurred 22 years earlier, when the patient (a Japanese man) was 20 years old. He experienced peri-prosthetic fracture of the femur, subsequent migration of the prosthesis, and a massive bone defect of the pelvic side acetabular roof. After bone union of the femoral shaft fracture, the patient was referred to our hospital for reconstruction of the acetabular roof. Intra-operatively, we placed two alloimplants of bone from around the transplanted femoral head into the weight-bearing region of the acetabular roof using an impaction bone graft method. We then implanted an acetabular roof reinforcement plate and a cemented polyethylene cup in the position of the original acetabular cup. Eighteen months post-operatively, X-rays showed union of the transplanted bone.

Conclusions

Treatment of femoral neck fractures in young adults is usually accomplished by osteosynthesis, but it may be complicated by femoral head avascular necrosis or by infection or osteomyelitis. In such cases, once an infection has subsided, either hip hemiarthroplasty using a bipolar cup or total hip arthroplasty may be required. However, if the acetabular side articular cartilage is damaged, a bipolar cup should not be used. Total hip arthroplasty should be performed to prevent migration of the implant.