Lumbar Column Research Articles

Age Estimation of Lumbar Vertebrae by Visual Assessment in a Thai Population.

The age estimation of bone is essential for identification of the unknown-identity persons in both forensic and anthropological sciences. The lumbar vertebrae carry the most weight; hence, they have more biomechanical stress than any other vertebrae. As a result, the degenerative changes commonly occur in them. However, the estimation from visual assessment in lumbar vertebrae has not been reported in a Thai population. To evaluate the age estimation from the degree of osteophyte formation, the macroporosity, and the cortical surface to develop equations of lumbar vertebrae. A total of 250 lumbar columns (125 males and 125 females) in age range of 22 to 89 years were collected from the Forensic Osteology Research Center (FORC), Faculty of Medicine, Chiang Mai University. The most appropriate linear regression equation was used to estimate age by the inferior surface of L1 vertebra (R2= 0.408) with the standard error of 11.686 years. It was clear to recognize that three morphological aspects will be useful methods for forensic situations.

Role of disc area and trabecular bone density on lumbar spinal column fracture risk curves under vertical impact

While studies have been conducted using human cadaver lumbar spines to understand injury biomechanics in terms of stability/energy to fracture, and physiological responses under pure-moment/follower loads, data are sparse for inferior-to-superior impacts. Injuries occur under this mode from underbody blasts. Objectives: determine role of age, disc area, and trabecular bone density on tolerances/risk curves under vertical loading from a controlled group of specimens. T12-S1 columns were obtained, pretest X-rays and CTs taken, load cells attached to both ends, impacts applied at S1-end using custom vertical accelerator device, and posttest X-ray, CT, and dissections done. BMD of L2-L4 vertebrae were obtained from QCT. Survival analysis-based Human Injury Probability Curves (HIPCs) were derived using proximal and distal forces. Age, area, and BMD were covariates. Forces were considered uncensored, representing the load carrying capacity. The Akaike Information Criterion was used to determine optimal distributions. The mean forces, ±95% confidence intervals, and Normalized Confidence Interval Size (NCIS) were computed. The Lognormal distribution was the optimal function for both forces. Age, area, and BMD were not significant (p > 0.05) covariates for distal forces, while only BMD was significant for proximal forces. The NCIS was the lowest for force-BMD covariate HIPC. The HIPCs for both genders at 35 and 45 years were based on population BMDs. These HIPCs serve as human tolerance criteria for automotive, military, and other applications. In this controlled group of samples, BMD is a better predictor-covariate that characterizes lumbar column injury under inferior-to-superior impacts.

Comparison of Intervertebral Disc Injuries Caused By Different Diode Laser Wavelengths

Background: Laser discectomy or laser nucleotomy comprises an increasingly important place in less invasive spinal procedures, but the ideal laser is still a subject of study. This research was aimed to compare the action of diode laser at different wavelengths, as well as the volume of the vaporization lesion caused by the different wavelengths in the percutaneous decompression procedures of the intervertebral disc (nucleotomy). Methods: Six pigs' lumbar columns had their intervertebral discs (region L1 to L5) underwent punctureinduced injury. The columns were then subjected to the nuclear magnetic resonance (MR) for pre-irradiation analysis. Later, the discs were irradiated with a laser at the wavelengths of 808 nm (G808), 980 nm (G980), 1470 nm (G1470) and 1908 nm (G1908), or not irradiated (Control group). The columns were then destined for MR and then immersed in 10% buffered formalin for histological analysis. After being decalcified the intervertebral discs were dissected and processed for paraffin embedding. Transverse sections of the disks were stained with hematoxylin and eosin for histomorphometry and carbonized and bubble areas were measured. Results: The lesions were equivalent within each group and there was no difference between the groups in the pre-irradiation. In the post-irradiation evaluation, the MR showed that the volume of the intervertebral disc lesion was smaller in the G1470 and G1908 groups compared to the other groups. The G808 and G980 groups showed a higher thickness of carbonized area compared to groups G1470 and G1908. In addition, G980 presented higher thickness bubble area compared to the other groups. These lesions were more pronounced and more localized in the G808 and G980 groups, compared the 1470 nm and 1908 nm lasers, which caused broader but less intense lesions. Conclusion: The intervertebral disc lesions caused by the 808 nm and 980 nm laser are more intense but more focal, compared to the 1470 nm and 1908 nm laser.

Biomechanical comparison between concentrated, follower, and muscular loads of the lumbar column

Experimental and numerical methods have been extensively used to simulate the lumbar kinematics and mechanics. One of the basic parameters is the lumbar loads. In the literature, both concentrated and distributed loads have been assumed to simulate the in vivo lumbar loads. However, the inconsistent loads between those studies exist and make the comparison of their results controversial. Using finite-element method, this study aimed to numerically compare the effects of the concentrated, follower, and muscular loads on the lumbar biomechanics during flexion. Two conditions of equivalent and simple constraints were simulated. The equivalent condition assumes the identical flexion at the L1 level and loads at the L5 level for the three types of loads. Another condition is to remove such kinematic and mechanical constraints on the lumbar. The comparison indices were flexed profile, distributed stress, and transferred loads of the discs and vertebrae at the different levels. The results showed that the three modes in the equivalent condition show the nearly same flexed profiles. In the simple condition, however, the L1 vertebra of the concentrated mode anteriorly translates about 3 and 5 times that of the follower and muscular mode, respectively. By contrast, the flexion profiles of the follower and muscular are comparable. In the equivalent condition, all modes consistently show the gradually increasing stress and loads toward the caudal levels. The results of both concentrated and muscular modes exhibit the quite comparable trends and even magnitudes. In the simple condition, however, the removal of flexion and load constraints makes the results of the concentrated mode significantly different from its counterparts. In both conditions, the predictedindices of the follower mode are more uniform along the lumbar. In conclusion, the kinematic and mechanical constraints significantly affect the profile, stress, and loads of the three modes. In the equivalent condition, the concentrated mode can simulate the similar results to the muscular mode and top-loading fashion seems to be more practicable for experimental setup. In the simple condition, the follower mode can serve as the alternative to avoid the unreasonably higher flexion at the L1 level and shear at the L5 level. In the future, the detailed studies about the load-related effects on both load-transferring mechanism and failure mode of the lumbar-implant construct should be conducted.

Vertebral numbers and human evolution.

Ever since Tyson (1699), anatomists have noted and compared differences in the regional numbers of vertebrae among humans and other hominoids. Subsequent workers interpreted these differences in phylogenetic, functional, and behavioral frameworks and speculated on the history of vertebral numbers during human evolution. Even in a modern phylogenetic framework and with greatly expanded sample sizes of hominoid species, researchers' conclusions vary drastically, positing that hominins evolved from either a "long-backed" (numerically long lumbar column) or a "short-backed" (numerically short lumbar column) ancestor. We show that these disparate interpretations are due in part to the use of different criteria for what defines a lumbar vertebra, but argue that, regardless of which lumbar definition is used, hominins are similar to their great ape relatives in possessing a short trunk, a rare occurrence in mammals and one that defines the clade Hominoidea. Furthermore, we address the recent claim that the early hominin thoracolumbar configuration is not distinct from that of modern humans and conclude that early hominins show evidence of "cranial shifting," which might explain the anomalous morphology of several early hominin fossils. Finally, we evaluate the competing hypotheses on numbers of vertebrae and argue that the current data support a hominin ancestor with an African ape-like short trunk and lower back.

Papular Cutaneous Amyloidosis Associated with Multiple Myeloma

We report a case of papular cutaneous amyloidosis associated with multiple myeloma in a 52 years old man who presented papular xanthoma like lesions in periorbital areas and scrotum with severe bone pain in thoracic and lumbar spinal column and lower limbs. Cutaneous histopathology revealed the presence of amorphous deposits in papillary dermis surrounded with small lymphoid infiltrates with erythrocyte containing slots. Congo red staining was positive and bone marrow aspiration showed dysplastic plasma cells. Lytic lesions were observed in long bones and skull radiography. 24 hours Proteinuria was 3.69 g / l. A combination of Melphalan and prednisone as treatment could restore renal function without any change in skin lesions after 14 months.

Polymorphisms in CYP17, COMT, and ESR1 genes in women after menopause and association with bone mineral density.

In this study, we evaluated genetic factors related to the mineral density during post-menopause. We evaluated 110 women in the first 5 years post-menopause, without previous hormone replacement therapy. Cytochrome P450 17 (CYP17) (rs743572), catechol-O-methyl transferase (COMT) (rs4680), and estrogen receptor 1 (ESR1) (rs9322331) were examined for the presence of polymorphisms. Clinical data were collected by anamnesis; all patients had the osseous densitometry examined using a lunar instrument to determine mineral osseous densitometry in the lumbar column (L2-L4). CYP17, COMT, and ESR1 genotyping was carried out by polymerase chain reaction with DNA collected from buccal swabs. The average age was 51.96 years. The average weights of the patients in control and osteopenia groups were 70.25 ± 12.00 and 62.45 ± 11.64, respectively (P = 0.001) and body mass index (P = 0.006; control: 29.43 ± 5.25; osteopenia: 26.72 ± 4.57). Related to CYP17 polymorphisms, 28.18% of women were TT (wild-type homozygous), 60% were TC (heterozygous), and 11.82% were CC (mutated homozygous). Related to COMT polymorphisms, 53.64% of women were GG (wild-type homozygous), 37.27% were GA (heterozygous), and 9.09% were AA (mutated homozygous). Related to ESR1, 53.64% of women were CC (wild-type homozygous), 40.91% were CT (heterozygous), and 5.45% were TT (mutated homozygous). The ESR1 variant allele was significantly higher in the osteopenia group when compared with women in the normal group (P = 0.02). ESR1 may be associated with low mineral osseous densitometry, while CYP17 and COMT gene polymorphisms were not associated with mineral osseous densitometry.

Validation of marrow fat assessment using noninvasive imaging with histologic examination of human bone samples

PurposeThe marrow composition throughout the body is heterogeneous and changes with age. Due to heterogeneity, invasive biopsies of the iliac crest do not truly represent the complete physiological status, impeding the clinical effectiveness of this method. Therefore, we aim to provide verification for an in vivo imaging technique using co-registered histologic examinations for assessment of marrow adiposity. MethodsFive recently expired (i.e. <24h) human cadavers were scanned with a dual source CT (DECT) scanner in order to measure marrow fat in the lumbar vertebrae. These donors were also imaged using water–fat MRI (wfMRI) which was used to estimate the fraction of yellow marrow. After imaging, lumbar columns were excised and the superior and inferior aspects of 21 vertebrae were removed. The remaining center section was processed for histological examination to find the ratio of adipocyte volume per tissue volume (AV/TV). ResultsResults of DECT and wfMRI had a high correlation (r=0.88). AV/TV ranged from 0.18 to 0.75 with a mean (SD) of 0.36 (0.18). Inter-evaluator reliability for AV/TV was r>0.984. There were similar correlations between AV/TV and the imaging modalities, DECT-derived MF and wfMRI (r=0.802 and 0.772, respectively). ConclusionsA high MF variation was seen among the 25 vertebrae imaged. Both DECT and wfMRI have a good correlation with the histologic adipocyte proportion and can be used to measure MF. This makes longitudinal studies possible without painful, less-effective, invasive biopsies.

Bone mineral density improvement after 48 weeks of switch to maraviroc+darunavir/ritonavir 300/800/100 mg QD, preliminary results of GUSTA study.

IntroductionLow bone mineral density (BMD) and osteoporosis are prevalent in HIV-infected patients and were associated with HIV infection and tenofovir-containing ART.Materials and MethodsThe GUSTA study (GUided Simplification with Tropism Assay) is a two-arm, prospective, multicenter, 1:1 randomized controlled trial designed to demonstrate the non-inferiority of therapeutic switch to maraviroc+darunavir/ritonavir (MVC+DRV/r) 300/800/100 mg QD against the continuation of previous triple cART in patients with stable virological suppression. Enrolment criteria include HIV1-RNA <50 copies/mL for >6 months, R5 tropism and CD4>200 cells/µL for >3 months. Dual energy X-ray absorptiometry scans of proximal femur and lumbar spine were performed at baseline and week 48. Bone composition was evaluated using L2-L4 lumbar column and proximal femoral BMD, T-score and the Z-score. At the same timepoints, plasma bone metabolism biomarkers were measured. Linear regression was used to compare means of differences between arms. The association between BMD changes and the baseline variables was assessed by linear regression.Results27 patients were included, 13 from study group and 14 from control group, 74.1% were males, 44.4% heterosexuals, 81.5% Caucasian, median age was 47 years (IQR 41–53), time from HIV diagnosis 13.4 years (9–19), CD4 553/µL (406–739), nadir CD4 201/µL (76–283). At baseline, median ART duration was 10.5 years (5.7–15.3), the majority of patients (70.4%) was on tenofovir, 63% was on a PI-based regimen and 14,8% on an NNRTI-based regimen. Mean proximal femur BMD from baseline increased over 48 weeks by 2.06% (SD 2.24) in the study arm and decreased by −2.77% (SD 4.63) in control arm (p=0.003). The change over 48 weeks in proximal femur T-score was significantly different between the study (+0.11, SD 0.22) and control arm (−1.14, SD 0.27, p=0.016). Also the changes in total alkalin phosphatase (−20 U/L vs −1.5, p=0.003) was significant between the two groups. After adjusting for time from HIV diagnosis and years of ART, study group was the only factor associated to higher mean percentage change from baseline femoral BMD (MVC+DRV/r +4.83, p=0.044).ConclusionsThe study demonstrated a significant improvement in femoral BMD and T-score after treatment simplification with MVC+DRV/r.

Rate-dependent fracture characteristics of lumbar vertebral bodies

Experimental testing incorporating lumbar columns and isolated components is essential to advance the understanding of injury tolerance and for the development of safety enhancements. This study incorporated a whole column axial acceleration model and an isolated vertebral body model to quantify compression rates during realistic loading and compressive tolerance of vertebrae. Eight lumbar columns and 53 vertebral bodies from 23 PMHS were used. Three-factor ANOVA was used to determine significant differences (p<0.05) in physiologic and failure biomechanics based on compression rate, spinal level, and gender. Results demonstrated a significant increase in ultimate force (i.e., fracture) from lower to higher compression rates. Ultimate stress also increased with compression rate. Displacement and strain to failure were consistent at both compression rates. Differences in ultimate mechanics between vertebral bodies obtained from males and females demonstrated non-significant trends, with female vertebral bodies having lower ultimate force that would be associated with decreased injury tolerance. This was likely a result of smaller vertebrae in that population. Combined with existing literature, results presented in this manuscript contribute to the understanding of lumbar spine tolerance during axial loading events that occur in both military and civilian environments with regard to effects of compression rate and gender.

Distribution and length of osteophytes in the lumbar vertebrae and risk of rupture of abdominal aortic aneurysms: a study of dry bones from Chiang Mai, Thailand.

Vertebral osteophytes are a characteristic feature of intervertebral disc degeneration. In the lumbar spinal region, the two major structures in close proximity anterior to the spine are the inferior vena cava and the abdominal aorta, both of which have been reported to be affected by osteophytes. The purpose of this study was to determine the distribution, classification and lengths of osteophytes in the lumbar vertebrae. One hundred and eighty lumbar columns of 90 males and 90 females from Chiang Mai, Thailand, in the age range 15 to 96 years (mean age, 63 years) were collected. The measuring length of osteophytes was assessed on vertebral body and articular facet. Statistical analysis was performed by descriptive analysis, chi-square and Pearson Correlation. Lumbar osteophytes were presented in 175 specimens (97.2%), 88 males and 87 females. The highest frequency was at L4, most were on the superior, inferior surface of body and articular facet (39.7%, 38.4%, and 22%), respectively. The greatest mean length was 3.47±2.21 mm at L5, and the longest length of anterior superior surface of body was 28.56 mm. The osteophyte length was significantly correlated directly with age (P<0.01), and males were significantly greater than females (P<0.05). The highest prevalence of osteophytes was on the anterior side of superior surface of body (30.4%), and the classification was traction. It can be proposed that the abdominal aorta could be damaged, especially a risk of rupture of abdominal aortic aneurysm.

Mineral and bone disorder and vascular calcification in patients with chronic kidney disease

Vascular calcifications has been associated with bone and mineral disorders. The alterations in the serum level of calcium concentrations and phosphate are importants factors implicated in the arterial calcification in chronic kidney disease. The pathogenesis of vascular calcification is a complex mechanism and not completely clear, being able to correspond to an active process of cellular transformation and heterotopic ossification. Beyond the hypercalcemia and hyperphosphatemia, they are involved in this process changes in the metabolism of inhibitors and promoters of calcification such as fetuin A, osteopontin, osteoprotegerin, and matrix gla protein. For the diagnosis of the calcified arterial injury are available several complementary methods, a method of estimate of the cardiovascular risk based on plain radiographs of the lumbar column and another method based on simple x-rays of the pelvis and hands. Below, we will present a review approching the link between vascular calcifications and mineral disorders.

Safety and efficacy of treatment switch to raltegravir plus tenofovir/emtricitabine or abacavir/lamivudine in patients with optimal virological control: 48-week results from a randomized pilot study (Raltegravir Switch for Toxicity or Adverse Events, RASTA Study)

The Raltegravir Switch for Toxicity or Adverse Events (RASTA) Study is a 2-arm randomized pilot study exploring the safety and efficacy at 48 weeks of a treatment switch to raltegravir associated with tenofovir/emtricitabine or abacavir/lamivudine in patients with regimens with optimal virological control. Patients treated with stable protease inhibitor (PI)-, non-nucleoside reverse transcriptase inhibitor (NNRTI)-, or nucleoside reverse transcriptase inhibitor (NRTI)-based regimens, with HIV-RNA levels < 50 copies/ml for ≥ 3 months and a CD4 cell count > 200 cells/μl were eligible. Enrollment of 40 patients was planned: at baseline patients were randomized 1:1 to switch to raltegravir plus tenofovir/emtricitabine (arm A) or abacavir/lamivudine (arm B). Laboratory parameters, raltegravir plasma levels, self- reported adherence, quality of life parameters, neurocognitive performance, bone composition, and body fat distribution were monitored. Virological failure was defined as HIV-RNA > 50 copies/ml on 2 consecutive determinations. After 48 weeks, 5/40 (12.5%) regimen discontinuations occurred: 2 were for low-level viremia virological failure (both in arm A, at weeks 24 and 48) and 3 were for adverse events (neurological disturbances and skin rash in arm B; proximal tubulopathy in arm A). Overall, a significant CD4 increase was observed at weeks 36 and 48, and a significant decrease in total cholesterol, non-high density lipoprotein cholesterol, and triglycerides was observed at each study visit. Physical health/satisfaction in therapy scores and neuropsychological performance improved. The lumbar column Z-score improved, with no modification in other bone composition and fat distribution parameters. The investigated switch strategy was associated with rare virological failure. Improvements in lipid levels, quality of life measures, neuropsychological performance, and bone composition suggest good tolerability of raltegravir-based regimens.

Biomechanical comparison of three stand-alone lumbar cages — a three-dimensional finite element analysis

BackgroundFor anterior lumbar interbody fusion (ALIF), stand-alone cages can be supplemented with vertebral plate, locking screws, or threaded cylinder to avoid the use of posterior fixation. Intuitively, the plate, screw, and cylinder aim to be embedded into the vertebral bodies to effectively immobilize the cage itself. The kinematic and mechanical effects of these integrated components on the lumbar construct have not been extensively studied. A nonlinearly lumbar finite-element model was developed and validated to investigate the biomechanical differences between three stand-alone (Latero, SynFix, and Stabilis) and SynCage-Open plus transpedicular fixation. All four cages were instrumented at the L3-4 level.MethodsThe lumbar models were subjected to the follower load along the lumbar column and the moment at the lumbar top to produce flexion (FL), extension (EX), left/right lateral bending (LLB, RLB), and left/right axial rotation (LAR, RAR). A 10 Nm moment was applied to obtain the six physiological motions in all models. The comparison indices included disc range of motion (ROM), facet contact force, and stresses of the annulus and implants.ResultsAt the surgical level, the SynCage-open model supplemented with transpedicular fixation decreased ROM (>76%) greatly; while the SynFix model decreased ROM 56-72%, the Latero model decreased ROM 36-91%, in all motions as compared with the INT model. However, the Stabilis model decreased ROM slightly in extension (11%), lateral bending (21%), and axial rotation (34%). At the adjacent levels, there were no obvious differences in ROM and annulus stress among all instrumented models.ConclusionsALIF instrumentation with the Latero or SynFix cage provides an acceptable stability for clinical use without the requirement of additional posterior fixation. However, the Stabilis cage is not favored in extension and lateral bending because of insufficient stabilization.

Bariatric surgery in an obese patient with Albright hereditary osteodystrophy: a case report

IntroductionWe report for the first time the case of a patient with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism who underwent a Roux-en-Y gastric bypass.Case presentationA 26-year-old obese Caucasian woman with Albright hereditary osteodystrophy with pseudopseudohypoparathyroidism (heterozygous mutation (L272F) in GNAS1 exon 10 on molecular analysis) was treated with gastric bypass. She had the classical features of Albright hereditary osteodystrophy: short stature (138cm), obesity (body mass index 49.5kg/m2), bilateral shortening of the fourth and fifth metacarpals, short neck, round and wide face with bombed front and small eyes. Before the gastric bypass was performed, biochemical determination revealed a slightly low serum calcium level (2.09mmol/L; normal range 2.1 to 2.5mmol/l), and an elevated parathyroid hormone level (87ng/L; normal range 10 to 70ng/L) associated with low vitamin D level (19μg/L; normal range 30 to 50μg/L). Vitamin D supplementation was prescribed before surgery. After the Roux-en-Y gastric bypass, she achieved a progressive substantial weight loss, from 94kg (body mass index 49.5kg/m2) to 49kg (body mass index 25.9kg/m2) in one year. Her weight then stabilized at 50kg (body mass index 26kg/m2) during our three years of follow-up. Before the operation and every three months after it, she was screened for nutritional deficiencies, and serum markers of bone turnover and renal function were monitored. Considering the deficiencies in zinc, magnesium, calcium, vitamin D and vitamin B12, appropriate supplementation was prescribed. Before and two years after the Roux-en-Y gastric bypass, a dual-energy X-ray absorptiometry assessment of bone density was performed that showed no changes on her lumbar column (0.882g/cm2 and both T-score and Z-score of −1.5 standard deviation). In addition, bone microarchitecture with a measurement of her trabecular bone score was found to be normal.ConclusionThis is the first case of Roux-en-Y gastric bypass described in a patient with pseudopseudohypoparathyroidism showing that such a procedure seems to be safe in obese patients with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism if appropriately followed up. As obesity is a prominent feature of Albright hereditary osteodystrophy, such patients might seek bariatric surgery. After a Roux-en-Y gastric bypass, patients with Albright hereditary osteodystrophy associated with pseudopseudohypoparathyroidism need long-term follow-up on nutritional and metabolic issues.

Modern or distinct axial bauplan in early hominins? A reply to Williams (2012)

There is current debate whether the Homo/Pan last common ancestor (LCA) had a short, stiff lumbar column like great apes or a longer, flexible column observed in generalized Miocene hominoids. Beyond having only four segments, three additional features contribute to lumbar stiffening: the position of the transitional vertebra (TV), orientation of the lumbar spinous processes, and entrapment of lumbar vertebrae between the iliac blades. For great apes, these features would be homologous if inherited from a short-backed LCA but likely functionally convergent through dissimilar phenotypes if evolved from a long-backed LCA. We quantitatively and qualitatively analyzed human, ape, and monkey thoracic and lumbar vertebrae using 3D surface scanning and osteological measurements to compare spinous process morphology and sacral depth. We also used a large sample of hominoid vertebral counts to assess variation in the position of the TV and lumbosacral boundary. All extant hominoids modally place the TV at the ultimate thoracic. However, humans and orangutans place the TV at the 19th postcranial vertebral segment, whereas other apes place the TV at the 20th. Furthermore, chimpanzees, gorillas, and orangutans each have distinct patterns of spinous process angulation and morphology associated with lumbar stiffening, while human spinous process morphology is similar to that of longer backed gibbons, monkeys, and Miocene hominoids Morotopithecus and Pierolapithecus. Finally, chimpanzees are unique compared with other hominoids with a greater sacral depth facilitating lumbar entrapment, and there are differences among African apes with respect to the mechanisms governing variation in the lumbosacral boundary. These differences suggest that lumbar stiffening is convergent among great apes and that human bipedalism evolved from a more generalized long-backed ancestor. Such a model is more consistent with evidence of TV placement in Australopithecus.

Placement of the diaphragmatic vertebra in catarrhines: Implications for the evolution of dorsostability in hominoids and bipedalism in hominins

A fundamental adaptation to orthograde posture and locomotion amongst living hominoid primates is a numerically reduced lumbar column, which acts to stiffen the lower back and reduce injuries to the intervertebral discs. A related and functionally complementary strategy of spinal stability is a caudal position of the diaphragmatic vertebra relative to the primitive condition found in nonhominoid primates and most other mammals. The diaphragmatic vertebra marks the transition in vertebral articular facet (zygapophysis) orientation, which either resists (prediaphragmatic) or allows (postdiaphragmatic) trunk movement in the sagittal plane (i.e., flexion and extension). Unlike most mammals, which have dorsomobile spines (long lumbar columns and cranially placed diaphragmatic vertebrae) for running and leaping, hominoids possess dorsostable spines (short lumbar columns and caudally placed diaphragmatic vertebrae) adapted to orthogrady and antipronogrady. In contrast to humans and other extant hominoids, all known early hominin partial vertebral columns demonstrate cranial displacement of the diaphragmatic vertebra. To address this difference, variation in diaphragmatic placement is assessed in a large sample of catarrhine primates. I show that while hominoids are characterized by modal common placement of diaphragmatic and last rib-bearing vertebrae in general, interspecific differences in intraspecific patterns of variation exist. In particular, humans and chimpanzees show nearly identical patterns of diaphragmatic placement. A scenario of hominin evolution is proposed in which early hominins evolved cranial displacement from the ancestral hominid condition of common placement to achieve effective lumbar lordosis during the evolution of bipedal locomotion.

Modern or distinct axial bauplan in early hominins? Comments on

The vertebral column plays a central role in the evolution and performance of positional behaviors, including upright posture and bipedal locomotion in the human lineage. The lumbar column, in particular, is associated with locomotor function. As such, its numerical composition has been a major source of contention in the paleoanthropological literature. Ever since Robinson’s (1972) description and interpretation of the nearly complete thoracolumbar vertebral column of Sts 14 (Australopithecus africanus), researchers have, with few exceptions, consistently stated that early hominins possessed six lumbar vertebrae (Benade, 1990; Latimer and Ward, 1993; Shapiro, 1993; Walker and Leakey, 1993; Sanders, 1995, 1998; Tobias, 1998; Pilbeam, 2004; Rosenman, 2008; McCollum et al., 2010). In 2002, Haeusler et al. demonstrated that these reconstructions were incorrect because they were based on aberrant vertebral morphologies, conflation of multiple definitions (costal versus zygapophyseal) of thoracic and lumbar vertebrae, and the fragmentary nature and associated uncertainty of consecutiveness of fossil vertebral elements in general (see also Williams, 2011). In a new study, Haeusler et al. (2011) describe newly identified vertebra and rib fragments associated with the KNM-WT 15000 juvenile Homo erectus skeleton that reinforce their previous contention (Haeusler et al., 2002) that this specimen has five instead of six lumbar vertebrae, a finding consistent with recent reconstructions of the A. africanus specimens Sts 14 and Stw 431

Morphology and Function of the Vertebral Column in Remingtonocetus domandaensis (Mammalia, Cetacea) from the Middle Eocene Domanda Formation of Pakistan

The archaeocete family Remingtonocetidae is a group of early cetaceans known from the Eocene of India and Pakistan. Previous studies of remingtonocetids focused primarily on cranial anatomy due to a paucity of well-preserved postcranial material. Here we describe the morphology of the known vertebral column in Remingtonocetus domandaensis based largely on a single well-preserved partial skeleton recovered from the upper Domanda Formation of Pakistan. The specimen preserves most of the precaudal vertebral column in articulation and includes seven complete cervical vertebrae, ten partial to complete thoracic vertebrae, six complete lumbar vertebrae, and the first three sacral vertebrae. Cervical centra are long and possess robust, imbricating transverse processes that stabilized the head and neck. Lumbar vertebrae allowed for limited flexibility and probably served primarily to stabilize the lumbar column during forceful retraction of the hind limbs. Vertebral evidence, taken together with pelvic and femoral morphology, is most consistent with interpretation of Remingtonocetus domandaensis as an animal that swam primarily by powerful movement of its hind limbs rather than dorsoventral undulation of its body axis.

Avaliação da carga de trabalho físico e da postura de trabalhadores na produção de mudas florestais

Nesta pesquisa, objetivou-se avaliar a carga de trabalho físico e a postura adotada pelos trabalhadores nas atividades de produção de mudas florestais, visando a reorganização ergonômica do trabalho para a melhoria dos níveis de segurança e saúde dos trabalhadores. O estudo foi realizado com trabalhadores do viveiro de uma empresa florestal localizada no Estado do Paraná. A carga de trabalho físico foi avaliada por meio do levantamento da frequência cardíaca dos trabalhadores nas diversas fases do ciclo de trabalho com uso de um monitor Polar da Finlândia e o trabalho classificado segundo metodologia proposta por Apud (1997). A avaliação da postura foi feita por meio de filmagens dos trabalhadores e os dados submetidos para análise no software "Winowas" de análises de posturas. Os resultados mostraram que as etapas consideradas de maior exigência física foram o preparo do substrato e o transporte das bandejas para a casa de vegetação, com frequências cardíacas médias de 120 e 115 bpm e cargas cardiovasculares médias de 42 e 37%, respectivamente, sendo as atividades classificadas como moderadamente pesadas. A postura mais crítica para os trabalhadores foi na atividade de retirada do substrato da betoneira, por exigir uma sobrecarga da coluna lombar. Durante a etapa de semeadura, observou-se a necessidade de correções na postura dos trabalhadores por atuarem em 97% do período de trabalho na posição em pé e com a coluna lombar curvada. Conclui-se que, na empresa em questão, há a necessidade de se adotar medidas preventivas para se evitar as lombalgias de forma educativa e também por meio de alterações no sistema operacional.