New fossils of Australopithecus sediba reveal a nearly complete lower back

Adaptations of the lower back to bipedalism are frequently discussed but infrequently demonstrated in early fossil hominins. Newly discovered lumbar vertebrae contribute to a near-complete lower back of Malapa Hominin 2 (MH2), offering additional insights into posture and locomotion in Australopithecus sediba. We show that MH2 possessed a lower back consistent with lumbar lordosis and other adaptations to bipedalism, including an increase in the width of intervertebral articular facets from the upper to lower lumbar column (‘pyramidal configuration’). These results contrast with some recent work on lordosis in fossil hominins, where MH2 was argued to demonstrate no appreciable lordosis (‘hypolordosis’) similar to Neandertals. Our three-dimensional geometric morphometric (3D GM) analyses show that MH2’s nearly complete middle lumbar vertebra is human-like in overall shape but its vertebral body is somewhat intermediate in shape between modern humans and great apes. Additionally, it bears long, cranially and ventrally oriented costal (transverse) processes, implying powerful trunk musculature. We interpret this combination of features to indicate that A. sediba used its lower back in both bipedal and arboreal positional behaviors, as previously suggested based on multiple lines of evidence from other parts of the skeleton and reconstructed paleobiology of A. sediba.

P.053 A clinical mystery finally revealed

Background: We report 2 brothers sharing FHL1 identified mutation. They presented in childhood with overlapping clinical features characterized by early onset stiffness and increased muscle definition with cardiac involvement. After 30 years of neurological followup, the diagnosis is finally revealed. Methods: At early ages, both had increased definition of upper trunk musculature. The older brother had hypophonic voice with raspy character, which is to our knowledge, not reported with this mutation before. He required a pacemaker for arrhythmias, while the younger developed congestive heart failure. Results: Their initial investigations failed to unveil a diagnosis, including a negative next generation sequencing (NGS) panel for AR LGMD. An expanded NGS sent on the older brother revealed he is hemizygous for 1770 bp deletion within FHL 1 gene, this deletion includes exon 7to 8, and confirmed on the other. Conclusions: First reported in 2008, FHL1 mutations result in phenotypically distinct neuromuscular disorders: X-linked myopathy with Postural Muscle Atrophy and generalized hypertrophy, X-linked dominant scapuloperoneal Myopathy, and Reducing Body Myopathy. Subsequently other phenotypes have been reported including Emery-Dreifuss muscular dystrophy and hypertrophic cardiomyopathy. Our patients present with a phenotype that had been reported with FHL1 mutation, highlighting the possible recognition of this presentation in aiding a diagnostic approach.

The association of lower trunk muscle strength with low back pain in elite lightweight judokas is dependent on lumber spine abnormalities

BACKGROUND: Lumbar radiological abnormalities (LRA) and trunk muscle weakness are major causes of the low back pain (LBP). We reported that the prevalence of LRA was approximately 90% in middle- and heavyweight-judokas, independent to the occurrence of LBP. However, the trunk muscle weakness, especially the rotators, plays a key role in occurrence of LBP in heavyweight judokas. OBJECTIVE: To examine the trunk muscle strength (TMS) and LRA impact on LBP occurrence in lightweight judokas. METHOD: The strength of the trunk extensors, flexors, and rotators was measured in 32 lightweight male judokas. LBP and LRA were identified using a questionnaire, X-ray, and MRI. RESULTS: The occurrence rate of LBP and LRA were 40.6% and 62.5%, respectively, without any significant correlation. Among judokas without LRA, TMS of those with LBP were significantly lower than those without LBP (P< 0.05, the extensor; 60∘/s: ES [d] = 1.38, 90∘/s: ES [d] = 0.78, and 120∘/s: ES [d] = 0.37, flexor; 60∘/s: ES [d] = 1.48, dominant rotator; 60∘/s: ES [d] = 1.66, and 90∘/s: ES [d] = 1.87, non-dominant rotator; 90∘/s: ES [d] = 0.17, and dominant/non-dominant rotator ratio; 90∘/s: ES [d] = 1.55). Moreover, there were significant negative correlations between LBP severity and TMS (P< 0.05, the extensor; 90∘/s: r=-0.63, dominant rotator; 90∘/s: r=-0.648, and dominant/non-dominant rotator ratio; 90∘/s: r=-0.621) in judokas without LRA. RESULTS: The occurrence rate of LBP and LRA were 40.6% and 62.5%, respectively, without any significant correlation. Among judokas without LRA, the extensor (60, 90, and 120∘/s), flexor (60∘/s), dominant rotator (60 and 90∘/s), non-dominant rotator (90∘/s), and dominant/non-dominant rotator ratio (90∘/s) of judokas with LBP were significantly lower than those of the judokas without LBP. Moreover, there were significant negative correlations (P< 0.05) between LBP severity and the extensor (90∘/s; r=-0.63) and dominant rotator (90∘/s; r=-0.648) strength, and dominant/non-dominant rotator ratio (90∘/s; r=-0.621) in judokas without LRA. CONCLUSION: Weak trunk musculature may be a co-factor in the occurrence of LBP in lightweight judokas without LRA.

New fossils of Australopithecus sediba reveal a nearly complete lower back

Adaptations of the lower back to bipedalism are frequently discussed but infrequently demonstrated in early fossil hominins. Newly discovered lumbar vertebrae contribute to a near-complete lower back of Malapa Hominin 2 (MH2), offering additional insights into posture and locomotion in Australopithecus sediba. We show that MH2 demonstrates a lower back consistent with human-like lumbar lordosis and other adaptations to bipedalism, including an increase in the width of intervertebral articular facets from the upper to lower lumbar column (“pyramidal configuration”). This contrasts with recent work on lordosis in fossil hominins, where MH2 was argued to demonstrate no appreciable lordosis (“hypolordosis”) similar to Neandertals. Our three-dimensional geometric morphometric (3D GM) analyses show that MH2’s nearly complete middle lumbar vertebra is human-like in shape but bears large, cranially-directed transverse processes, implying powerful trunk musculature. We interpret this combination of features to indicate that A. sediba used its lower back in both human-like bipedalism and ape-like arboreal positional behaviors, as previously suggested based on multiple lines of evidence from other parts of the skeleton and reconstructed paleobiology of A. sediba.

Understanding axial progenitor biology in vivo and in vitro

ABSTRACTThe generation of the components that make up the embryonic body axis, such as the spinal cord and vertebral column, takes place in an anterior-to-posterior (head-to-tail) direction. This process is driven by the coordinated production of various cell types from a pool of posteriorly-located axial progenitors. Here, we review the key features of this process and the biology of axial progenitors, including neuromesodermal progenitors, the common precursors of the spinal cord and trunk musculature. We discuss recent developments in the in vitro production of axial progenitors and their potential implications in disease modelling and regenerative medicine.

Magnetic Resonance Imaging of Trunk Musculature and Intervertebral Discs in Patients with Spinal Cord Injury with Thoracolumbar Vertebral Fractures: A Prospective Study

Study Design: This study is a prospective clinical study.Purpose: This study aims to evaluate the characteristics of trunk musculature and intervertebral discs by using magnetic resonance imaging in patients with spinal cord injuries (SCIs) with thoracic and lumbar fractures. Overview of Literature: Muscle atrophy is an immediate consequence of SCI and is associated with secondary complications. At present, there are limited clinical data on muscle and disc responses to fractures of the thoracic and lumbar spine.Methods: A total of 51 patients with a mean age of 31.75±10.42 years who suffered traumatic SCI were included in this study. Complete neurological examinations (American Spinal Injury Association grading) and magnetic resonance imaging (MRI) were performed at the time of admission and at 3–6 months after injury to study the neurological status and disc and trunk parameters. The type of management (operative or conservative) was decided on the basis of clinical, radiological, and MRI evaluations, and a robust rehabilitation program was initiated.Results: Disc parameters including disc angle, skin angle, cross-sectional area (CSA), and disc height and trunk parameters (mean trunk width, mean trunk depth, and CSA of the lumbar muscles) decreased significantly (p <0.001) during the first 3 months after SCI. However, improvements were observed in disc and muscle parameters at the 6-month follow-up, but these parameters did not return to normal levels. Neither initial neurological status (complete vs. incomplete) nor type of management (operative vs. conservative) had a significant effect on these parameters.Conclusions: Spinal trauma leads to alterations in the morphology of the vertebral column, spinal cord, intervertebral discs, and paraspinal muscles in the initial phase of injury. The extent of these changes may determine the initial neurological deficit and subsequent recovery. Although this study did not identify any statistically significant effect of neurological status or management strategy on these parameters, rehabilitation was found to result in the improvement of these parameters in the later phase of recovery. Future studies are required to evaluate the exact causes of these alterations and the potential benefits of rehabilitation strategies and to minimize these changes.

Activity of Trunk and Lower Extremity Musculature: Comparison Between Parallel Back Squats and Belt Squats

The back squat is widely used in strength training programs. Alternatively, the belt squat has been gaining popularity since it loads the weight on the hips, as opposed to the shoulders and spine. The purpose of this study was to determine whether using a belt squat would result in less lumbar extensor activation while providing similar excitation of other prime mover and stabilizer musculature. Ten participants (9 males, 1 female; age 29.3 ± 4.9 years; body mass 96.2 ± 17.8 kg) who regularly trained both belt squats and back squats performed three sets of 5 repetitions with 100% bodyweight for each exercise. Peak and integrated muscle activity was calculated and normalized to a maximum voluntary isometric contraction. A one-way ANOVA (p < 0.05) was used to compare conditions. Belt squatting decreased lumbar erector impulse (45.4%) and peak (52.0%) activation as compared to the back squat. Belt squatting did not alter activation of the lower extremities except for a decrease in the gluteus maximus (35.2% impulse and 32.1% peak), gluteus medius (54.1% impulse and 55.2% peak). Furthermore, belt squatting reduced activation of the rectus abdominus (44.3% impulse; 31.1% peak), and external obliques (45.8% impulse; 53.7% peak) as compared to back squatting. Our results suggest belt squatting provides similar muscular demands for the quadriceps, hamstrings, and plantar flexors, but is less demanding of trunk stabilizers, and gluteual muscles. Belt squats may be a suitable alternative to back squats in order to avoid stressing low back or trunk musculature.