Ancestral morphology of crown-group molluscs revealed by a new Ordovician stem aculiferan.

Exceptionally preserved fossils provide crucial insights into extinct body plans and organismal evolution. Molluscs, one of the most disparate animal phyla, radiated rapidly during the early Cambrian period (approximately 535-520 million years ago (Ma)). The problematic fossil taxa Halkieria and Orthrozanclus (grouped in Sachitida) have been assigned variously to stem-group annelids, brachiopods, stem-group molluscs or stem-group aculiferans (Polyplacophora and Aplacophora), but their affinities have remained controversial owing to a lack of preserved diagnostic characters.

A validation study of a new instrument for low cost bite force measurement.

Quantitative assessment of force in masticatory muscles is not a routine clinical test, probably due to the lack of an "easy-to-use" device. Aim of this study is (1) to present a low cost bite force instrument located in a custom-made housing, designed to guarantee a comfortable and effective bite action, (2) to evaluate its mechanical characteristics, in order to implement it in clinical settings and in experimental setups. Linearity, repeatability and adaptation over time were assessed on a set of four different sensors in bare and housed condition.

Atlanto-axial facet displacement during rotational high-velocity low-amplitude thrust: An in vitro 3D kinematic analysis.

Background: Very little is known about the kinematics of the upper cervical spine in particular during Manual Therapy techniques. In fact no data about displacement of the atlanto-axial joint during High-Velocity Low-Amplitude (HVLA) thrust are available. Knowing the precise kinematics of these vertebrae might allow a better comprehension of such important technique and possible vital structures involvement.

Anomalocaridid trunk limb homology revealed by a giant filter-feeder with paired flaps.

Exceptionally preserved fossils from the Palaeozoic era provide crucial insights into arthropod evolution, with recent discoveries bringing phylogeny and character homology into sharp focus. Integral to such studies are anomalocaridids, a clade of stem arthropods whose remarkable morphology illuminates early arthropod relationships and Cambrian ecology. Although recent work has focused on the anomalocaridid head, the nature of their trunk has been debated widely.

Intended and non-intended kinematic effects of atlanto-axial rotational high-velocity, low-amplitude techniques.

Introduction: The study of neck kinematics during high-velocity, low-amplitude manipulations of the atlanto-axial segment is essential to understanding cervical motion mechanisms and their impact and possible risk for soft-tissue injuries during treatment of spine disorders.

Methods: Twenty fresh-frozen specimens were tested during manual application of an axial rotation technique.

Findings: The kinematics indicate the thrust induced motion components of approximately 1° at the treated segment around all three axes of the local embedded reference frame.

Reproducibility of the kinematics in rotational high-velocity, low-amplitude thrust of the upper cervical spine: a cadaveric study.

Objective: This study aimed to investigate the reproducibility of the kinematics in rotational high-velocity, low-amplitude (HVLA) thrust of the upper cervical spine.

Methods: Twenty fresh human cervical specimens were studied in a test-retest situation with 2 manual therapists. Kinematics of C1-C2 and C0-C1 were examined during segmental rotational HVLA manipulation through an ultrasound-based tracking system.

A holomorph approach to xiphosuran evolution--a case study on the ontogeny of Euproops.

Specimens of Euproops sp. (Xiphosura, Chelicerata) from the Carboniferous Piesberg quarry near Osnabrück, Germany, represent a relatively complete growth series of 10 stages. Based on this growth sequence, morphological changes throughout the ontogeny can be identified.

The added value of an actuated ankle-foot orthosis to restore normal gait function in patients with spinal cord injury: a systematic review.

Objective: To provide an overview of robot-assisted rehabilitation devices developed for actuation of the ankle-foot complex and their ability to influence the attributes of normal gait in patients with spinal cord injury.

Methods: A search was conducted in MEDLINE, Web of Knowledge, National Academic Research and Collaborations Information System, and Physiotherapy Evidence Data-base (1985-2011), using, "ankle", "foot", "robotics", "orthotics" and "spinal cord injury" as most relevant keywords. Article inclusion was performed in 3 stages; at the level of: (i) title, (ii) abstract and (iii) full text.

A giant Ordovician anomalocaridid.

Anomalocaridids, giant lightly sclerotized invertebrate predators, occur in a number of exceptionally preserved early and middle Cambrian (542-501 million years ago) biotas and have come to symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair of anterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups--but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal.

Ultrasound findings in injuries of dorsal extensor hood: correlation with MR and follow-up findings.

Objective: The aim of this study was to use ultrasound to examine the dorsal hood in nine patients with a clinical suspicion of dorsal hood injuries.

Material And Methods: Clinical and imaging files from interesting case logbooks of nine patients were reviewed. Ultrasound was performed by one of the three radiologists experienced in musculoskeletal ultrasound.

Critical appraisal and hazards of surface electromyography data acquisition in sport and exercise.

The aim of this critical appraisal and hazards of surface electromyography (SEMG) is to enhance the data acquisition quality in voluntary but complex movements, sport and exercise in particular. The methodological and technical registration strategies deal with telemetry and online data acquisition, the placement of the detection electrodes and the choice of the most adequate normalization mode.Findings compared with the literature suggest detection quality differences between registration methods and between water and air data acquisition allowing for output differences up to 30% between registration methods and up to 25% decrease in water, considering identical measures in air and in water.

Ordovician faunas of Burgess Shale type.

The renowned soft-bodied faunas of the Cambrian period, which include the Burgess Shale, disappear from the fossil record in the late Middle Cambrian, after which the Palaeozoic fauna dominates. The disappearance of faunas of Burgess Shale type curtails the stratigraphic record of a number of iconic Cambrian taxa. One possible explanation for this loss is a major extinction, but more probably it reflects the absence of preservation of similar soft-bodied faunas in later periods.

Reproducibility of global three-dimensional motion during manual atlanto-axial rotation mobilization: an in vitro study.

The reproducibility of the three-dimensional (3D) kinematic aspects of motion coupling patterns during manual mobilizing techniques is still a debatable matter. The present in vitro study analysed segmental 3D motion of the atlanto-axial joint during manual axial rotation mobilization. Twenty fresh frozen human cervical specimens were studied in a test-retest situation with two examiners.

Functional anatomy of the dorsal hood or the hand: correlation of ultrasound and MR findings with cadaveric dissection.

The main aim of this study was to provide an overview of the anatomy of the dorsal hood (DH) based on the dissection of sixteen cadaver hands, correlated with magnetic resonance (MR) and ultrasound findings. A secondary aim was to assess the function of components of the DH. Sixteen embalmed hands were evaluated by MRI and ultrasound before being dissected.

Sonography of the normal ankle: a target approach using skeletal reference points.

Objective: Sonographic examination of the ankle depends on exact knowledge of the specific probe positions to acquire the best images.

Conclusion: In this article, we discuss these positions and illustrate them with drawings, anatomic slices or dissection, and sonograms. Positions studied include those for best imaging of the anterior tibiotalar joint, anterior tibiofibular ligament, anterior talofibular ligament, calcaneofibular ligament, peroneal tendons, Achilles tendon, flexor hallucis longus, posterior deltoid ligament, anterior deltoid ligament, and posterior medial tendons.

In vitro three dimensional morphometry of the lateral atlantoaxial articular surfaces.

Study Design: The present study verifies the 3-dimensional anatomic features of the lateral atlantoaxial joints with reference to a local reference frame using a direct in vitro approach.

Objective: To study the concordance between the axial and atlantal articular surfaces.

Summary Of Background Data: Detailed information of joint-configurations is imperative for understanding the complex kinematics of the upper cervical joint.

Machaeridians are Palaeozoic armoured annelids.

The systematic affinities of several Palaeozoic skeletal taxa were only resolved when their soft-tissue morphology was revealed by the discovery of exceptionally preserved specimens. The conodonts provide a classic example, their tooth-like elements having been assigned to various invertebrate and vertebrate groups for more than 125 years until the discovery of their soft tissues revealed them to be crown-group vertebrates. Machaeridians, which are virtually ubiquitous as shell plates in benthic marine shelly assemblages ranging from Early Ordovician (Late Tremadoc) to Carboniferous, have proved no less enigmatic.

Prevalence and MRI-anatomic correlation of bone cysts in osteoarthritic knees.

Objective: The objectives of this study were to determine the prevalence of cysts in the weight-bearing areas and interspinous bone cysts in tibial plateau specimens derived from knees with advanced osteoarthritis, to perform MRI-anatomic correlation of these cysts, and to define their histologic characteristics.

Materials And Methods: Forty-two tibial plateau specimens were recovered from patients undergoing total knee replacement surgery for severe osteoarthritis (14 men and 28 women; mean age, 74 years; age range, 58-87 years). The tibial specimens underwent MRI with T1- and T2-weighted MR sequences.

Sonography of the finger flexor and extensor system at the hand and wrist level: findings in volunteers and anatomical correlation in cadavers.

We present a review of sonography of the flexor and extensor system of the hand and wrist in volunteers and cadavers. CT tenography also was performed in cadaveric specimens. Anatomical structures of the extensor system that were assessed with sonography included the extensor tendons and insertions, retinaculum, and dorsal hood.

Normal MR imaging anatomy of the rotator cuff tendons, glenoid fossa, labrum, and ligaments of the shoulder.

The shoulder is commonly imaged using MR imaging, with or without intraarticular contrast medium. Some anatomic structures, such as the rotator cuff tendons and bony components, can be assessed without arthrographic technique, whereas the glenohumeral ligaments and labrum require arthrographic technique for more accurate assessment. In either case, an understanding of the normal anatomy of the shoulder with regard to bony and soft tissue structures is essential for MR imaging interpretation.

Intra-articular kinematics of the upper limb joints: a six degrees of freedom study of coupled motions.

In sport, leisure and certain occupational activities, joint lesions of the upper limb are very common. To understand their aetiology in order to prevent and treat these pathologies on a scientific basis, a comprehensive knowledge of the involved stress and kinematics is imperative. For many years intra-articular joint kinematics have been described hypothetically in terms of the convex-concave principle.

In vivo 3D arthrokinematics of the proximal and distal radioulnar joints during active pronation and supination.

Background: Pronation and supination of the forearm are important motions with major impact of impairment on daily activities. Despite this, the migration of contact of the articular surfaces of the proximal and distal radioulnar joints during active pronation has not been evaluated in vivo.

Method: Helical CT-data in elbow positions of full active supination, mid position and full pronation with the elbow in extension were acquired from three female subjects and processed in 3D skeletal reconstructions.

Normal MR imaging findings of the midhand and fingers with anatomic correlation.

In the present article, we correlate MR imaging studies of cadavers, volunteers and patients with cadaveric dissection and sectioning. First anatomy at wrist level is discussed. In a next section, we address the midhand with the flexor and extensor tendons, and interosseous and lumbricalis muscles.

ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion--Part II: shoulder, elbow, wrist and hand.

In this communication, the Standardization and Terminology Committee (STC) of the International Society of Biomechanics proposes a definition of a joint coordinate system (JCS) for the shoulder, elbow, wrist, and hand. For each joint, a standard for the local axis system in each articulating segment or bone is generated. These axes then standardize the JCS.