Medial Zone Research Articles

Immediate effects of insoles applied to the sound side lower extremity of patients with chronic hemiplegia during walking.

Asymmetric gait patterns are mostly observed in hemiplegic stroke patients. These abnormal gait patterns resulting in abnormal speed, and decreased ability in daily of activity living. This study aimed to determine the immediate changes in gait parameters and plantar pressure during elevation by wearing an insole on the sound side lower extremity of patients with hemiplegia. Thirty-six participants were recruited, comprising those with a post-stroke follow-up of ≥3 months and a functional ambulation category score of ≥2. The participants were asked to walk with and without a 1 cm insole in the shoe of their sound side, and the order of wearing or not wearing the insole was randomized. Gait parameters, bilateral gait parameters, and dynamic plantar pressure were measured using the GAITRite Walkway System. Paired t-test was used to examine immediate changes in gait parameters and plantar pressure with and without insoles during walking in the same group. Overall, gait velocity and step length significantly decreased (p < 0.05), whereas step time significantly increased (p < 0.05). The swing phase of the affected sidelower extremities significantly increased (p < 0.05), and the stance phase significantly decreased (p < 0.05). Double-support unloading phase (pre-swing phase) significantly increased (p < 0.05). The changes in plantar pressure were significantly increased in some lateral zones and significantly decreased in the medial zone of the mid-hindfoot, both in terms of pressure per time and peak pressure (p < 0.05). Although this study did not show immediate positive effects on gait parameters and gait cycle, it is expected that sensory input from the sole of the foot through changes in plantar pressure may help improve gait asymmetry and regulate postural symmetry.

Impact of foot progression angle on spatiotemporal and plantar loading pattern in intoeing children during gait

Intoeing in children is a common parental concern, but our understanding of the impact of foot progression angle (FPA) in these children leaves remains limited. This study examines the relationship between FPA and plantar loading pattern, as well as gait symmetry in children with intoeing. The sample included 30 children with intoeing caused by internal tibial torsion, uniformly divided into three groups: unilateral intoeing, bilateral mild intoeing, and bilateral mild-moderate intoeing. The relationship between FPA and plantar loading pattern, and gait symmetry within and among groups were assessed using dynamic pedobarographic and spatiotemporal data. Results indicated a significant correlation between FPA and peak pressure, maximum force, and plantar impulse in the medial and central forefoot, and also the medial and lateral heel zones for both bilateral intoeing groups. Significant differences were observed only in subdivided stance phase, including loading response, single support, and pre-swing phases, between the unilateral intoeing and bilateral mild intoeing groups. These findings suggest that FPA significantly affects the forefoot and heel zones, potentially increasing the load on the support structures and leading to transverse arch deformation. While children with intoeing demonstrate a dynamic self-adjustment capability to maintain gait symmetry, this ability begins to falter as intoeing becomes more pronounced.

Relationship between cement penetration and incidence of a radiolucent line around the tibia 2 years after total knee arthroplasty: A retrospective study

ObjectivesCement penetration (CP) plays a key role in implant stability for cemented total knee arthroplasty (TKA), and the radiolucent line (RLL) >2 ​mm is a preliminary sign for loosening of components. However, the direct relationship between CP and the frequency of RLL >2 ​mm is unclear, and the best cut-off value for CP to prevent RLL >2 ​mm also remains unclear. This study aimed to investigate this relationship between CP and RLL and to determine the clinical cut-off value for tibial CP in patients 2 years after TKA. MethodsThis retrospective study investigated 157 knees from 123 patients with osteoarthritis who underwent cemented TKA. The CP and RLL immediately after TKA and the RLL 2 years after TKA were measured for the medial, lateral, anterior, and posterior tibial baseplate zones. Receiver operating characteristic (ROC) curves were constructed to determine the best cut-off values for CP. ResultsRLL >2 ​mm was not observed just after TKA. An RLL >2 ​mm was observed in any tibial baseplate zone in 22 knees from 20 patients (RLL+ group) and was not observed in the remaining (RLL− group) 2 years after TKA. The mean CP for all zones was significantly higher in the RLL− group (2.5 ​± ​1.1 ​mm) than in the RLL+ group (1.7 ​± ​0.6 ​mm; P ​< ​0.001). An RLL >2 ​mm was seen in 21 knees in the medial zone, 9 knees in the lateral zone, 8 knees in the anterior zone, and 3 knees in the posterior zone. CP values with RLL >2 ​mm were significantly lower than those without the RLL at the medial, anterior, and posterior tibial baseplate zones. The best cut-off values from the ROC curve of CP in each zone were between 1.1 ​mm and 2.1 ​mm. ConclusionsThe depth of the CP directly affects the incidence of an RLL >2 ​mm. The best cut-off value for tibial CP to prevent an RLL >2 ​mm is 2.1 ​mm.

Sounding Sidewalks: Historicizing and Theorizing This Medial Zone

Sidewalks have long been a contested urban space existing between the private and public, thereby embodying conflicting sonic worlds of personal soundscaping, cultural world-building, and authority. This article theorizes and historicizes the lineage of the sidewalk as a medium of both control and resistance, addressed through an analysis of various sound technologies and techniques. Extending literature on the complex history of sidewalks as urban infrastructure, this article furthers scholarship by exploring the sounds of evolving social and political relations, the sonic environments imbued in this medial zone, and the shifting sound marks that accompany evolving urban policies.

Paleosol distribution and morphology along a late Cretaceous distributive fluvial system in the Bauru Basin, Brazil

Distributive Fluvial Systems (DFS) are fan-shaped landforms constituted by a radial system of channels that diverge downstream from an active apex, where the drainage emerges from the confinement valley. In such landforms, elevation, distance from fluvial channels, sedimentation rates, surface stability, and plant cover control weathering processes and soil development, but these features are obliterated within geological time. Thus, the micromorphological analysis of paleosols can be helpful for paleoenvironmental reconstruction of ancient DFS, improving the knowledge of soil genesis in these depositional landforms. Here, we describe macro and micromorphological features of twenty paleosols developed under arid to semiarid climates along the proximal to the medial zone of an Upper Cretaceous DFS in the Marília Formation, Bauru Basin, Brazil. Paleosols on the proximal zone typically showed features consistent with poor drainage, namely Bg, Btg and Bss horizons, and reddish Bt horizons in higher positions. Conversely, paleosols on the medial zone commonly showed reddish colours and pronounced secondary carbonate accumulation, consistent with a predominantly arid climate. Based on this distribution, we elaborated an evolution landscape model for the proximal and medial zone of the Bauru DFS, including allogenic and authigenic controls of soil development during the Campanian to the Maastrichtian epochs of southeastern Brazil.

Morphine- and foot shock-responsive neuronal ensembles in the VTA possess different connectivity and biased GPCR signaling pathway.

Background: Neurons in the ventral tegmental area (VTA) are sensitive to stress and their maladaptation have been implicated in the psychiatric disorders such as anxiety and addiction, etc. The cellular properties of the VTA neurons in response to different stressors related to different emotional processing remain to be investigated. Methods: By combining immediate early gene (IEG)-dependent labeling, rabies virus tracing, ensemble-specific transcriptomic analysis and fiber photometry recording in the VTA of male mice, the spatial distribution, brain-wide connectivity and cellular signaling pathways in the VTA neuronal ensembles in response to morphine (Mor-Ens) or foot shock (Shock-Ens) stimuli were investigated. Results: Optogenetic activation of the Mor-Ens drove approach behavior, whereas chemogenetic activation of the Shock-Ens increased the anxiety level in mice. Mor-Ens were clustered and enriched in the ventral VTA, contained a higher proportion of dopaminergic neurons, received more inputs from the dorsal medial striatum and the medial hypothalamic zone, and exhibited greater axonal arborization in the zona incerta and ventral pallidum. Whereas Shock-Ens were more dispersed, contained a higher proportion of GABAergic neurons, and received more inputs from the ventral pallidum and the lateral hypothalamic area. The downstream targets of the G protein and β-arrestin pathways, PLCβ3 and phosphorylated AKT1Thr308, were relatively enriched in the Mor-Ens and Shock-Ens, respectively. Cariprazine, the G-protein-biased agonist for the dopamine D2 receptor, increased the response of Mor-Ens to sucrose water and decreased the anxiety-like behavior during morphine withdrawal, whereas the β-arrestin-biased agonist UNC9994 decreased the response of Shock-Ens to tail suspension. Conclusions: Taken together, these findings reveal the heterogeneous connectivity and signaling pathways of the VTA neurons in response to morphine and foot shock, providing new insights for development of specific interventions for psychiatric disorders caused by various stressors associated with different VTA neuronal functions.

The Cambro-Ordovician Gondwana alluvial megafan in Central Africa: Insights from the Paleozoic sandstones of the Inkisi group, Congo Republic and Democratic Republic of the Congo.

The Paleozoic arkoses of the Inkisi Group in both the Republic and the Democratic Republic of the Congo has been investigated in order to examine whether they can represent an alluvial fan originating from the Gondwana supermountains in Northern and East Africa.This study focuses on outcrops’ description, lithofacies, bounding surfaces, architectural and sequential organization of sedimentary bodies and paleocurrents. The aim is to determine the nature of the Inkisi sandstones, the provenance of its sediments and the depositional setting, in order to test whether the East African orogen was also the sediments source for the formation of sedimentary fan in the western part of Central Africa.The study shows that the Inkisi Group consists of various sandstone lithofacies, amalgamated by conglomerates. The sediments are immature composed of quartz and feldspars associate with lithic fragments and micas. The sediments originated from the erosion of the West-Congolian belt and the Congo Craton, and were transported by braided fluvial system under mainly upper flow regime and secondarily lower flow regime. Sediments were deposited in the Inkisi basin, which was extensional and affected by burial.The Inkisi sediments setting up in a proximal to medial distributary zone of an alluvial megafan.The flows were directed southward, as opposed to paleofans originating from the Gondwana supermountain in Northern and East Africa. Thus, the Inkisi sandstone constitutes a new alluvial megafan distinguished from the Gondwana superfan derived from the Gondwana supermountain. It originated from the Pan-African belt of Mayombe and the Congo Craton. We name this megafan “the Cambro-Ordovician alluvial megafan of Central Africa”.

Study of bone density according to СT data before and in the remote period after unicondylar knee arthroplasty

Background. Unicondylar knee arthroplasty has become popular among orthopedists in recent years. The main complication of this technology is the instability of the tibial component of the endoprosthesis due to the development of local osteoporosis in the area of arthroplasty. Patients with decreased bone density are at high risk of developing instability of the tibial component of the endoprosthesis. Therefore, determining the levels of bone mineral density in patients with osteopenia before arthroplasty make it possible to calculate the risk of complications in the long term. Objective: to evaluate the bone mineral density according to the computed tomography (CT) of the tibial plateau resection zone for unicondylar arthroplasty in patients at risk. Materials and methods. The state of three cortical layer zones was assessed: anterior, middle, posterior and 4 zones of the plateau cut plane. The optical density of bone tissue was measured on CT images of the tibial plateau of the knee joint using the Hounsfield scale. Changes in bone structures in the area of placing tibial component of the endoprosthesis were studied in 2 groups of patients: group I — ten individuals who had undergone unicondylar knee arthroplasty 3–6 years ago and complained of negative phenomena in the prosthetic knee, group II — ten patients who had undergone unicondylar arthroplasty 1.2–2 years ago. These patients underwent CT densitometry at the follow-up examination. Results. Before arthroplasty, the maximum optical density of bone tissue was statistically the same. The density of the cortical layer was maximal in the anterior part of the bone (~ 720 HU), minimal — in the posterior part (580 HU). For the spongy bone zone, the maximum optical density was observed in the anterior part (~ 470 HU), and in the posterior part, it was lower. In 3–6 years, patients of group I showed a significant decrease in the optical density of the bone, both in its cortical layer and in the cancellous tissue. The greatest losses were detected in the medial zones of the cancellous bone. Patients had areas of cortical layer resorption, and in some individuals, its complete absence. At the same time, the absorption index of the cortical layer in the areas of destruction did not exceed 100 HU. The maximum optical density of the cortical layer in the zones also decreased. In patients of group II, 1.5–2 years after arthroplasty, there were no noticeable changes in the bone structures in the surgery area. Changes occurred in the medial zones of the cancellous bone of the tibial plateau. Patients with osteopenia reported changes in bone optical density already in the first years after arthroplasty, although they do not lead to instability of the tibial component of the endoprosthesis. Conclusions. Patients with decreased bone density (osteopenia) during joint arthroplasty are at risk of developing local osteoporosis in the area of bone resection. The first signs of resorption of the cancellous bone can be observed 1.5–2 years after arthroplasty. Timely treatment measures can slow down the further progression of osteoporosis.

A micromorphological analysis ofBolonia lataMeunier from the Cretaceous of the Neuquén Basin (Patagonia, Argentina): new insights into the tracemaker

AbstractPolychaetes, echinoids and gastropods have been proposed as tracemakers forBoloniaMeunier, an elongate positive epirelief trace fossil characterized by two lobes composed of biserial, subtriangular pads and a mostly heart‐shaped cross‐section. Here, the internal structure and micromorphology ofBoloniaare described for the first time using serial thin sections from shallow‐marine Lower Cretaceous intervals of the Agrio Formation (Neuquén Basin, Argentina). In vertical thin sections, a conical structure of variable width extends centrally from the base to the top of the trace. In horizontal thin sections, grains are reoriented and reworked, forming a central zigzag structure. The organic matter and clays form grain aggregates representing the internal structure of individual pads of the trace fossil. The sediment has mostly been reoriented, with grains making up subcircular pods. We interpret the central conical structure as the collapse of the medial zone of the trace fossil, which could have destroyed drain tubes, especially in the absence of early cementation. Studying horizontal thin sections, we reconstruct the diagnostic biserial pads as biserial concave structures. These are interpreted as backfilling structures produced by the aboral and lateral spines of irregular echinoids, which worked together to compact the sediment anteroposteriorly and moved alternatively, explaining the zigzag pattern in the menisci. We propose Spatangoidea or Cassiduloidea (or a closely related group) with a similar burrowing ability and spine movement as tracemakers of theseBoloniaspecimens.

Carpenter-moths (Lepidoptera, Cossidae) of the Korean peninsula with a new record of species

We present eight species in seven genera of the family Cossidae (Lepidoptera) from Korea, including one newly recorded species, Cossus siniaevi. Two females of C. siniaevi were collected in the middle part of Korea, and they were distinguished by the strongly elongate forewing with narrow wavy black streaks and a weakly grayish-white patch in the medial zone and at the apex. The female genitalia of C. siniaevi can be distinguished by the simple antrum simple with medially invaginated, the short and narrow ductus bursae, and the large pouch-shaped corpus bursae without a signum. We provided the diagnosis of each genus, including male and female genitalia, and the key to the species.

Downstream changes in floodplain sedimentation and their effects on channel avulsion in stream-dominated alluvial fans: The Cretaceous Duwon Formation in the southern Korean Peninsula

Stream-dominated alluvial fans are formed by the periodic channel avulsion running on their surfaces and are characterized by the downstream changes in hydrodynamics of stream flows and flood frequency. The spatial variations in hydrodynamics also control the sedimentation on the floodplain, which is important for sediment dispersal patterns on the stream-dominated alluvial fans as they feed back into channel avulsion processes. To understand the influence of downstream changes in hydrodynamics on the floodplain sedimentation and associated channel avulsion processes, we studied the Cretaceous Duwon Formation in the southern part of the Korean Peninsula. The Duwon Formation unconformably overlies the Paleoproterozoic basements and consists of gravelly braided stream deposits (FA-1), sandy braided stream deposits (FA-2), and calcretes-bearing floodplain deposits (FA-3). Close to the basements, FA-1 shows the radial paleoflow patterns, and the size of sediments and the ratio of channel to floodplain deposits decrease downstream over a relatively short distance (<7 km). This indicates that the Duwon Formation was deposited in the stream-dominated alluvial fans under arid to semi-arid climatic conditions, which can be classified into the proximal, medial, and distal zones.In the medial zone, the floodplain deposits are composed of the underlying, purple-colored sandstones and the overlying, compensational stacked crevasse channel and splay deposits (ca. 19 m thick) with the unsystematic paleoflow directions, finally overlain by the sandy braided stream deposits. In contrast, in the distal zone, the floodplain fines are composed of homogeneous clay and silt with calcretes and vegetation traces. These floodplain fines are interbedded with and overlain by the progradational stacked, coarsening- and thickening-upward trending, crevasse channel and splay deposits (ca. 18 m thick) with the constant paleoflow directions to those of the overlying sandy braided stream deposits. In the medial zone, a relatively large volume of discharge of the stream floods resulted in the frequent overbank flooding via the multiple breaching points and the concomitant growth of alluvial ridges by the combined effects of in-channel bed aggradation and compensational stacked crevasse channel and splay deposits resulted in a shift in the flow pathway of the sandy braided streams. In the distal zone, the floodplain fines containing calcretes and vegetation traces suggest the longer periods of non-deposition, providing sufficient time for the vegetation development. Once the channel levees collapsed, the vegetated channel levees stabilized the breaching point, and the breaching point progressively incised by the multiple flooding events, causing susceptibility to overbank flooding. Crevasse channel flows via the breaching point and associated overbank floodwaters led to a continuous supply of the coarse-grained sediments stacking on the cohesive, vegetated floodplain fines, with an increase in the cross-floodplain topographic gradient. As a result, crevasse channels were able to advance the distal floodplains, resulting in the development of progradational stacking pattern. With the cross-floodplain topographic gradient, the deposition of these erodible overbank flooding sediments on the cohesive, vegetated floodplain fines provided an alternative route for the parent channel, resulting in channel avulsion. Thus, this study suggests that downstream changes in hydrodynamics and associated floodplain sedimentation are important for channel avulsion and hence control the sediment dispersal patterns of coarse-grained sediments on the stream-dominated alluvial fans.

Poster 281: Current practice for meniscus repair rehabilitation amongst AOSSM members

Objectives: Meniscus repair has correspondingly become more popular, with promise of preservation of joint mechanics and hopes of preventing secondary arthritis. However, it is not clear the optimal rehabilitation protocol, with regards to the duration of limitation of range of motion and weight bearing, following repair of various meniscal tear types. The purpose of this study is to understand the current contextual landscape of how practitioners recommend rehabilitating patients that undergo meniscal repair. Methods: This is a cross-section observational survey study. A de-identified survey was designed using arthroscopic images from six cases of meniscal repair (Fig 1): Radial tear at popliteal hiatus, medial meniscus posterior root repair, lateral meniscus radial tear, lateral meniscus horizontal tear, medial meniscus red-white zone bucket-handle repair, and medial meniscus red-red zone longitudinal peripheral tear. This survey was distributed to American Orthopaedic Society for Sports Medicine (AOSSM) members by e-mail. Questions were designed to elicit, from the surveyed surgeons, their recommendations for duration of limitation of: 1. range of motion, and 2. weight bearing status, for each case. Additionally, use of meniscal repair adjuncts, including bracing and use of biologics, was elicited from the same cohort. Results: 451 completed surveys were obtained from 2973 AOSSM members (15.2%). A majority of AOSSM members recommend bracing after repair of tears that lost hoop integrity (83.3%) and that had intact hoop integrity (76.0%). A majority of members report routine use of synovial rasping/trephination (86.0%) and notch microfracture (66.5%), while a minority report use of more involved biologic supplementations including classic fibrin clot (4.9%), platelet-rich plasma (8.9%), and bone marrow aspirate concentrate (2.9%). Timing of return to weight-bearing and range of motion appear to depend on hoop stress integrity; tears with intact hoop integrity were, on average, permitted to return to weight bearing more quickly (1.4 weeks for partial weight bearing, 3.6 weeks for full weight bearing), versus tears that demonstrated loss of hoop integrity (3.9 weeks for partial weight bearing, 6.2 weeks for full weight bearing). Hoop integrity also appears to affect return to full range of motion, with tears that had a loss of hoop integrity demonstrating a longer period of post-operative restriction of range of motion. Full flexion was permitted at an average of 5.0 weeks for tears with intact hoop stress, versus 5.8 weeks for tears with loss of hoop stress. Out of the six cases presented, the most cautious tear types for post- repair rehabilitation were a radial tear at the popliteal hiatus, followed by a medial meniscus posterior root tear. Conclusions: Although there is no consensus on how each tear type should be rehabilitated following repair, initial tear hoop stress integrity appears to substantially affect rehabilitation decision-making, with loss of hoop stresses triggering a more conservative approach to rehabilitation, both with regards to permissive return to range of motion and weight bearing. A majority of AOSSM practitioners brace after meniscal repair. A majority of practitioners perform in situ adjuncts for biological healing, while a minority adds extrinsic biologics. [Table: see text]

Feasibility of C2 Pedicle Screw Fixation With the "in-out-in" Technique for Patients With Basilar Invagination.

Retrospective study. To evaluate the feasibility of C2 pedicle screw fixation with the "in-out-in" technique in patients with basilar invagination (BI). The "in-out-in" technique is a fixation technique in which the screw enters the vertebrae through the parapedicle. The technique has been used in upper cervical spine fixation. However, anatomic parameters associated with the application of this technique in patients with BI are unclear. We measured the C2 pedicle width (PW), the distance between the vertebral artery (VA) and the transverse foramen (VATF), the safe zone, and the limit zone. The lateral safe zone is the distance from the medial/lateral cortex of the C2 pedicle to the VA (LPVA/MPVA), and the medial safe zone is the distance from the medial/lateral cortex of the C2 pedicle to the dura (MPD/LPD). The lateral limit zone is the sum of LPVA/MPVA and VATF (LPTF/MPTF), and the medial limit zone is the distance from the medial/lateral cortex of the C2 pedicle to the spinal cord (MPSC/LPSC). PW, LPVA, MPVA, and VATF were measured on the reconstructed CT angiography. PW, MPD, LPD, MPSC, and LPSC were measured on MRI. We define a width greater than 4mm as safe for screw. The t -test was used to compare the parameters between male and female, left and right sides in all patients, and PW in CTA and MRI data in the same patient. For intrarater reliabilities, interclass correlation coefficients were calculated. A total of 154 patients (49 CTA, 143 MRI) were included. The average PW, LPVA, MPVA, LPTF, MPTF, MPD, LPD, MPSC, and LPSC were 5.30mm, 1.28mm, 6.60mm, 2.45mm, 8.94mm, 2.09mm, 7.07mm, 5.51mm, and 10.48mm, respectively. Furthermore, in patients with PW <4mm, 53.6% of MPVA, 86.2% of LPTF, and all limit zones were larger than 4mm. In patients with BI, there is sufficient space medially and laterally to the C2 pedicle for partial screw encroachment to achieve "in-out-in" fixation, even if the pedicle is small. Level-4.

In vivo evaluation of ankle kinematics and tibiotalar joint contact strains using digital volume correlation and 3 T clinical MRI

BackgroundIn vivo evaluation of ankle joint biomechanics is key to investigating the effect of injuries on the mechanics of the joint and evaluating the effectiveness of treatments. The objectives of this study were to 1) investigate the kinematics and contact strains of the ankle joint and 2) to investigate the correlation between the tibiotalar joint contact strains and the prevalence of osteochondral lesions of the talus distribution. MethodsEight healthy human ankle joints were subjected to compressive load and 3 T MRIs were obtained before and after applying load. The MR images in combination with digital volume correlation enabled non-invasive measurement of ankle joint kinematics and tibiotalar joint contact strains in three dimensions. FindingsThe total translation of the calcaneus was smaller (0.48 ± 0.15 mm, p < 0.05) than the distal tibia (0.93 ± 0.16 mm) and the talus (1.03 ± 0.26 mm). These movements can produce compressive and shear joint contact strains (approaching 9%), which can cause development of lesions on joints. 87.5% of peak tensile, compressive, and shear strains in the tibiotalar joint took place in the medial and lateral zones. InterpretationThe findings suggested that ankle bones translate independently from each other, and in some cases in opposite directions. These findings help explain the distribution of osteochondral lesions of the talus which have previously been observed to be in medial and lateral regions of the talar dome in 90% of cases. They also provide a reason for the central region of talar dome being less susceptible to developing osteochondral lesions.

Fin systems comparative anatomy in model Batoidea Raja asterias and Torpedo marmorata: Insights and relatioships between musculo-skeletal layout, locomotion and morphology.

The macroscopic and microscopic morphology of the appendicular skeleton was studied in the two species Raja asterias (order Rajiformes) and Torpedo marmorata (Order Torpediniformes), comparing the organization and structural layout of pectoral, pelvic, and tail fin systems. The shape, surface area and portance of the T. marmorata pectoral fin system (hydrodynamic lift) were conditioned by the presence of the two electric organs in the disk central part, which reduced the pectoral fin surface area, suggesting a lower efficiency of the "flapping effectors" than those of R. asterias. Otherwise, radials' rays alignment, morphology and calcification pattern showed in both species the same structural layout characterized in the fin medial zone by stiffly paired columns of calcified tiles in the perpendicular plane to the flat batoid body, then revolving and in the horizontal plane to continue as separate mono-columnar rays in the fin lateral zone with a morphology suggesting fin stiffness variance between medial/lateral zone. Pelvic fins morphology was alike in the two species, however with different calcified tiles patterns of the 1st compound radial and pterygia in respect to the fin-rays articulating perpendicularly to the latter, whose tile rows lay-out was also different from that of the pectoral fins radials. The T. marmorata tail-caudal fin showed a muscular and connective scaffold capable of a significant oscillatory forward thrust. On the contrary, the R. asterias dorsal tail fins were stiffened by a scaffold of radials-like calcified segments. Histomorphology, heat-deproteination technique and morphometry provided new data on the wing-fins structural layout which can be correlated to the mechanics of the Batoid swimming behavior and suggested a cartilage-calcification process combining interstitial cartilage growth (as that of all vertebrates anlagen) and a mineral deposition with accretion of individual centers (the tiles). The resulting layout showed scattered zones of un-mineralized matrix within the calcified mass and a less compact texture of the matrix calcified fibers suggesting a possible way of fluid diffusion throughout the mineralized tissue. These observations could explain the survival of the embedded chondrocytes in absence of a canalicular system as that of the cortical bone.

Morphometric Analysis of the Ophthalmic and Central Retinal Arteries via the Endoscopic Endonasal Trans-ethmoidal Approach: Surgical Relevance of Vascular Components Within the Medial Intraconal Zones

The endoscopic endonasal approach (EEA) offers a minimally invasive route to treat medial intraconal space (MIS) lesions. Understanding the configuration of the ophthalmic artery (OphA) and the central retinal artery (CRA) is crucial. An EEA to the MIS was performed on 30 orbits. The description of the intraorbital part of the OphA was divided into 3 segments and classified as type 1 and type 2 and the MIS was divided into three surgical zones (A, B, C). The CRA's origin, course, and point of penetration (PP) were analyzed. The relationship between the position of the CRA in the MIS and the OphA type was analyzed. The OphA type 2 was present in 20% of specimens. The site of origin of the CRA from the OphA was found on the medial surface in type 1 and on the lateral surface of type 2. The point of penetrationof the central retinal arterywas found in 87% of the specimens on the inferomedial surface, just anterior to the inferior muscular trunk, at an average distance of 9.5mm±1 from the globe and 17mm±1.5 from the AZ. The presence of the CRA in Zone C was associated only with OphA type1. OphA type 2 is a common finding and can compromise the feasibility of an EEA to the MIS. A detailed preoperative analysis of the OphA and CRA should be conducted prior to approaching the MIS due to the implications of the anatomical variations that can compromise safe intraconal maneuverability during an EEA.

Emplacement of lava flows on eroded terrain, part I: The case of the Tiretaine valley (Chaîne des Puys, France)

Lava flows often erupt onto eroded landscapes, flowing across plateaus, into valleys and basins, and down escarpments. With the Tiretaine lava flow system in the Chaîne des Puys (Central France), lava flowed over the complex topography of an ancient rift margin. Erupted 41.3 ± 1.3 ka ago onto the granite plateau of the Massif Central, flow initially advanced over a surface that sloped 2°E. On reaching a fault scarp that delimits the plateau, flows descended the 6° slopes of a ravine that cuts the scarp E-W. In part 1 of this work we thus consider the case where lava is emplaced onto relatively flat terrain, then passes over a break-in-slope onto steeper slopes. To do this, we carried out mapping and facies analysis down this ∼6-km-long system, collecting 24 samples on which we completed textural and geochemical analyses. Results reveal three lava facies:(i)a 3 × 2 km proximal zone of inflated pāheohoe with a thickness of 25–50 m;(ii)a channelized medial zone with simple rubble levees nested in the ravine; and(iii)a valley-ponded distal zone with tubes and well-formed columnar jointing.Through simple mass balance calculations, and analogy with systems displaying similar facies, we find that the proximal inflated zone was fed at relatively low (1–5 m3/s) effusion rates. This built the proximal portion of the flow field over a period of 1–6 years, forming a volume of flow-field stored, degassed lava. Failure of the eastern edge of the proximal flow field at the head of the Tiretaine ravine fed high (215–315 m3/s) effusion rate flow down the ravine, to build a channelized flow system in just a few hours. However, the presence of a lava dam at the mouth of the ravine impeded further flow and resulted in ponding. This ponded volume then cooled in-place over a period of 10–11 years. Breaks-in-slope, and the resulting lava–topography interaction, thus created a system of reservoirs and transfers, with different flow rates, dynamics and emplacement time scales. For our case, where the lava flow system is mostly in a UNESCO World Heritage site, the study provides scientific support for Geoheritage efforts, outreach, and initiatives to support protection of geologically important sites.

Alignment and Fixation in Revision Total Knee Arthroplasty With Press-Fit, Offset, Diaphyseal-Engaging Stem Extensions, and Eccentric Reaming Technique

BackgroundA revision total knee arthroplasty must control limb alignment, often to address the cause of failure. Press-fit stems that engage the diaphysis with cement restricted to the metaphysis constitute one fixation technique. These long stems restrict coronal alignment of the prosthesis and as a result reduce the likelihood of extreme malposition. For the same reasons, long stems can make it difficult to manipulate alignment and achieve a specific coronal alignment angle. Nevertheless, femoral stems with a tight diaphyseal fit may still occupy a small range of varus-valgus positions due to the conical distal femoral metaphysis. Pulling the reamer toward the lateral endosteum increases femoral component coronal alignment toward a valgus direction and pushing the reamer medially increases alignment in a more varus direction. A straight stem, in combination with a medially directed reaming, would result in a femoral component that overhangs medially, but an offset stem can recenter the femoral component and maintain the desired alignment. We hypothesized that diaphyseal fit plus this reaming technique can control limb coronal alignment and provide fixation. MethodsThis was a retrospective clinical and long-leg radiographic study of consecutive revision total knee arthroplasties with minimum 2-year follow-up. Outcomes were correlated with New Zealand Joint Registry data to identify rerevisions of 111 consecutive revision knee arthroplasties, 92 after exclusions, at a minimum 2-year (range, 2 to 10) follow-up. ResultsMean femoral and tibial canal fill exceeded 91% on antero-posterior and lateral radiographs. The mean hip-knee-ankle angle was 179.6o (174.9-184.0) with 80% within ± 3o of neutral. The hip-ankle axis crossed the central Kennedy zone in 76.5% of cases and the other 24.6% crossed the inner medial and inner lateral zones. Tibial components: 99.0% ± 3o. Femoral components: 89.5% within ± 3o. There were 5 knees that failed due to infection, 3 from femoral loosening, and 1 due to recurvatum instability from polio. ConclusionsThis study describes a surgical plan and technique for achieving target coronal alignment with press-fit diaphyseal fixation. It is the only series of revision knee arthroplasties with diaphyseal press-fit stems to report canal fill in 2 planes and coronal alignment on full-length radiographs.

Serial Quantitative Assessment of Load Redistribution After Medial Open-Wedge High Tibial Osteotomy.

The maximum standardized uptake value (SUVmax), as determined on combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT), can be an indicator of biomechanical changes due to the load redistribution effect after medial open-wedge high tibial osteotomy (MOW-HTO). The purposes of this study were to (1) analyze serial changes in the SUVmax in the medial, lateral, and patellofemoral compartments after MOW-HTO and (2) identify the contributing factors that affect changes in the SUVmax. The hypotheses were that (1) an elevated SUVmax in the medial compartment would be transferred to the lateral compartment because of the load redistribution effect and (2) there would be contributing factors that cause SUVmax changes. Case series; Level of evidence, 4. Included were 67 knees that were treated with biplanar MOW-HTO between March 2019 and December 2020. SPECT/CT was performed immediately after surgery and at 3 months and 1 year postoperatively to determine the serial load redistribution effect of MOW-HTO. The Pearson correlation coefficient was used to evaluate the relationship between SUVmax and radiological parameters, and subgroup analyses were conducted to compare the SUVmax according to associated cartilage procedures and the weightbearing line ratio (WBLR). The SUVmax in the medial and lateral compartments increased at 3 months but decreased at 1 year postoperatively. The load redistribution effect was most prominent in the anterior zones of the femur (medial: P = .041; lateral: P = .012). In the patella, the SUVmax decreased in both the medial and the lateral zones at all follow-up times (P < .001 for all). The SUVmax in the anterolateral and posterolateral articular zones of the femur increased with a greater preoperative WBLR (r = 0.256, P = .039; and r = 0.261, P = .036, respectively). Patients who underwent an associated cartilage procedure had a significantly higher SUVmax in the anteromedial and posteromedial articular zones of both the femur and the tibia at 1 year postoperatively (P ≤ .002 for all). After MOW-HTO, the unloading effect in the anteromedial articular zone of the femur was the most significant. A greater SUVmax in the lateral zones of the femur was observed in cases of overcorrection. The SUVmax in the medial zones was higher postoperatively in patients with associated cartilage procedures.

Apical constriction during embryogenesis is driven by self-assembled actomyosin networks that spontaneously develop radial polarity and pulsing.

During embryogenesis, cells exert coordinated forces to sculpt tissues into complex shapes that are precursors of organs and other specialized structures. Apical constriction is a conserved deformation mode that contracts and folds tissues. In many organisms, apical constriction is driven by contractile pulses generated by apical actomyosin cellular networks (Martin and Goldstein, 2014) with radial polarity: formins and actin filament barbed ends localize to peripheral cell-cell junctions, while actin filaments point inwards with myosin II in the medial apical zone (Mason et al., 2013).