Single Hand Research Articles

Different effects of smooth pursuit eye movements on motion-based stimulus response congruency.

In the motion-based stimulus-response compatibility (SRC) effect, responses are faster when the task-irrelevant stimulus motion is congruent with the response movement performance. In the present study, we tested whether smooth pursuit eye movements, related to tracking a moving object, influence motion-based SRC when present on their own or when combined with position-based SRC. We examined the motion-based SRC effect during both the response selection and response execution stages. When investigating motion-based SRC alone, participants responded with left or right movements of the single hand to the left or right movements of a centrally presented stimulus, either with their eyes fixated at the center or tracking the moving object. In the case of combined motion-based and position-based SRC, participants responded with left or right movements of the left or right hand to stimulus motion presented on the left or right side of the screen, again with eyes either fixated at the center or following the moving target. Results showed that during the response selection stage, smooth pursuit type eye movements had no effect on the motion-based SRC when the stimulus moved in the center, whereas the effect was enhanced when the stimulus presentation was lateralized. This aligns with the idea that attentional shifts differ between central and peripheral vision and that cognitive system computes various spatial maps for stimulus and response. In the case of response execution, smooth pursuit type eye movements had no effect on the motion-based SRC effect, regardless of stimulus location.

Insights Into Magma Reservoir Dynamics From a Global Comparison of Volcanic and Plutonic Zircon Trace Element Variability in Individual Hand Samples

AbstractTrace element compositional trends in zircons separated from single hand samples have been used to infer dynamic processes in magma reservoirs. Here, we compile published zircon trace element chemistry to quantify any systematic difference between the range of compositions observed in zircon from individual volcanic and plutonic hand samples and compare these results with geochemical modeling to derive implications for magma reservoir dynamics. We find that both rock types span a wide range of hand‐sample scale variability (i.e., wide range of coefficients of variation), but there is no systematic difference in the average variability between plutonic and volcanic samples (i.e., no difference in the mean coefficient of variation). This indicates that dynamic processes related to eruption are not necessarily required as a fundamental process to create hand sample‐scale compositional heterogeneity beyond what is present due to dynamic processes in the reservoir recorded in plutonic samples. Modeling of felsic systems (>68.5 wt.% SiO2) indicates that the similar average variability in felsic volcanic and plutonic hand samples cannot be reproduced by closed‐system crystallization of compositionally distinct melts locally within a magma reservoir (i.e., isolated melt pockets in a crystal mush) but requires mixing of at least two felsic melt compositions at a small spatial scale. This study provides a framework for focused studies on individual volcanic‐plutonic systems exploring how plutonic and volcanic zircon compositional variability records the time and length scales of magma reservoir processes.

Hand Gesture Recognition Using Ultrasonic Array with Machine Learning

In the field of gesture recognition technology, accurately detecting human gestures is crucial. In this research, ultrasonic transducers were utilized for gesture recognition. Due to the wide beamwidth of ultrasonic transducers, it is difficult to effectively distinguish between multiple objects within a single beam. However, they are effective at accurately identifying individual objects. To leverage this characteristic of the ultrasonic transducer as an advantage, this research involved constructing an ultrasonic array. This array was created by arranging eight transmitting transducers in a circular formation and placing a single receiving transducer at the center. Through this, a wide beam area was formed extensively, enabling the measurement of unrestricted movement of a single hand in the X, Y, and Z axes. Hand gesture data were collected at distances of 10 cm, 30 cm, 50 cm, 70 cm, and 90 cm from the array. The collected data were trained and tested using a customized Convolutional Neural Network (CNN) model, demonstrating high accuracy on raw data, which is most suitable for immediate interaction with computers. The proposed system achieved over 98% accuracy.

Short-latency afferent inhibition is reduced with cold-water immersion of a limb and remains reduced after removal from the cold stimulus.

The experience of pain that is induced by extremely cold temperatures can exert a modulatory effect on motor cortex circuitry. Although it is known that immersion of a single limb in very cold water can increase corticomotor excitability it is unknown how afferent input to the cortex shapes excitatory and inhibitory processes. Therefore, the purpose of this study was to examine motor-evoked potentials (MEP), short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI) in response to immersion of a single hand in cold water. Transcranial magnetic stimulation (TMS) was used to assess MEPs, and peripheral nerve stimulation of the median nerve paired with TMS was used to measure SAI and LAI in motor circuits of the ipsilateral hemisphere. Measurements were obtained from electromyography (EMG) of the first dorsal interosseous (FDI) at baseline, during cold-water immersion, and during recovery from cold-water immersion. The intervention caused unconditioned MEPs to increase during exposure to the cold stimulus (P=0.008) which then returned to baseline levels once the hand was removed from the cold water. MEP responses were decoupled from SAI responses, where SAI was reduced during exposure to the cold stimulus (P=0.005) and remained reduced compared to baseline when the hand was removed from the cold water (P=0.002). The intervention had no effect on LAI. The uncoupling of SAI from MEPs during the recovery period suggests that the mechanisms underlying the modulation of corticospinal excitability by sensory input may be distinct from those affecting intracortical inhibitory circuits. HIGHLIGHTS: What is the central question of this study? Does immersion of a limb in very cold water influence corticospinal excitability and the level of afferent inhibition exerted on motor cortical circuits? What is the main finding and its importance? In additional to perception of temperature, immersion in 6°C water also induced perceptions of pain. Motor evoked potential (MEP) amplitude increased during immersion, and short-latency afferent inhibition (SAI) of the motor cortex was reduced during immersion; however, these responses differed after the limb was removed from the cold stimulus, as MEPs returned to normal levels while SAI remained suppressed.

A surge in the incidence of invasive Group A Streptococcus hand infections: a single Hand Unit experience.

We highlight an increase in the number of invasive Group A streptococcal soft tissue infections and present the impact of those on the hand surgery service, based on a single Hand Unit experience at the Pulvertaft Hand Centre.

Biodesign: Engineering an aortic endograft explantation tool

Endovascular aortic repair (EVAR) graft failure can be as high as 16% to 30% owing to endoleak, graft migration, or infection, often necessitating explantation, leading to potential morbidity (31%) and mortality (6.3%). Graft prongs frequently tear through the endothelium during explantation, leading to endothelial damage and subsequent fatal bleeding. The current standard of care involves different suboptimal techniques such as the syringe technique in which a cylinder is improvised by cutting a syringe in half and pushed over the graft hooks in a rotating motion, until covered for manual explantation. Because there is no commercially available product to address this shortcoming in graft explantation, we engage in the biodesign process to produce a functional explantation device. We designed and prototyped multiple potential solutions to remove EVAR endografts safely. Silicone tubing with EVAR endografts deployed in the lumen were used to simulate a grafted aorta and test each prototype. Prototypes were compared in their ability to meet design criteria including decrease in graft diameter, prevention of arterial dissection, ease of use, and decrease in procedure time. After determining the single best prototype, surgeon feedback was elicited to iteratively improve the original design. The most effective design uses a tapered lumenal geometry that decreases the EVAR graft diameter and uses stainless steel beads to prevent shear stress to the simulated aorta. A distal grip allows for easy single hand manipulation of the device, while a latching mechanism allows for smooth placement and removal over the endograft. After rigorous prototyping, our device proved feasible and effective for safe EVAR explantation, allowing this procedure to be performed safely.

Ligament Suspensionplasty With Suture Tape Augmentation​ for Basal Thumb Arthritis.

Thumb carpometacarpal arthritis is common with aging, more common in women than men, and usually occurs after age 40. If a patient fails conservative treatments such as splinting, medications, and corticosteroid injections, then surgical intervention may be appropriate. Currently, there is no consensus on the best surgical treatment. By limiting metacarpal subsidence, ligament suspensionplasty with suture tape augmentation offers great pain relief, excellent functional outcomes, and limited postoperative immobilization. With this technique, trapeziectomy is first performed. A portion of the abductor pollicis longus tendon is resected and loaded onto the SwiveLock anchor using 4-0 FiberLoop, in addition to suture tape. The prepared graft and tape construct is anchored into the lateral first metacarpal (MC) base and index metacarpal base. After surgery, patients are put in a short arm thumb spica splint, interphalangeal (IP) joints free. Active motion is initiated at the first postoperative visit, usually within 1 week. All patients who had thumb arthritis treated with carpometacarpal suspensionplasty and suture tape augmentation between 2015 and 2022 by a single hand surgeon at our institution were queried. A total of 110 patients were invited to take part in this study, and 61 patients consented and were included in this study. Mean last in-office follow up was at 7.5±4.0 months, which showed significant improvements in pinch strength (P=0.011). A survey taken at a mean 2.8±1.3 years (range: 0.5 to 5.2y) after surgery reports a postoperative DASH score of 7.3±7.7 (range: 0 to 23.3), and VAS pain score of 0.7±1.1 (range: 0 to 5).

Risk prediction model for distracted driving: Characterizing interactions of eye glances and manual sequences

Distracted driving substantially undermines road safety, and the frequent, low-accuracy distracted driving risk prediction alarms may detrimentally affect drivers’ judgments. The study aims to improve risk prediction accuracy by mapping the distinctive interactions of eye glances and manual sequences in distracted driving into a graph structure of nodes and edges. Distraction patterns are categorized as visual distractions (VD), manual distractions (MD), and visual-manual distractions (VMD) based on daily driving behaviours, such as eating, drinking, reaching for something, and using mobile phones. 1,806 distraction alarm records came from an active safety platform (ASP) in Beijing, covering 69 drivers from 23 hazardous materials road transport companies. The study extracts characteristics to assess distracted driving risks, including visual, manual, and driving performance features. Subsequently, unsupervised learning is used to cluster risk features into three categories (low, medium, and high), which serve as labels for the risk prediction model. In addition, each distraction alarm sequence is divided into nodes and edges of a graph. More specifically, five visual areas, forward (F), object of distraction (Dis), left window (LW), rear-view mirror (RM), center dashboard (C), as well as manual sequences, single hand (H), double hands (2H) are represented as nodes. The edges are connected in parallel (occurring simultaneously) or in series (occurring sequentially), with arrows pointing from the earlier node to the later one. Furthermore, coupled with time, global, and environmental features, a temporal graph attention network (TGAT) with integrated time functions and multi-head attention mechanisms is developed to predict distracted driving risks. The results indicated that VMD demanded more visual and manual resources and led to more high-risk alarms than VD and MD. Besides, TGAT reached a promising result, outperforming other time series methods. This study is valuable for driver distraction monitoring and driving risk assessment, significantly contributing to the enhancement of road safety.

Origami manipulation by robot hand utilizing electroadhesion

This study presents strategies for the three fundamental origami operations of grasping, bending, and folding using a novel robot hand and simple motions. These operations are executed using a simple geometric model and without any visual feedback or physical modeling not to restrict the motions. With a few applications in the field of paper manipulation, the electroadhesion technology is employed to perform single hand grasping. Bending is realized by a single hand utilizing the elasticity of origami and friction. Folding is performed by holding an origami with more than two points to fix it at any moment for preciseness. In addition to the design of hardware and motions, operations are demonstrated with general criteria for the crease precision evaluation.

Analysis of Instantaneous Kinematic Properties Regarding the Shape of Robotic Mechanisms

Abstract A theoretical framework for analyzing instantaneous kinematic properties regarding the shape of robotic mechanisms is proposed. Conventional research on kinematic analysis regarding the shape has been conducted with the primary goal of approximating a target shape. In contrast, this study does not set a target shape, and instantaneous kinematic properties regarding the shape formed by multiple reference links are analyzed. The properties provide information about the shape change that is easy to achieve and about the controllability of the shape. Furthermore, in contrast to the standard kinematic analysis of robot manipulators that assumes having a single hand link configuration with respect to the base link, the kinematic analysis in this study is free from this assumption. When analyzing instantaneous kinematic properties regarding the shape, it is crucial to decompose motions of reference links into rigid and nonrigid components. After formulating this decomposition, the Jacobian matrices that relate active joint velocities and nonrigid motions are defined. The indices of instantaneous kinematic properties regarding the shape are defined on the basis of the Jacobian matrices. Moreover, application examples using the defined indices are demonstrated.

Ice cooling challenge as a means to probe skin microvascular function

Skin microvasculature provides a window to study both systemic and local physiology. In vascular medicine, various challengers such reactive hyperemia, hypoxia or hyperoxia, and heat, have been used to study function and search for potential clinical biomarkers. A positive relationship between increased skin temperature and skin perfusion has been suggested, but skin cooling as a challenger has not been well explored. In the present study, the adaptive cardiovascular and hemodynamic impacts of single hand cooling were examined in a group of ten healthy women, 27.3±7.9 years old, of normal body mass index and ankle-brachial index, normotensive, non-smoking, and free from any medication and supplements. The study followed all principles of good clinical practice and ethics commission approval. After complete stabilization, a participant’s palm, randomly chosen, was placed in contact with a frozen surface covered by a plasticized cotton cloth. Blood perfusion was measured using a laser Doppler flowmetry (LDF) instrument, and temperature were continuously registered in both hands, before, during, and after (early and late recovery) the ice cooling challenge. Nominal values for blood perfusion and temperature were considered, as well as their wavelet transform (WT) components, translating endothelial [0.0095; 0.021] Hz, autonomic [0.021; 0.052] Hz, myogenic [0.052; 0.015] Hz, respiratory [0.15; 0.6] Hz, and cardiac [0.6; 2] Hz activities. No significant differences were observed between limbs regarding nominal LDF values for each experimental phase. Nonetheless, significant differences were observed for nominal temperature signals between limbs during the challenge (Wilcoxon’s signed rank test; p=0.047), and for early (p=0.028) and late (p=0.028) recovery phases. Significant differences were observed for ipsi- and contralateral LDF signals (Friedmann’s test, p<0.001, and p=0.012, respectively), and also for ipsi- and contralateral temperature signals (Friedmann’s test, p<0.001, and p=0.004, respectively). These contralateral responses have been previously described with other challengers applied only in the ipsilateral limb, whilst it is known that local cooling stimulates cutaneous thermoreceptors, sympathetic nerve activity and cutaneous vascular resistance. However, our findings also show that temperature may be more sensitive than LDF for studying the ice cooling challenge, and that the WT analysis approach can provide potential physiological interpretations. Nonetheless, a strong positive correlation (Spearman’s rs = 0.820, p<0.001) was observed between temperature and LDF signals overall for both limbs. In conclusion, this preliminary study suggests that this cooling challenger is effective to elicit vascular physiological changes in both limbs, indicating a putative centrally-mediated adaptive process that might be quantified by changes in cardiac and respiratory activities, as shown from WT analysis. Additionally, temperature signals and the use of WT analysis seem to provide more sensitive and explanatory insights than the use of LDF signals and nominal values alone. Suported by COFAC/ALIES. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Bi-DexHands: Towards Human-Level Bimanual Dexterous Manipulation.

Achieving human-level dexterity in robotics remains a critical open problem. Even simple dexterous manipulation tasks pose significant difficulties due to the high number of degrees of freedom and the need for cooperation among heterogeneous agents (e.g., finger joints). While some researchers have utilized reinforcement learning (RL) to control a single hand in manipulating objects, tasks that require coordinated bimanual cooperation are still under-explored due to the fewer suitable environments, which can result in difficulties and sub-optimal performance. To address these challenges, we introduce Bi-DexHands, a simulator with two dexterous hands featuring 20 bimanual manipulation tasks and thousands of target objects, designed to match various levels of human motor skills based on cognitive science research. We developed Bi-DexHands in Issac Gym, enabling highly efficient RL training at over 30,000 frames per second using a single NVIDIA RTX 3090. Based on Bi-DexHands, we present a comprehensive evaluation of popular RL algorithms in different settings, including single-agent/multi-agent RL, offline RL, multi-task RL, and meta RL. Our findings show that on-policy algorithms, such as PPO, can master simple manipulation tasks that correspond to those of 48-month-old babies, such as catching a flying object or opening a bottle. Furthermore, multi-agent RL can improve the ability to perform manipulations that require skilled bimanual cooperation, such as lifting a pot or stacking blocks. Despite achieving success in individual tasks, current RL algorithms struggle to learn multiple manipulation skills in most multi-task and few-shot learning scenarios. This highlights the need for further research and development within the RL community.

Study of Hamate Fractures in a Single Tertiary Hands Unit: A Retrospective Cohort Study and Literature Review

The primary purpose of our study was to investigate hamate fractures at a single tertiary hand surgery unit in Western Australia, particularly comparing operative and nonsurgical outcomes. Patients with hamate and/or hamate plus fifth carpometacarpal injury at our hand unit between 2019 and 2022 were identified. All patients had Quick Disability of the Arm, Shoulder and Hand (QuickDASH) patient-reported outcome measures recorded post treatment. Patients managed operatively and nonsurgically had a period of splinting with plaster of Paris and/or thermoplastic splint for a minimum of 2 weeks. All patients underwent hand therapy. Forty-eight patients with hamate and/or hamate plus fifth carpometacarpal injury were included in this study. Thirteen patients had Milch type 1 fractures, and 35 had Milch type 2 fractures. Six Milch type 1 fractures were managed operatively, and seven were managed nonsurgically. The average QuickDASH score for the operative group was 0.38. The average QuickDASH score for the nonsurgical group was 0.65. Sixteen Milch type 2 fractures were managed operatively, and 19 were managed nonsurgically. The average QuickDASH score for the operative group was 1.3. The average QuickDASH score for the nonsurgical group was 3.5. For Milch type 2 fractures, patient-reported outcome measures were better for the operative group compared with the nonsurgical group. Therapeutic IV.

Autonomous Navigated IOT Enabled Smart Wheel Chair - A Healthcare and Mobility solution

WHO disability statistics indicate that about 8 million people worldwide, or 1% of the total population, suffer from a mobility handicap. It is also known that the elderly residents in the area cannot move independently. Many hospital patients can force their hand with assistance but cannot move independently. We also understand that real-time health monitoring is necessary for patients, the elderly, and individuals with impairments. Therefore, this work aims to develop and provide a smart wheelchair that can be controlled with a single hand gesture and tracks many health indicators, such as blood pressure, body temperature, oxygen saturation, and pulse rate, using an Internet of Things-based real-time health monitoring system. Users can effortlessly maneuver the wheelchair using simple gesture control enabled by the Internet of Things (IoT), promoting independence and enhancing general well-being. This innovative approach to healthcare and mobility meets users' urgent requirements and establishes a new benchmark for assistive technology, a significant advancement in technology and healthcare. The benefit of this strategy is that the caregiver can view all of these health indicators and the wheelchair user's GPS location using a smartphone application. Taking care of oneself while employed by a firm might be easy.

Outcomes in Patients with Bilateral Distal Radius Fractures

Abstract Background Fractures of the distal radius that occur bilaterally are comparatively uncommon, with the incidence of these injuries and patient outcomes following different modes of treatment being unknown. Questions/Purposes This article evaluates the demographics, management, and functional outcomes of patients that sustain bilateral distal radius fractures (DRFs). Patients and Methods We retrospectively identified 85 patients that sustained bilateral DRF and were treated at a single institution from 2016 to 2019. Thirty-four patients were treated operatively, 41 patients were treated nonoperatively, and 10 patients were treated operatively in one extremity and nonoperatively in the other. Fractures were classified by a single fellowship-trained orthopaedic hand surgeon. Range of motion (ROM) data and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) scores were collected. Differences between the three groups with regards to demographics, mechanism of injury (MOI), and complications were recorded. Results The pediatric population had significantly higher energy MOIs compared to the adult population. There was no difference between the groups with regard to associated injuries or complications. The pediatric population had significantly more AO type A fractures compared to the adult population, which had a bimodal distribution of AO type A and C fractures. The pediatric population saw significantly more patients undergo nonoperative treatment. Both populations had a higher rate of operative intervention for bilateral DRF than noted in the literature for unilateral. In the adult population there were no significant differences in DASH scores between the operative and nonoperative groups. Conclusion Bilateral DRFs appear to have a similar bimodal age distribution to unilateral DRF. Younger patients undergo nonoperative management more commonly than operative or mixed management. Postoperative ROM and complications appear to be equivalent across all three groups regardless of age. Level of Evidence Level IV, Prognostic study.

Outcomes and Complications of Intramedullary Metacarpal Fixation.

Metacarpal fractures are common orthopedic injuries with potentially debilitating outcomes. Ideal surgical treatment remains a topic of debate, with intramedullary fixation becoming popular as a technique to allow for earlier mobilization with few reported complications. The aim of this study was to report observed outcomes and complications of intramedullary metacarpal fixation using the ExsoMed INnate metacarpal nail. A retrospective chart review of 37 patients with 44 metacarpals treated with the ExsoMed INnate between July 2020 and December 2021 by a single fellowship-trained hand surgeon at a single level 1 trauma center was performed. Variables recorded included both patient and injury demographics, surgical complications, and postoperative outcomes. We also measured metacarpal isthmus diameter of the second to fifth metacarpals on all patients to determine the intramedullary canal diameter to assist in implant size selection. Average follow-up was 5.84 weeks with average time to radiographic healing of 5.5 weeks, and time to full activity 6.32 weeks. The mean postsurgical active total arc of motion was 250°, while passive total arc of motion was 259.74°. A total of 10 complications (22%) were identified, including 4 bent screws which occurred as a result of a punching event postoperatively. Intramedullary fixation of metacarpal fractures using the ExsoMed INnate metacarpal nail has shown to preserve range of motion and quick return to full activity, with a low rate of major complications. Our study highlights the potential major complication of the bent intramedullary screw and its association with an initial punching mechanism.

Single and Multi-Hand Gesture based Soft Material Robotic Car Control

In this research article, authors have engineered the model to control soft material robotic car with single and multi-hand gestures based on Artificial Intelligence and Machine Learning approach. A user centric representation of this features is obtained by using hand detection and hand gesture recognition mechanism. Authors have assigned the desire hand gestures to move the soft material robotic car in 360 degrees. In this research work, different gestures of human hands are simulated in terms of landmarks using Mediapipe. Each combination of hand landmark performs different actions to control the robotic car in multiple directions. In this research work, the soft material robotic car has been controlled using single hand as well as multi hands gesture-based approach. Our motive of this research work is to reduce human efforts by controlling the soft material robotic car through hand gestures based on AIML techniques. The proposed CNN model has yielded high accuracy as compared to baseline ML algorithms such as KNN, Decision Tree, SVM etc. It is also observed that CNN model remains ahead of other ML algorithms for both single hand and multi-hand gesture based robotic car control. The performance of proposed CNN model for controlling robotic car has been represented in term of ROC curve using validation and test data set. The average performances of single hand gesture and multi hand gestures using proposed CNN are found as 97% and 98% respectively.

Feasibility of Freedom of Information Requests for Amputee Epidemiology in the United Kingdom.

While each of the 44 National Health Service commissioned artificial limb clinics in the United Kingdom record information about their own prosthetic limb users, these are not collated to give a national picture of amputee epidemiology. The requirement to respond to Freedom of Information (FoI) requests within 20 working days offers another way of extracting data from all centres, and this study describes a first attempt to use this method to update national epidemiological data. Questions were sent to the FoI email addresses of all 44 centres, requesting numbers of adult unilateral below-knee amputees, adult unilateral above or through-knee amputees and child unilateral above or through-knee amputees (all of K2 level mobility), numbers of people consistently using a prosthesis with a single axis myoelectric hand, and access to an occupational therapist with skills to teach someone to use a myoelectric hand. A FoI request was sent to NHS England seeking release of data that they collect every month from all the prosthetic services which they commission in England. All but one of the UK centres responded, the great majority within 31 days. Incomplete results were generally due to centres finding the questions ambiguous and many did not record mobility levels consistently. While 33 centres had access to skilled occupational therapy, only 4 reported more than 10 patients who constantly used a single axis myoelectric hand. Eighteen centres were unable to provide complete data, and the remainder reported a ranges of 5 to 992 below-knee amputees, 7 to 574 adult above-knee amputees and 0 to 137 child above-knee amputees, suggesting different approaches to managing missing mobility level data. Freedom of Information requests are an inexpensive way of gathering data from NHS prosthetic clinics, which can identify age, sex, level of amputation but not activity levels or use of a prosthesis and hence only gives limited demographic information of the amputee cohort.

Distribution of Sesamoid Bones in the Foot and Hand Radiographs; A Descriptive Cross-Sectional Study in a Tertiary Care Center in Nepal

Objective: The aim of this study was to present data about the prevalence and distribution of sesamoid bones of the hands and feet in Nepalese population by using radiographs, to determine the number of the sesamoid bones of the foot and hand, commonest site of occurrence and to correlate the findings between gender and age. Methodology: This prospective quantitative study was performed in the Department of Radiology and Imaging, TUTH. The radiographs of foot and hand were reviewed to evaluate the presence or absence of sesamoid bones and patient demographics were also noted. Data collection was done for a period of three months and random probability sampling method was used. Results: This study resulted that in foot radiographs, the most common sites of sesamoid bones was first metatarsophalangeal joint (1st MTPJ) where two sesamoid bones were found, whereas single sesamoid bone was found in other sites. The percentage of sesamoid bones in first interphalangeal joint (1st IPJ), second metatarsophalangeal joint (2nd MTPJ), third metatarsophalangeal joint (3rd MTPJ), fourth metatarsophalangeal joint (4th MTPJ) and fifth metatarsophalangeal joint (5th MTPJ) were 7.9%, 15.4%, 0 %, 0.4%, and 26.7% respectively. The number of sesamoid bones ranged from 2- 5 in single foot with frequency of occurrence of 2 bones being highest (58.3%). The percentage of sesamoid bones in foot was found to be relatively higher in female than male. In the analysis of hand radiographs, the most common sites of sesamoid bones was 1st MCPJ ( single sesamoid bone in 80.33% and a pair of sesamoid bones in 19.67% ) .The percentage of sesamoid bones in 1st IPJ, 2nd MCPJ, 3rd MCPJ, 4th MCPJ and 5th MCPJ were 37.33%, 58.67% ,5.33% , 5.33% and 59.33% respectively. The number of sesamoid bones ranged from 1 - 6 in single hand with frequency of occurrence of 3 bones being higher (32%). The percentage of sesamoid bones in hand was relatively higher in male than female. Conclusion: The distribution and frequency of sesamoid bones differ according to sites, gender and age. This study improves the knowledge on distribution of sesamoid bones of the foot and hand and also provides anatomical data that could help clinicians in diagnosis and management of various sesamoid bone disorders in patients who present with pain and discomfort in the foot and hand.

Bimanual Ultrasound Mid-Air Haptics for Virtual Reality Manipulation.

The ability to manipulate and physically feel virtual objects without any real object being present and without equipping the user has been a long-standing goal in virtual reality (VR). Emerging ultrasound mid-air haptics (UMH) technology could potentially address this challenge, as it enables remote tactile stimulation of unequipped users. However, to date, UMH has received limited attention in the field of haptic exploration and manipulation in virtual environments. Existing work has primarily focused on interactions requiring a single hand and thus the delivery of unimanual haptic feedback. Despite being fundamental to a large part of haptic interactions with our environments, bimanual tasks have rarely been studied in the field of UMH interaction in VR. In this paper, we propose the use of non-coplanar mid-air haptic devices for providing simultaneous tactile feedback to both hands during bimanual VR manipulation. We discuss coupling schemes and haptic rendering algorithms for providing bimanual haptic feedback in bimanual interactions with virtual environments. We then present two human participant studies, assessing the benefits of bimanual ultrasound haptic feedback in a two-handed grasping and holding task and in a shape exploration task. Results suggest that the use of multiple non-coplanar UMH devices could be an interesting approach for enriching unencumbered haptic manipulation in virtual environments.