Morphological, histological and biomechanical adaptation of the rat musculoskeletal system to electrical muscle stimulation

Musculoskeletal tissues exhibit a remarkable extent of plasticity throughout life, with tissues continually able to adapt in line with functional demands. As the skeleton plays a major structural role, its form is profoundly influenced by its mechanical environment, which is largely determined by muscular contraction. Despite the clear functional link between muscle and bone relatively little is known about the biomechanical relationship between these tissues. This thesis therefore focuses upon the use of implantable neuromuscular stimulators to provide controlled muscular mechanical stimuli. Stimulators were implanted into Wistar rats, inducing muscular contraction every 30 seconds for 28 days. Following stimulation, microCT, histology, and nanoindentation were used to establish changes occurring at the micro and macro-scale in muscle and skeletal architecture. Analysis revealed a localised region of extensive bone growth, with significant increases in cross-sectional area (28.61%,

A comparison of virtual reality anatomy models to prosections in station-based anatomy teaching.

Immersive virtual reality (i-VR) is a powerful tool that can be used to explore virtual models in three dimensions. It could therefore be a valuable tool to supplement anatomical teaching by providing opportunities to explore spatial anatomical relationships in a virtual environment. However, there is a lack of consensus in the literature as to its effectiveness as a teaching modality when compared to the use of cadaveric material. The aim of our study was to compare the effectiveness of i-VR in facilitating understanding of different anatomical regions when compared with cadaveric prosections for a cohort of first- and second-year undergraduate medical students. Students (n = 92) enrolled in the MBBS program at Queen Mary University of London undertook an assessment, answering questions using either Oculus i-VR headsets, the Human Anatomy VR™ application, or prosection materials. Utilizing ANOVA with Sidak's multiple comparison test, we found no significant difference between prosections and i-VR scores in the abdomen (p = 0.6745), upper limb (p = 0.8557), or lower limb groups (p = 0.9973), suggesting that i-VR may be a viable alternative to prosections in these regions. However, students scored significantly higher when using prosections when compared to i-VR for the thoracic region (p < 0.0001). This may be due to a greater need for visuospatial understanding of 3D relationships when viewing anatomical cavities, which is challenged by a virtual environment. Our study supports the use of i-VR in anatomical teaching but highlights that there is significant variation in the efficacy of this tool for the study of different anatomical regions

Impact of an in-person small group surgical skills course for preclinical medical students in an era of increased e-learning.

Objective: The COVID-19 pandemic led to a dramatic decrease in face-to-face teaching. This can particularly impact medical students' skills development. This prompted development of an in-person surgical skills course as guided by the General Medical Council "Outcomes for Graduates" facilitated by tutors with surgical experience. This study aimed to primarily assess participant confidence in surgical skills following the course. Design: This was an interventional study assessing both qualitative and quantitative data collected prior to, during, and post course completion. Data were collected from students via online forms, which included a mixture of "Yes/No" responses, self-assessed confidence levels via Likert scales, and free type questions. Setting: The study assessed feedback for a 5-session surgical skills course delivered at the authors' institution. This is a newly designed course using low-cost materials which was free for all attendees. Participants: Participants were all in the first or second year of medical school. There was capacity for 60 students, and all attendees provided informed consent to participate. Results: A total of 446 students applied for the course with 58 participants in the final study, 31% of whom had prior surgical skills experience. There was a statistically significant increase in student confidence levels following the course for all taught surgical skills (P = .0001). Participants were also more confident that they possessed the skills required for clinical placements (P = .0001) and to work as a junior doctor (P = .01). Thematic qualitative analysis revealed a reliance on third parties for previous surgical experience; this course improved knowledge and skills for future practice. Limitations included session duration and equipment choice. Conclusion: This study demonstrates high demand and student satisfaction from this course, offering a potential framework to improve undergraduate surgical skills teaching. The results presented here have the potential to inform wider curricula development across medical schools in the future. Competencies: Medical knowledge; practice-based learning and Improvement

Digital dissection of the masticatory muscles of the naked mole-rat, Heterocephalus glaber (Mammalia, Rodentia)

The naked mole-rat, Heterocephalus glaber, of the family Bathyergidae is a subterranean rodent that feeds on underground roots and tubers and digs extensive tunnel systems with its incisors. It is a highly unusual mammal with regard to its social structure, longevity, pain insensitivity and cancer resistance, all of which have made it the subject of a great deal of research in recent years. Yet, much of the basic anatomy of this species remains undocumented. In this paper, we describe the morphology of the jaw-closing musculature of the naked mole-rat, as revealed by contrast-enhanced micro-computed tomography. This technique uses an iodine stain to enable the imaging of soft tissues with microCT. The iodine-enhanced scans were used to create 3D reconstructions of the naked mole-rat masticatory muscles from which muscle masses were calculated. The jaw-closing musculature of Heterocephalus glaber is relatively very large compared to other rodents and is dominated by the superficial masseter, the deep masseter and the temporalis. The temporalis in particular is large for a rodent, covering the entirety of the braincase and much of the rear part of the orbit. The morphology of the masseter complex described here differs from two other published descriptions of bathyergid masticatory muscles, but is more similar to the arrangement seen in other rodent families. The zygomaticomandibularis (ZM) muscle does not protrude through the infraorbital foramen on to the rostrum and thus the naked mole-rat should be considered protrogomorphous rather than hystricomorphous, and the morphology is consistent with secondarily lost hystricomorphy as has been previously suggested for Bathyergidae. Overall, the morphology of the masticatory musculature indicates a species with a high bite force and a wide gape–both important adaptations for a life dominated by digging with the incisors

A novel miniature in-line load-cell to measure in-situ tensile forces in the tibialis anterior tendon of rats.

Direct measurements of muscular forces usually require a substantial rearrangement of the biomechanical system. To circumvent this problem, various indirect techniques have been used in the past. We introduce a novel direct method, using a lightweight (~0.5 g) miniature (3 x 3 x 7 mm) in-line load-cell to measure tension in the tibialis anterior tendon of rats. A linear motor was used to produce force-profiles to assess linearity, step-response, hysteresis and frequency behavior under controlled conditions. Sensor responses to a series of rectangular force-pulses correlated linearly (R2 = 0.999) within the range of 0-20 N. The maximal relative error at full scale (20 N) was 0.07% of the average measured signal. The standard deviation of the mean response to repeated 20 N force pulses was ± 0.04% of the mean response. The step-response of the load-cell showed the behavior of a PD2T2-element in control-engineering terminology. The maximal hysteretic error was 5.4% of the full-scale signal. Sinusoidal signals were attenuated maximally (-4 dB) at 200 Hz, within a measured range of 0.01-200 Hz. When measuring muscular forces this should be of minor concern as the fusion-frequency of muscles is generally much lower. The newly developed load-cell measured tensile forces of up to 20 N, without inelastic deformation of the sensor. It qualifies for various applications in which it is of interest directly to measure forces within a particular tendon causing only minimal disturbance to the biomechanical system

Three-dimensional visualisation of soft biological structures by X-ray computed micro-tomography.

Whereas the two-dimensional (2D) visualisation of biological samples is routine, three-dimensional (3D) imaging remains a time-consuming and relatively specialised pursuit. Current commonly adopted techniques for characterising the 3D structure of non-calcified tissues and biomaterials include optical and electron microscopy of serial sections and sectioned block faces, and the visualisation of intact samples by confocal microscopy or electron tomography. As an alternative to these approaches, X-ray computed micro-tomography (microCT) can both rapidly image the internal 3D structure of macroscopic volumes at sub-micron resolutions and visualise dynamic changes in living tissues at a microsecond scale. In this Commentary, we discuss the history and current capabilities of microCT. To that end, we present four case studies to illustrate the ability of microCT to visualise and quantify: (1) pressure-induced changes in the internal structure of unstained rat arteries, (2) the differential morphology of stained collagen fascicles in tendon and ligament, (3) the development of Vanessa cardui chrysalises, and (4) the distribution of cells within a tissue-engineering construct. Future developments in detector design and the use of synchrotron X-ray sources might enable real-time 3D imaging of dynamically remodelling biological samples

From Lecture Halls to Zoom Links: How Can Educational Theory Help Us to Deliver Effective and Engaging Teaching in an Online Environment?

Anatomical education has a long and colourful history, ranging from the anatomical theatre and artistic flourish of the renaissance period to modern-day virtual reality. Over the centuries, the body has been taken apart and mapped in exquisite detail. We are now able to access virtual models of the body anywhere, anytime, which allow for unlimited dissection and manipulation. Despite this progress, the majority of anatomical educators continue to deliver anatomy in a laboratory setting, using hands-on learning approaches such as dissection of cadaveric material. These methods are robustly supported by educational theories, such as information processing theory and experiential learning but require students to be present in a dissection room with access to human cadaveric material.The 2020 COVID-19 pandemic forced anatomy educators out of familiar dissection laboratories and into unfamiliar and uncomfortable virtual environments. When moving online during the pandemic, active learning theories, which form the basis of face-to-face classes, were used to construct interactive anatomy webinars to replace the on-campus practical laboratory-based teaching. The focus of these webinars was on student interactivity, and visual content with drawing activities, breakout groups, virtual three-dimensional models, and identifying activities being integrated into each session. Student feedback showed an appreciation of the interactive nature of these sessions, and staff were surprised at how well the webinars delivered engaging and interactive teaching at a time of limited social contact. This approach was not only useful during the restrictions of a pandemic but could offer a complementary approach to delivering practical anatomy teaching as we return to blended and on-campus learning again