Profiling learning strategies of medical students: A person-centered approach.

BACKGROUND: Students within a cohort might employ unique subsets of learning strategies (LS) to study. However, little research has aimed to elucidate subgroup-specific LS usage among medical students. Recent methodological developments, particularly person-centred approaches such as latent profile analysis (LPA), offer ways to identify relevant subgroups with dissimilar patterns of LS use. In this paper, we apply LPA to explore subgroups of medical students during preclinical training in anatomy and examine how these patterns are linked with learning outcomes. METHODS: We analysed the LS used by 689 undergraduate, 1st and 2nd-year medical students across 6 German universities who completed the short version of the Learning Strategies of University Students (LIST-K) questionnaire, and answered questions towards external criteria such as learning resources and performance. We used the thirteen different LS facets of the LIST-K (four cognitive, three metacognitive, three management of internal and three management of external resources) as LPA indicators. RESULTS: Based on LPA, students can be grouped into four distinct learning profiles: Active learners (45% of the cohort), collaborative learners (17%), structured learners (29%) and passive learners (9%). Students in each of those latent profiles combine the 13 LS facets in a unique way to study anatomy. The profiles differ in both, the overall level of LS usage, and unique combinations of LS used for learning. Importantly, we find that the facets of LS show heterogeneous and subgroup-specific correlations with relevant outcome criteria, which partly overlap but mostly diverge from effects observed on the population level. CONCLUSIONS: The effects observed by LPA expand results from variable-centered efforts and challenge the notion that LS operate on a linear continuum. These results highlight the heterogeneity between subgroups of learners and help generate a more nuanced interpretation of learning behaviour. Lastly, our analysis offers practical implications for educators seeking to tailor learning experiences to meet individual student needs.

Distribution of corpora amylacea in the human midbrain: using synchrotron radiation phase-contrast microtomography, high-field magnetic resonance imaging, and histology.

Corpora amylacea (CA) are polyglucosan aggregated granules that accumulate in the human body throughout aging. In the cerebrum, CA have been found in proximity to ventricular walls, pial surfaces, and blood vessels. However, studies showing their three-dimensional spatial distribution are sparse. In this study, volumetric images of four human brain stems were obtained with MRI and phase-contrast X-ray microtomography, followed up by Periodic acid Schiff stain for validation. CA appeared as hyperintense spheroid structures with diameters up to 30 µm. An automatic pipeline was developed to segment the CA, and the spatial distribution of over 200,000 individual corpora amylacea could be investigated. A threefold-or higher-density of CA was detected in the dorsomedial column of the periaqueductal gray (860-4,200 CA count/mm3) than in the superior colliculus (150-340 CA count/mm3). We estimated that about 2% of the CA were located in the immediate vicinity of the vessels or in the peri-vascular space. While CA in the ependymal lining of the cerebral aqueduct was rare, the sub-pial tissue of the anterior and posterior midbrain contained several CA. In the sample with the highest CA density, quantitative maps obtained with MRI revealed high R2* values and a diamagnetic shift in a region which spatially coincided with the CA dense region.

Effects of tablet-based drawing and paper-based methods on medical students' learning of gross anatomy.

The way medical students learn anatomy is constantly evolving. Nowadays, technologies such as tablets support established learning methods like drawing. In this study, the effect of drawing on a tablet on medical students' anatomy learning was investigated compared to drawing or summarizing on paper. The quality of drawings or summaries was assessed as a measure of the quality of strategy implementation. Learning outcome was measured with an anatomy test, both immediately afterward and after 4-6 weeks to assess its sustainability. There were no significant group differences in learning outcome at both measurement points. For all groups, there was a significant medium strength correlation between the quality of the drawings or summaries and the learning outcome (p < 0.05). Further analysis revealed that the quality of strategy implementation moderated outcomes in the delayed test: When poorly implemented, drawing on a tablet (M = 48.81) was associated with lower learning outcome than drawing on paper (M = 58.95); The latter (M = 58.89) was related to higher learning outcome than writing summaries (M = 45.59). In case of high-quality strategy implementation, drawing on a tablet (M = 60.98) outperformed drawing on paper (M = 52.67), which in turn was outperformed by writing summaries (M = 62.62). To conclude, drawing on a tablet serves as a viable alternative to paper-based methods for learning anatomy if students can make adequate use of this strategy. Future research needs to identify how to support student drawing, for instance, by offering scaffolds with adaptive feedback to enhance learning.

Microvascular imaging of the unstained human superior colliculus using synchrotron-radiation phase-contrast microtomography.

Characterizing the microvasculature of the human brain is critical to advance understanding of brain vascular function. Most methods rely on tissue staining and microscopy in two-dimensions, which pose several challenges to visualize the three-dimensional structure of microvessels. In this study, we used an edge-based segmentation method to extract the 3D vasculature from synchrotron radiation phase-contrast microtomography (PC-µCT) of two unstained, paraffin-embedded midbrain region of the human brain stem. Vascular structures identified in PC-µCT were validated with histology of the same specimen. Using the Deriche-Canny edge detector that was sensitive to the boundary between tissue and vascular space, we could segment the vessels independent of signal variations in PC-µCT images. From the segmented volumetric vasculature, we calculated vessel diameter, vessel length and volume fraction of the vasculature in the superior colliculi. From high resolution images, we found the most frequent vessel diameter to be between 8.6-10.2 µm. Our findings are consistent with the known anatomy showing two types of vessels with distinctive morphology: peripheral collicular vessels and central collicular vessels. The proposed method opens up new possibilities for vascular research of the central nervous system using synchrotron radiation PC-µCT of unstained human tissue.

Developing formalin-based fixative agents for post mortem brain MRI at 9.4 T.

PURPOSE: To develop fixative agents for high-field MRI with suitable dielectric properties and measure MR properties in immersion-fixed brain tissue. METHODS: Dielectric properties of formalin-based agents were assessed (100 MHz-4.5 GHz), and four candidate fixatives with/without polyvinylpyrrolidone (PVP) and different salt concentrations were formulated. B1 field and MR properties (T1 , R2∗ , R2 , R2' , and magnetic susceptibility [QSM]) were observed in white and gray matter of pig brain samples during 0.5-35 days of immersion fixation. The kinetics were fitted using exponential functions. The immersion time required to reach maximum R2∗ values at different tissue depths was used to estimate the Medawar coefficient for fixative penetration. The effect of replacing the fixatives with Fluoroinert and phosphate-buffered saline as embedding media was also evaluated. RESULTS: The dielectric properties of formalin were nonlinearly modified by increasing amounts of additives. With 5% PVP and 0.04% NaCl, the dielectric properties and B1 field reflected in vivo conditions. The highest B1 values were found in white matter with PVP and varied significantly with tissue depth and embedding media, but not with immersion time. The MR properties depended on PVP yielding lower T1 , higher R2∗ , more paramagnetic QSM values, and a lower Medawar coefficient (0.9 mm/h ; without PVP: 1.5). Regardless of fixative, switching to phosphate-buffered saline as embedder caused a paramagnetic shift in QSM and decreased R2∗ that progressed during 1 month of storage, whereas no differences were found with Fluorinert. CONCLUSION: In vivo-like B1 fields can be achieved in formalin fixatives using PVP and a low salt concentration, yielding lower T1 , higher R2∗ , and more paramagnetic QSM than without additives. The kinetics of R2∗ allowed estimation of fixative tissue penetration.

Anatomical work-up of an individual with multiple muscular variants on both forearms.

Muscular variants of the forearm are common and frequently cause neurovascular compression syndromes, especially when interfering with the compact topography of the carpal tunnel or the Canalis ulnaris. Here, we report on a male body donor with multiple muscular normal variations on both forearms. The two main findings are (1) an accessory variant muscle (AVM) on the right forearm originating from the M. brachioradialis, the distal radius, and the M. flexor pollicis longus. It spanned the wrist beneath the Fascia antebrachia and inserted at the proximal phalanx of the digitus minimus. (2) Moreover, we found a three-headed palmaris longus variant on the left arm with proximal origin tendon and a distal, trifurcated muscle belly, with separated insertions at the palmar aponeurosis, the flexor retinaculum, and, in analogy to the accessory muscle on the contralateral arm, at the base of the proximal phalanx of the digitus minimus. We found a considerable thickening of the left-hand median nerve right before entering the carpal tunnel indicative of a possible chronic compression syndrome adding clinical relevance to this anatomical case. We also discuss the notion that both, the AVM and the contralateral three-headed palmaris variant are developmental descendants of the M. palmaris longus. Additionally, we found a previously not recorded variant of the M. palmaris brevis on the left hand.

Observing Interprofessional Collaboration: Impact on Attitude and Knowledge Acquisition.

Interprofessional collaboration (IPC) in the medical field is an important factor for good clinical outcomes and should be taught as early as in undergraduate medical education. Since implementing IPC training is an organizational challenge, students are often limited in their opportunities to experience real-life IPC. Therefore, an approach where students observe successful IPC activities of role models in an applied anatomical format was proposed. It was studied whether observing IPC activities in undergraduate anatomical education has an impact on both students' attitude toward IPC and on knowledge acquisition. Further, it was examined whether the attitudes and knowledge of students from different medical disciplines were influenced in different ways. Therefore, 75 medical students and thirty-eight physiotherapy students participated in a study with the task of observing a live broadcast of an interprofessional teaching session. Participants were asked about their attitudes toward interprofessional learning, their evaluation of professional responsibilities, and their profession-specific knowledge before and after observing the IPC session. The participants' attitude toward interprofessional learning improved for both groups of students. Moreover, students of physiotherapy adjusted their evaluation of their own and others' professional responsibilities after observing IPC. In both student groups, knowledge increased, in particular, with respect to the field of knowledge in other professions. So, observing IPC can modify students' attitudes and support knowledge acquisition. The implementation of IPC observations provides students from various healthcare disciplines with a clearer impression of professionals' responsibilities and gives learners the opportunity to acquire knowledge from healthcare fields unfamiliar to them.

Observing Inter-Professional Videos: Impact of Collaboration Between Physicians and Psychologists on Attitude and Knowledge Acquisition.

BACKGROUND: Inter-professional collaboration (IPC) is an important prerequisite for successful patient care. Even though inter-professional education (IPE) is increasingly common in undergraduate medical education, few IPE approaches explicitly address the IPC among medical students and students of psychology. IPE videos can be used to give learners the opportunity to gather relevant knowledge from different professional perspectives. So far it has been unclear whether it is enough when the topic of the video itself is inter-professional or if it is necessary for experts from different professions explicitly to appear in the video. METHODS: In an online experiment, medical students watched 1 of 2 videos about Parkinson's disease (PD) and the care of PD patients. The information was either provided by protagonists from only 1 profession (ie, physicians; mono-professional condition) or provided by protagonists from 2 different professions (ie, physicians and a psychologist; inter-professional condition). Attitude toward inter-professional interaction and learning, evaluation of the entertaining and illustrative character of the video, attitude toward physicians and psychologists, importance of IPC, evaluation of psychological treatment support, and knowledge acquisition served as dependent variables. RESULTS: The analysis was based on 140 participants (74 in the mono-, 66 in the inter-professional condition). We found that the inter-professional video was perceived to be more entertaining than the mono-professional video (t (138) = -2.227; P = .028; d = 0.38). The inter-professional video was also considered to be more illustrative (t (138) = -6.269; P < .001; d = 1.06). Moreover, participants improved their attitude toward physicians by watching the video (F (1,138) = 4.860, P < .001, η 2 p = 0.11), but they did not change their attitude toward psychologists (P = .146). Participants who watched the inter-professional video considered IPC to be more important than participants who watched the mono-professional video (t (138) = -7.954; P < .001; d = 1.354). Finally, the inter-professional video led to better performance in the knowledge test (t (138) = -2.285; P = .024; d = 0.04). CONCLUSION: Inter-professional videos showing explicitly the appearance of experts from different professions come along with several advantages. We discuss the implications of their application in educational practice. TRIAL REGISTRATION: The study was pre-registered on the pre-registration platform AsPredicted (aspredicted.org) before we began data collection (registration number: #33143). The pre-registration document can be accessed via the following link: https://aspredicted.org/blind.php?x=gd5hd8.

An Insight into Professional Identity Formation: Qualitative Analyses of Two Reflection Interventions During the Dissection Course.

The professional behavior of future doctors is increasingly important in medical education. One of the first subjects in the curriculum to address this issue is gross anatomy. The Tuebingen Medical Faculty implemented a learning portfolio and a seminar on medical professionalism during the dissection course. The aims of this research project are to get an overview of how students form a professional identity in the dissection course and to compare the content of both their oral and written reflections on the course. A qualitative analysis was conducted of the oral and written reflections on the dissection laboratory experience. This study was conducted during winter term 2013/2014 with a cohort of 163 participants in the regular dissection course. Written reflection texts (from n = 96 students) and audio recordings from four oral reflection seminar discussions (with n = 11 students) were transcribed and deductively categorized with Mayring's qualitative content analysis method. Both qualitative analyses show that students reflected on many topics relevant to professional development, including empathy, respect, altruism, compassion, teamwork, and self-regulation. Quantitative analysis reveals that students who attended the oral reflection wrote significantly more in their written reflection than students who did not. There is, however, no difference in the reflection categories. Reflection content from students corresponds with categories derived from existing competency frameworks. Both the seminar (oral reflections) and the learning portfolio (written reflections) present excellent opportunities to foster professional development during anatomy education; the key is using them in conjunction with the dissection course.

The impact of physicians' recommendations on treatment preference and attitudes: a randomized controlled experiment on shared decision-making.

Making decisions based on their own evaluation of relevant information and beliefs is very challenging for patients. Many patients feel that they lack the knowledge to make a decision and expect a recommendation by their physician. We conducted an experimental study to examine the impact of physicians' recommendations on the decision-making process. N = 194 medical laypeople were placed in a hypothetical scenario where they suffered from a cruciate ligament rupture and were faced with the decision about a treatment (surgery or physiotherapy). In a 3 × 2 between-group design we investigated the impact of physicians' recommendations (for surgery, for physiotherapy, no recommendation) and reasoning style (scientific, narrative) on treatment preference, certainty and satisfaction regarding treatment preference, and attitudes. We found that the recommendation had a significant influence on treatment preference and attitudes toward both treatments. Additionally, we found a significant increase in certainty and satisfaction after the intervention, independently of whether they received a recommendation. This finding suggested that a recommendation was not required to strengthen participants' confidence in their decision. There were no effects of reasoning style. We discuss the implications and suggest that physicians should be careful with recommendations in situations in which patients' preferences are important.

Acquiring Clinical Knowledge from an Online Video Platform: A Randomized Controlled Experiment on the Relevance of Integrating Anatomical Information and Clinical Practice.

Basic subjects in medical education, such as anatomy, are often taught through teaching formats that do not always sufficiently demonstrate the relevance of this basic information for clinical practice. Accordingly, it is a recent trend in anatomy education to link anatomical information more explicitly to clinical practice. This article presents an online video platform (Tuebingen's Sectio Chirurgica [TSC]) as one means of explicitly integrating preclinical anatomical knowledge and clinical application. The purpose of the study presented here was to examine the effects of videos through which medical students were educated about Anterior Cruciate Ligament reconstruction. A TSC video about this surgical procedure was compared to a video with a traditional lecture providing the identical information. Participants (n = 114) perceived the TSC video to be superior in comprehensibility of the presentation (P = 0.003) and conceivability of the surgical procedure (P = 0.027), and to be more entertaining (P < 0.001). Moreover, participants in the TSC condition acquired more clinical knowledge than in the lecture condition (P = 0.043) but did not differ in their acquisition of anatomical knowledge. Mediation analyses indicated that the effect on the acquisition of clinical knowledge was mediated by comprehensibility, conceivability, and entertainment. These findings are discussed regarding their implications for medical education in terms of contributing to the general trend of linking preclinical anatomical knowledge to clinical application. A discussion about the limitations of the study and suggestions for future research are also provided.

The Impact of Visualization Format and Navigational Options on Laypeople's Perception and Preference of Surgery Information Videos: Randomized Controlled Trial and Online Survey.

BACKGROUND: Patients need to be educated about possible treatment choices in order to make informed medical decisions. As most patients are medical laypeople, they find it difficult to understand complex medical information sufficiently to feel confident about a decision. Multimedia interventions such as videos are increasingly used to supplement personal consultations with medical professionals. Former research has shown that such interventions may have a positive effect on understanding, decision making, and emotional reactions. However, it is thus far unclear how different features of videos influence these outcomes. OBJECTIVE: We aimed to examine the impact of visualization formats and basic navigational options in medical information videos about cruciate ligament surgery on recipients' knowledge gain, emotions, attitude, and hypothetical decision-making ability. METHODS: In a between-group randomized experiment (Study 1), 151 participants watched 1 of 4 videos (schematic vs realistic visualization; available vs unavailable navigational options). In a separate online survey (Study 2), 110 participants indicated their preference for a video design. All participants were medical laypeople without personal experience with a cruciate ligament rupture and were presented with a fictional decision situation. RESULTS: In Study 1, participants who used navigational options (n=36) gained significantly more factual knowledge (P=.005) and procedural knowledge (P<.001) than participants who did not have or use navigational options (n=115). A realistic visualization induced more fear (P=.001) and disgust (P<.001) than a schematic video. Attitude toward the surgery (P=.02) and certainty regarding the decision for or against surgery (P<.001) were significantly more positive after watching the video than before watching the video. Participants who watched a schematic video rated the video significantly higher than that by participants who watched a realistic video (P<.001). There were no significant group differences with regard to hypothetical decision making and attitude toward the intervention. In addition, we did not identify any influence of the visualization format on knowledge acquisition. In Study 2, 58 of 110 participants (52.7%) indicated that they would prefer a schematic visualization, 26 (23.6%) preferred a realistic visualization, 17 (15.5%) wanted either visualization, and 9 (8.2%) did not want to watch a video at all. Of the participants who wanted to watch a video, 91 (90.1%) preferred to have navigational options, 3 (3.0%) preferred not to have navigational options, and 7 (6.9%) did not mind the options. CONCLUSION: Our study indicates that the perception of medical information videos is influenced by their design. Schematic videos with navigational options are the most helpful among all videos to avoid negative emotions and support knowledge acquisition when informing patients about an intervention. The visualization format and navigational options are important features that should be considered when designing medical videos for patient education. TRIAL REGISTRATION: Deutsches Register Klinischer Studien DRKS00016003; https://www.drks.de/drks_web/ navigate.do?navigationId= trial.HTML&TRIAL_ID=DRKS00016003 (Archived by WebCite at http://www.webcitation.org/746ASSAhN).

Pull out Strength of Dual Outer Diameter Pedicle Screws Compared to Uncemented and Cemented Standard Pedicle Screws: A Biomechanical in vitro Study.

OBJECTIVE: To analyze the potential of the dual outer diameter screw and systematically evaluate the pull-out force of the dual outer diameter screw compared to the uncemented and cemented standard pedicle screws with special regard to the pedicle diameter and the vertebra level. METHODS: Sixty vertebrae of five human spines (T 6 -L 5 ) were sorted into three study groups for pairwise comparison of the uncemented dual outer diameter screw, the uncemented standard screw, and the cemented standard screw, and randomized with respect to bone mineral density (BMD) and vertebra level. The vertebrae were instrumented, insertion torque was determined, and pull-out testing was performed using a material testing machine. Failure load was evaluated in pairwise comparison within each study group. The screw-to-pedicle diameter ratio was determined and the uncemented dual outer diameter and standard screws were compared for different ratios as well as vertebra levels. RESULTS: Significantly increased pull-out forces were measured for the cemented standard screw compared to the uncemented standard screw (+689 N, P < 0.001) and the dual outer diameter screw (+403 N, P < 0.001). Comparing the dual outer diameter screw to the uncemented standard screw in the total study group, a distinct but not significant increase was measured (+149 N, P = 0.114). Further analysis of these two screws, however, revealed a significant increase of pull-out force for the dual outer diameter screw in the lumbar region (+247 N, P = 0.040), as well as for a screw-to-pedicle diameter ratio between 0.6 and 1 (+ 488 N, P = 0.028). CONCLUSIONS: For clinical application, cement augmentation remains the gold standard for increasing screw stability. According to our results, the use of a dual outer diameter screw is an interesting option to increase screw stability in the lumbar region without cement augmentation. For the thoracic region, however, the screw-to-pedicle diameter should be checked and attention should be paid to screw cut out, if the dual outer diameter screw is considered.

How much GK is in the NKLM? A comparison between the catalogues of exam-relevant topics (GK) and the German National Competence-based Learning Objectives Catalogue for Undergraduate Medical Education (NKLM).

Background: The German National Competence-Based Learning Objectives for Undergraduate Medical Education (NKLM) being adopted in 2015 is designed to contribute to improve the quality of teaching and learning in medicine with respect to competence orientation. For departments, the coherence between teaching, assessment and the content of the catalogues of exam-relevant topics (GK) is a crucial factor. Before making use of the NKLM seriously in curricular development, many faculties demand more transparency regarding the representation in the NKLM of GK topics and in what aspects the NKLM exceeds the GK. Therefore, the aim of the study was to assign the NKLM competencies and objectives to the systematic GK terms, to reveal gaps in their congruence and to determine the percentage of agreement between GK and NKLM. Additionally, the distribution among the NKLM chapters (chap.), of GK content and further competencies relevant for medical practice were analysed. Methods: The textual comparison of GK and NKLM was done by advanced students that were familiar with the NKLM from previous analyses. The comparison was done independently (keyword search, face validity), afterwards consented and matched with independent ratings of GK-2 and chapter 21 done by experts as well as with cross-references to the GK indicated in chapter 12, 13 and 15 of the NKLM. Detailed data is available online: www.merlin-bw.de/gk-nklm-abgleich.html. Results: The degree of correspondence of the GK's six preclinical parts with the NKLM ranges between 94% and 98%, with the clinical GK the degree of correspondence ranging between 84% and 88%. This demonstrates a consistently very high congruence of content. Only 6-16% of the content per GK part could not be assigned to NKLM equivalents. Regarding the distribution of GK content among NKLM chapters, the chapters with classic medical expertise (chapters 12, 13, 16, 17 as well as 20 and 21) show the highest correspondences. Practical medical skills (chapter 14b) can be found in the clinical GK "Health Disorders". Doctor-patient interaction (chapter 14c) and medical scientific skills (chapter 14a) are represented only marginally in the GK. As expected, there were no equivalents to be found in the GK for the new professional roles for medical doctors (chapter 06-11). Discussion: The results presented provide faculties with a useful and detailed data base to evaluate the NKLM more reliably, especially with respect to its relevance for exams. The increased transparency supports the implementation process of the NKLM by reducing content-related uncertainties of departments, invalidating sweeping arguments against the NKLM resulting from uncertainties and thereby minimizing resistance. At the same time a critical review process of the NKLM is encouraged.

Interactive anatomical and surgical live stream lectures improve students' academic performance in applied clinical anatomy.

Tuebingen's Sectio Chirurgica (TSC) is an innovative, interactive, multimedia, and transdisciplinary teaching method designed to complement dissection courses. The Tuebingen's Sectio Chirurgica (TSC) allows clinical anatomy to be taught via interactive live stream surgeries moderated by an anatomist. This method aims to provide an application-oriented approach to teaching anatomy that offers students a deeper learning experience. A cohort study was devised to determine whether students who participated in the TSC were better able to solve clinical application questions than students who did not participate. A total of 365 students participated in the dissection course during the winter term of the 2012/2013 academic year. The final examination contained 40 standard multiple-choice (S-MC) and 20 clinically-applied multiple-choice (CA-MC) items. The CA-MC items referred to clinical cases but could be answered solely using anatomical knowledge. Students who regularly participated in the TSC answered the CA-MC questions significantly better than the control group (75% and 65%, respectively; P < 0.05, Mann-Whitney U test). The groups exhibited no differences on the S-MC questions (85% and 82.5%, respectively; P > 0.05). The CA-MC questions had a slightly higher level of difficulty than the S-MC questions (0.725 and 0.801, respectively; P = 0.083). The discriminatory power of the items was comparable (S-MC median Pearson correlations: 0.321; CA-MC: 0.283). The TSC successfully teaches the clinical application of anatomical knowledge. Students who attended the TSC in addition to the dissection course were able to answer CA-MC questions significantly better than students who did not attend the TSC. Thus, attending the TSC in addition to the dissection course supported students' clinical learning goals. Anat Sci Educ 10: 46-52. © 2016 American Association of Anatomists.

Clinically relevant variations of the superior thyroid cornu.

PURPOSE: The superior thyroid cornu (STC) of the thyroid cartilage is a variable structure that maybe associated with different clinical symptoms. This study evaluates the three-dimensional anatomy of the STC. METHODS: Measurements were conducted on 97 CT scans (45 male and 52 female). The protocol models a vector from the base to the tip of the STC and references the cornu to the midline. From these data, the length (C), the rotation angle (γ), the inclination angle (ß), and the deviation of STC base (X 2) and tip (X 3) from the midline were measured. An additional measure of the medial inclination quotient (Q = X 3/X 2) was calculated. RESULTS: The STC has a mean length of 13.9 ± 3.26 mm. The male STC is more bent inwards (rotation angle (γ) 60.95° vs. 12.15°; p < 0.001), and the female STC is more steep (inclination angle (ß) 75.44° vs. 73.44°; p < 0.001). The mean Q in men was significantly lower (0.85 ± 0.15 vs. 0.97 ± 0.15; p < 0.001). An extreme medial deformation was found in 13.4 % of the patients. This variation is associated with Q ≤ 0.7, most of the time unilateral and more common in men (86.7 vs. 13.3 %). Furthermore, we can describe STC variations with close proximity to the common carotid artery or the cervical spine. CONCLUSIONS: The clinically most relevant variation of the STC seems to be the extreme medial deviation, which may lead to symptoms described with the superior thyroid cornu syndrome. The evaluation of Q in axial CT scans is easily done and may propose a helpful tool for clinical diagnostics.

Fronto-temporal branch of facial nerve within the interfascial fat pad: is the interfascial dissection really safe?

BACKGROUND: The study was conducted to clarify the presence or absence of fronto-temporal branches (FTB) of the facial nerve within the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. METHODS: Eight formalin-fixed cadaveric heads (16 sides) were used in the study. The course of the facial nerve and the FTB was dissected in its individual tissue planes and followed from the stylomastoid foramen to the frontal region. RESULTS: In the fronto-temporal region, above the zygomatic arch, FTB gives several small twigs running anteriorly in the fat pad above the superficial temporalis fascia and a branch within the temporo-parietal fascia (TPF) to the muscles of the forehead. There were no twigs of the FTB within the interfascial fat pad. CONCLUSIONS: No branches of the FTB are found in the interfascial (between the superficial and deep leaflet of the temporalis fascia) fat pad. The interfascial dissection can be safely performed without risk of injury to the FTB and potential subsequent frontalis palsy.

Three distinct fiber pathways of the bed nucleus of the stria terminalis to the amygdala and prefrontal cortex.

The bed nucleus of the stria terminalis (BNST) is an important relay for multiple cortical and subcortical regions involved in processing anxiety as well as neuroendocrine and autonomic responses to stress, and it is thought to play a role in the dysregulation of these functions as well as in addictive behavior. While its architecture and connection profile have been thoroughly examined in animals, studies in humans have been limited to post-mortem histological descriptions of the BNST itself, not accounting for the distribution of its various connections. In the current study, we used diffusion-weighted magnetic resonance imaging (DW-MRI) to investigate the courses of fiber tracks connected to the BNST in humans. We restricted our seed region for probabilistic fiber tracking to the dorsal part of the BNST, as the ventral BNST is not distinguishable from the surrounding grey matter structures using magnetic resonance imaging. Our results show two distinct pathways of the BNST to the amygdala via the stria terminalis and the ansa peduncularis, as well as connections to the hypothalamus. Finally, we distinguished a route to the orbitofrontal cortex (OFC) running through the head of the caudate nucleus (CN) and the nucleus accumbens (NAcc). Pathways to brainstem regions were found to show a considerable inter-individual variability and thus no common pathway could be identified across participants. In summary, our findings reveal a complex network of brain structures involved in behavioral and neuroendocrine regulation, with the BNST in a central position.

Two-leg alternate loading model--a different approach to biomechanical investigations of fixation methods of the injured pelvic ring with focus on the pubic symphysis.

The dorsal component of the pelvic ring is considered to be the most essential element for the stability of the pelvic ring. None of the current biomechanical set-ups include the effect of shear stresses by alternating loads that the pelvic ring has to withstand during walking. We hypothesize that a biomechanical test set-up with two-leg alternate loading will lead to stress imitation at the pubic symphysis that are more similar to existing strains than other test set-ups, and would, therefore, be more adequate for biomechanical testing of fixation methods. A new biomechanical two-leg standing test set-up with an alternate pelvic loading was constructed and was validated with six human pelvises from fresh frozen cadavers. Three-dimensional motion tracking was performed. The specimens were subjected to a non-destructive quasi-static test and a non-destructive cyclic test with progressive load amplitude from 170 N to 340 N over 1000 cycles. The initial rotational 'range of motion' and 'mean displacement' around the vertical axis for a pre-load of 170 N was about 0.3° and 0.2°, respectively, increasing by 0.1-0.2° at a load of 340 N. The rotation around the vertical axis and the translation along the frontal horizontal axis confirmed the stability of the pubic symphysis. The rate of ascend of displacements decreased, once the rotation reached 1° or the translation reached 1mm. The current biomechanical test set-up was compared with previous clinical findings, and the method was found valid for measuring inter-segmentary movements at the pubic symphysis.