Annals of Anatomy-Anatomischer Anzeiger最新文献

Background

The aim of this study was to determine the effect of root canal filling using different obturation materials combined with apicoectomy in upper central incisors under loading with 1 N and 100 N. The effect of incomplete root formation was also investigated.

Methods

Based on a CBCT-scan, a model of an upper central incisor was created. The model was altered to simulate different clinical situations: root canal treatment, apicoectomy at two different lengths and with different obturation protocols, and immature root formation after trauma. In each model the tooth was loaded with 1 and 100 N, and peak Von Mises stress of bone and tooth, elastic strain of the periodontal ligament, as well as rotation and displacement of the tooth were measured.

Results

Periapical surgery increases stress in dentin and the surrounding bone. Different obturation materials only produce minor differences in a coronally intact tooth.

Conclusions

Interincisal angle or loading direction strongly affects all measured values and needs to be considered when planning periapical surgery or comparing finite element analysis. Immature roots show the highest stress values in this study, reaching half the yield strength of dentine.

Background

The ossification centers in rabbit limbs are related to fetal age and bone maturation. Objective: To address the limited studies on ossification in the hind limbs of New Zealand rabbits, we investigated the prenatal and postnatal development of the pelvic and femur bones.

Methods

Double staining with Alcian Blue and Alizarin Red, computed tomography (CT), and 3D reconstruction were employed to visualize and analyze ossification centers in detail.

Results

Using double staining, we observed these patterns: At prenatal days 18 and 21, ossification centers appeared in the ilium. By prenatal days 23 and 25, ossification began in the ischium. On postnatal day 1, ilium ossification centers spread across most of the ilium wings, except for the iliac crest, and new centers appeared in the pubis and cotyloid bones. Most bones had ossified by the third week and one month postnatal, except for the iliac crest and ischial tuberosity. At 1.5 months, both were fully ossified. On day 18 post coitum, an ossification center was visible in the middle of the femur shaft. By day 28 post coitum, ossification extended through the shaft, and postnatally, new ossification spots appeared at the extremities by day one and week one. By the third week, complete ossification of the femur head, lesser trochanter, third trochanter, medial condyle, and lateral condyle was observed. At 1.5 months, the entire proximal extremity was ossified.

Conclusion

3D CT provided clear imaging of ossification progression in the pelvic and femur bones. This study enhances our understanding of vertebrate skeletal development.

To learn and comprehend the large amount of information in gross anatomy, undergraduate students must self-regulate their learning to be properly prepared for the exams within the available time. Even though there are many studies on learning strategies and their influence on test results and motivation, the aim of this study is to investigate characteristics of learning strategies in detail and in relation to the anatomy course of first semester students and how their use is related to anatomy test performance. For assessing the learning strategies, we used the short version of the questionnaire “Learning Strategies of University Students” (LIST-K) (Klingsieck, 2018). Further, we investigated potential influences of motivation and resources used during the self-regulated learning process. The participants in this study (N = 108) filled in the above-mentioned questionnaire LIST-K and a written multiple-choice anatomy test. A k-means cluster analysis revealed three groups of students differing in their self-reported use of learning strategies. Students used either (1) predominantly metacognitive and resource-related strategies, (2) predominantly cognitive strategies, or (3) no specific learning strategies at all. We found no significant overall relationships between the use of learning strategies and test performance. A stepwise linear regression identified the use of cognitive learning strategies (β =.269) as a significant predictor for test performance (R² =.149, p =.003), possibly as these specific learning strategies help with a systematic and effective approach while studying anatomy and retrieving large amount of memorized information. Further, motivation was identified as a negative predictor (β = −.277), which might be a result of the short time periods students have to study for exams. Overall findings underline the importance of self-regulated learning as a positive predictor for academic performance. By understanding these factors, a more student-centered approach could be adopted by educators to improve medical education and equip students with valuable approaches for their continuous education, even beyond university.

Background

The present study aims to investigate the feasibility of labeling ligaments using ultrasound-guided injections. On formalin-fixed cadavers, the anterolateral ligament was selected and targeted for demonstration. The development of portable ultrasound machines and the ability to connect them to tablets via Bluetooth or WLAN makes it an accessible tool to implement into the anatomical dissection courses in order to associate medical imaging (MRI and ultrasound), anatomical structures and their subsequent dissection.

Methods

8 formalin fixed human cadavers were used for the ultrasound-guided injections of 1 mL of blue latex into the anterolateral ligament. 8 cadavers were not injected with latex for comparative purposes. The injections were performed by an experienced ultra-sonographer. After approximately 10 months, five dissections were carried out by students during the dissection course and three specimens were dissected by anatomists.

Results

The anterolateral ligament was successfully marked and demonstrated in 7 out of 8 cases. In 4 out of 5 cases, the dissection was primarily conducted by students, while in 3 out of 3 cases, it was performed by anatomists. The accuracy was 80 % and 100 %, respectively.

Conclusion

The present study demonstrated that labeling obscure ligaments, such as the anterolateral ligament, using ultrasound guidance is feasible on formalin-fixed cadavers. It also showed that students can successfully perform the dissections as the structure is highlighted and that the time between injection and dissection (approximately 10 months) has little impact on the outcome. The use of ultrasound in dissection courses should be further encouraged.

Background

The Achilles tendon is one of the thickest, largest, and strongest tendons in the human body. Biomechanically, the AT represents the conjoint tendon of the triceps surae muscle, placed in series with the plantar fascia (PF) to ensure force transmission from the triceps surae toward the toes during walking, running, and jumping. Commonly encountered in the diagnostic evaluation of heel pain, Achilles tendinopathy (AT) refers to a combination of pathological changes affecting the tendon itself often resulting from excessive repetitive stress and overuse. Nevertheless, increasing evidence demonstrates that structural alterations due to overuse or abnormal patterns of skeletal muscle activity are not necessarily restricted to the muscles or tendons but can also affect the fascial tissue. At the same time, there has been recent discussion regarding the role of the fascial tissue as a potential contributor to the pathophysiological mechanisms of the development of several musculoskeletal disorders including tendinopathies. To the best of our knowledge, ultrasound (US) imaging studies on the fascial structures related to the triceps surae complex, as well as their possible correlation with Achillodynia have never been presented in the current literature.

Methods

In the present study, a comparative US imaging evaluation of textural features of the suro-Achilleo-plantar complex was performed in 14 healthy controls and 14 symptomatic subjects complaining of midportion AT. The thickness of the Achilles tendon, paratenon, intermuscular fascia, and PF has been assessed with US. In addition, both groups underwent the Victorian Institute of Sport Assessment-Achilles (VISA-A), a disease-specific questionnaire that measures the severity of symptoms of AT. Correlations between quantitative ultrasound measures and VISA-A scores were determined through Pearson or Spearman's rho correlations.

Results

Our ultrasonographic findings revealed statistically significant differences (p<0.05) in Achilles tendon and paratenon thicknesses between AT patients and controls. No significant differences were observed between groups in PF at the calcaneal insertion as all mean measures were within the expected range of a normal PF on US imaging. In contrast, in tendinopathic subjects, the deep intermuscular fascia between medial gastrocnemius (MG) and soleus (SOL) muscles is significantly (p<0.01) and considerably thickened compared to those of healthy subjects. Moderate correlations exist between tendon and paratenon thicknesses (r= 0.54, p= 0.04) and between MG-SOL fascia and tendon thicknesses (r= 0.58, p= 0.03). Regarding symptom severity and US morphological findings, the Spearman ρ test showed no correlation.

Conclusions

Our data demonstrate that, in symptomatic subjects, US alterations are not restricted to paratenon and intratendinous areas, but also