Dissection Laboratory Research Articles

A two-headed accessory muscle on the sole of the foot

Anatomical variations include the absence of a muscle or tendon or its presence as an accessory muscle or tendon. Clinically, anatomic variations play an important role in diagnosis and theraphy. In anatomy dissection laboratory, during routine dissection for educational purposes, a 83 -year- old male cadaver was dissected and a two-headed accessory muscle was observed on the plantar surface of the left foot. The medial and lateral heads of the muscle were observed close to the medial and lateral plantar neurovascular bundles. The accessory muscle was pierced by the tendon of the flexor digitorum longus muscle and both muscles were inserted to the distal phalanx of the fifth toe. The variations of the accessory muscles should be taken into consideration in surgical interventions, since, they may change the course of the intervention or as in the case of abductor hallucis muscle, they may be used in reconstructive procedures as grafts. Therefore, it is crucial for surgeons, orthopedic physicians, and anatomists to have a detailed knowledge of the intrinsic muscles of the foot.22-07-2024

The Nasopharyngo-Septal Butterfly Flap: A Novel Adjunct for Reconstructing Large Skull Base Defects.

Skull base defects can be challenging to reconstruct. The nasoseptal flap (NSF) remains the first-line option for reconstruction. However, it can be inadequate to cover wide defects or compromised by tumor invasion or prior surgery requiring additional reconstructive options. The goal of the study is to describe a novel flap for clival and craniovertebral junction (CVJ) reconstruction. Cadaveric study with an illustrative clinical case. Cadaver dissection laboratory and tertiary university hospital. Endoscopic endonasal dissection was performed in 15 cadavers. A modification of the inferior incision of the NSF was carried out. The inferior incision was performed at a more cranial location, sparing the mucosa of the posterior septum. Two lateral longitudinal incisions were carried out at the pterygo-sphenoidal junction freeing the nasopharyngeal mucosa. A third incision was performed separating the rostral mucosa from the nasal floor. The resulting flap was rotated postero-superiorly covering the clivus and CVJ. An inferiorly based butterfly-shaped nasopharyngo-septal flap, consisting of nasopharyngeal and posterior septal mucosa and receiving blood supply from the bilateral ascending pharyngeal arteries, was formulated. The lower wings comprised nasopharyngeal mucosa while the upper wings comprised posterior septal mucosa. The mean surface area of the flap was 12.35 ± 0.21 cm2 covering the clivus and CVJ in all cadavers. The nasopharyngo-septal flap is a novel vascularized flap that is well-suited for reconstructing clival and CVJ defects where the NSF is insufficient and can also be used as a salvage flap in cases where the NSF is unobtainable.

Dissection of the Sympathetic Nerves Around the Mesorectum at the Abdominopelvic Border.

Introduction Along the border between the abdominal cavity and pelvis are nervous structures that belong to the autonomous nervous system, which is delicate. These can be easily injured during regional surgical procedures such as the total mesorectal excision, where the preservation of the nervous structures should be one of the main objectives. In our study, we aimed to dissect all the sympathetic nerve formations listed at the abdominopelvic border and to present their formation, anatomical routes, and relations, as well as the surgical importance of their preservation. Method We performed anatomical dissections on eight 60- to 75-year-old cadavers (three male and five female) in the Dissection Laboratory of Carol Davila University of Medicine and Pharmacy, Bucharest, ROM. We sectioned each pelvis along the right pararectal line and exposed the hypogastric plexuses and their branches, following their pathways toward the pelvic viscera. Results We highlight the main nervous structures in the pelvis, namely the paravertebral sympathetic ganglion chain, which continues into the pelvis with the sacral ganglion chain, and the prevertebral component of the abdominal sympathetic system, represented by the superior hypogastric plexus and its continuation via the hypogastric nerves toward the inferior hypogastric plexuses. We followed the pathway of the superior hypogastric plexus from its origin down to its bifurcation into the two hypogastric nerves. We then followed the nerves into the pelvis and observed the formation of the inferior hypogastric plexuses, from which branches emerged toward the pelvic organs. Along the way, we point out anatomical landmarks that are crucial in an attempt to spare these nervous structures during regional surgical procedures. Conclusions While performing surgeries such as rectal resection with the excision of the mesorectum, radical hysterectomy, and radical prostatectomy, a thorough knowledge of the sympathetic nerve structures that pass from the abdominal cavity into the pelvis is required to spare pelvic innervation. In such a context, the dissection and anatomical assessment of regional sympathetic nerves can prove to be crucial in establishing operative protocols.

Cadaveric Study: Sign of Leser-Trélat Associated with Breast Cancer

INTRODUCTION: Seborrheic keratoses (SK) is considered the most common benign skin lesions found in individuals that are middle aged and older. In dermatology practice, these lesions pose no threat to the individual but can be concerning for cosmetic and underlying malignancy reasons when they cover most of the skin surface. Of specific concern is the sign of Leser-Trélat, which has been documented as a cutaneous harbinger of underlying malignancy associated with proliferation of the size and/or number seborrheic keratoses. The rare sign is usually caused by malignancies such as gastrointestinal adenocarcinoma, but also lung, kidney, liver, or pancreatic cancer. This case report will describe the histology of the skin lesions in Lesar Trélat and analyze the current literature regarding its association with breast cancer, which is quite rare. RESOURCES: For this case study, a cadaver from the body donor program in Philadelphia College of Osteopathic Medicine (PCOM), South Georgia was used. Skin samples were sent to Colquitt Regional Center for processing, where sections were embedded in paraffin and were stained with H&E stain. A pathologist reported histopathological findings of the skin lesions and the breast tissue samples. DESCRIPTION: Multiple SK lesions covering the face, abdomen, back, as well as both upper and lower extremities were observed in one of the cadavers in the gross anatomy laboratory. Due to the significant number of pigmented, verrucous lesions, the sign of Leser-Trélat was clinically postulated, later confirmed during routine laboratory dissection of the breast tissue. Histology sections confirmed not only multiple SK lesions in the skin, but also revealed an associated breast cancer in the form of an infiltrative ductal carcinoma. SIGNIFICANCE: The sign of Leser-Trélat is rare by itself and its association with breast cancer is even more uncommon. Once a clinician recognizes the multiple SK eruptions, the patient should be meticulously investigated for not only for an underlying GI malignancy, but also for other cancers like breast cancer. Additionally, a case report confirmed malignant melanoma that mimicked sign of Leser-Trélat, warranting the importance of further analyzing the pathology diagnosis when there is a proliferation of multiple seborrheic keratoses.Therefore, biopsy and histology diagnosis is crucial for ruling out both cutaneous as well as underlying malignancies and should be encouraged when patients present in clinic rather than assuming the typical benign characteristics of seborrheic keratosis.

Combined Endoscopic Endonasal Transclival and Contralateral Transmaxillary Approach to the Petrous Apex and the Petroclival Synchondrosis: Working "Around the Corner" of the Internal Carotid Artery-Quantitative Anatomical Study and Clinical Applications.

The endoscopic contralateral transmaxillary (CTM) approach has been proposed as a potential route to widen the corridor posterolateral to the internal carotid artery (ICA). In this study, we first refined the surgical technique of a combined multiportal endoscopic endonasal transclival (EETC) and CTM approach to the petrous apex (PA) and petroclival synchondrosis (PCS) in the dissection laboratory, and then validated its applications in a preliminary surgical series. The combined EETC and CTM approach was performed on three cadaver specimens based on four surgical steps: (1) the nasal, (2) the clival, (3) the maxillary and (4) the petrosal phases. The CTM provided a "head-on trajectory" to the PA and PCS and a short distance to the surgical field considerably furthering surgical maneuverability. The best operative set-up was achieved by introducing angled optics via the endonasal route and operative instruments via the transmaxillary corridor exploiting the advantages of a non-coaxial multiportal surgery. Clinical applications of the combined EETC and CTM approach were reported in three cases, a clival chordoma and two giant pituitary adenomas. The present translational study explores the safety and feasibility of a combined multiportal EETC and CTM approach to access the petroclival region though different corridors.

A thyroidea ima artery variation providing collateral circulation to the mediastinum.

The thyroidea ima artery (TIA) is a highly variable arterial deviation of the blood supply to the thyroid gland with critical implications for surgical neck procedures such as tracheostomy. Though relatively common in the population at large (~ 4%), most TIA variations are related to the origin of the artery and whether it emerges from the common sites of the brachiocephalic trunk, aortic arch, and right common carotid artery, or another more unique vessel-as opposed to its dispersion pattern. TIA variants generally supply the thyroid gland, occasionally co-occurring with absent thyroid arteries. Here, we report on a unique case of a four-pronged variation of the TIA discovered during an anatomy laboratory dissection of first-year medical students. This variant originated from the brachiocephalic trunk and had three branches terminating in the thyroid gland and a fourth branch traveling into the thorax to provide accessory circulation in the mediastinum. Specifically, small arterial branches from the inferior TIA branch supplied the anterior pericardium and surrounding adipose tissue, in addition to normal pericardiacophrenic circulation. We discuss the potential embryological and clinical relevance of this unique variation and voice further support for imaging as a requirement before surgical neck procedures to prevent catastrophic bleeding in the event of a TIA variant.

Craniovertebral Junction Surgical Approaches: State of Art.

Surgical approaches directed toward craniovertebral junction (CVJ) can be addressed to the ventral, dorsal, and lateral aspects through a variety of 360° surgical corridors Herein, we report features, advantages, and limits of the updated technical support in CVJ surgery in clinical setting and dissection laboratories enriched by our preliminary surgical results of the simultaneous application of O-arm intraoperative neuronavigation and imaging system along with the 3D-4K EX in TOA for the treatment of CVJ pathologies.In the past 4years, eight patients harboring CVJ compressive pathologies underwent one-step combined anterior neurosurgical decompression and posterior instrumentation and fusion technique with the aid of exoscope and O-arm. In our equipped Cranio-Vertebral Junction Laboratory, we use fresh cadavers (and injected "head and neck" specimens) whose policy, protocols, and logistics have already been elucidated in previous works. Five fresh-frozen adult specimens were dissected adopting an FLA. In these specimens, a TOA was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances.A complete decompression along with stable instrumentation and fusion of the CVJ was accomplished in all the cases at the maximum follow-up (mean: 25.3months). In two cases, the O-arm navigation allowed the identification of residual compression that was not clearly visible using the microscope alone. In four cases, it was not possible to navigate C1 lateral masses and C2 isthmi due to the angled projection unfitting with the neuronavigation optical system, so misleading the surgeon and strongly suggesting changing surgical strategy intraoperatively. In another case (case 4), it was possible to navigate and perform both C1 lateral masses and C2 isthmi screwing, but the screw placement was suboptimal at the immediate postoperative radiological assessment. In this case, the hardware displacement occurred 2months later requiring reoperation.

Paying Respect to the Silent Mentors: A Sri Lankan Experience

Donation of bodies is one of the foremost methods of obtaining cadavers for dissection laboratories. Thanksgiving and memorial services are held by many anatomy institutions and medical schools worldwide, for the donors who selflessly bequeathed their bodies for medical education. In this article, an institutional experience of conducting a memorial service in the form of a Buddhist ceremony to invoke blessings to the donors and their families at the Faculty of Medical Sciences of the University of Sri Jayewardenepura in Sri Lanka, for over 25 years, is presented by the authors. The bodies are donated to the medical faculty with informed written consent taken from the donors prior to their deaths. This process is entirely a voluntary service of goodwill towards medical education by the donors, as no financial compensation is provided by the university to them or to their families. Additionally, the benefits of holding such a memorial ceremony for the students as well as for the family members of the deceased are discussed.

Additional Tendon Slip of the Extensor Carpi Radialis Longus: A Case Report with Clinical Application

Additional tendon slips of the extensor carpi radialis longus are rare anatomical variants, with incidence ranging from 12-35%. While this anatomical variant is typically benign, it is clinically important as it can contribute to neuromusculoskeletal dysfunction. Medical providers should be aware of variations of the wrist extensors during surgeries involving the forearm and wrist. The presence of additional tendons may cause confusion when interpreting imaging findings. This case report details findings of an additional wrist extensor tendon identified during a cadaveric dissection lab in a physical therapist education program.

Role of Co-curricular Activities in Enhancing Conceptual Learning of Anatomy – An Undergraduate Perspective

Introduction: Human anatomy deals with spatial orientation and organization of major systems of the body. Routine didactic lectures and dissection lab practical’s need to be supplemented with other learning modalities to enhance deeper and holistic approach towards the fabric of nature. Many educationists have provided surplus information regarding the use of one or few of the co-curricular activities in promoting learning in various fields of education. Literature is scarce on use of multiple co-curricular activities in the discipline of anatomy. The present study aims to ascertain the participation rate and explore the perspectives of phase-1 MBBS students on the role of cocurricular activities in conceptual learning of anatomy. Methods: Study design: cross sectional study. Study participants and study area: 150 phase-1 MBBS students ‘of 2021 batch, study conducted in the department of anatomy at Dr. Pinnamaneni SIMS & RF. Sampling: convenience/purposive Data collection: online survey via google forms was collected from students who have participated in one or all the co-curricular activities. The co-curricular activities included video-making, seminars, model making, WhatsApp assessments, peer tutoring and tutored and student volunteering. The forms consisted of self-rating (5-point Likert scale) and close end questions. Data analysis: Responses in the form of agreements and disagreements of the students were analyzed in percentages for simplification of data. Results: A total of 128 responses were received. Out of 128 students 75.8% participated in video-making,81.3 % in seminar presentations, 98.4% in model making,81.3% in WhatsApp assessments,76.6% tutored their peers,88.3% got tutored from their peers in turn.64 (50%) students participated as volunteers in anatomy state conference. Students feedback revealed a positive impact of all the above co-curricular activities in promoting conceptual learning in anatomy. Conclusions: Blending of supplementary methods in learning can promote qualitative comprehension of anatomy in undergraduate students. Co-curricular activities enhance critical thinking and deeper understanding of subjects through healthy recreation in a stress-free environment. KEYWORDS: co-curricular activities, critical thinking, deeper learning, video-making, WhatsApp assessments.

Students' Perception of a Virtual Dissection Laboratory in Undergraduate Anatomy and Physiology of Speech and Hearing: A Focus Group Study.

Hands-on laboratory experience that allows for manipulation of realistic and relevant materials in course curricula has been shown to improve students' learning, understanding, and critical thinking skills. The purpose of this study was to gain insight into the experiences of students who engaged in laboratory coursework using a virtual dissection (VD) table as part of an undergraduate course in anatomy and physiology of speech and hearing. Undergraduate students enrolled in an anatomy and physiology of speech and hearing course at a single university for the fall 2021 semester consented to participate. Nine students, divided into two focus groups, were encouraged to describe their experiences and perspectives about the VD table and corresponding laboratory assignments. Following verbatim transcription of the data, the authors conducted a thematic analysis. Five themes emerged from the body of data: (1) using the VD table, (2) completing the VD lab assignments, (3) preparation for laboratory sessions, (4) suggested modifications, and (5) enriched learning. Students believed using the VD table aided in a better understanding of course material than traditional methods. Moreover, they surmised that this method of learning, particularly for speech-language pathologists, may be superior to learning through models and cadavers.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Lateral Supraorbital Approach with Expanded Indications.

Objectives The lateral supraorbital (LSO) approach is a less-invasive alternative to the pterional craniotomy that provides rapid transsylvian access. Establishing familiarity with the LSO technique and its features as compared with other anterolateral approaches is an important component of advanced skull base training. We present a step-by-step demonstration of the LSO approach using cadaveric dissection in a manner that is digestible for trainees at various levels. Design This is anatomic step-by-step dissection and representative case series. Setting This study was carried out in the cadaveric dissection laboratory. Participants A formalin-fixed, latex-injected cadaveric head specimen was dissected under microscopic magnification by a neurosurgery resident under faculty supervision. Following dissection, representative case applications were reviewed. Main Outcome Measures Dissection and case illustration were the main outcome measures. Results A single-layer myocutaneous flap is developed, and a single-burr-hole technique is used, followed by extensive drilling of the sphenoid wing. The dura is opened in a C-shaped fashion centered on the Sylvian fissure, exposing the inferior frontal and superior temporal lobes. Labeled photographs of dissections with pertinent anatomical structures are presented. Three case examples illustrating the versatility of the LSO approach, including the resection of a large pituitary adenoma, an inferior frontal melanoma metastasis presenting to the Sylvian surface, and a frontoinsular low-grade glioma, are reviewed. Conclusion As compared with the pterional craniotomy, the LSO approach involves a shorter incision, smaller craniotomy, and faster exposure; it can be conveniently tailored to various indications. Understanding the step-by-step dissection and indications of the LSO approach is of paramount importance to neurosurgery trainees.

Anastomosis between the facial nerve - ansa cervicalis and the facial nerve - hypoglossal nerve in rabbits: technical note for a practical use in peripheral facial palsy.

To emphasize the importance of laboratory dissections in perfecting surgical techniques. In this paper, we describe the technical details on rabbit dissection for practical applications. Four New Zealand rabbits were distributed into two groups and underwent anastomosis between the Facial Nerve and Ansa Cervicalis (group 1) and between the Facial Nerve and Hypoglossal Nerve (group 2). They were clinically and neurophysiologically evaluated after ten weeks. Electroneurography with skin electrodes were used to identify the motor activity of the involved muscles and nerves. Facial and ipsilateral tongue reinnervation was analyzed 40 weeks after anastomosis. Evoked electromyographic muscle tension was used to evaluate facial and tongue reinnervation. Facial and ipsilateral tongue reinnervation was analyzed 40 weeks after anastomosis. Recorded evoked potentials showed improvement in facial reinnervation in all four rabbits. Rabbits undergoing FN-HN anastomosis still showed ipsilateral lingual paresis, based on EMG tests. The survival rate was 100%. The laboratory dissection plays a crucial role in training surgical specialists to achieve favorable patient outcomes. Both types of anastomosis can be used to achieve facial reinnervation; however, it is imperative to prevent ipsilateral lingual paralysis that may arise from using the hypoglossal nerve.

Application of Otoform to Study Variations of Sinus Tympani: A Novel Technique.

The sinus tympani is a deep pocket of varying dimensions situated in the retrotympanum. It lies medial to the facial nerve thereby making surgical access difficult. It is this area which is frequently involved in chronic otitis media attico-antral type. Removal of disease from sinus tympani is cumbersome and expedites Cholesteatoma Recidivism. In India, very limited studies have been conducted describing the variations of Sinus tympani. Hence, this study is dedicated to estimating it's variations in volume. This is a one-year Observational Cross-sectional study conducted between January 2020 to December 2020 in Temporal Bone Dissection Lab of Department of Otorhinolaryngology and Head and Neck Surgery, J. N. Medical College, KAHER, Belgaum. 40 Human temporal bone (both left and right) have been dissected. The middle ear cavity was filled carefully with a moulding material i.e. Otoform. Once set, a 3-dimensional model of the middle ear cavity was made, which was removed carefully without causing any damage. The volume of the middle ear cavity was calculated. The other contents and parameters were measured using a measuring probe. Forty bones were dissected. The volume of the sinus tympani was measured to be 8.77 cubic mm with a range of 6.5 cubic mm to. 10.9 cubic mm hence showing that sinus tympani show a larger variability in terms of size, shape and volume. The ponticulus was Complete in 65% of the cases (26 bones) and incomplete in 35% of the cases (14 bones). The ponticulus and subiculum were found to be complete in a well pneumatized mastoid bone. The volume of the middle ear cavity was measured to be 1.17 cubic cm. The sinus tympani volume was calculated in this study employing a novel technique called the Otoform mould in cadaveric temporal bones, enabling for accurate measurement. The study concluded that sinus tympani showed a wide range in volume thus owing that it is the structure which has highest variability in terms of size and shape in the middle ear.

DISSECTION HALL ETHICS: ROLES AND RESPONSIBILITIES

Anatomy is the key to various streams of medical profession. To attain proper knowledge of subject, the student must go through the dissection hall in very first year of his professional life. Cadaver always remains the grace of dissection hall, which not only makes the department of anatomy alive but also facilitates practice of clinical techniques for safe clinical practice. Thus, for medical scholars it is must to have some basic ethical knowledge about good conduct in dissection hall and understanding moral values in regards to cadaver. This review highlights the ethics in context to dissection laboratory for being the first place of clinical practice.

Incision Precision: Engaging Students during Dissection Labs.

Active learning tools, such as gamification, have facilitated teamwork and improved decision-making skills in Anatomy and Physiology classes. However, most Anatomy and Physiology labs currently contain dissection activities where students are not likely to engage in inquiry, critical thinking, or problem-solving. Usually, the instructor gives a brief lecture on the topic, and students are left to dissect without understanding how the lecture relates to what is in front of them, which is frustrating. Coupled with the frustration, some students have adverse opinions on dissecting specimens, including hesitation to dissect the specimen and religious or ethical concerns with dissection. Utilizing similar game mechanics to Taboo (Hasbro) and Milton Bradley's Operation, Incision Precision is a card game that was made to engage students in the dissection lab by allowing them to connect lecture-based information to a physical structure within an organ system. Each card contains an anatomical or physiological description of the organs commonly dissected in the undergraduate Anatomy and Physiology laboratory. For effective gameplay and full participation, the class should be divided into groups containing 3 to 4 students. The group will draw two cards where members can either correctly name the organ or identify the named organ on the dissected specimen. Playing Incision Precision resulted in participation from all group members during the dissection activity, including those with negative feelings about touching the dissected specimen. Due to positive student feedback, Incision Precision has been adapted and played with system-specific organ dissections.

Assessing the impact of neurosurgery and neuroanatomy simulation using 3D non-cadaveric models amongst selected African medical students.

Laboratory dissections are essential to acquire practical skills to perform neurosurgical procedures. Despite being traditionally done on cadavers, they are often unavailable and suffer from cultural barriers in the African context. Non-cadaveric UpSurgeOn neurosurgery models have been developed to bridge this barrier, providing an almost similar experience with the human body. This study aimed to assess the impact of the UpSurgeOn hands-on-touch non-cadaver model training amongst selected Cameroon medical students. An anonymous 35-item questionnaire was distributed online using Google drive systems to medical students who attended UpSurgeOn's hands-on-touch non-cadaver model training course. These questions aimed to capture data on previous experience with neuroanatomy and neurosurgery practicals and the perception, attitudes, and impact of the UpSurgeOn neurosurgery tool. Eighty-six students completed the survey. The mean age was 21.2 ± 1.868 years, 61.6% were males with 62.8% of respondents being medical students in preclinical years. Before the training, 29.4% had a fair knowledge of neuroanatomy. Textbooks and Youtube videos were the main sources of neuroanatomy and neurosurgery knowledge for more than half of the respondents. Up to 91.5% had no prior exposure to a neuroanatomy/neurosurgery cadaver laboratory dissection, and 22.6% and 17.6% had witnessed and performed at least one craniotomy before, respectively. There were 11.1%, 15.5%, and 31.3% of our respondents who had used a surgical microscope, a neurosurgical instrument, and the UpSurgeOn Neurosurgery tool before, respectively. The majority perceived the UpSurgeOn tool easy to use and felt they needed to learn just a few things before getting going with the box. Most thought of increasing the use of the UpSurgeOn Box and saw the need to be part of the training curriculum. Finally, the majority felt this tool helped to increase familiarity and acquire neurosurgical skills, and to develop the orientation skills needed during neurosurgical approaches. Undergraduate exposure to traditional neurosurgery/neuroanatomy labs is limited in Cameroon. Neurosurgery/neuroanatomy practical skills are gained essentially using non-practical means. Most students found the UpSurgeOn tool user-friendly, saw the need to incorporate it as part of their training, and perceived it to be essential in getting acquainted with neurosurgical skills.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Frontotemporal and Orbitozygomatic Craniotomies.

Introduction Although many neuroanatomic atlases have been published, few have detailed complex cranial approaches and pertinent anatomic considerations in a stepwise fashion intended for rapid comprehension by neurosurgery students, residents, and fellows. Methods Five sides of formalin-fixed latex-injected specimens were dissected under microscopic magnification. The frontotemporal and orbitozygomatic approaches were performed by neurosurgical residents and fellows at different training levels with limited previous experience in anatomical dissection mentored by the senior authors (M.P.C. and M.J.L.). Meticulous surgical anatomic dissections were performed until sufficient visual and technical completion was attained, with parameters of effectively demonstrating key surgical steps for educational training purposes. Following the completion of dissection and three-dimensional photography, illustrative case examples were reviewed to demonstrate the relative benefits and optimal applications of each approach. Results The frontotemporal and orbitozygomatic approaches afford excellent access to anterior and middle skull base pathologies, as well as the exposure of the infratemporal fossa. Key considerations include head positioning, skin incision, scalp retraction, fat pad dissection and facial nerve protection, true or false MacCarty keyhole fashioning, sphenoid wing drilling and anterior clinoidectomy, completion of the craniotomy and accessory orbital osteotomy cuts, dural opening, and intradural neurovascular access. Conclusion The frontotemporal and orbitozygomatic approaches are core craniotomies that offer distinct advantages for complex cranial operations. Learning and internalizing their key steps and nuanced applications in a clinical context is critical for trainees of many levels. The orbitozygomatic craniotomy in particular is a versatile but challenging approach; operative-style laboratory dissection is an essential component of its mastery and one that will be powerfully enhanced by the current work.

Possible Points of Ulnar Nerve Entrapment in the Arm and Forearm: An Ultrasound, Anatomical, and Histological Study.

Ulnar nerve entrapment is one of the most common entrapment neuropathies, usually occurring in the cubital tunnel of the elbow and in Guyon's canal of the wrist. However, it can also occur at other anatomical locations. Our aim was to review other possible locations of ulnar nerve entrapment in an ultrasound and anatomical study. Eleven upper limbs from eight adult corpses were ultrasonographically examined and subsequently dissected in a dissection laboratory. Four specific anatomical points were analysed, and any anatomical variations were documented. Moreover, six samples of the nerve were taken for histological analysis. Distinct anatomical relationships were observed during ultrasound and dissection between the ulnar nerve and the medial intermuscular septum, the triceps aponeurosis, Osborne's fascia at the elbow, the arcuate ligament of Osborne and the intermuscular aponeurosis between the flexor carpi ulnaris and the flexor digitorum superficialis muscles. A statistical study showed that these locations are potential areas for ulnar nerve compression. In addition, a fourth head of the triceps brachii muscle was found in some specimens. Results demonstrate that ultrasound is a good tool to investigate ulnar nerve entrapment neuropathy and to identify other anatomical points where the nerve can remain compressed.

Impact of modified teaching strategies used in a gross anatomy course on the academic performance of dental students during the COVID-19 pandemic.

Modified teaching strategies (MTS), asynchronous online teaching and smaller dissection groups, were applied to a gross anatomy course for dental students in the National Taiwan University in April 2020 in response to the COVID-19 pandemic. This study aimed to investigate the effects and perceptions of MTS on dental students. Scores for anatomy examinations for 2018-2019 (without MTS) and 2019-2020 (with MTS) cohorts were compared to explore the effect on academic performance. Moreover, questionnaire from the 2019-2020 cohort was analysed to determine dental students' perceptions about MTS. The lecture performance in the final examination of the second semester for the 2019-2020 cohort was significantly higher than that of the first semester (pre-COVID-19) and that for the 2018-2019 cohort. However, the laboratory performance in the midterm examination of the second semester for the 2019-2020 cohort was significantly lower than that for the 2018-2019 cohort and showed no difference in the final examination of the first semester. The questionnaires revealed that the majority of students displayed positive attitudes towards MTS and agreed with the importance of peer discussion during laboratory dissection. Asynchronous online learning for anatomy lecture may be beneficial for dental students; however, a smaller dissection group accompanied by reduced peer discussion may temporarily exert negative effects on their laboratory performance at the beginning of the application. Furthermore, more dental students exhibited positive perceptions towards smaller dissection groups. These findings could illuminate the learning condition of dental students in anatomy education.