Anatomical Science International最新文献

The vertebral artery (VA) demonstrates considerable variability, including infrequent morphologic variants like double origin. The current imaging report presents an atypical case of a dual origin of a left vertebral artery (LVA), which was identified incidentally during routine computed tomography angiography of a 51-year-old male patient. The typical LVA originated from the left subclavian artery (LSCA), and the other one was an aberrant LVA (ALVA) that arose from the aortic arch (AA) in between the left common carotid artery (LCCA) and the LSCA. The two vessels (LVA and ALVA) converged proximally to the transverse process of the C6 vertebra. The embryological explanation for this variant likely pertains to the persistence of primitive dorsal aortic segments and intersegmental arteries. Although rare, with a prevalence of 0.1%, the occurrence of LVA double origin may have significant clinical implications, including alterations in hemodynamics, an increased risk of VA dissection, and complications during surgical or endovascular procedures. The identification of such variants through preoperative imaging is essential to prevent iatrogenic complications.

Medical educators should understand the differences within the medical student population, including gender. Research on gender effects on learning and skill acquisition has yielded contradictory results, particularly in anatomy learning among undergraduate medical students. While various dissection course settings have been evaluated, gender-specific differences have largely been overlooked. This study examined gender differences in several aspects of anatomy education. First, the ability of undergraduate medical students to identify anatomical structures was assessed to determine gender differences in learning gains. Second, learning outcomes were compared between a 3-month and a 1-month regional anatomy course, with attention to gender. Third, knowledge retention was evaluated at 6- and 12-month follow-ups. Finally, student perceptions of different embalming methods for anatomy learning were assessed with a focus on gender. Minor differences were observed between genders across different regions in learning gains. Scores from the 3-month course were higher than those from the 1-month course, regardless of gender, particularly for the neck, thorax, and abdomen. A significant knowledge gain was noted in abdominal anatomy at the 6- and 12-month follow-up: scores improved by 56% in females and by 68% in males. The comparison of Thiel- versus ethanol-based embalming revealed gender differences regarding tissue pliability and the utility of tissues for achieving learning objectives. In conclusion, subtle differences appear to exist between female and male students in terms of perceptions and learning outcomes in gross anatomy dissection courses. These findings will be useful in developing new curricula for undergraduate medical students, taking into account gender differences in the context of regional anatomy dissection courses.

Semicircular canal dehiscence (SSCD), is a rare bony defect that reveals a third window of semicircular canal except oval and round window. Dizziness, acute vertigo attacks, conductive hearing loss, tinnitus and amplified heartbeat sounds are the symptoms of dehiscence. The aim of this article is to analyze the length and location of semicircular canal dehiscence as superior (anterior), inferior (posterior), or lateral (horizontal) canals using micro-CT and compare it with Cone beam CT. A total of 39 dry temporal bones without visible damage were examined both in Micro CT and Cone beam CT. Measurements were made on these cross-sectional images using the CTAn software. Statistical significance was defined as p < 0.05. When examining Micro-CT images, only 4 canals showed dehiscence among 39 bones. The dehicences were observed in both lateral, superior, and posterior semicircular canals. One dehiscence was in the lateral semicircular canal, two were in the superior semicircular canal, and the last one was in the posterior semicircular canal. In CBCT images, dehiscence was observed in a total of 11 canals among the 39 bones. Two dehiscences were in the lateral semicircular canal, three in the posterior semicircular canal, and six in the superior semicircular canal. There was a significant difference between Micro CT and Cone beam CT in terms of dehiscence detection (p < 0,05). Consequently, this study emphasizes the potential danger of an uncertain diagnosis of canal dehiscence with CT in individuals with minor irregularities in Cone beam CT scans, which could result in potentially inappropriate surgical interventions.

Presently, a few brachioradialis muscle (BR) variants have been reported, mainly concerning their inserting tendons or the accessory forms (accessory BR muscles). During a routine dissection of a 74-year-old female donated cadaver, a unique muscle variant was observed unilaterally. An aberrant origin of the BR from the lateral head of the triceps brachii was identified on the left arm. The radial nerve (RN) superficial branch coursed posteriorly to the BR before obtaining its superficial position. On the right arm, the BR was typical. So far, some of the BR variants in its origins have been reported, such as arising from the muscular belly of the brachialis or the insertion of the deltoid muscle. Thus, the present variant could be a worth noting rare case. Furthermore, the posterior position of the RN superficial branch could have potential clinical significance and may cause entrapment neuropathy.

The vascular systems of the kidneys and gonads are highly susceptible to variations because of the degeneration of the mesonephros and mesonephric artery and the progressive ascending development of the metanephros. In this report, we present a rare case of a common arterial trunk originating from the left renal artery and supplying the left diaphragm, adrenal gland, and testis. Anatomical dissection of a 95-year-old male was conducted during the 2023 academic year at Tokai University Medical School. The left renal artery had a common trunk that bifurcated to superior and inferior branches, forming a T-shape. The superior branch was distributed in the left adrenal gland and diaphragm, whereas the inferior branch was distributed in the left testis. This anatomical variation likely results from the remnant of the mesonephric artery network structure, particularly the rete arteriosum urogenitale. Understanding such variations is crucial for radiologists and surgeons to avoid potential complications during diagnostic procedures and surgical interventions.

Duplicated inferior vena cava (DIVC) is a congenital anomaly where the inferior vena cava (IVC) is present on either side of the abdominal aorta. Previous studies have noted smaller IVC widths in DIVC cases, but detailed structural characteristics remain unclear. This study aimed to characterize the histological structure of the IVC in DIVC and normal cases. Histological analysis was performed on the IVC just below the liver (IVC-Liver), the IVC at the 4th lumbar vertebra level (IVC-L4), and the external iliac vein (EIV) from donated cadavers. The tissues underwent HE staining and immunohistochemistry to detect elastin and alpha smooth muscle actin, with the cross-sectional area of vessel lumina and immunopositive area calculated. The study found that the combined cross-sectional areas of the right and left IVC-L4 in DIVC cases were smaller than the single IVC-L4 area in normal cases. Histologically, DIVC cases showed a significantly decreased ratio of elastin immunopositive areas, compared to normal cases. This reduction in cross-sectional areas and elastin ratio suggests that IVCs in DIVC cases hold less blood volume and have weaker contractility by elastic fibers after dilation, potentially leading to disrupted blood circulation in the lower body.

Botulinum toxin A injection is commonly used to treat splenius muscle dystonia; however, the optimal injection site within the muscle remains unidentified. This study identified the optimal target for botulinum toxin A based on the distribution of intramuscular nerves and spindles in the splenius muscles. This study included 24 adult individuals. The curve connecting the external occipital protuberance and the third thoracic spinous process was the longitudinal reference line (line L). The curve connecting the external occipital protuberance and the mastoid process was the horizontal reference line (line H). Modified Sihler's staining showed an intramuscular nerve-dense region in the splenius muscles. Muscle spindle abundance was calculated after hematoxylin and eosin staining. The center of the region of the highest muscle spindle abundance was localized using computed tomography. The projection points (P and P') of the center of the region of the highest muscle spindle abundance behind and in front of the neck, position of P (P_L and P_H) projected onto the L and H lines, and depth of the center of the region of the highest muscle spindle abundance were determined under the Syngo system. P_L, P_H, and depth of the center of the region of highest muscle spindle abundance of splenius capitis and splenius cervicis muscles were 17.33% and 40.59% of the L line, 42.42% and 60.44% of the H line, and 26.30% and 32.60% of the PP' line, respectively. These results will provide morphological guidance for improved efficiency and efficacy of target localization for botulinum toxin A treatment for splenius muscle dystonia.

The cerebral vascular supply has always stirred interest among researchers since ischemic stroke in 30% cases can be managed by early intervention and reperfusion of brain tissue. Variations of collateral arterial circle at the base of brainor Circle of Willis are not uncommon which can be dated back to embryological causes. The aim of the study is to update the variations and to propose a clinically applicable simple classification for completeness of Circle of Willis. The present study was done on 65 formalin fixed adult human brains of both genders. Each component of the circle was observed carefully and the external diameters were measured. Accordingly, the vessels were defined into different categories as classical, narrow and hypoplastic as per their diameter. Absence of any segment was taken into account. Consequently, the circles were classified into Type I, II, III and IV as per presumed functional competence. 30.8% of the circles were found to be complete. In anterior segment fused cerebral artery and aplastic communicating artery were the commonest variations. In the posterior segment, narrow cerebral artery and fetal type of communicating artery were encountered most frequently. Hypoplasia and aplasia were more on the right posterior segment of the circle. P value for means of right and left side variations was statistically significant (p < 0.0001). Fetal PCoA was the most common variation noted. Incidence of hypoplasia was more common in cerebral arteries as opposed to aplasia, which was more common in communicating arteries. Type II was the most common variant. Left posterior quadrant had the highest incidence of incompleteness.

Surgeons frequently approach the foramen ovale (FO) via the infratemporal fossa (ITF) to treat trigeminal neuralgia. However, this percutaneous procedure could be unsuccessful due to anatomical factors. The present study aimed to assess the FO morphology and its relationship with the lateral pterygoid process plate (LPPP), emphasizing coexisting ITF variants. One-hundred-and-eight (216 sides) adult dried skulls were evaluated at the ITF (FO and LPPP). The FO maximum anteroposterior and lateromedial distances (APD and LMD) were calculated and correlated with the FO morphology. The FO-LPPP relationship was observed, and the presence of a sphenoidal emissary foramen (SEF) and possible ossified sphenoid bone’s ligaments variants (pterygoalar and pterygospinous—PTA and PTS variable ossification) were recorded. Statistical analysis was performed using the SPSS statistical program. The FO morphology was classified into three types after taking into consideration the FO morphometry. Type 1 FO was considered when the APD was two times more than the LMD (45.83%), Type 2 FO was identified when the APD was more than the LMD but no more than two times (51.85%), and Type 3 FO was considered when the APD and LMD were equal (2.32%). The FO and LPPP relationships were classified into the following four types: the direct type when the LPPP base ended at the FO center (32.3%), the lateral type was observed when the LPPP base ended at the FO lateral margin (28.76%), the far type was considered when the LPPP base ended distally to the FO (22.57%), and the medial type was when the LPPP base ended at the FO medial margin (11.95% of cases). Concerning the impact of the sphenoid bone variants on the FO-LPPP, the SEF did not alter the FO-LPPP relationship, while the PTA or PTS bar presence significantly affected it (p < 0.001 and p = 0.007, respectively). When the sphenoid bone ossified bars were present, the most common type of FO was the medial one. A novel classification system was proposed for the FO morphology, assessing possible coexisting ITF variants that could alter the FO-LPPP relationship. Knowledge of these details would help clinicians perform percutaneous procedures to treat trigeminal neuralgia.