Anatomical Science International最新文献

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.

The ophthalmic artery plays a vital role in supplying the eyeball and neighboring structures, and is associated with various clinical conditions. In this study, high-resolution cadaver-sectioned images were used to provide an intricate morphology of the ophthalmic artery and its branches, along with the oculomotor, trochlear, ophthalmic, and abducens nerves. This study presents a combination of schematics and cadaver-sectioned images, allowing for a clear representation of intricate anatomic structures. This study elucidated the spatial relationships among the ophthalmic artery, cranial nerves, and adjacent anatomic features. The branches of the ophthalmic artery were classified into three categories. The complex anatomy of the ophthalmic artery and adjacent nerves was examined on cadaver-sectioned images and is schematically illustrated. The utilization of cadaver-sectioned images presents advantages over traditional dissection techniques. This approach maintains the original positioning of the ophthalmic artery and nerves, enhancing accuracy. This study enriches the comprehension of ophthalmic anatomy, offers a helpful resource for interpreting clinical images, and facilitates various medical procedures. As a result, we anticipate that our research will contribute to advancing the diagnosis and management of eye disorders, offering fresh perspectives on the relationship between the ophthalmic artery and the surrounding structures.

This study aimed to discuss the clinical implications associated with the absence of the stapedius muscle and concomitant otosclerosis. The causes of mixed hearing loss are presented based on its embryonic development, audiological tests, and high-resolution computed tomography (CT) imaging. This case describes a 35-year-old female patient diagnosed due to bilateral conductive hearing loss. The patient complained of a significant deterioration of hearing and speech understanding lasting for several months. Preoperative audiometric work-up revealed air–bone gap with the presence of Carhart’s notch characteristic for otosclerosis. In CT scans otospongiotic focus was confirmed and the absence of stapedius muscle, its tendon, and pyramidal eminence was discovered. The patient underwent stapedotomy with good hearing result after healing. Understanding the stapedius muscle's development process is essential to comprehend the reason for its failure – the absence of the stapedius muscle results in exposure to acoustic trauma. Patients may experience hypersensitivity to sound, although it was not discovered in the described patient. High-resolution CT is a handy tool for analyzing congenital malformations of the middle ear. The absence of the stapedius muscle may also be indicated by other anatomical variations of the middle ear detected with high-resolution computed tomography images. The absence of the stapedius muscle may coexist with otosclerosis. Detailed in-depth analysis of high-resolution computed tomography images is the only tool to assess for stapes muscle defects without surgical intervention.

Satellite glial cells in the dorsal root ganglion are integral to the biology of sensory neurons. This review explores their unique fine structures, as well as their roles in pain signaling and neuronal differentiation. Satellite glial cells exhibit remarkable plasticity, including stem cell-like properties and the ability to influence neuronal morphology and function. Less-studied glial types, such as axonic satellite glial cells and newly identified glial populations, also offer insights into glial cell diversity and specialization. By focusing on the cellular and molecular mechanisms underlying satellite glial cell function, this review contributes to enhancing the foundational understanding of sensory system organization and glial biology.

Cadaveric surgical training (CST) can safely improve surgical skill. Recently, various innovations have made surgical training more realistic. Saturated salt solution (SSS) and urea methods are useful for plastic surgery training, because they better preserve the color and texture of soft tissues than formalin fixation (FA). Microvessels are invisible to the naked eye, and in this study, we visualized skin perforators by injecting dye into the flaps of nutrient vessels during hand and foot surgery. During each CST session, the instructor used three cadavers for demonstration. From 2017 to 2021, these cadavers were not stained, whereas from 2022 to 2023, the cadavers were stained to enhance the visualization of nutrient and perforating vessels. We compared the self-rated skill gains of participants who observed demonstrations on unstained cadavers from 2017 to 2021 and participants who observed demonstrations on stained cadavers from 2022 to 2023. Among 36 participants from the 2022–2023 group, 28 rated the staining of nutrient vessels and perforating branches as adequate. Of 32 participants, 29 preferred the use of dyed cadavers during training. Trainee skill increase for the digital artery flap, reverse digital artery flap, and dorsal metacarpal artery perforator flap was significantly higher in 2022–2023 (with stained cadavers) than in the earlier course without stained cadavers. SSS-fixed and urea-treated cadavers combined with vascular staining may be useful training models for flap elevation.

This case report presents an atypical transverse cervical artery with its detailed anatomy, morphogenesis, and association with the high arch-shaped subclavian artery. The atypical arteries, related arteries, and adjacent cervical and brachial plexuses were macroscopically examined in a 98-year-old Japanese female cadaver donated to The Nippon Dental University for medical education and research. The atypical deep branch of the transverse cervical artery originated from the internal thoracic artery and passed through between the C5 and C6 roots, in close contact with the C5 and C6 junction, to reach the dorsal side of the brachial plexus. The right subclavian artery exhibited a high arch-shaped coursing and traveled approximately 18 mm higher than the left subclavian artery. This atypical transverse cervical artery exhibits a combination of rare variations in its origin and course. The previous reports revealed that the transverse cervical artery arising from the proximal part of the subclavian artery tends to pass the lower part of the brachial plexus. However, this does not apply to the present case, implying that this atypical artery develops in a different manner from those previously described. Furthermore, the high arch-shaped subclavian artery in this case presumably arose by the suspension of the atypical transverse cervical artery at the C5 and C6 roots junction in a pulley-like structure. Clinicians performing pre- and intraoperative evaluations of neck surgery and catheterization of related arteries should consider that congenital anatomic variations in the transverse cervical artery may have cause anomalous subclavian artery coursing.