Anatomical Science International最新文献

During the anatomical dissection of the pelvis, a duplication of the uterine artery was identified unilaterally on the left side in a 59-year-old Korean female cadaver. The first uterine artery was found to arise directly from the anterior division of the internal iliac artery and supply the upper uterine body and tube. The second uterine artery shared a common stem with the superior and inferior vesical arteries, supplying the lower uterine body. The external diameter of each uterine artery at its origin on the left side was smaller than that of the right uterine artery. One vaginal artery was identified to arise from the left internal pudendal artery. Embryologically, a duplicated uterine artery could imply the presence of two primordial arteries separately supplying the cranial and caudal parts of the Müllerian duct during the early fetal period. This case of variational anatomy is noteworthy: clinicians could elucidate it and successfully perform uterine artery embolization or hysterectomy with minimal complications.

Sociality is an instinctive property of organisms that live in relation to others and is a complex characteristic of higher order brain functions. However, the evolution of the human brain to acquire higher order brain functions, such as sociality, and the neural basis for executing these functions and their control mechanisms are largely unknown. Several studies have attempted to evaluate how human sociality was acquired during the course of evolution and the mechanisms controlling sociality from a neurodevelopment viewpoint. This review discusses these findings in the context of human brain evolution and the pathophysiology of autism spectrum disorder (ASD). Comparative genomic studies of postmortem primate brains have demonstrated human-specific regulatory mechanisms underlying higher order brain functions, providing evidence for the contribution of oligodendrocytes to human brain function. Functional analyses of the causative genes of ASD in animal models have demonstrated that the neural basis of social behavior is associated with layer 6 (L6) of the neocortex and oligodendrocytes. These findings demonstrate that both neurons and oligodendrocytes contribute to the neural basis and molecular mechanisms underlying human brain evolution and social functioning. This review provides novel insights into sociability and the corresponding neural bases of brain disorders and evolution.

Recently, it has become clear that peri-muscular tissues play a significant role in the deterioration of muscle function. Understanding the function and regeneration of muscle, as well as its surrounding tissues, is crucial to determining the causes of muscular illnesses. However, the regeneration process of the myotendinous junction (MTJ), the most closely related peri-muscular tissue, is still unknown. Therefore, we generated a mouse model of MTJ injury by collagenase injection and searched for the process of regeneration of the MTJ and its adjacent regions. The MTJ region was damaged by collagenase injection, which greatly increased the tendon cross sectional area. Collagenase injections increased the proportion of myofibers with a central nucleus, which is a characteristic of regenerating muscle. The collagenase injection group had myofibers with central nuclei and expressing MTJ markers. Additionally, we measured the length of MTJs using serial cross sections of the soleus muscle and discovered that MTJs at 2 weeks after collagenase injection were shorter compared to the control group, with a propensity to progressively recover their length over time. The results showed that MTJs undergo morphological regeneration even when severely damaged, and that this regeneration occurs in conjunction with muscle regeneration. We anticipate that these findings will be valuable in upcoming research on motor unit regeneration.

Groin pain is prevalent in orthopedic and sports medicine, causing reduced mobility and limiting sports activity. To effectively manage groin pain, understanding the detailed anatomy of supporting muscles is crucial. This study aimed to investigate the musculoaponeurotic attachments on the pubis and the relationship among intramuscular aponeuroses of abdominal and thigh adductor musculatures. Macroscopic analyses were performed in 10 pelvic halves. The bone morphology of the pubis was assessed in two pelvic halves using microcomputed tomography. Histological investigations were conducted in two pelvic halves. The external oblique aponeurosis extended to the adductor longus aponeurosis, forming conjoined aponeurosis, which attached to a small impression distal to the pubic crest. The gracilis aponeurosis merges with the adductor brevis aponeurosis and is attached to the proximal part of the inferior pubic ramus. The rectus abdominis and pyramidalis aponeuroses were attached to the pubic crest and intermingled with the gracilis-adductor brevis aponeurosis, forming bilateral conjoined aponeurosis, which attached to a broad area covering the anteroinferior surface of the pubis. Histologically, these two areas of conjoined aponeuroses were attached to the pubis via the fibrocartilage enthesis. Microcomputed tomography revealed two distinctive bone morphologies, a small impression and an elongated osseous prominence on pubis, corresponded to the two areas of conjoined aponeuroses. This study demonstrated close relationships between the aponeurotic attachment of the external oblique and adductor longus, and between the rectus abdominis, pyramidalis, gracilis, and adductor brevis. The findings of aponeurotic complexes would aid in diagnostic and surgical approaches for athletic groin pain.

Many studies have described the muscle anatomy of the domestic fowl (Gallus gallus domesticus), a commonly used animal in developmental experiments. However, some major differences in terminology existed among studies, making it difficult to precisely discuss the muscle homologies between domestic fowl and other animals. In this study, the innervations of shoulder girdle muscles in five sides of the domestic fowl were elucidated and the homology of the shoulder girdle muscles between domestic fowl and other tetrapods was discussed using terminology that conforms to Nomina Anatomica Avium (1993). Unlike previous descriptions, the supracoracoideus, being developed in domestic fowl, is thought to have a different muscular origin from the deltoid muscle. The coracobrachialis cranialis, coracobrachialis caudalis and coracobrachialis muscles, previously described as the coracobrachialis muscle group, had different innervations; the coracobrachialis cranialis should be grouped with the deltoid muscles, and the coracobrachialis caudalis appears to belong to the pectoral muscle group. I propose that the subcoracoscapularis in domestic fowl, keeping the reptilian form, is divided into the subcoracoideus and subscapularis muscles. Based on the innervation, the subscapularis in domestic fowl is homologous with the subscapularis in reptiles and a major part of the subscapularis in mammals. Unlike the descriptions in previous studies, the scapulohumeralis cranialis and caudalis in the domestic fowl in this study, being innervated by the common branch, were found to have a close relationship with the subcoracoscapularis muscle. Based on the observations in this study, a new classification of the shoulder girdle muscles in domestic fowl is proposed.

The intra-articular popliteal tendon (iPT) is responsible for the dynamic stability of the posterolateral part of the knee joint. In this study, the involvement of the iPT in posterolateral stability in response to knee flexion was investigated anatomically. Thirty-one knees from thirty formalin-fixed room cadavers (17 male knees, 14 female knees; average age 86.9 years) were used. The knee was prepared with the distal 1/3 of the lower femur and crus and was flexed at 0°, 30°, 60°, and 90° in a special jig to limit knee rotation. The series of movements was plotted on the coordinate system using the Quadrant method. The iPT was in strong contact with a thick cartilage area, which we called the “popliteal eminence”, at the lateral condyle of the femur. The average iPT angles with respect to the femoral axis were 28.78°, 49.79°, 77.74°, and 115.44° at knee flexion of 0°, 30°, 60°, and 90°, respectively. The iPT was strongly associated with the popliteal eminence at 29.5° in Type I and 27.09° in Type II knee flexion. The iPT has been conventionally regarded as a secondary restraint of posterior movement, acting as a stabilizer. However, the iPT appears to work more positively on knee joint stability because it was in strong enough contact to create the popliteal eminence. The iPT supports the femur in the posterolateral region in mild knee flexion.

The middle colic artery usually arises from the superior mesenteric artery, but in rare cases it may arise from the coeliac trunk or its branches. The aim of this study was to investigate variant origins of the middle colic artery on computed tomography and anatomical dissection. Variant middle colic arteries were identified on computed tomography as part of an ongoing study investigating anatomical variations of vessels of the upper abdomen. Three-dimensional reconstructions were made to demonstrate the variant findings. Cadaveric dissections were performed as part of a routine dissection course. We report five cases of rare variant origins of the middle colic artery arising from the coeliac axis. Among these sites of origin were the coeliac trunk, the gastrosplenic trunk, the splenic artery, and the common hepatic artery. Four cases were identified on multi-detector computed tomography and one in a cadaver. In all cases, the vessels passed posterior to the body of the pancreas before entering the transverse mesocolon. Knowledge of middle colic artery variations is important to prevent inadvertent injury in digestive surgery, especially in the hepatopancreatic area. Variant origins of the middle colic artery are rare, and their knowledge is crucial to prevent unnecessary iatrogenic injury during abdominal surgery.

Brain computation relies on the neural networks. Neurons extend the neurites such as dendrites and axons, and the contacts of these neurites that form chemical synapses are the biological basis of signal transmissions in the central nervous system. Individual neuronal outputs can influence the other neurons within the range of the axonal spread, while the activities of single neurons can be affected by the afferents in their somatodendritic fields. The morphological profile, therefore, binds the functional role each neuron can play. In addition, synaptic connectivity among neurons displays preference based on the characteristics of presynaptic and postsynaptic neurons. Here, the author reviews the “spatial” and “temporal” connection selectivity in the neocortex. The histological description of the neocortical circuitry depends primarily on the classification of cell types, and the development of gene engineering techniques allows the cell type-specific visualization of dendrites and axons as well as somata. Using genetic labeling of particular cell populations combined with immunohistochemistry and imaging at a subcellular spatial resolution, we revealed the “spatial selectivity” of cortical wirings in which synapses are non-uniformly distributed on the subcellular somatodendritic domains in a presynaptic cell type-specific manner. In addition, cortical synaptic dynamics in learning exhibit presynaptic cell type-dependent “temporal selectivity”: corticocortical synapses appear only transiently during the learning phase, while learning-induced new thalamocortical synapses persist, indicating that distinct circuits may supervise learning-specific ephemeral synapse and memory-specific immortal synapse formation. The selectivity of spatial configuration and temporal reconfiguration in the neural circuitry may govern diverse functions in the neocortex.

Since its inception, the International Anatomical Terminology has been an indispensable and widely embraced resource for authors, anatomists, researchers, and medical professionals, ensuring standardized anatomical terminology across various disciplines. Nonetheless, it is widely acknowledged that periodic updates and enhancements are necessary to incorporate the latest scientific knowledge and advancements in imaging techniques. The current version of Terminologia Anatomica includes a section dedicated to the paranasal sinuses, encompassing ethmoidal cells and three sinuses: frontal, sphenoidal, and maxillary. However, the anatomical lexicon pertaining to the paranasal sinuses is more extensive. In clinical practice, multiple terms related to clinically significant structures are commonly employed. This article focuses on the clinical terminology associated with the paranasal sinuses, proposing significant extensions to the existing Terminologia Anatomica. These extensions aim to enrich the anatomical nomenclature and facilitate a harmonious convergence between the language of clinicians and the anatomical lexicon. Further endeavors should bridge the gap in anatomical nomenclature and improve communication between anatomists, researchers, and clinicians, thereby enhancing diagnostic accuracy and improving interdisciplinary research collaboration.

The mode of diabetes-induced muscle and motor neuron damage depends on the type of muscle and motor neuron. One of the purposes of exercise therapy for diabetes is to improve blood glucose levels; however, information on the effects of low-intensity exercise on muscle and motor neuron disorders remain unknown. Therefore, this study aimed to examine the effects of low-intensity exercise on diabetes-induced muscle and motor neuron damage in a rat model of type 1 diabetes mellitus. We subjected adult male Wistar rats treated with streptozotocin to develop type 1 diabetes and age-matched rats to low-intensity treadmill exercise for 12 weeks. We recorded electrically evoked maximum twitch tension in leg muscles, and examined the number of motor neurons and cell body sizes. Low-intensity exercise ameliorated the prolonged half-relaxation time and the decreased numbers of the retrograde-labeled motor neurons observed in the soleus muscle of type 1 diabetic rats. However, no effect was observed in the diabetic group, as atrophy was not improved and the twitch force in the medial gastrocnemius muscle was decreased in the diabetic group. In addition, there was no improvement in the blood glucose levels after exercise. These data indicate that low-intensity exercise may relieve the onset of muscle and motor neuron damage in the soleus muscle of type 1 diabetic rats.