Anatomical Science International最新文献

The common marmoset (Callithrix jacchus) is a valuable laboratory animal offering various advantageous characteristics, including ease of husbandry and phylogenetic proximity to humans. However, anatomical knowledge of the common marmoset remains inadequate despite its recognized value as a laboratory animal. The livers of primate species have been reported to exhibit species-specific patterns of arterial supply, an understanding of which may be one important prerequisite to perform experiments. However, the arterial branching pattern in common marmosets has yet to be reported in detail. We thus dissected six male and nine female common marmosets to clarify the extra-hepatic arterial branching pattern using the latex injection method. The common marmoset liver received a single to triple arterial supply from the hepatic artery, left gastric artery, caudal phrenic artery, and celiac artery. In two cases, only the hepatic artery provided branches to the liver. The liver received a double arterial supply from the hepatic and caudal phrenic arteries in one case and from the hepatic and left gastric arteries in five cases. A triple arterial supply from the hepatic, left gastric, and celiac arteries was detected in one case, and from the hepatic, left gastric, and caudal phrenic arteries in six cases. The present study revealed characteristic patterns of arterial supply to the liver in the common marmoset, and may provide a prerequisite anatomical background for conducting experiments involving the liver in this species.

In aortic arch surgery, preoperative evaluation of variations in the aortic arch branching is necessary. The present study investigated variations in the aortic arch branches in Japanese patients using contrast-enhanced computed tomography. In this study, we included 2,923 Japanese patients who underwent computed tomography at our institution in 2022. The following eight types of variations in the aortic arch branching were observed. Type 1, with the brachiocephalic trunk, left common carotid artery, and left subclavian artery, was found in 2,541 patients (86.9%). Additionally, seven subtypes were found in 382 patients (13.1%) as follows: Type 2, the common trunk of brachiocephalic trunk and left common carotid artery (8.0%); Type 3, with the left vertebral artery, branching directly from the aortic arch between left common carotid artery and left subclavian artery (4.3%); Type 4, left vertebral artery branching directly from the aortic arch distal to left subclavian artery (0.1%); Type 5, aberrant right subclavian artery (0.5%); Type 6, the common trunk of bilateral common carotid arteries (0.1%); Type 7, the common trunk of left common carotid artery and left subclavian artery (0.01%); and Type 8, the right aortic arch complicated with aberrant left subclavian artery (0.1%). The subtypes of the variations in aortic arch branching were found in 13.1% of Japanese patients. In this study, only a few patients had aortic disease. Further studies are required to investigate the relationships between variations in the aortic arch branching and aortic disease.

This study aimed to examine the morphology of the fetal medial meniscus in cadavers, including both quantitative analysis and the identification of new shape variants. Fifty fetal cadavers were analyzed (36 from the second trimester, 13-25 weeks;14 from the third trimester,26-37 weeks). Of 53 available specimens, three with musculoskeletal malformations were excluded. Surgical microdissection under a stereomicroscope exposed the medial meniscus, which was measured using a calibrated digital caliper. Morphology was documented and classified into five primary types and five subtypes. Data were analyzed using SPSS version 21.0(IBM Corp., Armonk, NY, USA). Significant growth in all parameters was observed between the second and third trimesters, with notable morphological differences between male and female fetuses, emphasizing the influence of gestational age and sex. The study identified distinct medial meniscus shapes: 46% were sickle-shaped, 16% C-shaped, 13% crescent-shaped, 4% U-shaped, and 1% V-shaped. Additionally, 20% of medial menisci exhibited variant subtypes derived from the crescentic and C-shaped types. This study provides a novel and comprehensive evaluation of fetal medial meniscus morphology, identifying both previously known and new shape variants. These findings expand current anatomical knowledge and suggest that morphological diversity of the medial meniscus may have functional implications for knee joint biomechanics. This is the first study to describe three-dimensional fetal MM morphology, including five previously unclassified subtypes. Further research could clarify clinical implications of these morphological variants of fetal medial meniscus in orthopedic diagnosis and management across all age groups.

This study aims to elucidate the morphometric and morphological details of teeth in the Syrian hamster (Mesocricetus auratus, Waterhouse, 1839) and guinea pig (Cavia porcellus, Linnaeus, 1758) using µ-CT and stereology (n = 5). Notably, the hamsters exhibited distinctive roots in their cheek teeth, in contrast to the guinea pigs, where the tooth body extended as a dental root into the alveolar socket, making anatomical diagnosis challenging. The first and second cheek teeth of the hamster had four roots, but the last one had three roots. The hamster incisor teeth had a more voluminous pulp cavity compared to those of guinea pigs. While the ratio differences of arch parameters and enamel thickness were not statistically significant (P ≥ 0.05). The enamel layer in guinea pig incisor teeth were significantly thicker than that in the hamster teeth (P ≤ 0.05). Regarding the dentine-tooth width, the difference between the upper incisor teeth of the hamster and guinea pig was significant (P ≤ 0.05). The ratio of pulp-tooth volume in all incisor teeth of the hamster was significantly higher than that in the guinea pig's teeth (P ≤ 0.05) indicating hamsters might have better regenerative dental health despite dietary variances. These insights contribute to deeper understanding of the evolutionary adaptations in rodent dentition and suggest improved information and methodologies for translational dental studies and selecting more appropriate animal models in dental research.

The sternalis muscle is a relatively rare anatomical variant that lies superficial to the pectoralis major muscle. In English-language literature, it is commonly referred as "sternalis muscle" or "rectus sternalis." Although the second edition of the Terminologia Anatomica (TA) officially designates "sternalis muscle" as the standard term, terminological inconsistencies persist. This study investigated the actual usage of these terms based on a literature review of previously published case reports. We analyzed 77 articles comprising 92 cases, retrieved through PubMed and Google Scholar, examining the types of terms employed, their frequency, regional distribution, and temporal trends. As per the first and second editions of TA, the terms were categorized into two groups: the S group ("sternalis muscle" or "sternalis") and the R group ("rectus sternalis" or "rectus sternalis muscle"). Our analysis showed that unilateral cases and male patients were more frequently reported. Regionally, the highest number of reports originated from Asia. The frequency of S group usage exceeded that of R group usage by scale factors of 1.6, 2.3, and 3.8 in Asia, Europe and the Middle East, and North America, respectively. Furthermore, S group term usage increased after the release of the first edition of TA (TA1) and stabilized following the release of the second edition (TA2). These findings suggest that the TA-compliant term "sternalis muscle" has become dominant in English-language literature, supporting standardized anatomical nomenclature and facilitating consistent communication among anatomists and clinicians. This framework may also serve as a model for standardizing terminology related to other anatomical variants.

Most studies of the ascending pharyngeal artery (APA) observed its different possibilities of origin. No evidence had been previously presented of either double or partly duplicated APAs. The anatomic variants reported here were found during the retrospective review of archived angioCT imaging data from two adult males, both aged 65 years. In the first case, a double APA was found on the right side. The inferior APA and a linguofacial trunk had infrahyoid origins from the external carotid artery (ECA) and coursed over the greater horn of the hyoid. The superior APA had a suprahyoid origin from the ECA. On the left side, the APA, lingual, and facial arteries had infrahyoid origins and ascended on the inner side of the greater hyoid horn. In Case #2, there were two roots of the left APA, leaving the ECA above the greater hyoid horn. An anastomotic branch united the APA and the ascending palatine artery. A superiorly looped long sternocleidomastoid branch left the ECA proximally to the origin of the lingual artery. We brought here the first convincing evidence of double and, respectively, two-rooted (partly duplicated) APAs. These possibilities warrant caution during open-field surgeries. Care should be taken to the arteries expected to originate from the ECA at a distance from the greater hyoid horn because they can have infrahyoid origins and may course over or under this surgical landmark.

The interincisive suture (sutura interincisiva) connects the left and right premaxilla at the midline of the anterior palate and plays a role in craniofacial development. Despite its anatomical and developmental importance, postnatal changes in this suture remain understudied. Here, we investigated the age-dependent growth and closure of the interincisive suture using CT scans from 384 patients aged 0-94 years. Suture presence, length, and width were assessed in five-year age groups. Results show a progressive closure of the suture with age, with complete obliteration in most individuals over 35. Rates of open interincisive sutures in older patients are up to 25%. Sex differences emerged, with females showing a higher rate of suture closure in early years but a higher rate of open sutures in old age. A strong negative correlation was observed between age and both suture width (r = -0.545, p < 0.001) and length (r = -0.530, p < 0.001). The findings highlight similarities with, but also distinctions from, other midfacial sutures such as the midpalate suture and the incisive suture. Clinical implications include timing considerations for orthodontic interventions and improved understanding of midfacial growth patterns.