Anatomical Variations Research Articles

Anatomical characteristics of pulmonary superior and subsuperior segment in right lower lobe based on three-dimensional reconstruction

ObjectiveSegmentectomy has been widely performed in clinical practice, which required a comprehensive understanding of anatomical structure. In right lower lobe, studies of superior segment (S6) were relatively small-sized. And only one study focusing on subsuperior segment (S∗) was published, which showed different results with previous ones. As the close relationship between S6 and S∗, variation types and their prevalence rate were reported, aiming to providing larger-size study of S6 and showing new evidence on anatomical structure of S∗. Methods800 CT imaging data were collected from patients in our hospital. Three-dimensional reconstruction was performed after quality check. All images were screened according to the definition of corresponding segment and anatomical variations were analyzed. ResultsThe proportion of S6 variation types in the largest scale (718 patients) was reported with no significant difference compared to previous studies and newly classified subtypes of two-stem V6. The prevalence rate for S∗ in right lower lobe reached 28.3 % (203/718) with similar proportion of three types. Variation types and origins of pulmonary artery were analyzed in detail, finding two-stem A∗ only be observed in type III B∗. ConclusionsThrough this study, the variation types and incidence rate of S6 were confirmed, and a different result of S∗ has been provided as well. The feasibility of the current classification standards and proposed new subclassifications were verified. The results would be a supplement to lung segmental anatomy and could advance researches in the future.

Metopic suture: formation and clinical implications – a review

The timing of suture closure and clinical implications of the metopic suture are still unknown. Premature fusion, causing craniosynostosis, happens rarely, but it may result in serious complications, such as craniofacial dysmorphology and neurodevelopmental problems. The clinical significance of metopism is still uncertain. The aim of this study was to review the literature and identify uncertain aspects associated with the formation and clinical implications of the metopic suture. The review showed significant variations in the typical age of metopic suture closure reported in the literature (from five months to seven years). Premature fusion of the suture, usually occurring before birth, may cause skull deformity and developmental disorders. Aetiology is probably multifactorial. Craniosynostosis may result in different phenotypes, ranging from mild changes to trigonocephaly. Diagnosis is achieved based on physical examination and computed tomography scans. Treatment is surgical and aims to achieve two goals: correction of craniofacial dysmorphology and prevention of further complications. Persistence of the metopic suture is diagnosed based on computed tomography scans and is considered to be an anatomical variant. The metopic suture is clinically significant if premature fusion occurs, causing craniofacial and neurodevelopmental disorders. The timing of the closure of the suture, and the aetiology of craniosynostosis and metopism require further research.

Pediatric Foot: Development, Variants, and Related Pathology.

Pediatric foot development throughout childhood and adolescence can present a diagnostic dilemma for radiologists because imaging appearances may be confused with pathology. Understanding pediatric foot development and anatomical variants, such as accessory ossification centers, is essential to interpret musculoskeletal imaging in children correctly, particularly because many of these variants are incidental but others can be symptomatic. We first briefly review foot embryology. After describing common accessory ossification centers of the foot, we explain the different patterns of foot maturation with attention to irregular ossification and bone marrow development. Common pediatric foot variants and pathology are described, such as tarsal coalitions and fifth metatarsal base fractures. We also discuss pediatric foot alignment and various childhood foot alignment deformities.

Pediatric Shoulder Girdle.

The pediatric shoulder girdle is a complex anatomical structure uniting the upper extremity and trunk. The osseous structures, their articulations, and the surrounding soft tissue support structures (muscles, tendons, and ligaments) allow for a wide range of motion at the shoulder. Growth and maturation of the components at the shoulder girdle vary, particularly the osseous structures. This characteristic renders interpretation of imaging of the pediatric shoulder girdle more challenging because normal or variant anatomy can be confused for pathology. We review the physiologic growth and maturation of the shoulder girdle with special emphasis on the development of the bones and their articulations. The role of various imaging modalities and the common osseous and soft tissue variants in the pediatric shoulder are also discussed.

The Arterial Anatomy of the Cerebellum-A Comprehensive Review.

The cerebellum, a major feature of the hindbrain, lies posterior to the pons and medulla and inferior to the posterior part of the cerebrum. It lies beneath the tentorium cerebelli in the posterior cranial fossa and consists of two lateral hemispheres connected by the vermis. The cerebellum is primarily supplied by three arteries originating from the vertebrobasilar system: the superior cerebellar artery (SCA), the anterior inferior cerebellar artery (AICA), and the posterior inferior cerebellar artery (PICA). However, variations of the cerebellar arteries may occur, such as duplication of the SCA, SCA creating a common trunk with the posterior cerebral artery, triplication of the AICA, and agenesis of PICA, amongst others. Knowledge of the arterial anatomy of the cerebellum is crucial, as inadequate blood supply to this region can result in diminished motor functioning, significantly impacting the quality of life for patients. The present study demonstrated the importance of adequate anatomical knowledge of the arteries supplying the cerebellum. The PubMed and Embase databases were searched to gather articles on the anatomical characteristics and variations of the arterial supply of the cerebellum. It is the most comprehensive and up-to-date review available in the literature. The possible variations of these vessels may be clinically silent or present with clinical symptoms such as neurovascular compression syndromes of the cranial nerves and aneurysms. With a comprehensive understanding of the cerebellar arterial system, physicians can enhance their diagnostic and treatment capabilities, ultimately leading to more effective management of cerebellar vascular-related issues and other neurological deficits.

Gallbladder agenesis associated with dextrocardia in an adult patient: case report

The aim was to disseminate information about gallbladder agenesis and its association with some congenital malformations, in this case, with dextrocardia. The case report of a patient with dextrocardia and diagnosis of cholecystolithiasis (by ultrasound) who presented with agenesis of the gallbladder is presented. The patient was scheduled for laparoscopic cholecystectomy, however, during the surgical procedure, the absence of a gallbladder was evident. Gallbladder agenesis is a rare anatomical variant and its association with cardiac malformations in adult patients is uncommon.

Comprehensive analysis of root canal morphology in maxillary premolars among the Pakistani subpopulation: a CBCT-based study

BackgroundUnderstanding the root canal morphology is essential for the success of root canal treatment. Therefore, this study aimed to evaluate and analyze the root canal configuration of maxillary premolars using Cone Beam Computed Tomography in the Pakistani subpopulation.MethodThis cross-sectional study utilized CBCT scans from two distinct centres: Aga Khan University in Karachi and Jinnah MRI and Body Scans in Lahore. The CBCT images were visualized using GALAXIS version 1.9 (SICAT GmbH and Co. KG, Bonn, Germany), integrated within the Sirona Dental System (D-64625 Bensheim, Germany). The scanning parameters were standardized at 85 kV, 7 mA, with a 15-s exposure time and a voxel size of 0.16 mm. A total of 707 CBCT scans were collected, encompassing 2180 maxillary premolars. Root canal configurations were classified based on (Ahmed et al. Int Endod J. 2017;50(8):761–70). Statistical analyses were performed using SPSS version 26, employing the Chi-square test with a significance level set at p < 0.05.ResultsThe distribution of root canal morphologies varied significantly with age and gender. Among maxillary premolars, 50% exhibited the typical configuration of 2MPMB1 L1 (two roots, single canal in each buccal and lingual root), while 26% of maxillary right second premolars displayed 1MPM1 (one root, one canal). Overall, 1MPM1 accounted for 27.4% of the total cases in the second premolars. There was no statistically significant relationship between age and root canal distribution in either first premolars (p = 0.338) or second premolars (p = 0.833). Regarding gender, a significant difference was observed in the distribution of right maxillary 1st premolars (p = 0.022*), with a higher prevalence among females.ConclusionThis study offers significant insights into the anatomical variations of root canals in maxillary premolars across diverse regional subpopulations in Pakistan. While specific root canal configurations were prevalent, the findings indicate no statistically significant correlation between age and root canal morphology in maxillary premolars. However, a notable gender disparity was observed in the distribution of the right maxillary first premolars.

Advanced Abdominal Aortic Aneurysm Modeling in Mice by Combination of Topical Elastase and Oral ß-aminopropionitrile.

The topical elastase murine model of abdominal aortic aneurysm (AAA) is enhanced when combined with ß-aminopropionitrile (BAPN)-supplemented drinking water to reliably produce true infrarenal aneurysms with behaviors that mimic human AAAs. Topically applying elastase to the adventitia of the infrarenal aorta causes structural damage to the elastic layers of the aortic wall and initiates aneurysmal dilation. Co-administering BAPN, a lysyl oxidase inhibitor, promotes sustained wall degeneration by reducing collagen and elastin crosslinking. This combination results in large AAAs that progressively expand, form intraluminal thrombus, and are capable of rupture. Refining surgical techniques, such as circumferentially isolating the entire infrarenal aortic segment, can help standardize the procedure for a consistent and thorough application of porcine pancreatic elastase despite different operators and anatomic variations between mice. Therefore, the elastase/BAPN model is a refined approach to surgically inducing AAA in mice, which may better recapitulate human aneurysms and provide additional opportunities to study aneurysm growth and rupture risk.

AN ANATOMICAL VARIATION OF GREAT SAPHENOUS VEIN : A RARE CASE REPORT

The longest vein in the body and a superficial vein of the leg is called the great saphenous vein (GSV, also known as the "long saphenous vein"). Blood is being brought back from the foot, leg, and thigh to the deep femoral vein at the saphenofemoral Junction along the length of the lower limb. The clinical significance of GSV has gained interest in its anatomical variations. The variant vein and GSV are frequently confused because of their extensive tributary system. The two clinically significant structural variations of the GSV that are commonly used interchangeably are duplication and persistence of accessory GSV. GSV in this case, we found a duplicate GSV that originates from the lower one-third of the leg region, and both veins are of even calibres, which before drain into the femoral vein reunites to form a single vein. Finding such variations of the duplicate GSV, which is a rare variation of the GSV, is difficult from a therapeutic and diagnostic perspective, especially in venography procedures where it could cause iatrogenic traumatic injury to the vessel.

Ultrasonography of the ulnar nerve loop in relation to the flexor carpi ulnaris tendon.

The purpose of this study is to present the ultrasound appearance of a previously undescribed-at-imaging variant of the ulnar nerve near the Guyon's canal. The ultrasound database of one of the authors, who has more than 10 years of experience in peripheral nerve ultrasound, was searched for the phrases "UN variant" or "UN loop." The other two authors, with more than 10 years of experience in nerve imaging, retrospectively reviewed the static sonograms as well as the videoclips stored, to confirm the findings. Between October 2019 and October 2023, six cases were found in five patients, where ultrasound demonstrated previously undescribed-at-imaging anatomical variations of the distal ulnar nerve on six distal forearms. The variant was symptomatic in three cases in which possible distal compression was clinically suspected. A branch of the ulnar nerve made a loop around the flexor carpi ulnaris, which also presented with a variation of normal anatomy. In symptomatic patients, the diameter of the aberrant branch (retrospectively measured) was significantly enlarged. High-resolution ultrasound can accurately demonstrate ulnar nerve variants even when only small nerve fascicles are involved, which may be clinically relevant and misinterpreted. Loops of the ulnar nerve are rare, but likely under-recognized. We think that symptoms are generally tolerated by patients if the motor branch of the ulnar nerve is not affected, as in our cases.

Accessory foot bones in a Portuguese identified skeletal collection

Data from dry bone samples, collected from anatomical or archaeological collections, can improve the knowledge regarding accessory foot bones, including prevalence, size, shape and laterality, that can be useful in disparate fields of research, from medicine to bioarcheology. In the present study, the prevalence of six accessory foot bones (os trigonum, calcaneus secundarium, accessory navicular bone, os vesalianum, os sustentaculum and os intermetatarseum) was assessed in a sample of 486 individuals (226 females, 260 males) from the Coimbra Identified Skeletal Collection (CISC). The most frequent accessory bones are os trigonum (9.9%; 48/485) and calcaneus secundarium (6.0%; 29/486), while the most uncommon is os sustentaculum (0.4%; 2/486). No sex differences were observed. All accessory bones occur more often unilaterally, with the exception of the accessory navicular bone that, in the majority of cases, occurs bilaterally. The unilateral expression of os trigonum, calcaneus secundarium and os vesalianum was mostly in the right foot. The co-occurrence of accessory foot bones was recorded in 1.7% of the individuals (8/486), and the combinations of os trigonum and calcaneus secundarium were the most frequently observed. This research emphasizes the relevance of conducting studies on reference skeletal collections in order to gain a comprehensive understanding of anatomical variations in the foot. This understanding is crucial for accurate diagnoses and successful treatment in clinical settings, as well as for establishing population comparison standards in the fields of bioarchaeology and forensic anthropology.

Anatomical variations of Sphenoid sinus among the population of the Eastern province of Saudi Arabia

Anatomical variations of Sphenoid sinus among the population of the Eastern province of Saudi Arabia

An Unusual Third Root of the Median Nerve from the Musculocutaneous Nerve: A Case Report

Nerve variations in the brachial plexus, particularly the median nerve, are clinically significant due to their implications in surgeries and nerve compression syndromes. This case report details an anatomical variation observed during the routine dissection of a 72-year-old male cadaver. A third root of the median nerve originating from the musculocutaneous nerve was found in the right upper limb. This finding aligns with previous studies on brachial plexus variations and underscores their importance in surgical planning and nerve repair procedures. Knowledge of such anomalies is crucial for preventing iatrogenic injuries and improving outcomes in reconstructive surgeries. Keywords: Prosection; Brachial plexus; Median nerve; Musculocutaneous nerve

Long-Term Outcomes of the Restoration of Uterovaginal Continuity and Vaginoplasty—Utero-Colo-Neovaginoplasty—in Cervicovaginal Agenesis Using the Sigmoid Colon

Introduction and HypothesisCongenital cervicovaginal agenesis in the presence of a functional endometrium is a rare Müllerian anomaly. The management ranges from hysterectomy historically to various reconstructive procedures more recently. We report our experience with utero-colo-vaginoplasty in the management of this anomaly and its long-term follow-up.MethodsThe case records of all the patients with vaginal or cervicovaginal agenesis in our hospital from January 2002 to December 2019 were reviewed retrospectively. The patients were then called for an outpatient visit and examined in detail. The anatomical variations, surgical procedures and outcomes were recorded and analysed.ResultsSixteen patients aged 14 to 26 years were included during the study period. They presented with cyclical painful cryptomenorrhea. Magnetic resonance imaging (MRI) confirmed cervicovaginal or distal vaginal agenesis. All the patients underwent utero-colo-vaginoplasty. Intraoperative rectal injury led to post-operative faecal leak from the perineal wound in one patient in the post-operative period. Restoration of painless menstrual flow was possible in all 16 cases. Long-term complications were seen in 4 patients. These were stenosis of the perineal neovaginal orifice in 2 patients, obstruction at colo-uterine anastomosis in 1 patient and mucosal prolapse at the neovagina in 1 patient. Three of these patients needed secondary surgical procedures. Five were sexually active and reported consummation of penetrative intercourse. None of them had conceived.ConclusionIn our experience, utero-colo-vaginoplasty allows for regular painless menstruation and coitus with minimal long-term complications. The sole disadvantage is the failure to conceive.

A single Angiofil-latex injection for both radiological and anatomical assessment of arterial territories in the limbs

IntroductionPostmortem evaluation of the human vascular system has a long history, with advancements ranging from dissections to modern imaging techniques like computed tomography (CT scan). This study designs a novel combination of Angiofil, a liquid radiopaque polymer, and latex, a flexible cast material, for cadaveric vascular analysis. Material & methodsThe aim was to synergize the advantages of both components, providing accurate radiological images and optimal dissection conditions. Three arterial territories (lateral circumflex femoral artery, profunda brachii artery, and radial artery) were injected and assessed through CT scans and dissections. ResultsThe Angiofil-latex mixture allowed successful visualization of the vascular networks, offering a simple, reproducible, and non-toxic approach. Quantitative assessments of the three territories, including diameters and lengths, showed comparable results between CT scan and dissection. DiscussionThe technique precision and versatility make it an accessible and valuable tool for anatomical studies, potentially extending its application to MRI analyses. Overall, the Angiofil-latex combination presents a cost-effective solution for researchers, offering enhanced visibility and detailed anatomical insights for various applications, including anatomical variation studies.

An Explorative Anatomical Study on Inter-Individual Variation of the Tibial Nerve and Landmarks for Perineural Anesthesia in Horses.

Perineural anesthesia of the tibial nerve can be performed ultrasound-guided or blindly, with the latter still being commonly used in equine practice due to practical constraints, despite its lower accuracy and hence, common failure to achieve desensitization. This may be associated with anatomical variations or inadequate landmarks for injection. To examine the course of the tibial nerve, document potential anatomical variations, and determine optimal landmarks for perineural injection, dissection was conducted along the medial aspect of the tibia in 10 paired cadaver hindlimbs. No anatomical variations of the tibial nerve were observed. Mean tibial nerve thickness was 6 ± 1 mm. The junction with the plantar nerves was located at a maximum of 85 mm and the junction with the medial cutaneous branch was at a maximum of 150 mm proximal to the proximal aspect of the calcaneal tubercle. The mean distance of the tibial nerve to the cranial border of the superficial digital flexor was 11 ± 6 mm. In conclusion, problems with perineural anesthesia of the tibial nerve cannot simply be attributed to anatomical variations. The thickness of the nerve and the amount of perineural tissue may present specific challenges for achieving adequate desensitization. Our results support the generally recommended site for tibial nerve perineural injection at 100 mm proximal to the calcaneal tubercle and 11 mm cranial to the superficial digital flexor.

Ultrasound-guided localization of the radial nerve along the humerus: providing reference points for safer upper arm surgery.

The close proximity of the radial nerve to the humerus poses a risk during upper arm surgery. Although the general course of the radial nerve is well-known, its exact position in relation to anatomical reference points remains poorly investigated. This study aimed to develop a standardized protocol for the sonographic and clinical identification of the radial nerve in the upper arm. The ultimate goal is to assist surgeons in avoiding iatrogenic radial nerve palsy. A total of 76 measurements were performed in 38 volunteers (both sides). Ultrasound measurements were performed using a linear transducer (10MHz) to identify the radial nerve at two key points: RD (where the radial nerve crosses the dorsal surface of the humerus) and RL (where the radial nerve crosses the lateral aspect of the humerus). Distances from specific reference points (acromion, lateral epicondyle, medial epicondyle, olecranon fossa) to RD and RL were measured, and the angle between the course of the nerve and the humeral axis was recorded. Humeral length was defined as the distance between the posterodorsal corner of the acromion and the lateral epicondyle. The distance from the lateral epicondyle to RD was on average 15.5cm ± 1.3, corresponding to 50% of the humeral length. The distance from the lateral epicondyle to RL was on average 6.7cm ± 0.8, corresponding to 21% of the humeral length. The course of the nerve between RD and RL showed an average angulation of 37° to the anatomical axis of the humerus. Gender, BMI, dominant hand, and arm thickness did not correlate with the distances to RD or RL. Measurements were consistent between the left and right side. The radial nerve can typically be identified by employing a 1/2 and 1/5 ratio on the dorsal and lateral aspects of the humerus. Due to slight variations in individual anatomy, the utilization of ultrasound-assisted visualization presents a valuable and straightforward approach to mitigate the risk of iatrogenic radial nerve palsy during upper arm surgery. This study introduces an easy and fast protocol for this purpose.

CC vs. CC-Plus: A Comparison between Two Cranial-to-Caudal Approaches for Laparoscopic Right Hemicolectomy: A Single-Center Retrospective Study.

Colorectal cancer is a leading cause of cancer-related deaths worldwide, with approximately 1.9 million new cases and over 935,000 deaths in 2020. Right-sided colon cancer, a subset of colorectal cancer, represents a significant health burden. Laparoscopic colon surgery has significantly improved postoperative recovery. The superiority of one approach or landmark over another is still argued about due to the lack of large-scale prospective studies. However, deep understanding both of the anatomical variation and characteristics of each approach is of extreme importance to minimizing adverse effects and maximizing patient benefit after laparoscopic right hemicolectomy. Among these, the cranial-to-caudal approach offers advantages such as reduced intraoperative blood loss, shorter operation time, and decreased risk of vascular injury. The purpose of this study is to compare the efficacy and safety of two cranial-to-caudal approaches for laparoscopic right hemicolectomy (LRH). Specifically, the study aims to evaluate the differences between the conventional cranial-to-caudal approach with medial ligation of the middle colic vein (MCV), and the cranial-to-caudal approach with cranial MCV ligation and surgical trunk sheath opening (CC-plus). The goal is to determine which method offers superior outcomes in terms of intraoperative blood loss, operation time, and overall patient recovery. This single-center retrospective study compared two cranial-to-caudal approaches for LRH. The study included 51 patients who underwent LRH between January 2021 and November 2023 at the Second Affiliated Hospital, Zhejiang University School of Medicine. Patients were divided into two groups: Group A (26 patients) used the cranial-to-caudal approach with medial ligation of the middle colic vein (MCV), and Group B (25 patients) used the cranial-to-caudal approach with cranial MCV ligation and surgical trunk sheath opening (CC-plus). General characteristics, intraoperative parameters, and postoperative outcomes were compared. Statistical analysis was performed using SPSS version 20.0, with significance set at p < 0.05. There were no significant differences between the groups regarding age, gender, tumor location, or clinical staging. All patients achieved R0 resection with no perioperative deaths. The CC-plus group had significantly reduced intraoperative blood loss and shorter operation time compared to the CC group (p < 0.05). No significant differences were found in first postoperative exhausting time, first postoperative defecation time, and postoperative hospital stay between the two groups. Furthermore, no significant differences were evaluated in postoperative complications (surgical site infection (SSI), ileus or bowel obstruction, refractory diarrhea, anastomotic leakage, deep vein thrombosis (DVT), hemorrhage) between the two groups on a median follow up of 12.6 months. Pathological examination showed no significant differences in total lymph nodes dissected and tumor stage. The cranial-to-caudal approach with MCV ligation via the cranial approach (CC-plus) is a safe and effective method for LRH, offering advantages in terms of reduced operation time and intraoperative blood loss. This study's findings suggest that the CC-plus approach may be superior to the conventional cranial-to-caudal approach.

Woody plant phytolith morphology and representation in surface sediments across the Northern Territory, Australia

Phytoliths are a good tool for investigating vegetation change in northern Australia. However, there is a lack of phytolith reference material across the Australian continent, particularly for woody plants. The development of reference material from woody plants is critical to understand regional patterns of phytolith production and preservation. This study analyses phytolith material from 40 woody plants to examine morphological and anatomical variation in phytolith production among Australian plant families. This is paired with phytolith assemblages from nine surface sediment samples to assess the representation and preservation of woody plant phytolith morphotypes. All woody plant species examined produce identifiable phytolith morphotypes, but most morphotypes cannot be differentiated between woody eudicots, monocots, and conifers. However, some woody plant morphotypes do have good potential for taxonomic or anatomical discrimination of plant groups. The analysis of surface sediment phytolith assemblages reveals that not all woody plant morphotypes preserve equally in surface sediments, potentially restricting their ability for taxonomic discrimination. Finally, the relevance of phytolith morphotypes for palaeoecological reconstruction is discussed.

A true bicuspid tricuspid valve: 3D imaging to better understanding the forgotten valve.

Nowadays, understanding the anatomy of the tricuspid valve is crucial. The bicuspid tricuspid valve is a rare anatomical variation of this valve. We present highly illustrative images with 3D echo that allow a more realistic analysis of the forgotten valve.