Quantitative anatomy of the large variant right hepatic vein: A systematic three-dimensional analysis.

Anatomical variations of the right hepatic vein, especially large variant right hepatic veins (≥5 mm), have important clinical implications in liver transplantation and resection. This study aimed to evaluate anatomical variations of the right hepatic vein using quantitative three-dimensional visualization analysis. Computed tomography images of 650 patients were retrospectively analyzed, and three-dimensional visualization was applied using the derived data to analyze large variant right hepatic veins. The proportion of the large variant right hepatic vein was 16.92% (110/650). According to the location and number of the variant right hepatic veins, the configuration of the right hepatic venous system was divided into seven subtypes. The length of the retrohepatic inferior vena cava had a positive correlation with the diameter of the right hepatic vein (rs = 0.266, p = 0.001) and the variant right hepatic veins (rs = 0.211, p = 0.027). The diameter of the right hepatic vein was positively correlated with that of the middle hepatic vein (rs = 0.361, p < 0.001), while it was inversely correlated with that of the variant right hepatic veins (rs = -0.267, p = 0.005). The right hepatic vein diameter was positively correlated with the drainage volume (rs = 0.489, p < 0.001), while the correlation with the variant right hepatic veins drainage volume was negative (rs = -0.460, p < 0.001). The number of the variant right hepatic veins and their relative diameters were positively correlated (p < 0.001). The volume and percentage of the drainage area of the right hepatic vein decreased significantly as the number of the variant right hepatic vein increased (p < 0.001). The findings of this study concerning the variations of the hepatic venous system may be useful for the surgical planning of liver resection or transplantation.

Anatomical variation of femoral vessels and ultrasound-guided femoral vein puncture for catheter ablation of arrhythmias.

OBJECTIVE: This study aims to investigate the anatomical variations in femoral vasculature and evaluate the clinical value of ultrasound-guided femoral vein puncture in catheter ablation procedures. METHODS: In this retrospective analysis conducted from January 2023 to March 2023, we examined data from patients who underwent catheter ablation with ultrasound-guided femoral venipuncture. We evaluated the anatomy of the femoral vasculature at both high and low inguinal levels. Based on the relationship between the femoral vein and artery, we classified the anatomy into four types: Type I (vein parallel to artery without overlap), Type II (vein medial to artery with lumen overlap ≤50%), Type III (vein posterior to artery with lumen overlap > 50%), and Type IV (vein lateral to artery). Additionally, we assessed procedure-related vascular complications that required interventions or prolonged hospital stays. RESULTS: A total of 254 patients were included in this study. At the upper inguinal level, most cases (92.5%) exhibited Type II, followed by Type I (6.5%), while Type III (0.6%) and IV (0.4%) were less common. At the lower inguinal level, Type II accounted for 70.7%, there was a significantly higher proportion of Type III (23.4%) and Type IV (5.9%). The overall complication rate was 0.4%, no pseudoaneurysm or hematoma was observed in our study. CONCLUSION: Our study revealed significant anatomical variations in the relationship between the femoral vein and femoral artery. Ultrasound-guided femoral venipuncture significantly reduced vascular complication rate, making it a valuable tool for guiding puncture procedures.

Variations and thicknesses of anterior belly of the digastric muscle: an ultrasonographic study.

PURPOSE: This study aims to evaluate the anatomy and anatomical variations of the anterior belly of the digastric muscle. METHODS: Hundred and fifty one ultrasonographic images of the digastric muscle pairs were evaluated in Near East University Faculty of Dentistry Department of Dentomaxillofacial Radiology. Morphological variations were recorded using the classification of the digastric muscle into 12 types by Kim et al. For the analysis, the Mann-Whitney U test and Chi-square test were used, and for the correlational analysis, Spearman's rho test was applied. P < 0.05 was considered statistically significant in all tests. RESULTS: Seventy female and 81 male patients aged 19-60 years were evaluated. Type 1 digastric muscle was observed in 145 of 151 patients, Type 2 in 3 patients, and Type 7 in 3 patients. The thicknesses of the right and left digastric muscles were measured, and a statistically significant difference was observed between the groups when the genders were compared. It was observed that both right and left digastric muscle thicknesses were higher in males than females. There was a statistically significant positive high correlation between right and left digastric muscle thicknesses (p = 0.000; r = 0.736). No statistically significant difference was found between genders (p = 0.596) in terms of anatomical variations. CONCLUSION: Considering that the variations of the digastric muscle may have a clinical significance role, the normal anatomy and variations of this muscle should be well known by maxillofacial surgeons and radiologists.

Evaluating Pelvic Tilt Using the Pelvic Antero-Posterior Projection Images: A Systematic Review.

BACKGROUND: Pelvic tilt (PT) is a routinely evaluated parameter in hip and spine surgeries, and is usually measured on a sagittal pelvic radiograph. This may not always be feasible due to limitations such as landmark visibility, pelvic anomaly, and hardware presence. Tremendous efforts have been dedicated to using pelvic antero-posterior (AP) radiographs for assessing sagittal PT. Thus, this systematic review aimed to collect these methods and evaluate their performances. METHODS: Two independent reviewers searched the PubMed, Ovid, Cochrane, and Web of Science databases in June 2023 with backward reference trailing (Google Scholar archive). There were 30 studies recruited. Risk of bias was assessed using the prediction model risk of bias assessment tool. The relevant data were tabulated in a standardized form for evaluating either the absolute PT or relative PT. Disagreement was resolved by discussing with the senior author. RESULTS: There were 19 parameters from pelvic AP projection images involved, with 4 studies which used artificial intelligence, eyeball, or statistical shape method not involving a specific parameter. In comparing the PT values from pelvic sagittal images with those extrapolated from antero-posterior projection images, the highest correlation coefficient was found to be 0.91. The mean absolute difference (error) was 2.6°, with a maximum error reaching 10.9°. Most studies supported the feasibility of using AP parameters to calculate changes in PT. CONCLUSIONS: No individual AP parameter was found to precisely estimate absolute PT. However, relative PT can be derived by evaluating serial AP radiographs of a patient in varying postures, employing any AP parameters.

Regarding a human costoscapular joint by Prof. Dr. H. von Luschka (1870): A translation.

Knowledge of variant anatomy was important during the time of Dr. Hubert von Luschka (1820-1875) and continues to be of relevance in current practice to prevent medical and surgical errors and to improve patient outcomes. Dr. H. von Luschka described an anatomical variant observed in the left scapula of a 40-year-old male: a connection between the medial superior angle of the scapula, piercing through the serratus posterior muscle to connect via a synovial capsule to the articular surface of the thoracic wall. The clinical relevance of this so-called "Luschka's tubercle" of the shoulder continues to be discussed. This translation is intended to broaden access to this hallmark manuscript to a wide audience of English readers. The introduction places the manuscript in the context of historical and current discussions. Three authors, all proficient in the German and English languages and educated in the anatomy of the shoulder, conducted the translation. The skeletal process that is part of the described joint structure appears similar to what is now called Luschka's tubercle. The full structure, including its connecting parts, are not currently included in anatomical nomenclature. In conclusion, Luschka's text and named tubercle continue to contribute to the discussion of scapulothoracic joint disorders.

An accessory head of the extensor indicis: a rare case report.

PURPOSE: A deep knowledge of the variations of the posterior forearm musculature is crucial for assessing and diagnosing conditions in this region. Extensor indicis (EI) is one of the muscles in this region, which exhibits diverse anatomical variations. This report documents an extremely unusual form of the EI with an accessory head on the dorsum of the hand. METHODS: During routine dissection, an extremely rare presentation of the EI was found in the left forearm of a 94-year-old female cadaver. RESULTS: This unusual EI consisted of two muscle bellies. The traditional belly originated from the distal two-thirds of the ulna. The muscle became tendinous around the carpal area, distal to the extensor retinaculum. The tendon was subsequently joined by an accessory muscle belly originating from the distal radioulnar ligament. The EI tendon inserted onto the dorsal expansion of the index finger, ulnar to that of the extensor digitorum. The posterior interosseous nerve innervated the muscle. CONCLUSION: Herein, we report an extremely rare form of the EI. To our knowledge, EI with an accessory head has only been reported rarely over the past 200 years. Moreover, our report appears to be the first case with photographic details of this anatomical variation. Clinicians should be aware of this variation for proper diagnosis and treatment.

Vertebral arteria lusoria-Hyrtl's original description (1859), case illustration, and literature analysis.

PURPOSE: A translation of the initial observation of vertebral arteria lusoria reported by Hyrtl in 1859 is followed by a review of all cases published until May 2023 to identify the anatomical and clinical features characterizing the typical form of this rare variant. METHODS: PubMed, Google Scholar, and Google queries were performed with "vertebral arteria lusoria", "retroesophageal vertebral artery", and "aberrant vertebral artery" as keywords (in English, German, and French). A feature was considered typical when present in at least 75% of analyzed cases. A case of incidentally discovered vertebral arteria lusoria illustrates the typical form of the variant. RESULTS: The analysis of 56 publications yielded 66 observations of right-sided vertebral arteria lusoria published between 1859 and May 2023. A small caliber, a retro-esophageal location, and passage through the foramen transversarium of C7 were typical. There was no evidence of association with clinical symptoms or other cardiovascular anomalies. CONCLUSION: A typical vertebral arteria lusoria is an incidentally discovered nondominant aberrant right VA originating from the proximal descending aorta and following a retro-esophageal course to enter the C7 foramen transversarium, without associated aortic arch branching anomalies or congenital cardiovascular pathologies.

Intrahepatic and anterior course of the inferior vena cava: CT image and 3D reconstruction of a rare anatomical variation.

The widespread use of computed tomography (CT) for diagnosing and screening abdominal conditions often reveals rare, asymptomatic anomalies. There is a wide range of documented congenital variations in the anatomy of the inferior vena cava (IVC) and hepatic veins. In this report, we detail an exceptionally unusual variant of the IVC that follows a frontward and intraliver course, terminating at the anterior section of the right atrium. To gain a deeper insight into this anomaly, we employed 3D reconstruction techniques using the software Slicer and Blender.

Two arterial variations of the hand and wrist present bilaterally (persistent median artery and superficial dorsal branch of the radial artery): ultrasound findings.

PURPOSE: Arterial variations of the upper limb may bear high importance for many clinical procedures, including the use of flaps in plastic surgery. We present a feasible way for visualization and confirmation of presence of these variations. METHODS: All variations were detected by ultrasonography and confirmed by Color Doppler Imaging. Proper documentation was taken in order to present our findings. RESULTS: We report a case of a 19-year-old female who showed two concomitant arterial variations of the forearm and the hand bilaterally. These two variations were the persistent median artery and the superficial dorsal branch of the radial artery which both significantly contributed to the blood supply of the hand. All examinations were performed by the same investigator and all findings were reviewed by an experienced sonographist. CONCLUSION: An unusual arrangement of the arterial system can be easily detected. We present a feasible way to prevent iatrogenic injuries and increase utilization of anatomical variants knowledge in surgery by using ultrasound prior to planning surgical procedures.

Rare case of divided phrenic nerve variation: a cadaveric case report.

The phrenic nerve innervates the respiratory diaphragm, the primary muscle active during ventilation. The canonical path of the phrenic nerve originates from the cervical spine at C3-C5 spinal nerves and travels inferiorly through the neck and thoracic cavity to reach the diaphragm. During a cadaver dissection, a variation of the phrenic nerve was discovered in a 93-year-old male specimen. A traditional origin of the phrenic nerve was noted; however, the nerve branched into medial and lateral components at the level of the superior trunk of the brachial plexus. The branches reconnected at the apex of the aortic arch and continued inferiorly to innervate the ipsilateral diaphragm. This case study describes a rare type of branching of the phrenic nerve and explores its potential impact on clinical procedures.

Jugular bulb anatomical variations and pneumatization patterns: a comprehensive CBCT analysis.

PURPOSE: This study aims to assess the anatomical possibilities of the jugular bulb (JB). METHODS: Fifty archived CBCT scans were analyzed. RESULTS: The average distance between the internal acoustic canal (IAC) and the JB was 7.97 mm on both sides (Right: SD = 2.56 mm, range 3.16-13.3 mm; Left: SD = 2.5 mm, range 2.9-13.6 mm). JB walls' pneumatization was classified into eight patterns. Deep petrosal cells (DPCs) prevailed in the lateral wall of the JB. The absence of pneumatization (NP) was commonly found on the left side. The presence of infralabyrinthine and hypotympanic cells varied. Less common types included accessory occipital cells (AOCs), posteromedial tracts (PMTs), and basi-occipital cells (BOCs), which determined a consistent variation of the lateral wall pneumatization patterns. Pneumatization of the medial wall was not observed in 50 right sides and 49 left sides. The inferior wall analysis revealed symmetry in AOC distribution and a predominant occurrence of NP. Cases with hypotympanum (HT) in the lateral wall showed a statistically significant IAC-JB distance increase by an average of 4.67 mm compared to NPs. Specific pneumatizations, particularly HT on the lateral side, have a significant effect on the IAC-JB distance, showing a clear pattern of increasing distance from DPC to NP and then to HT. A significant distance increase in HT pneumatization was noted. There were also recorded instances of JB hypoplasia and hyperplasia, JB diverticula, dehiscent JBs, and high JBs. CONCLUSION: This study establishes a novel classification of JB pneumatizations to aid in the understanding of the temporal bone anatomy.

Evaluation of the superior pubic ramus and supra acetabular corridors using statistical shape modelling.

INTRODUCTION: The incidence of osteoporotic pelvic fractures is increasing. The broken anterior pelvic ring is preferentially fixed with long intramedullary screws, which require a good understanding of the patient-specific anatomy to prevent joint perforation. The aim of this study was to assess the variability of the superior pubic ramus and the supra acetabular corridors' length and width using statistical shape modelling. MATERIALS AND METHODS: A male and female statistical shape model was made based on 59 forensic CT scans. For the superior pubic ramus and the supra acetabular corridor the longest and widest completely fitting cylinder was created for the first 5 principal components (PC) of both models, male and female pelvises separately. RESULTS: A total of 59 pelvises were included in this study of which 36 male and 23 female. The first 5 principal components explained 75% and 79% of the pelvic variation in males and females, respectively. Within 3 PCs of the female statistical shape model (SSM) a superior pubic ramus corridor of < 7.3 mm was found, 5.5 mm being the narrowest linear corridor measured. Both corridors in all PCs of the male SSM measured > 7.3 mm. CONCLUSION: Within females a 7.3 mm and 6.5 mm screw won't always fit in the superior pubic ramus corridor, especially if a flat sacrum, a small pelvis or a wide subpubic angle are present. The supra acetabular corridor did not seem to have sex-specific differences. In the supra-acetabular corridor there was always enough space to accommodate a 7.3 mm screw, both in males and females.

Anatomy of the pudendal nerve in clinically important areas: a pictorial essay and narrative review.

PURPOSE: The pudendal nerve is an anatomical structure arising from the ventral branches of the spinal roots S2-S4. Its complex course may be affected by surrounding structures. This may result in irritation or entrapment of the nerve with subsequent clinical symptoms. Aim of this study is to review the anatomy of the pudendal nerve and to provide detailed photographic documentation of the areas with most frequent clinical impact which are essential for surgical approach. METHODS: Major medical databases were searched to identify all anatomical studies investigating pudendal nerve and its variability, and possible clinical outcome of these variants. Extracted data consisted of morphometric parameters, arrangement of the pudendal nerve at the level of roots, formation of pudendal nerve, position according to sacrospinal and sacrotuberal ligaments and its terminal branches. One female cadaver hemipelvis was dissected with common variability of separate course of inferior rectal nerve. During dissection photodocumentation was made to record course of pudendal nerve with focus on areas with recorded pathologies and areas exposed to iatrogenic damage during surgical procedures. RESULTS: Narrative review was done to provide background for photodocumentation. Unique photos of course of the pudendal nerve was made in areas with great clinical significance. CONCLUSION: Knowledge of anatomical variations and course of the pudendal nerve is important for examinations and surgical interventions. Surgically exposed areas may become a site for iatrogenic damage of pudendal nerve; therefore, unique picture was made to clarify topographic relations.

Anatomical study and meta-analysis of the episternal ossicles.

Episternal ossicles (EO) are accessory bones located superior and posterior to the manubrium, representing an anatomical variation in the thoracic region. This study aimed to investigate the prevalence and developmental aspects of EO in global populations. The prevalence of EO in pediatric populations was assessed using the "Pediatric-CT-SEG" open-access data set obtained from The Cancer Imaging Archive, revealing a single incidence of EO among 233 subjects, occurring in a 14-year-old patient. A meta-analysis was conducted using data from 16 studies (from 14 publications) through three electronic databases (Google Scholar, PubMed, and Journal Storage) encompassing 7997 subjects. An overall EO prevalence was 2.1% (95% CI 1.1-3.0%, I2 = 93.75%). Subgroup analyses by continent and diagnostic methods were carried out. Asia exhibited the highest prevalence of EO at 3.8% (95% CI 0.3-7.5%, I2 = 96.83%), and X-ray yielded the highest prevalence of 0.7% (95% CI 0.5-8.9%, I2 = 0.00%) compared with other modalities. The small-study effect was indicated by asymmetric funnel plots (Egger's z = 4.78, p < 0.01; Begg's z = 2.30, p = 0.02). Understanding the prevalence and developmental aspects of EO is crucial for clinical practitioners' awareness of this anatomical variation.

A thyroidea ima artery variation providing collateral circulation to the mediastinum.

The thyroidea ima artery (TIA) is a highly variable arterial deviation of the blood supply to the thyroid gland with critical implications for surgical neck procedures such as tracheostomy. Though relatively common in the population at large (~ 4%), most TIA variations are related to the origin of the artery and whether it emerges from the common sites of the brachiocephalic trunk, aortic arch, and right common carotid artery, or another more unique vessel-as opposed to its dispersion pattern. TIA variants generally supply the thyroid gland, occasionally co-occurring with absent thyroid arteries. Here, we report on a unique case of a four-pronged variation of the TIA discovered during an anatomy laboratory dissection of first-year medical students. This variant originated from the brachiocephalic trunk and had three branches terminating in the thyroid gland and a fourth branch traveling into the thorax to provide accessory circulation in the mediastinum. Specifically, small arterial branches from the inferior TIA branch supplied the anterior pericardium and surrounding adipose tissue, in addition to normal pericardiacophrenic circulation. We discuss the potential embryological and clinical relevance of this unique variation and voice further support for imaging as a requirement before surgical neck procedures to prevent catastrophic bleeding in the event of a TIA variant.

The anatomical variations of the cubital tunnel in a South African body donor sample.

PURPOSE: The ulnar nerve (UN) courses through the cubital tunnel, which is a potential site of entrapment. Anatomical variations of the cubital tunnel may contribute towards cubital tunnel syndrome (CuTS), however, these are not well described. The aim was to compare the range of variations and dimensions of the cubital tunnel and the UN between sexes and sides of the body. METHODS: Sixty elbows from 30 embalmed bodies (17 males and 13 females) were dissected. The prevalence of the cubital tunnel retinaculum (CuTR) or anconeus epitrochlearis (AE) forming the roof of the tunnel was determined. The length, width, thickness, and diameter of the cubital tunnel and its roof were measured. The diameter of the UN was measured. RESULTS: The AE was present in 5%, whereas the CuTR was present in the remaining 95% of elbows. The tunnel was 32.1 ± 4.8 mm long, 23.4 ± 14.2 mm wide, 0.18 ± (0.22-0.14) mm thick, and the median diameter was 7.9 ± (9.0-7.1) mm, while the median diameter of the UN was 1.6 ± (1.8-1.3) mm. The AE was thicker than the CuTR (p < 0.001) and the UN was larger in elbows with the AE present (p = 0.002). The tunnel was longer in males (p < 0.001) and wider on the right (p = 0.014). CONCLUSION: The roof of the cubital tunnel was more frequently composed of the CuTR. The cubital tunnel varied in size between sexes and sides. Future research should investigate the effect of the variations in patients with CuTS.

Replaced posterior cerebral artery.

PURPOSE: Replaced posterior cerebral artery (PCA), defined as a hyperplastic anterior choroidal artery (AChA) supplying all branches of the PCA, is an extremely rare anatomical variation. To the best of our knowledge, there are only a few reports of replaced PCA. METHODS: Herein, we report a case of replaced PCA diagnosed by digital subtraction angiography. RESULTS: A 76-year-old woman visited a neurosurgical clinic because of headache and vertigo. Magnetic resonance imaging and magnetic resonance angiography incidentally revealed a left internal carotid artery aneurysm. She was referred to our hospital for further examination and treatment of the unruptured intracranial aneurysm. Left internal carotid angiography revealed a paraclinoid aneurysm. We also incidentally found an anomalous hyperplastic AChA distal to the aneurysm. This hyperplastic AChA supplied not only the AChA territory but also the entire PCA territory. No vessels that could be a normal AChA or posterior communicating artery were identified along the left internal carotid artery. Vertebral angiography demonstrated that the left PCA was not visualized. With these findings, we diagnosed anomalous hyperplastic AChoA in this case as replaced PCA. CONCLUSION: Careful imaging assessment is important to identify replaced PCA. Both direct findings of a hyperplastic AChA course and perfusion territory and indirect findings of the absence of the original PCA are useful in the diagnosis of replaced PCA.

Accessory Flexor Carpi Ulnaris Muscle in Humans: A Rare Anatomical Case with Clinical Considerations.

Anatomical variations of the forearm flexor muscles are occasionally encountered. Though usually observed incidentally during autopsies or imaging studies, they may at times cause concern due to associated clinical symptoms. This report presents a case of unilateral accessory flexor carpi ulnaris (AFCU) muscle observed in a human male cadaver aged 78 years. During routine cadaveric dissection, an anomalous AFCU muscle was observed in the left forearm of a human male cadaver aged 78 years. Standard institutional guidelines pertaining to the use of human cadaver for teaching and research were followed. A thorough literature review about the flexor carpi ulnaris (FCU) through the PubMed, Embase and Google scholar databases was undertaken, using the keywords - accessory flexor carpi ulnaris muscle, aberrant flexor carpi ulnaris muscle and anatomical variation of flexor carpi ulnaris muscle. Relevant gross anatomical findings were recorded and photographed. AFCU was identified on the medial aspect of the distal third of the left forearm. The AFCU was found originating from the ante-brachial fascia and the fascia covering the FCU on the left forearm, forming a small separate belly deep to the main muscle. It terminated as a thin tendon running alongside the hypothenar muscles and attached distally to the base of the proximal phalanx of the little finger. The AFCU was found to be innervated by a branch of the ulnar nerve. Awareness about the rare AFCU muscle is clinically important as a possible cause of ulnar nerve compression but also as a possible graft in reconstruction surgeries.

Course and Relation of the Facial Vessels-An Anatomical Study.

Background and Objectives: Facial vascular anatomy plays a pivotal role in both physiological context and in surgical intervention. While data exist on the individual course of the facial artery and vein, to date, the spatial relationship of the vasculature has been ill studied. The aim of this study was to assess the course of facial arteries, veins and branches one relative to another. Materials and Methods: In a total of 90 halved viscerocrania, the facial vessels were injected with colored latex. Dissection was carried out, the relation of the facial vessels was studied, and the distance at the lower margin of the mandible was measured. Furthermore, branches including the labial and angular vessels were assessed. Results: At the base of the mandible, the facial artery was located anterior to the facial vein in all cases at a mean distance of 6.2 mm (range 0-15 mm), with three cases of both vessels adjacent. An angular vein was present in all cases, while an angular artery was only present in 34.4% of cases. Conclusions: The main trunk of the facial artery and vein yields a rather independent course, with the facial artery always located anterior to the vein, while their branches, especially the labial vessels, demonstrate a closer relationship.

Bilateral accessory flexor indicis muscle: A case study.

Muscular variations within the upper extremities are common and widely documented. They can have a range of implications including nerve compression and misdiagnosis but are often silent. Our report herein describes a bilateral accessory muscle found in the forearm during routine cadaveric dissection. The muscle originates from the medial epicondyle of the humerus between the origins of the flexor digitorum superficialis and flexor carpi radialis muscles. The muscle is digastric, with the distal belly existing as the first lumbrical and the proximal serving as a supernumerary flexor. This functionally atavistic variation could prove clinically relevant for the purposes of donor muscle or tendon tissue as well as surgical complications and compressive neuropathies.