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Abstract Masticatory muscle forces influence craniofacial morphology development. The antegonial notch (Notch) is a bony concavity on the inferior border of the mandible. Considering the Notch is located anteriorly to the insertion of the masseter muscle and varies among individuals, we hypothesised that these muscles influence the formation of the Notch. Therefore, this study aimed to investigate the correlation between mandible morphology and Notch formation. Sixty Japanese patients who visited the Department of Orthodontics at our university hospital were retrospectively evaluated. Morphological and morphometric analyses of the Notch and related craniofacial parameters were conducted using lateral cephalograms taken at the patients’ initial visits. Standard values for the Notch area and depth were determined, and the morphology of the Notch and mandible was analysed using Spearman’s rank correlation coefficient (p

This study consists of a retrospective cohort study, a systematic review, and a meta-analysis which were separately conducted. This study aimed to investigate the prevalence of atlas arch defects, generate an evidence-based synthesis, and propose a common classification system for the anterior and combined atlas arch defects. Atlas arch defects are well-corticated gaps in the anterior or posterior arch of the atlas. When both arches are involved, it is known as a combined arch defect. Awareness of these defects is essential for avoiding complications during surgical procedures on the upper spine. The prevalence of arch defects was investigated in an open-access OPC-Radiomics (Radiomic Biomarkers in Oropharyngeal Carcinoma) dataset comprising 606 head and neck computed tomography scans from oropharyngeal cancer patients. A systematic review and meta-analysis were performed to generate prevalence estimates of atlas arch defects and propose a classification system for the anterior and combined atlas arch defects. The posterior arch defect was found in 20 patients (3.3%) out of the 606 patients investigated. The anterior arch defect was not observed in any patient, while a combined arch defect was observed in one patient (0.2%). A meta-analysis of 13,539 participants from 14 studies, including the present study, yielded a pooled-posterior arch defect prevalence of 2.07% (95% confidence interval [CI], 1.22%–2.92%). The prevalences of anterior and combined arch defects were 0.00% (95% CI, 0.00%–0.10%) and 0.14% (95% CI, 0.04%–0.25%), respectively. The anterior and combined arch defects were classified into five subtypes based on their morphology and frequency. The present study showed that atlas arch defects were present in approximately 2% of the general population. For future studies, larger sample sizes should be used for studying arch defects to avoid the small-study effect and to predict the prevalence accurately.

Abstract Background Distal first metatarsal osteotomy is used to correct mild or moderate hallux valgus (HV). We designed a cadaveric study to compare the resistance to axial load between two percutaneous distal first metatarsal osteotomies: Bösch osteotomy and percutaneous chevron. The first aim of this study was to develop a systematic technique for measuring the sagittal displacement on lateral foot X-rays. Our second objective was to measure the resistance to axial load for both of these osteotomies. Methods Ten pairs of freshly frozen cadaveric feet were randomly assigned to one of the two techniques investigated. Pre- and post-operative lateral X-rays were obtained. After surgery, the feet were placed under progressive axial loads up to 60 kg. Metaphyseo-diaphyseal angle (MDA) and the distance between bone fragments were measured, and the differences between the two techniques were statistically assessed. Results The MDA decreased in both surgical techniques. The mean plantar tilt was −6.90 degrees (SD = 10.251) for chevron osteotomy and −5.34 degrees (SD = 16.621) for Bösch osteotomy. There was no significant difference between the techniques (p = 0.41). Regarding the distance between the bone fragments, the Bösch osteotomy produced more plantar displacement than the chevron osteotomy, which was statistically significant for the 10 and 20 kg loads (p = 0.031 and 0.04, respectively). At loads ≥ 30 kg, the bone fragment distance did not differ significantly between the techniques (p = 0.114). Conclusions Although the chevron technique confers higher stability regarding fragment displacement during axial loading, both techniques increase the plantar angulation of the metatarsal head. Level of evidence Cadaveric study. Level V.

Objective: The aim of this study was to describe the main anatomical variants and morphofunctional alterations in the lower limb that compress surrounding nervous structures in the gluteal region, thigh region, and leg and foot region. Methods: We searched the Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception up to October 2023. An assurance tool for anatomical studies (AQUA) was used to evaluate methodological quality, and the Joanna Briggs Institute assessment tool for case reports was also used. Forest plots were generated to assess the prevalence of variants of the gluteal region, thigh, and leg. Results: According to the forest plot of the gluteal region, the prevalence was 0.18 (0.14–0.23), with a heterogeneity of 93.52%. For the thigh region, the forest plot presented a prevalence of 0.10 (0.03–0.17) and a heterogeneity of 91.18%. The forest plot of the leg region was based on seven studies, which presented a prevalence of 0.01 (0.01–0.01) and a heterogeneity of 96.18%. Conclusions: This review and meta-analysis showed that, in studies that analyzed nerve compressions, the prevalence was low in the thigh and leg regions, while in the gluteal region, it was slightly higher. This is mainly due to the PM region and its different variants. We believe that it is important to analyze all the variant regions defined in this study and that surgeons treating the lower limb should be attentive to these possible scenarios so that they can anticipate possible surgical situations and thus avoid surgical complications.

BackgroundThis study aimed to determine the patterns of invasion of oral squamous cell carcinoma (OSCC) into the bucco-mandibular space (BMS) using detailed histopathological analysis and to assess clinical outcomes.MethodsPatients with OSCC who underwent segmental mandibulectomy or hemi-mandibulectomy combined with resection of the BMS between 2012 and 2021 were included. The invasions of the BMS were classified into three patterns. Pattern A was defined as a horizontal invasion, Pattern B as a vertical invasion, and Pattern C as an expansive invasion.ResultsIn total, 109 patients were reviewed. Of these 109 patients, the primary tumor affected the lower gingiva in 78 patients, the buccal mucosa in 18 patients, and was a primary intraosseous carcinoma of the mandible in 13 patients. Invasion of the BMS was significantly associated with a higher pathological T stage, positive/close margins, and lower disease-free survival (DFS) rates. The DFS rates were 86.7% and 66.0% in the BMS non-invasion and invasion groups, respectively. The DFS rates for each type of invasion were 82.1% for Pattern A, 67.4% for Pattern B, and 48.0% for Pattern C (P=0.277).ConclusionPatients with BMS invasion have a poorer prognosis than those without invasion of the BMS. Therefore, adjuvant therapy is necessary, especially in Patterns B and C. Evaluation of preoperative BMS invasion patterns is important for predicting the prognosis of OSCC.

Background: The petrosphenoidal ligament is the superior boundary of Dorello's canal and typically covers the abducens nerve and dorsal meningeal artery from above. The ligament is usually located within the inferomedial paraclival triangle and can be considered a crucial surgical landmark. Aim: This report describes a rare variant of PSL duplication and its topographical relationships. Case presentation: The duplicated petrosphenoidal ligament was found on the left side during the skull base dissection of a male cadaver. The first band of the duplicated PSL ran between the petrous apex and the dorsolateral border of the clivus. The accessory shorter band of the duplicated PSL was located below and slightly posterior to the previous one, between the edges of the inferior petrosal sinus origin. The abducens nerve, covered by a dural sleeve, ran together with the dorsal meningeal artery between these two PSL bands. Abducens nerve's dural sleeve was firmly attached to the upper surface of the accessory PSL band. On the contralateral side, the topographical relationships were typical with a single PSL. Conclusions: Topographical relationships between the petrosphenoidal ligament and surrounding structures can be highly variable, which should be considered during neurosurgical procedures in the petroclival region.

Background: Although Meckel's diverticulum is a well-known variation, there is rarely an opportunity to trace the detailed anatomy of this structure in dissection material with resin-injected arteries, especially in fetuses. This report presents a detailed description of the ileal diverticulum found in a human fetus, including its vascularization and relationship to the mesentery. Case description: A persistent and well-developed Meckel's diverticulum was found during dissection of a female fetus (CRL = 19 cm). The diverticulum was located in the distal portion of the ileum, among the small intestine loops, and occupied the antimesenteric border of the intestine. It had a broad base and narrowed towards the end; its end was free. Since the arteries were injected with red resin, nutrient branches to the diverticulum from the ileal arteries could be traced in detail. Conclusions: Anatomically, diverse variants of Meckel's diverticulum can occur. The diverticulum can have its own mesentery, and its primary blood supply is from the remnant vitelline artery.

Introduction: The petrosphenoidal ligament (also termed as petroclival ligament) was described in 1859 by Wenzel Gruber, a Russian anatomist. Hence, the popular eponym of Gruber's ligament. Typically, the petrosphenoidal ligament is stretched between the petrous apex and in the vicinity of the posterior clinoid process, forming the posteromedial wall of the Dorello's canal located within the inferomedial paraclival triangle. This report presents a previously unreported attachment of the petrosphenoidal ligament to the posterior genu of the cavernous internal carotid artery. Since the ligament can be a helpful landmark during neurosurgical procedures, our report might have practical value. Case description: During routine dissection of the isolated sagittal section of the head from a male cadaver, an atypical attachment of the petrosphenoidal (petroclival) ligament was observed. The proximal ligament's attachment was bifid. Some ligament bundles originated from the lateral aspect of the clivus, while another group of bundles originated from the posteromedial aspect of the posterior genu of the cavernous internal carotid artery. The ligament had a triangular shape with a broader distal attachment to the petrous apex. The meningohypophysial trunk was in juxtaposition to the arterial attachment of the ligament. It was noted that the arterial attachment was well-fixed to the internal carotid artery's adventitia. Conclusions: The dual origin of the petrosphenoidal ligament to the clivus and internal carotid artery's posterior genu causes atypical fixation of both structures. It can potentially alter selected surgical procedures, such as mobilization of the internal carotid artery's short vertical segment and posterior genu.

Background: The profunda brachii artery (PBA), also known as the deep brachial artery or deep artery of the arm, is one of the principal branches of the brachial artery. Typically The PBA accompanies the radial nerve in the posterior compartment of the arm. Both the PBA and radial nerve pass backward through the triangular interval of the arm and enter the radial sulcus. Since there are few studies on the anatomy of the PBA, the data on its course and branching pattern have remained unchanged for years. However, everyday clinical practice shows that anatomical variability is common, so a detailed description of the divergences from the most typical morphology is needed. Methods: In this report, three different anatomical variants of the course and division of the PBA were described, including a detailed description of its topographical relationships especially with the radial nerve. Results: Case No. 1 involves a variant of the PBA in which both terminal branches of the artery take separate origins directly from the posterior aspect of the brachial artery. Case No. 2 presents a variant in which both terminal branches of the artery have a very distal origin. Case No. 3 is a variant in which the PBA crosses the radial nerve's posterior aspect. Conclusions: Variations of the PBA and its terminal branches should be considered in planning and conducting orthopedic, plastic, and reconstructive surgeries.

Background and Objectives: Anatomical variations in the head, neck and chest are common, and are observed as occasional findings on computed tomography (CT). Although anatomical variations are mostly asymptomatic and do not cause any negative influence on the body function, they may jeopardize diagnosis and may be confused with pathological conditions. The presence of variations may also limit surgical access during tumor removal. The aim of this study was to investigate the prevalence of six anatomical variations—os acromiale, episternal ossicles, cervical rib, Stafne bone cavity, azygos lobe and tracheal bronchus—in an open-access computed tomography dataset obtained from oropharyngeal cancer patients. Materials and Methods: A total of 606 upper-chest and neck computed-tomography scans (79.4% male and 20.6% female) were retrospectively investigated. Sex difference was evaluated using the z-test for two proportions. Results: Os acromiale, episternal ossicles, cervical rib, Stafne bone cavity, azygos lobe, and tracheal bronchus were present in 3.1%, 2.2%, 0.2%, 0%, 0.3% and 0.5%, respectively, of all patients. Os acromiale was identified as meso-acromion in 86.6%, and as pre-acromion in 17.4%, of all acromia. Episternal ossicles were present unilaterally in 58.3%, and bilaterally in 41.7%, of all sterna. Only the cervical rib showed a sex difference in prevalence. Conclusions: awareness of these variations is important for radiologists interpreting head, neck and chest CTs; for example, those of oropharyngeal cancer patients. This study also illustrates the applicability of publicly available datasets in prevalence-based anatomical research. While most of the variations investigated in the present study are well-known, the episternal ossicles are not well explored, and need further investigation.

Background: The spleen is the largest secondary immune organ in the body. Knowledge regarding the normal splenic vascular anatomy and its anatomical variants is crucial in the medical practice of surgeons and radiologists and is useful for diagnostic evaluations and the guidance of various surgical procedures. Hence, in this research, we aim to characterize the behavior of the lineal or splenic artery in humans from an anatomoclinical point of view. Methods: A systematic search was carried out in electronic databases to compile the available literature on the research subject. Searches were undertaken in the following databases: Medline, Scielo, Wos, Cinahl, Scopus, and Google Scholar. The search terms were “Splenic artery”, “Splenic vascularization”, “Anatomical variations’’, “Splenic organ”, and “Clinical anatomy”. Results: From the 35 studies included in this review, clinical correlations of anatomical variations in the splenic artery with surgical procedures in the abdominal region were reported in 8 studies. These correlations are mainly associated with surgical procedures for the pancreas, liver, stomach, and bile ducts through imaging of the spleen. To verify our conclusions, the risk of bias of the anatomical studies was measured using the AQUA checklist. Conclusions: Recognition of the usual anatomy and anatomical variants of the splenic artery is crucial for both morphology professionals and clinicians addressing the abdominal region and its vascular components. In this review, we determined that the splenic artery could present a variation in its origin or entry into the splenic hilum, which could mean that in any abdominal intervention there may be complications if the splenic artery variation is overlooked. More anatomic clinical studies considering this variation in both diagnostic and surgical processes are suggested for further investigations.

Purpose: The aim of this review is to reflect on the question of gross anatomical normality and variability. Particular attention has been paid to what is considered normal in gross anatomy and the premises for recognizing a given structure as normal. The earliest historical sources referring to anatomical variations are described in the paper. The general significance of anatomical variations is also discussed. Results: Having established and classified the laws of nature, scientists gradually achieved the skill of judging what is most typical and what is rare or deviates from the commonly-observed pattern. Normality in anatomy can be considered relative (linked to a specific set of assumptions) and is inferred from numerous repeated observations. In anatomy textbooks, the term “norm” is associated with such concepts as general pattern, rule, or canon. Deviations from the most common (assumed to be typical) morphology are described as variants or types of organs or anatomical structures. The term “anomaly” is also used in the anatomical and medical literature to describe variations; however, this designation can also be applied to pathological conditions. Nevertheless, the “norm” in anatomy is not as precise a concept as one would wish, and can be considered an approximation. In fact, anatomical variability is the rule, though most variations are within the normal range. Thus, the idea of a medical and anatomical norm is analogous the sorites paradox because the boundaries between what is considered normal and what is anomalous are blurred. Nevertheless, the anatomical norm should only be regarded as an idealized scientific model; anatomical variations should be kept in mind in clinical practice. Conclusions: “Anatomical norm” can be considered on the one hand as a useful reference point for clinicians and on the other as an idealized scientific model.

The aim of the present study was to determine the contribution of the orbicularis oculi (OOc) to the zygomaticus major (Zmj) in connecting the orbital region to the corner of the mouth. The OOc and Zmj of 22 embalmed adult Korean cadavers were dissected in 44 hemifaces. The OOc fibers were traced to determine their contribution to the Zmj. Parts of the superficial bundle in the orbital region of the OOc extended directly or indirectly to the Zmj in 22.7% of the specimens. The anatomical contribution of the OOc to the Zmj was divided into three categories depending on whether the connection between them was direct or indirect: (1) superficial orbital OOc fibers extended directly to the Zmj in 6.8% of the specimens, (2) superficial orbital OOc fibers extended to the zygomaticus minor and their small portion joined to the upper fibers of the Zmj in 15.9% of the specimens, and (3) no connection was identified between the OOc and Zmj in 77.3% of the specimens. The results of this study provide further anatomical insight into the relationship between the OOc and zygomaticus muscle complex. This information could be helpful for elucidating the anatomy of smiling and treatment and surgery designs for balanced or ideal smiles.

ObjectivesThe aim of this study was to elucidate the positional relationship between the courses of the angular veins and the facial muscles, and the possible roles of the latter as alternative venous valves.MethodsThe angular veins of 44 specimens of embalmed Korean adult cadavers were examined. Facial muscles were studied to establish their relationships with the angular vein, including the orbicularis oculi (OOc), depressor supercilii (DS), zygomaticus minor (Zmi), zygomaticus major (Zmj), and levator labii superioris (LLS).ResultsIn the upper face of all specimens, the angular vein passed through the DS and descended to the medial palpebral ligament. In the midface, it passed between the origin of the levator labii superioris alaeque nasi (LLSAN) and the inferior OOc fibers. The vein coursed along the deep surface of the inferior margin of the OOc in all specimens. At the level of the nasal ala, the course of the angular vein was classified into three types: in type I it passed between the LLS and Zmi (38.6%), in type II it passed between the superficial and deep fibers of the Zmi (47.7%), and in type III it passed between the Zmi and Zmj (13.6%). In the lower face of all specimens, the angular or facial vein passed through the anterior lobe of the buccal fat pad.ConclusionThis study found that the angular vein coursed along the sites where facial muscle contractions are assumed to efficiently compress the veins, likely controlling venous flow as valves. The observations made and analysis performed in this study will improve the understanding of the physiological function of the facial muscles as alternative venous valves.

The median cubital vein is the most prominent superficial vein in the cubital region and usually the most clearly outlined vein in the entire human body. It can be found quite easily, even in obese, swollen, or shocked patients. It runs diagonally upwards, leaving the cephalic vein and traveling medially to the basilic vein. Topographical relationships make the vein particularly convenient for access in various procedures such as venous punctures. However, high-risk procedures are usually performed in other areas because unusual anatomical variations are possible. A detailed anatomical description of an unusual variant of median cubital vein duplication is presented in this report, including its communications with deep veins and topographical relationships to the bicipital aponeurosis, brachial artery, medial cutaneous nerve of the forearm, and the median nerve. The potential clinical significance of this variant is discussed.

Having established and classified the laws of nature, scientists gradually achieved the skill of judging what is most typical and what is rare or deviates from the commonly-observed pattern. Normality in anatomy can be considered relative (linked to a specific set of assumptions) and is inferred from numerous repeated observations. In anatomy textbooks, the term “norm” is associated with such concepts as general pattern, rule, or canon. Deviations from the most common (assumed to be typical) morphology are described as variants or types of organs or anatomical structures. The term “anomaly” is also used in the anatomical and medical literature to describe variations; however, this designation can also be applied to pathological conditions. Nevertheless, the “norm” in anatomy is not as precise a concept as one would wish, and can be considered an approximation. In fact, anatomical variability is the rule, though most variations are within the normal range. Thus, the idea of a medical and anatomical norm is analogous the sorites paradox because the boundaries between what is considered normal and what is anomalous are blurred. Nevertheless, the anatomical norm should only be regarded as an idealized scientific model; anatomical variations should be kept in mind in clinical practice.The aim of this review is to reflect on the question of gross anatomical normality and variability. Particular attention has been paid to what is considered normal in gross anatomy and the premises for recognizing a given structure as normal. The earliest historical sources referring to anatomical variations are described in the paper. The general significance of anatomical variations is also discussed.

Historical sources can serve as an important point of reference for anatomical research. In this report, we present an atypical origin of the brachioradial artery from the distal fourth of the arm. The radial recurrent artery originated from the ulno-interosseous trunk and crossed the brachioradial artery posteriorly at the level of the neck of the radius. This case reported herein was observed during a review of the historical specimens collection prepared in the 19th century by the prominent Polish anatomist Ludwik Karol Teichmann and his collaborators and exhibited in the Anatomy Museum of Jagiellonian University Medical College. The goal of this study was to provide data on the course and branching pattern of a rare variant of the brachioradial artery.

Introduction: The superficial anterior atlanto-occipital ligament (SAAOL) is a narrowband located anterior to the anterior atlanto-occipital membrane. Nearly forgotten, it has not been well described in older anatomical textbooks and is missing in the current anatomical literature. As all of the binding structures of the craniocervical junction (CCJ) are important in maintaining stability, this study aims to clarify the anatomy and potential function of the SAAOL. Materials and Methods: The CCJ from ten fresh-frozen cadavers was studied. These specimens were derived from three males and seven females, and the age at death ranged from 57 to 91 years (mean, 79.8 years). The length, width, and thickness of the SAAOL were measured. In five specimens, the force to failure was recorded. Results: The SAAOL was found between the anterior tubercle of the atlas and the occiput and located as central thick fibers in front of the anterior atlanto-occipital membrane in 9 (90%) specimens. In one specimen, the vertical band to the occipital bone did not attach to the anterior tubercle of the atlas, but extended to the anterior aspect of the axis. The mean length, width, and thickness of the SAAOL were 19.8, 6.2, and 0.6 mm, respectively. The force to failure for the ligament was 38.8 N. Conclusion: The SAAOL was a constant structure of the anterior atlanto-occipital joint. This ligament seems to be a secondary stabilizer of the CCJ by limiting the extension of CCJ. Knowledge of this ligament may help in further understanding of craniocervical stability.

The carotid sinus nerve (CSN) originates from the glossopharyngeal nerve, and consists of afferent fibers responsible for mediating the baroreceptor reflex. This case study provides the first report of a neuronal loop linking the glossopharyngeal nerve to the vagus nerve, and supplying dual innervation to the CSN. Although few anatomical studies exist on the nerve, anatomical variations of the CSN have been documented, and may be clinically relevant in procedures with close proximity to this nerve. Keywords: Carotid sinus nerve, Anatomy, Glossopharyngeal nerve, Vagus nerve, Hering's nerve

Purpose: The purpose of this review is to provide an overview of reported ectopic locations of arachnoid granulations and their potential clinical sequelae of the space-occupying lesions. Review: Arachnoid villi greater than 2 mm are termed arachnoid granulations. The hypertrophied arachnoid villi 3 cm from midline are termed “ectopic” Arachnoid granulations are usually asymptomatic, but due to their location and size, they can clinically present as non-specific symptoms of venous hypertension, including headache, nausea, vomiting, and papilledema. More specific findings have also been noted, including osteolytic lesions and otorrhea. Conclusions: Arachnoid granulations found outside their normal anatomical location are considered ectopic. Patients are usually asymptomatic but can experience a wide variety of non-specific symptoms. Keywords: Ectopic, Arachnoid granulations, Cerebrospinal fluid, Arachnoid villi

Abstract Previous investigators have reported that transplanted demineralised dentin matrix (DDM) influences bone formation in vivo. However, the specific mechanism of how dentinal tubules contribute to bone formation has not been determined with regard to DDM transplantation therapy. In this study, we ultrastructurally investigated how DDM contacted the surrounding newly formed bone using a scanning electron microscopy (SEM) three-dimensional reconstruction method that is based on focused ion beam slicing and SEM (FIB/SEM). A pulverised and processed DDM derived from human teeth was implanted into rat calvarial bone defects, and a series of X-ray computed tomographic images were obtained over 12 weeks. Implants with surrounding new bone were removed and histologically examined using FIB/SEM. After obtaining objective block-face images, the target boundary face was reconstructed three-dimensionally. The osteocytes of the new bone tissue surrounding the DDM formed a network connected by their cellular processes and formed bone tissue. It is also interesting that the cellular processes of the osteocytes extended into the dentinal tubules, and that bone tissue with canaliculi had formed and filled the DDM surface.

The anterior cingulate cortex is considered to play a crucial role in cognitive and affective regulation. However, this area shows a high degree of morphological interindividual variability and asymmetry. It is especially true regarding the paracingulate sulcus and paracingulate gyrus (PCG). Since the reports described in the literature are mainly based on imaging techniques, the goal of this study was to verify the classification of the PCG based on anatomical material. Special attention was given to ambiguous cases. The PCG was absent in 26.4% of specimens. The gyrus was classified as present in 28.3% of cases. The prominent type of the PCG was observed in 37.7% of the total. Occasionally, the gyrus was well-developed and roughly only a few millimeters were missing for classifying the gyrus as prominent, as it ended slightly anterior the level of the VAC. The remaining four cases involved two inconclusive types. We observed that the callosomarginal artery ran within the cingulate sulcus and provided branches that crossed the PCG. Based on Klingler’s dissection technique, we observed a close relationship of the PCG with the superior longitudinal fascicle. The awareness of the anatomical variability observed within the brain cortex is an essential starting point for in-depth research.

The inferomedial triangle is one of the two surgical triangles in the paraclival subregion of the skull base. It is delineated by the posterior clinoid process, the dural entrance of the trochlear nerve and the dural entrance of the abducens nerve. The aim of the present article is to describe the anatomical variations within the inferomedial triangle. Measurements of the triangle’s borders and area were supplemented by detailed observations of the topographical anatomy and various arrangements of its contents. Nine adult cadaveric heads (18 sides) and 28 sagittal head sections were studied. The mean area of the inferomedial triangle was estimated to be 60.7 mm2. The mean lengths of its medial, lateral and superior borders were 16.1 mm, 11.9 mm and 10.4 mm, respectively. The dorsal meningeal artery was identified within the inferomedial triangle in 37 out of 46 sides (80.4%). A well-developed petrosphenoidal ligament of Grüber was identified within the triangle on 36 sides (78.3%). Although some structures were variable, the constant contents of the inferomedial triangle were the posterior petroclinoid dural fold, the upper end of the petroclival suture, the gulfar segment of the abducens nerve and the posterior genu of the intracavernous internal carotid artery.

The present study aims to provide detailed observations on the cavernous segment of the abducens nerve (AN), emphasizing anatomical variations and the relationships between the nerve and the internal carotid plexus. A total of 60 sides underwent gross-anatomical study. Five specimens of the AN were stained using Sihler’s method. An additional five specimens were subjected to histological examination. Four types of AN course were observed: a single nerve along its entire course, duplication of the nerve, division into separate rootlets at the point of contact with the cavernous part of the internal carotid artery (ICA), and early-branching before entering the orbit. Due to the relationships between the ICA and internal carotid plexus, the cavernous segment of the AN can be subdivided into a carotid portion located at the point of contact with the posterior vertical segment of the cavernous ICA and a prefissural portion. The carotid portion of the cavernous AN segment is a place of angulation, where the nerve always directly adheres to the ICA. The prefissural portion of the AN, in turn, is the primary site of fiber exchange between the internal carotid plexus and either the AN or the lateral wall of the cavernous sinus.

The coracoid process is an anteriorly projecting, hook-like structure, on the lateral edge of the superior anterior portion of the scapula. The tip of the process points laterally and together with the acromion and their associated ligaments is responsible for stabilizing the shoulder joint. The process articulates with the humerus and clavicle and is the point of attachment for several muscles, the short head of biceps brachii, the coracobrachialis, the pectoralis minor, and also the costocoracoid and conoid ligaments. It is palpable in the deltopectoral groove between the deltoid and pectoralis major muscles. Congenital anomalies of the coracoid process are rare such as bifid coracoid processes. Measurement of the size as well as the angle of the coracoid pillars to the glenohumeral space has been used to provide the anatomical positioning of the coracoid process and has aided in radiographic imaging.

Introduction: Split cord malformation is a congenital condition that varies in form and severity, primarily diagnosed in pediatric patients. Surgical treatment is the most common method of correction. Herein, we discuss an extremely rare case of a split cord malformation associated with a midline cervical rib. Presentation of case: A 49-year-old male patient presented to the emergency department with cervical spine trauma. MRI and CT scans were performed of the patient, revealing an unknown cervical rib structure and underlying split cord malformation. Conclusion: To our knowledge, this is the first report of an anomalous midline cervical rib related to a split cord malformation. Such a finding should prompt the clinician to further evaluate such a patient for underlying congenital occult spinal dysraphism such as split cord malformation. Keywords: Cervical rib, Split cord malformation, Spine

Objective: The goal of our study was to determine the incidence of adjacent segment level pathology preoperatively in patients with Klippel-Feil syndrome (KFS) and compare it to the incidence in patients who have undergone anterior cervical discectomy and fusion. Secondarily, we hypothesized that patients with KFS and anterolisthesis would be more likely to develop symptomatic and radiological adjacent segment level disease. Methods: Twenty patients with Klippel-Feil syndrome from a single institution were followed for 33 months; range 4–108 months. Serial imaging and follow-up (serial visits) were used to determine adjacent segment level disease. Patients were separated in two categories: those with anterolisthesis adjacent to their congenitally fused segments and those without. Results: Twenty patients with an average age of 9.5 yrs were identified. The average follow-up period was 33 months; range 4–108 months. Nineteen patients received a diagnosis of KFS during incidental imaging. One patient was diagnosed as part of a workup for myelopathy caused by a disc herniation adjacent to two fused segments. Eight patients had no listhesis in cervical levels adjacent to fused vertebral segments while 12 had listhesis. The two most common levels of listhesis were at C3–C4 and C4–C5 (five patients each). Five patients in the listhesis group had an increase in listhesis through the follow-up period. There were no differences in the development of symptoms between patients who had and did not have listhesis. All non-operative patients were asymptomatic at last follow-up. Conclusion: Our follow-up was limited, but this study does not support the assumption that a congenitally fused segment predisposes a patient to a rate of adjacent segment level disease similar to patient who has undergone an anterior cervical discectomy and fusion. We found no increased risk of symptomatic adjacent segment level disease in KFS patients who had anterolisthesis adjacent to a congenitally fused segment. Keywords: Congenital, Discectomy, Klippel-Feil syndrome, Spinal diseases, Spine, Surgery

The mental spines (superior and inferior), also called the genial tubercles, are located in the midline on the lingual surface of the mandible. Normally, the mental spine consists of a superior pair and an inferior pair of prominences and is of small size. The mental spine provides muscle attachments to the genioglossus muscle, which attaches to the superior pair, and to the geniohyoid muscle, which attaches to the inferior pair. Here, we report a case of the mandible with an elongated mental spine harvested from a 57-year-old Caucasian woman’s cadaveric head. The dimensions of the elongated mental spine are 10.00 mm (length) x 2.72 mm (width) x 8.55 mm (height). Elongated mental spines are rarely reported as they are usually asymptomatic. Practitioners who intend to perform any procedures in the sublingual and submental regions should be aware of such structural variation.

Abstract Introduction Several arterial variants have been reported to occur around the posterior arch of the atlas. Understanding the various anomalies and diagnosing them preoperatively can dramatically reduce the risk of surgical insult during neurosurgical procedures. Herein we report a case of an arterial variant found just below the posterior arch of C1. Case Report During the routine dissection of the suboccipital region via a posterior approach, an unusual bulge was identified just inferior to the inferior capitis oblique muscle. With further dissection, the structure was identified as a tortuous internal carotid artery. Conclusion Arterial variants around the posterior arch of C1 are surgically significant and can result in catastrophic injuries if unappreciated. Most of these variants will be related to the vertebral artery. To our knowledge, an arterial variant of the internal carotid artery in this location, as reported herein, has not been previously reported.

Eminectomy which is one of the popular and most effective treatments for habitual temporomandibular joint luxation was first described by Myrhaug in 1951. There are few reports which described eminectomy being performed under local anesthesia and conscious sedation. We present a case series of habitual luxation of the TMJ treated by eminectomy performed under local anesthesia and conscious sedation and general anesthesia. Five patients were examined and found to have recurrent luxation of the TMJ. The age of patients ranged from 18 to 93 years. Bilateral eminectomy of the TMJ was performed for two patients, and unilateral eminectomy was performed for three patients. Two were examined under intravenous propofol sedation and local anesthesia, while three patients were examined under general anesthesia. One patient died from ileus one month after surgery. The follow-up period except for the case that died from ileus ranged from 12 to 33 months. No recurrent dislocation of the TMJ has been identified. Based on our experience and two other series in the literature, eminectomy with sedation and local anesthesia can be considered and might be a good option in elderly patients.

Along with the popularization of dental implant surgery, there has been considerable research on the lingual foramen using cone-beam computed tomography. Anatomical research has also revealed that the arteries entering the lingual foramina are branches of the submental and sublingual arteries. There have been no reports, however, of the submental or sublingual artery entering the mandible from the lingual foramen, perforating it, and then distributing to the inferior labial region. A 69-year-old man who donated his body to our department in 2015 was dissected. The mandible with overlying soft tissue of the mental region was resected and examined with microcomputed tomography, which showed that the canal perforated from the lingual foramen to the midline of the labial cortical plate. The canal was thus named the median perforating canal. To the best of our knowledge, there have been no other reports of a perforating artery of the mandible, so this case is thought to be rare. Hence, the existence of perforating arteries, such as in the present case, should be taken into consideration in preoperative diagnoses such as for dental implant surgery. Thus, the fusion of anatomical and radiological study is useful and necessary to understand surgical anatomy.

A tortuous common carotid artery poses a high risk of injury during tracheotomy. Preoperative diagnosis is therefore important to avoid serious complications. We found four cases of tortuous common carotid artery during an anatomical dissection course for students. The first case was a 91-year-old woman who had bilateral tortuous common carotid arteries without arteriosclerosis. Case 2 was a 78-year-old woman who had bilateral tortuous common carotid arteries without arteriosclerosis. Case 3 was an 86-year-old woman who died from bladder cancer and who also had a right tortuous common carotid artery without arteriosclerosis. Case 4 was an 89-year-old woman who had bilateral tortuous common carotid arteries and a tortuous brachiocephalic artery with severe arteriosclerosis. Case 4 was also examined using computed tomography to evaluate the arteriosclerosis. Computed tomography revealed severe calcification of the vascular wall, which was confirmed in the aortic arch and origins of its branches. In all four cases, the tortuosity was located below the level of the thyroid gland. Based on prior study results indicating that fusion between the carotid sheath and visceral fascia was often evident at the level of the thyroid gland, we speculated that the major region in which tortuosity occurs is at the same level or inferior to the level of the thyroid gland.