Multiple Fenestrated Dural Venous Sinuses: A Case Report.

Variations of the intradural venous sinuses are common. However, to the best of our knowledge, multiple fenestrated sinuses in the same specimen have not previously been reported. Herein, we report the cadaveric findings of fenestrations found in the left and right transverse and superior sagittal sinuses (SSS). The right transverse sinus was more superiorly located compared to its left counterpart. No occipital sinus was identified, and the straight sinus drained near the proximal left transverse sinus. The right transverse sinus was dominant and slightly larger in diameter throughout its course. Variation in the dural venous system is essentially a rule rather than an exception; however, configurations of these structures can be used as anatomical landmarks, making knowledge of potential anatomical variations of the dural venous sinuses critical for precluding complications during endovascular or neurosurgical procedures. The embryological development of these sinuses is also discussed.

A cephalometric analysis of the antegonial notch in relation to the direction of mandibular growth.

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 < 0.05). The mean Notch area and depth was 78.71 ± 36.54 mm2 and 3.11 ± 1.09 mm, respectively. The Notch area was significantly correlated with ramus inclination (p = 0.044, r = 0.261) and with the Y-axis (p = 0.039, r = 0.267). This study indicated that both the masticatory muscles and mandibular growth could contribute to the Notch formation.

Basilar Artery Band Thrombus: Report of a Unique Case.

Basilar artery bands (BAB) are described in scant reports in the literature as shelves, bridges, septa, or webs within the lumen of the basilar artery. The anatomy and histology of these bands have only recently been fully explored and classified. Although there has been evidence of non-atherosclerotic calcification of these structures and vertebrobasilar atherosclerosis, previous studies have not demonstrated any plaque or thrombus formation on the basilar artery bands. Herein, we report the unique finding of a thrombus associated with a BAB. This case report warns interventionalists and neurosurgeons that there could be a thrombus around the BAB.

Impact of articles written in non-alphabet languages.

Nowadays, English is the lingua franca of science, and the reference lists in most English articles are dominated by other English articles. Publications in languages other than English are most often in French, Italian, Spanish, or German. The minority written languages, that is, non-alphabet languages, have often not been included in reference lists in the scientific literature. However, to accord with the "diversity, equity, and inclusion" concept, non-alphabet languages should be included and discussed. Failure to cite articles in non-alphabet or non-standard languages ignores knowledge that could be useful to both the author and the reader. We hope the present article will promote more discussion of this often-overlooked topic.

Trans-obliquus inferior capitis course of the greater occipital nerve: A potential cause of occipital neuralgia?

Occipital neuralgia can be due to multiple etiologies. One of these is potential compression of the greater occipital nerve (GON). In this regard, one relationship of the GON, its course through the obliquus inferior capitis muscle (OIC), has yet to be well studied. Therefore, the current anatomical study was performed to elucidate this relationship better. In the prone position, the suboccipital triangle was exposed, and the relationship between the GON and OIC was documented in 72 adult cadavers (144 sides). The GON was found to pierce the OIC on four sides (2.8%), unilaterally in two cadavers and bilaterally in one cadaver. Two cadavers were male, and one was female. Histological samples were taken from GONs with a normal course around the OIC, and nerves were found to pierce the OIC. The GON of all four sides identified histological changes consistent with nerve potential compression (e.g., epineurial and perineurial thickening). This is also the first histological analysis of the trans-OIC course of the GON, demonstrating signs of chronic nerve potential compression. Although uncommon, entrapment of the GON by the OIC may be an underrecognized etiology of occipital neuralgia.

Revisiting morphology of xiphoid process of the sternum in human: a comprehensive anatomical study.

BACKGROUND: The xiphoid process (XP) in animals such as sheep and rats are well known to have cartilage called xiphoidal cartilage (XC). In humans, the cartilage in the xiphoid process is considered an anatomical variant and is not well understood. The aim of this study was to investigate the morphology of the XP. METHODS: A total of twenty embalmed European descendant cadaveric sterna (aged 52 to 98 years) were used. Transilluminated XPs and midsagittal sections of XPs were used to examine the bone and cartilage. Subsequently, a sagittally-sectioned XP was harvested for histology and stained with Masson's trichrome. The results of the transillumination and histological examinations were compared qualitatively. RESULTS: The dark area visible in transilluminated XPs was consistent with the bony part in the midsagittal XP sections, which contained bone marrow; the bright area was consistent with the cartilage part in the midsagittal XP sections. This was all demonstrated histologically. Most of the XPs (85%) had some portion of cartilage. The XP was classified into four types based on its proportions of bone and cartilage: Type I, no ossification (< 1/3 ossification) 45%; Type II, minor ossification (1/3 - 1/2 ossification) 20%; Type III, major ossification (1/2-2/3 ossification) 20%; Type IV, complete ossification (> 2/3 ossification) 15%. Most of the XPs (85%) had bone and cartilage, which could have been overlooked in studies using skeletons or CT. CONCLUSION: Previous studies probably underestimated or overestimated the size of the XP. The XC needs to be considered as normal anatomy.

Radiological assessment of the dissection area in supraomohyoid neck dissection.

PURPOSE: The current supraomohyoid neck dissection (SOHND) is performed above the omohyoid muscle to dissect levels I, II, and III in the levels of cervical lymph nodes. However, the anatomical boundary between levels III and IV is the inferior border of the cricoid cartilage. We investigated the anatomical relationship between the omohyoid muscle and cricoid cartilage using contrast-enhanced CT (CE-CT) images to assess the validity of the current SOHND. METHODS: CE-CT images of the head and neck regions in patients were reviewed. The patients were divided into two groups: "malignant tumors" and "others". The vertebral levels corresponding to the positions of anatomical structures such as the intersection of the omohyoid muscle and internal jugular vein (OM-IJ), and the inferior border of the cricoid cartilage (CC), were recorded. RESULTS: The OM-IJ was located around the seventh cervical to the first thoracic vertebra. There was a significant difference between the malignant tumor and others groups in females (p = 0.036). The CC was located around the sixth to seventh cervical vertebrae. There was a significant sex difference in each group (malignant tumor: p < 0.0001; others: p = 0.008). Both sexes tended to have lower OM-IJ than CC, and females had significantly lower OM-IJ than males. CONCLUSION: This study provides clear anatomical evidence showing the difference between the SOHND dissection area and levels I, II, and III. It could be considered that in most cases SOHND invades level IV, not just levels I, II, and III, especially in female patients.

Lingual nerve revisited-A comprehensive review Part I: Anatomy and variations.

The lingual nerve (LN) is a branch of the mandibular division of the fifth cranial nerve, the trigeminal. It primarily carries sensory fibers from the lingual gingiva, mucous membranes of the floor of the mouth, sublingual gland, and the anterior two-thirds of the tongue. Recent studies have explored and reclassified the five branches of the LN as branches to the isthmus of the fauces, lingual branches, sublingual nerves, posterior branch to the submandibular ganglion, and branches to the sublingual ganglion. The knowledge of the LN anatomy and its variants is clinically relevant to avoid its injury during oral procedures. The objective of this paper is to review the literature on the LN and to describe the anatomy, its course, and its functions.

Lingual nerve revisited-A comprehensive review Part II: Surgery and radiology.

The lingual nerve (LN) is a branch of the mandibular division of the fifth cranial nerve, the trigeminal nerve, arising in the infratemporal fossa. It provides sensory fibers to the mucous membranes of the floor of the mouth, the lingual gingiva, and the anterior two-thirds of the tongue. Although the LN should rarely be encountered during routine and basic oral surgical procedures in daily dental practice, its anatomical location occasionally poses the risk of iatrogenic injury. The purpose of this section is to consider this potential LN injury risk and to educate readers about the anatomy of this nerve and how to treat it.

Does the anatomy around the pterygomaxillary suture contribute to the risk of bad fractures in Le Fort I osteotomy?

Le Fort I (LF1) osteotomy, a common orthognathic procedure for the maxilla aimed at achieving maxillary mobility by separating the pterygomaxillary suture, poses a risk of bad fracture that may lead to complications and inadequate mobility. Our study analyzed two- and three-dimensional computed tomography images to identify the anatomical factors associated with bad fractures due to an LF1 osteotomy. Point 'a' is where the lateral pterygomaxillary suture on the axial image aligns with the zygomatic alveolar line near the line used for an LF1 osteotomy, with the base line connecting the bilateral 'a' points.Two risk factors were identified on the pterygoid side: (i) when the distance from point 'a' to the intersection of the base line and the medial pterygoid plate was <6.0 mm; and (ii) when the distance from the piriform aperture margin to the base line was <44.78 mm. Six risk factors were identified on the maxillary side, including the distance between the most anterior and most lateral points of the internal surface of the maxillary sinus being <31.9 mm. Our analyses revealed that fractures that occur during pterygomaxillary suture separation in an LF1 osteotomy are influenced by anatomical factors of the maxilla and pterygoid process, which form the pterygomaxillary suture.

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.

An anatomical study of the nasal foramina.

PURPOSE: The nasal foramen is located in the nasal bone and for vessels passage to supply the nasal area. This project aimed to establish reliable references for the nasal foramina for future clinical applications. METHODS: The 72 dried skulls, 46 from the Division of Anatomy, University of Phayao, Thailand, and 26 from the Tulane University School of Medicine, USA, were collected and examined. The location, number, and sizes of nasal foramina were noted. The distances from each nasal foramen to the internasal suture, frontonasal suture, nasomaxillary suture, nasion, and rhinion were also recorded and used in the statistical analytical programs. RESULTS: The most common type of nasal foramen in all skulls was type II (one external opening) at 65.97%, followed by type I (no foramen opening) at 20.83%, type III (two external openings) at 11.11% and type IV at 2.08% (three external openings). Nasal foramen subtypes in many of the Thai and American skulls were type IIb and type IIa. The diameter of a connecting nasal foramen was significantly larger than that of a non-connecting. Results from embalmed confirmed the passage of the external nasal artery through the nasal cavity. CONCLUSION: The study shows no significant difference in nasal foramen morphometry between Thai and American. It illustrates recent data on type and subtype classifications and the location of a vascular passage through the nasal foramen. This is the first study of NF variations and their respective classifications.

New anatomical findings in the mandibular body region: Two parts that make up bucco-mandibular space.

Soft tissue spaces not only enable gliding by contraction of the facial muscles, but they also cause drooping of the superficial fat due to gravity in the upright position. This study was performed to clarify the structures around the bucco-mandibular space (BMS) and to apply this anatomical knowledge to clinical practice. Four sides of the face were dissected using a conventional gross anatomical dissection technique, and 10 sides (5 horizontal and 5 frontal sections) of the removed semi-facial soft tissue were dissected using the stretched tissue dissection (STD) method. Histological examination of the mandible was performed on two sides to confirm the findings of conventional gross anatomical dissection and STD. In all cases, both gross dissection and STD revealed that the BMS was composed of two parts. The superficial part was filled with adipose tissue containing nerves and vessels, including the marginal mandibular branch of the facial nerve, facial artery, facial vein, and mental nerve. We named this part the adipo-neuromandibular part. By contrast, the deep part was separated from the adipo-neurovascular part by facial deep fascia and composed of loose connective tissue. We named this deep part the loose connective tissue part. The STD method enabled us to obtain detailed anatomical findings of the mandibular region and elucidate two parts of the BMS in which the neurovasculature is distributed. We believe that these findings provide new insights into facial anatomy by resolving existing anatomical uncertainties and will contribute to safer surgical treatment in the facial region.

Improvement of the temporomandibular joint symptoms due to the condylar position change following modified L-shaped intraoral vertico-sagittal ramus osteotomy: a single-center, retrospective study.

PURPOSE: Intraoral vertico-sagittal ramus osteotomy (IVSRO) was first reported by Choung in 1992 as a surgical procedure to decrease postoperative condylar dislocation. In 2017, Iwanaga et al. developed modified L-shaped IVSRO (mIVSRO) to reduce postoperative nerve dysfunction and achieved favorable outcomes. This study aimed to clarify the effect of mIVSRO on changes in temporomandibular joint (TMJ) symptoms and three-dimensional condylar position. METHODS: We conducted a retrospective study of thirty sides in fifteen Japanese adults diagnosed with jaw deformities who underwent mIVSRO and sagittal split ramus osteotomy (SSRO). TMJ symptoms were assessed chronologically, and the condylar long axis and the condylar position were analyzed two- and three-dimensionally using axial cephalograms and cone-beam computed tomography. RESULTS: Postoperative TMJ symptoms improved by 90% (9/10 sides) in the mIVSRO group and by 50% (7/14 sides) in the SSRO group. The mIVSRO group exhibited outward rotation of the condylar long axis, while the SSRO group exhibited inward rotation. Moreover, mIVSRO induced residual anteromedial-inferior deviation of the condyle. The inclination angle of the condylar process was not significantly different between the two procedures pre- and postoperatively. CONCLUSION: These results clearly demonstrated the effect of mIVSRO on symptomatic TMJ. Residual changes in the position of the condyle following mIVSRO may not affect jaw function.

Anatomy of the Buccal Space: Surgical and Radiological Perspectives.

Among the anatomical spaces in the head and neck area, the buccal space has often been studied in dental/oral surgery and cosmetic surgery because it contains the facial vessels, mandibular and facial nerves, and adipose tissue called the buccal fat pad. In addition, as the space can communicate with other spaces, it can be significant in infections. Although the anatomy of the buccal space has been reported in several studies, there have been discrepancies concerning its boundaries, and its communications have often been overlooked. The aim of this review is to examine the anatomy of buccal space including its boundaries, contents, continuity with adjacent spaces, and clinical significance. A literature review was performed on Google Scholar and PubMed. The literature has depicted the anterior, medial, and lateral boundaries more or less consistently, but descriptions of the posterior, superior, and inferior borders are controversial. The buccal space includes the facial arteries, veins, facial nerves, parotid duct, and lymph nodes, which can be described differently depending on definitions and the extent of the space. As it communicates with other anatomical spaces including the masticatory space, it can be a reservoir and a channel for infections and tumors. Buccal fat pads have various clinical applications, from a candidate for flap reconstruction to a target for removal for cosmetic purposes. This review will help understand the anatomy of the buccal space including its boundaries, residing structures, and communication with other spaces from surgical and radiological perspectives.

Newly revealed anatomy of the bucinator muscle: An anatomical and histological study.

BACKGROUND: Current anatomical knowledge of the origin of the bucinator muscle (BM), i.e., long thin attachments on the maxilla and mandible and the pterygomandibular raphe (PMR), is not supported by anatomical dissection of this muscle. The aim of this study was therefore to investigate the detailed morphology of the BM and associated structures and to discuss its function. METHODS: The anatomy of the BM and related structures was investigated in 15 cadaveric heads using a surgical microscope and histological analysis. RESULTS: The inferior fibers of the BM originated from a small retromolar area (internal oblique line), which shared a common tendon with the deep tendon of the temporalis. The superior fibers of the BM originated from the maxillary tuberosity. The middle fibers originated the pterygoid hamulus. No PMR was identified in any of the specimens, but the border between the BM and superior pharyngeal constrictor muscle (SC) was clear because the muscle fibers followed different directions. Some horizontal fibers were continuous between the BM and SC. CONCLUSIONS: Our results suggest the need to revise established accounts of the origins of the bucinator (the maxillary tuberosity, conjoint tendon of the temporalis, and pterygoid hamulus without a pterygomandibular raphe. It also needs to be noted that some of its fibers merge directly with the SC.