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.

Enhancing medical anatomy education with the integration of virtual reality into traditional lab settings.

In medical education, traditional anatomy labs have relied heavily on the hands-on dissection of cadavers to teach the complex spatial relationships within the human body. However, the advent of virtual reality (VR) technology offers the potential for significantly enhancing this traditional approach by providing immersive, interactive 3D visualizations that can overcome some of the limitations of physical specimens. This study explores the integration of VR into a traditional gross anatomy lab to enrich the learning experience for medical students. Methods included the deployment of a VR application developed to complement the dissection process, featuring detailed 3D models of human anatomy that students could manipulate and explore digitally. Approximately 60 s-year medical students participated in the lab, where they engaged with both traditional dissection and the VR application. Results indicated that the VR integration not only increased engagement and satisfaction but also improved the students' ability to understand anatomical structures and their spatial relationships. Moreover, feedback from students suggested more efficient learning and retention than with traditional methods alone. We conclude that VR technology can significantly enhance medical anatomy education by providing an adjunct to traditional dissection, potentially replacing certain aspects of physical specimens with digital simulations that offer repeatable, detailed exploration without the associated logistical and ethical constraints.

A Rare Case of Sural Schwannoma With Involvement of the Medial Sural Cutaneous Nerve: A Case Report and Literature Review.

Schwannomas are benign tumors derived from Schwann cells, typically occurring in the head, neck, and upper extremities, but are less frequent in the lower extremities. They can arise sporadically or from genetic conditions such as neurofibromatosis type 2, associated with NF2 gene mutations. This report details the case of a 57-year-old female with a two-year history of a painless, slowly growing mass in the posterior aspect of the right proximal cruris. Physical examination revealed a 2 cm, elastic-hard, mobile, non-tender mass with a positive Tinel's sign. Ultrasound and magnetic resonance imaging suggested a benign nerve sheath tumor characterized by hypoechoic features. The performed surgery revealed that the tumor involved the medial sural cutaneous nerve. Histologic analysis confirmed the diagnosis of schwannoma, showing typical Antoni A and Antoni B regions. Postoperative recovery was uneventful, with no recurrence or neurological deficits at the two-month follow-up. This case demonstrates an unusual localization of a sural schwannoma and highlights the importance of precise physical examination and imaging to diagnose schwannomas accurately. Clinicians should consider schwannoma as a differential diagnosis in patients presenting with slow-growing palpable masses in the lower extremities.

Anatomical Study of the Inferior Oblique Muscle and Its Innervation: Morphometric Characteristics, Anatomical Variations, and Histological Evaluation of the Nerve to the Inferior Oblique Muscle.

BACKGROUND: This report aims to supplement the existing knowledge on the inferior oblique muscle. In particular, this study presents detailed anatomical and histological data concerning the muscle's entry point (or entry zone) of the nerve to the inferior oblique muscle. Particular attention was paid to the topographical relationships of the nerve to the inferior oblique muscle (NTIO), including the location of its entry point to the muscle's belly and its anatomical variations. METHODS: Sixty orbits from cadaveric hemi-heads fixed in 10% formalin were studied. The course of the NTIO was traced along the lateral border of the inferior rectus muscle as far as its entry point to the inferior oblique muscle. Particular attention was paid to the various ways in which the NTIO's muscular sub-branches penetrated between the fibers of the inferior oblique muscle. RESULTS: Three types of NTIO entries to the inferior oblique muscle's belly were distinguished. In the most common type (48.3%), the nerve entered the muscle's inferior (orbital) surface. In the next most common type (36.7%), terminal muscular sub-branches of the NTIO joined the superior (also referred to as ocular or global) surface of the inferior oblique muscle. In the remaining four cases (15%), the terminal sub-branches of the NTIO were divided into two main groups (superior and inferior) that joined both the superior and inferior surfaces of the muscle. Histological examination confirmed that the distal part of the NTIO shows a characteristic arcuate course (angulation) just before reaching the muscle's belly. The process for splitting and forming separate muscular sub-branches of the NTIO was observed for all the examined histological specimens at the level of the nerve's angulation. CONCLUSIONS: The presented findings enhance the understanding of the anatomical variations and precise distribution of motor sub-branches reaching the inferior oblique muscle, which may deepen anatomical knowledge and potentially enhance the management of ocular motor disorders.

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.

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.

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.

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.

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.

The use of diffusion tensor imaging in spinal pathology: a comprehensive literature review.

STUDY DESIGN: We reviewed the available literature systematically without meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. OBJECTIVE: To evaluate contemporary literature on use of spinal diffusion tensor imaging(sDTI) in spinal pathology. BACKGROUND: sDTI reveals the location and functional state of critical long tracts and is a potentially useful adjunct in disease management. METHODS: Studies were included if they presented or discussed data from investigative or therapeutic procedures involving sDTI on human subjects in the setting of surgically amenable spinal pathology. Studies were excluded if they were (1) restricted to computational models investigating parameters using data not obtained clinically, (2) about cranial DTI methods, (3) about spinal pathology data not related to surgical management, (4) discussions or overviews of methods/techniques with minimal inclusion of objective experimental or clinical data. RESULTS: Degenerative pathologies of interest were restricted to either cervical myelopathy (22/29,75.9%) or lumbar spondylosis 7/29,24.1%). Mass-occupying lesions included intradural pathology and discussed preoperative (7/9,77.8%) and intraoperative imaging(2/9,22.2%) as an adjunct to surgery 22.2%. Traumatic pathology focused on spinal cord injury prognosis and severity grading. CONCLUSIONS: sDTI seems useful in surgical decision making and outcome measurements and in establishing clinical prognoses over a wide range of surgical pathologies. Further research is warranted with longer follow-up and larger population sizes in a prospective and controlled protocol.

Anatomy of mamillo-accessory foramen and prevalence of ossified mamillo-accessory ligament in lumbar vertebrae related to age.

PURPOSE: Ossification of the mamillo-accessory ligament (MAL) results in the formation of a mamillo-accessory foramen (MAF), which is associated with aging. The MAL tethers the medial branches of the lumbar dorsal rami to the lumbar vertebrae. A MAL ossified at the lumbar vertebrae can cause low back pain by compressing the medial branch of a dorsal ramus. Age ranges related to ossification of the MAL have not been reported in previous studies. The objective of the present study was to determine the prevalence of ossification of the MAL in the lumbar column and its relationship to aging, and to measure the newly formed MAF at each level of the lumbar vertebrae. METHODS: This study examined 935 dried lumbar vertebrae from 187 donors at Khon Kaen University, Thailand, consisting of 93 females and 94 males. The research focused on ossification patterns of the MAL, categorizing them into three patterns. RESULTS: We found that over 50% of ossified MAL occurred in the 30-45-year-old range and the frequency increased with age. The prevalence of ossified lumbar MAL was 72.73%, especially in L5 on the left side in females (76.92%). The width of the MAF did not differ significantly between the sexes, but it was greater on the left side (2.46 ± 1.08; n = 76) than the right (2.05 ± 0.95; n = 72) (p = 0.016). CONCLUSION: Ossification of the MAL into the MAF progresses with age, leading to low back pain from nerve compression. Physicians should be aware of the MAF during anesthesia block to treat low back pain.

Intrafacet Spacer Placement as a Mobility-Sparing Bailout Option in Atlantoaxial Fusion Construct Salvage.

Background: Salvage revisions of atlantoaxial (AA) joint complex posterior segmental instrumented fusion constructs require careful individualized planning to prevent occipital extension. In this case report, we describe the use of bilateral intrafacet spacer placement as a mobility-sparing bailout option for the revision surgery. Case Report: A 64-year-old male with a history of diffuse idiopathic skeletal hyperostosis, extremely limited baseline cervical mobility, and prior AA posterior segmental instrumented fusion presented with increasing pain at his 6-month follow-up. Imaging showed fusion and hardware failures and dynamic instability. To prevent occipitocervical fixation, AA intra-articular fusion via a DTRAX spinal system (Providence Medical Technology, Inc) was used as an adjunct to a navigated C1 lateral mass and C2 pars screw posterior segmental instrumented fusion construct. The patient had an uneventful postoperative course and was discharged with resolution of symptoms. Three-month postoperative follow-up confirmed persistent resolution of symptoms and absence of complaints, along with successful arthrodesis on imaging. Conclusion: AA posterior segmental instrumented fusion revision is technically challenging, particularly when partial preservation of craniovertebral junction mobility is required. Bilateral intra-articular cages may be used as an adjunct to hardware revision in construct salvage when sturdy arthrodesis is desired without occipital extension and may represent a major potential strength of intra-articular cages.

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.