Are enlarged peroneal tubercle and accessory anterolateral talar facet associated with calcaneal spur?

BACKGROUND

As the anatomical variations of the foot, enlarged peroneal tubercle (EPT) and accessory anterolateral talar facet (AALTF) have attracted the attention of foot surgeons in recent years. However, EPT and AALTF have not been examined for a relationship with calcaneus spur (CS) as a common osteophyte.

METHODS

The subjects were 369 individuals who died in northeastern Thailand and were preserved as skeletal specimens. The authors examined for the presence of left and right EPT, AALTF, and calcaneus spur (CS). We divided the EPT (+) group with EPT and the EPT (-) group without it and also divided the AALTF (+) group with AALTF and the AALTF (-) group without it. The age at death and the presence of CS were compared statistically between the EPT (+) and EPT (-) groups and between the AATLF (+) and AALTF (-) groups.

RESULTS

Out of the total 369 cases, EPT was found in 117 cases (31.7%), AALTF was positive in 91 cases (24.7%), and CS was found in 194 cases (52.3%). In comparison between EPT (+) and EPT (-) groups, CS was significantly higher (p < 0.0001) in the EPT (+) group, but there was no significant difference in age at death. In comparison between AALTF (+) and AALTF (-) groups, there was no significant difference in age at death or CS.

CONCLUSION

This study showed a strong relationship between EPT and CS, and the prevalence of EPT and AALTF by age in Thailand was first reported. We believe it helps to know the pathogenesis and biomechanism of EPT and AALTF.

TRIAL REGISTRATION

Not applicable.

The Posterior Auricularis Muscle as Superficial Landmark for the Sigmoid Sinus and Transverse-Sigmoid Sinus Junction: An Anatomical Study

OBJECTIVE

Neuronavigation systems coupled with previously reported external anatomical landmarks assist neurosurgeons during intracranial procedures. We aimed to verify whether the posterior auricularis muscle (PAM) could be used as an external landmark for identifying the sigmoid sinus (SS) and the transverse-sigmoid sinus junction (TSSJ) during posterior cranial fossa surgery.

METHODS

The PAM was dissected in 10 adult cadaveric heads and after drilling the underlying bone, the relationships with the underlying SS and TSSJ were noted. The width and length of the PAM, and the distance between the muscle and reference points (asterion, mastoid tip, and midline), were measured.

RESULTS

The PAM was identified in 18 sides (9 left, 9 right). The first 20 mm of the muscle length (mean 28.28 mm) consistently overlay the mastoid process anteriorly and the proximal half of the SS slightly posteriorly on all sides. The superior border was a mean of 2.22 mm inferior to the TSSJ and, especially when the muscle length exceeded 20 mm, this border extended closer to the transverse sinus; it was usually found at a mean of 3.11 mm (range 0.0-13.80 mm) inferior to the distal third of the transverse sinus.

CONCLUSIONS

Superficial landmarks give surgeons improved surgical access, avoiding overexposure of deep neurovascular structures and reducing brain retraction. On the basis of our cadaveric study, the PAM is a reliable and accurate direct landmark for identifying the SS and TSSJ. The PAM could potentially be used for guiding the retrosigmoid approach.

Renal vein valves: a prevalence, microanatomical and histological study

PURPOSE

In the modern era of robotic renal procedures and diagnostics, an even more detailed anatomical understanding than hitherto is necessary. Valves of the renal veins (RVV) have been underemphasized and have been disputed by some authors, and few textbooks describe them. The current anatomical study was performed to address such shortcomings in the literature.

METHODS

One hundred renal veins were studied in fifty adult formalin-fixed cadavers. Renal veins were removed from the abdomen after sectioning them flush with their entrance to the renal hilum. The inferior vena cava was then incised longitudinally and opened, and RVV were examined grossly and histologically. A classification scheme was developed and applied to our findings.

RESULTS

Nineteen RVVs were observed in the fifty cadavers (38%). Four (8%) valves were found on right sides and fifteen (30%) on left sides. The valves were seen as cord/band-like, folds, and single and double leaflets. Histologically, they were all extensions of the tunica intima.

CONCLUSION

On the basis of our study, RVV are not uncommon. They were more common on left sides, and on both sides, they were found within approximately one centimeter of the junction of the inferior vena cava and renal vein. Although the function of such valves cannot be inferred from this anatomical study, the structures of the Single leaflet valve (TS2) and Double leaflet valve (TS3) valves suggest they could prevent venous reflux from the IVC into the kidney.

Buccal gland within the bucinator muscle

There are major and minor salivary glands that aid in the digestive process. Major glands are discrete and exist in predictable locations; minor salivary glands are more widespread and usually found dispersed in the mucosa of the mouth. Glands have their own contractile abilities, which allow them to secrete products without the assistance of vasculature or skeletal, or smooth muscle. This study will describe a cadaveric histological specimen in which an ectopic buccal gland was embedded within bucinator muscle fibers. Potential causes and explanations for this finding will be discussed, as well.

Angulation of the dural venous sinuses of the posterior cranial fossa: Anatomical study with clinical and surgical applications

Cerebral vein and dural venous sinus thromboses (CVST) account for 0.5%-1% of all strokes. Some structural factors associated with a potentially higher risk for developing CVST have been described. However, angulation of the dural venous sinuses (DVS) has yet to be studied as a structural factor. The current study was performed because this variable could be related to alterations in venous flow, thus predisposing to a greater risk of CVST development. Additionally, such information could help shed light on venous sinus stenosis (VSS) at or near the transverse-sigmoid junction. The angulations formed in the different segments of the grooves of the transverse (TS), sigmoid (SS), and superior sagittal sinuses (SSS) were measured in 52 skulls (104 sides). The overall angulation of the TS groove was measured using two reference points. Other variables were examined, such as the communication pattern at the sinuses' confluence and the sinus grooves' lengths and widths. The patterns of communication between sides were compared statistically. The most typical communication pattern at the sinuses' confluence was a right-dominant TS groove (82.98%). The mean angulations of the entire left TS groove at two different points (A and B) were 46° and 43°. Those of the right TS groove were 44° and 45°. The median angulations of the left and right SSS-transverse sinus junction grooves were 127° and 124°. The mean angulations of the left and right TS-SSJsv grooves were 111° (range 82°-152°) and 103° (range 79°-130°). Differentiating normal and abnormal angulations of the DVSs of the posterior cranial fossa can help to explain why some patients are more susceptible to pathologies affecting the DVSs, such as CVST and VSS. Future application of these findings to patients with such pathologies is now necessary to extrapolate our results.

Complete transverse basilar cleft associated with hemifacial microsomia

Transverse basilar cleft (TBC) is an extremely rare variation of the clivus or the basilar part of the occipital bone. In this report, a unilateral transverse basilar fissure was found at the clivus in a head computed tomography of an 18-year-old female patient diagnosed with hemifacial microsomia (HFM). Image analysis of this patient showed shortening of the ramus of the right mandible along with medial displacement of the right temporomandibular joint and hypoplastic right maxilla. In addition, observation of the clivus showed a cleft between the basioticum and basioccipital bones at the level of the pharyngeal tubercle on the right side. This cleft was identified as TBC. Clival variations, TBC included, attributed to HFM have never been reported. This report draws attention to the complex relationship between abnormal development of clivus and HFM syndrome, and sheds light on a possible genetic and molecular association between these two conditions.

L5 spondylolysis: Anatomical study comparing healed and unhealed lesions

The anatomy and pathogenesis of spondylolysis has been widely studied; however, the microanatomy of spondylolysis of the lumbar vertebra has not been well described. Therefore, we aim to better elucidate this anatomy. Twenty dry bone specimens of healed and unhealed spondylolysis of the L5 vertebra were collected from human skeletal remains. Twelve L5 vertebrae were examples of unhealed spondylolysis and eight specimens exhibited a healed (i.e., bony fusion of the lesion) spondylolysis lesion. The specimens underwent macro and microanatomical analysis followed by CT and microCT imaging. Finally, selected healed and unhealed lesions were submitted for histological analysis using Mason Trichrome staining. The pars interarticularis of two L5 vertebrae without signs of healed/unhealed spondylolysis were evaluated histologically as controls. Of the 12 unhealed L5 pars defects, three were unilateral on left side. Of the eight healed pars defects, all were unilateral and seven of these were on left sides. One unilateral pars defect also had spina bifida occulta. Both on imaging and histological analysis, healed pars defects were only so superficially and not at deeper levels. Histologically, unhealed edges were made up of dense cortical bone while healed edges were made up primarily of trabecular bone. Based on our anatomical findings, the so-called healed spondylolysis lesions, although externally fused, are not thoroughly fused internally. Moreover, the anterior and posterior edges of the unhealed spondylosysis lesions are irregular and show signs of long-term disarticulation. Taken together, these data suggest that such 'healed' lesions might not be as stable as the normal L5 pars interarticularis.

Is low carotid bifurcation determined by vertebral level always convenient for surgical approach?

Although high-level carotid bifurcation (HCB) could lead to notable surgical difficulty, the definitive reference point for HCB is unclear. HCB is typically characterized as carotid bifurcation (CB) located higher than the level of the third cervical vertebra (C), however, a major obstacle regarding carotid artery surgical exposure is angle of the mandible (AM). The objective of this study was to investigate CB level, define HCB in relation to AM and vertebral levels, and measure the vertical distance from HCB to ipsilateral AM. Moreover, the percentage of surgically challenged CBs, misclassified as low CBs (LCB) based on vertebral level, was investigated. Patients who underwent neck computed tomography angiography were retrospectively studied. HCBs were classified into two categories: CBs above the C3 and either at or above the ipsilateral AM. Of 172 CBs (86 patients; 57 men, 29 women), CB was mostly found at C3 (44.19%), whereas AM was commonly located at C2 (51.16%). Based on vertebral level and AM, HCBs were detected in 10.47% and 20.35% of CBs, respectively. The association of HCBs determined by either C3 or AM between both sides in each individual was nonsignificant (p>0.05), but HCBs determined by C3 level were predominant in women (OR = 3.58, 95%CI = 1.31-9.80). Considering both C3 and AM, there was 8.72% of HCBs. The remaining 91.28% was classified as LCBs, including 11.63% of CBs located at both C3 and AM which were actually classified as HCBs if determined by AM. In cases of CBs above AM level, the mean vertical distance was as high as 6.56 ±2.41mm.

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.

Alterations of serum biochemical parameters and tyrosine phosphorylation in kidney and liver of chronic stress-induced rats

Abstract Chronic stress (CS) can contribute to dysfunction in several organs including liver and kidney. This study was performed to investigate the changes in serum biochemistry, histological structure, as well as in localization of tyrosine phosphorylated proteins (TyrPho) and Heat shock protein 70 (Hsp-70) in liver and kidney tissues of CS rats induced by two stressors (restrained and force swimming) for 60 consecutive days. Samples of blood, liver, and kidney were collected from adult male Sprague–Dawley rats in each group. Our results showed that serum biochemical parameters including corticosterone, blood sugar, urea nitrogen, creatinine, cholesterol, triglyceride, HDL-C, LDL-C, ALT, AST, alkaline phosphatase in CS group were significantly different from that in normal group in both liver and kidney tissues. Although histological structure was not changed. TyrPho expression was significantly increased in liver lysate but significantly decreased in kidney. Hsp-70 expression in liver increased whereas in kidney decreased. In conclusion, CS can induce changes in liver and kidney functions.

Anatomical study of the mastoid foramina and mastoid emissary veins: classification and application to localizing the sigmoid sinus

The mastoid foramen (MF) is located on the mastoid process of the temporal bone, adjacent to the occipitomastoid suture or the parietomastoid suture, and contains the mastoid emissary vein (MEV). In retrosigmoid craniotomy, the MEV has been used to localize the position of the sigmoid sinus and, thus, the placement of the initial burr hole. Therefore, this study aimed to examine the exact location and variants of the MF and MEV to determine if their use in localizing the sigmoid sinus is reasonable. The sample in this study comprised 22 adult dried skulls (44 sides). MF were identified and classified into five types based on location, prevalence, whether they communicated with the sigmoid sinus and exact entrance into the groove of the sigmoid sinus. The diameters and relative locations of the MF in the skull were measured and recorded. Finally, the skulls were drilled to investigate the course of the MEV. Additionally, ten latex-injected sides from human cadavers were also dissected to follow the MEV, especially in cases with more than one vein. We found that type I MFs (single foramen) were the most prevalent (50%). These MFs were mainly located on the occipitomastoid suture; only one case on the right side was adjacent to the parietomastoid suture. Type II (paired foramina) was the second most prevalent (22.73%), followed by type III (13.64%), type 0 (9.09%), and type IV (4.55%). The diameter of the external opening in a connecting MF (2.43 ± 0.79) was twice that of a non-connecting MF (1.14 ± 0.56). Interestingly, on one side, two MFs on the external surface shared a single internal opening; the MEV bifurcated. MFs followed three different courses: ascending, almost horizontal, and descending. Regardless of how many external openings there were for the MF, these all ended at a single opening in the groove for the sigmoid sinus. For cadaveric specimens with multiple MEVs, all terminated in the sigmoid sinus as a single vein, with the more medial veins terminating more medially into the sinus. Based on our study, the MF/MEV can guide the surgeon and help localize the deeper-lying sigmoid sinus. Knowledge of this anatomical relationship could be an adjunct to neuronavigational technologies.

Review of the caroticotympanic nerves: Anatomy, function and pathology

The caroticotympanic nerves provide postganglionic sympathetic fibres to the tympanic plexus. However, there are scant reports in the literature detailing with these nerves in great depth. As the caroticotympanic plexus lies near the often-operated tympanic nerve, it is important for the surgeon to understand the anatomy, pathology and surgical implications of it. Here, we present a review of the available literature regarding the caroticotympanic nerves.

Trabeculae in the basilar venous plexus: anatomical and histological study with application to intravascular procedures

Few studies have examined the basilar venous plexus (BVP) and to our knowledge, no previous study has described its histology. The present anatomical study was performed to better elucidate these structures. In ten cadavers, the BVP was dissected. The anatomical and histological evaluation of the intraluminal trabeculae within this sinus were evaluated. Once all gross measurements were made, the clivus and overlying BVP were harvested and submitted for histological analysis. A BVP was identified in all specimens and in each of these, intraluminal trabeculae were identified. The mean number of trabeculae per plexus was five. These were most concentrated in the upper half of the clivus and were more often centrally located. These septations traveled in a posterior to anterior direction and usually, from inferiorly to superiorly however some were noted to travel horizontally. In a few specimens the trabeculae had wider bases, especially on the posterior attachment to the meningeal layer of dura mater. More commonly, the trabeculae ended in a denticulate form at their two terminal ends. The trabeculae were on average were 0.85 mm in length. The mean width of the trabeculae was 0.35 mm. These septations were consistent with the cords of Willis as are found in the lumen of some of the other intradural venous sinuses. An understanding of the internal anatomy of the BVP can aid in our understanding of venous pathology. Furthermore, this knowledge will benefit patients undergoing interventional treatments that involve the BVP.

Basilar tubercles and eminences of the clivus: Novel anatomical entities

BACKGROUND

The clivus forms the central skull base between the dorsum sellae and the foramen magnum. Although bony variations of the inferior surface of the clivus are well-recognized and have been well studied, studies of bony variations of the basilar (superior) surface of the clivus are scarce. Therefore, the present study was performed to investigate bony anatomical variations on the basilar part of the clivus.

METHODS

Computed tomography scans belonging to 407 Indian subjects from the CQ500 open-access dataset were retrospectively reviewed.

RESULTS

Bony tubercles on the basilar surface of the clivus were found in 40 cases (9.83%). They were classified into three types including single, double and triple. A single tubercle was found in 35 cases (8.60%) including 12 on the left (2.95%), 10 on the right (2.46%) and 13 in the center (3.19%). The tubercles were doubled in four cases (0.98%) and tripled in one case (0.25%). The average width and height of the tubercles were 4.4 ± 1.5 mm (range 1.4-7.9 mm) and 1.7 ± 0.7 mm (range 0.8-4.2 mm), respectively. Ninety-five (95%) percent of the tubercles were located on the lower half of the clivus.

CONCLUSIONS

To our knowledge, these tubercles have not been previously described. Therefore, we suggest the terms "basilar tubercles of the clivus" and "basilar eminences of the clivus", depending on their sizes. Knowledge of these newly described structures is important when interpreting radiological images of the skull base.

Radiological Study of Atlas Arch Defects with Meta-Analysis and a Proposed New Classification

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.

Innervation of pineal gland by the nervus conarii: a review of this almost forgotten structure

The nervus conarii provides sympathetic nerve innervation to the pineal gland, which is thought to be the primary type of stimulus to this gland. This underreported nerve has been mostly studied in animals. One function of the nervus conarii may be to activate pinealocytes to produce melatonin. Others have also found substance P and calcitonin gene-related peptide from the nervus conarii ending in the pineal gland. The following paper reviews the extant medical literature on the nervus conarii including its anatomy and potential function.

An unusual arrangement between the highest denticulate ligament and posterior inferior cerebellar artery

The posterior inferior cerebellar artery (PICA) is often involved in pathologies of the posterior cranial fossa. Therefore, a good understanding of the vessel's normal and variant courses is important to the neurosurgeon or neurointerventionalist. During the routine microdissection of the craniocervical junction, an unusual arrangement between the highest denticulate ligament and PICA was observed. On the right side, the PICA was given rise to by the V4 segment of the vertebral artery 9 mm after the artery entered the dura mater of the posterior cranial fossa. The artery made an acute turn around the lateral edge of the highest denticulate ligament to then recur 180 degrees and travel medially toward the brainstem. Invasive procedures that target the PICA should be aware of the variant as described herein.

The laryngopharyngeal nerve: a comprehensive review

The laryngopharyngeal nerve has received much less attention that the other contributions to the pharyngeal plexus i.e., glossopharyngeal and vagus nerves. Often, in descriptions and depictions, the nerve is simply labeled as the sympathetic contribution to the pharyngeal plexus. As there is such scant information available regarding this nerve, the present review was performed. Very little is found in the extant medical literature regarding the laryngopharyngeal nerve. However, based on available data, the nerve is a consistent contributory to the pharyngeal plexus and serves other adjacent areas e.g., carotid body. Therefore, a better understanding of this structure's anatomy is important for those who operate in this area. Further studies are necessary to better elucidate the true function of the laryngopharyngeal nerve.

Histology and immunohistochemistry of the human carotid sinus nerve

The carotid sinus nerve (CSN) is well known as mediating baroreflexes. However, studies of its detailed histological analysis are scant in the literature. Therefore, the current anatomical study sought to better elucidate the microanatomy of the CSN. Ten fresh frozen adult cadavers underwent dissection of the CSN. Then, it was harvested and submitted for histological and immunohistochemical staining. Specimens were all shown to be nerve fibers on histology and immunohistochemistry. We identified tyrosine hydroxylase positive fibers in all CSN specimens. These fibers were always found to be within the CSN and not on its surface i.e., epineurium. Based on our findings, the majority of fibers contained in the CSN are tyrosine positive in nature. Further studies are necessary to understand the true function of this autonomic nerve fibers.

Revisiting the transorbital approach for emergency external ventricular drainage: an anatomical study of relevant parameters and their effect on the effectiveness of using Tubbs' point

The transorbital approach (TOA) can provide immediate access to the lateral ventricles by piercing the roof of the orbit (ROO) with a spinal needle and without the need of a drill. Reliable external landmarks for the TOA ventriculostomy have been described, however, the necessary spinal needle gauge and other relevant parameters such as the thickness of the ROO have not been evaluated. Nineteen formalin-fixed adult cadaveric heads underwent the TOA. Spinal needles of different gauges were consecutively used in each specimen beginning with the smallest gauge until the ROO was successfully pierced. The thickness of the ROO at the puncture site and around its margins was measured. Other parameters were also measured. The TOA was successfully performed in 14 cases (73.68%), where the most suitable needle gauge was 13 (47.37%), followed by a 10-gauge needle (36.84%). The mean thickness of the ROO at the puncture site, and the mean length of the needle to the puncture site were 1.7 mm (range 0.2-3.4 mm) and 15.5 mm (range 9.2-23.4 mm), respectively. A ROO thickness of greater than 2.0 mm required a 10-gauge needle in seven cases, and in five cases, a 10-gauge needle was not sufficient for piercing the ROO. The presence of hyperostosis frontalis interna (HFI) (21.05%) was related to the failure of this procedure (80%; p < 0.00). Using a 13/10-gauge spinal needle at Tubbs' point for TOA ventriculostomy allowed for external ventricular access in most adult specimens. The presence of HFI can hinder this procedure. These findings are important when TOA ventriculostomy is considered.

An analysis of pain intensity, injury incidence, and their associations with socio-demographic factors in high school athletes: A cross-sectional study during the COVID-19 pandemic

This cross-sectional study explored the relationship between pain intensity, injury incidence, and sociodemographic factors in 120 high school athletes (mean age 16.78±0.91) participating in various sports. The aims of this study are to examine the correlation between factors and Verbal Rating Scale (VRS) for pain intensity, to investigate the correlation between sport types and injured region, and to explore the correlation between injured regions and VRS during training and game competition. Using VRS, we found 64 (53.3%) participants experienced pain during training, with varying degrees of intensity. Chi-square analysis revealed a significant association between VRS scores and school grade (p = 0.044) and cool-down practices (p = 0.037). However, no significant associations were found with gender, age, or sport type. In game competition, 29 (24.2%) participants reported experiencing pain. Here, there was no significant association between VRS and any considered variables. Lower limb injuries were predominant (n = 64), particularly to the knee (n = 23) and ankle/foot (n = 18). Certain sports, like Athletics, Karate-Do, Football, and Western Boxing, demonstrated multiple injury sites, whereas Thai boxing was associated primarily with ankle and foot injuries. Pain intensity varied by injury location, with the highest 'worst pain' reported for elbow injuries during training and knee injuries during competition. Significant associations were found between injured region and pain intensity level during both training and competition (p<0.001). Our findings highlight the need for injury prevention strategies and pain management among high school athletes, emphasizing proper cool-down activities. Further research is warranted to confirm these findings and explore underlying mechanisms.

The superior vesical artery: A review of conflicting definitions and how these could affect invasive procedures

Since the superior umbilical artery is the only functioning branch of the patent umbilical artery, some anatomical and surgical books/atlases fail to clarify that it is a branch of the umbilical artery and not a direct branch of the anterior division of the internal iliac artery and so specifically state that it is a direct branch of the internal iliac artery. This discrepancy in nomenclature can obviously affect invasive procedures and communication between physicians. Therefore, the present review is intended to highlight this issue. The term "superior vesical artery" was searched using standard search engines, for example, PubMed and Google Scholar. Several standard and specialized anatomy textbooks were also examined to ascertain how the superior vesical artery was described. Thirty-two articles were identified that used the terms "superior vesical artery" or "superior vesical arteries." After applying exclusion criteria, in 28 papers, the definition of the superior vesical artery was undetermined in eight, described as a direct branch of the internal iliac artery in 13, described as a branch of the umbilical artery in six, and defined as being equivalent to the umbilical artery in one. Of the sampled textbooks, some defined the superior vesicle artery as a branch of the umbilical artery, some as a direct branch of the internal iliac artery and some as both. Taken all together, most define the superior vesical artery as a branch of the umbilical artery. As the superior vesical artery is described as a branch of the umbilical artery in the internationally accepted terminology (Terminologia Anatomica), we recommend that this definition be used by anatomists and physicians alike so that communication is clear.

Nerve to subclavius for neurotization procedures: an anatomical feasibility study

Injuries to the inferior trunk of the brachial plexus and its components can be debilitating. As such injuries are prioritized by surgeons during repair, an additional nerve transfer is considered herein. In the supine position, 13 adult cadavers (26 sides) underwent dissection of the nerve to subclavius and the proximal brachial plexus in the supraclavicular region. Once the nerve was located and isolated from origin to termination, measurements of its length and diameter were made. Next, the C8 and T1 roots and inferior trunk were identified. The distal end of the nerve to subclavius was transected and swung to these roots and the inferior trunk. Once the nerves to subclavius were transposed and in a tension-free manner, the length of excess nerve following being brought to each of these nerves was measured. A nerve to subclavius was identified on all sides. The nerve originated from the superior trunk and traveled anterior to the middle and inferior trunks on all sides. The mean diameter of the nerve to subclavius was 0.8 mm, and the mean length was 57 mm. After cutting the nerve to subclavius at its entrance into the subclavius muscle, the distal nerve could be transferred tension free to the inferior trunk of the brachial plexus and T1 ventral ramus on all sides. The distal nerve to subclavius reached the T1 ventral ramus with an average of 18 mm of additional length and to the C8 ventral ramus with an average of 19 mm. The nerve also could be transferred to the inferior trunk of the brachial plexus with an average of 20 mm of additional length. The nerve to subclavius was found to have approximately 3000 axons. To our knowledge, use of the nerve to subclavius has previously not been used for nerve transfer procedures. Based on our cadaveric study, this often-overlooked nerve can be easily transposed to other regional nerves such as the inferior trunk of the brachial plexus.

Quadricuspid Pulmonary Valve With Fenestration: Cadaveric Findings

Quadricuspid pulmonary valves (QPV) are rare entities. Such valves can be associated with other cardiac anatomical anomalies. In this report, we present a case of a quadricuspid valve with an additional variant and discuss the morphometrics of this anatomical variation. During the routine dissection of an adult male body, two anatomical variations were found within the pulmonary trunk. This individual had a QPV. In addition, one of the leaflets of this valve contained fenestrations. No additional cardiac anomalies were identified. Clinicians who review imaging of the heart or treat patients with cardiac conditions should be well-informed about QPV.

What is the C2 pedicle, pars interarticularis, and isthmus? Anatomical study and review of the literature regarding these confusing terms with proposal of new nomenclature

INTRODUCTION

The atypical anatomy of the C2 vertebra has led to terminological discrepancies within reports and studies in the literature regarding the location of its pedicle, pars interarticularis, and isthmus. These discrepancies not only limit the power of morphometric analyses, but they also confuse technical reports regarding operations involving C2, and thus confuse our ability to properly communicate this anatomy. Herein, we examine the variations in nomenclature regarding the pedicle, pars interarticularis, and isthmus of C2, and via an anatomical study, propose new terminology.

METHODS

The articular surface and underlying superior and inferior articular processes and adjacent transverse processes were removed from 15 C2 vertebrae (30 sides). Specifically, the areas regarded as the pedicle, pars interarticularis, and isthmus were evaluated. Morphometrics were performed.

RESULTS

Our results indicate that, anatomically, C2 has no "isthmus" and that a pars interarticularis for C2, when present, is very short. Deconstruction of the attached parts allowed for visualization of a bony arch extending from the anterior most aspect of the lamina to the body of C2. The arch is composed almost entirely of trabecular bone and without its attached parts, e.g., transverse process, really has no cortical bone laterally.

CONCLUSIONS

We propose a more accurate terminology, the pedicle, for pars/pedicle screw placement of C2. Such a term more accurately describes this unique structure of the C2 vertebra and would alleviate terminological confusion in the future literature on this topic.

Twenty Intracranial Skull Base Variations in the Same Specimen

Anatomists and clinicians often encounter single bony anatomical variations in dry skulls and on imaging. However, a constellation of 20 such variants some that, to our knowledge, have not been previously described is noteworthy. Here, we describe an adult skull with multiple bony variations, and these are detailed and discussed. These included clival canals, an interclinoid bar with resultant foramen at the uppermost aspect of the clivus, middle clinoid process, posterior petroclinoid ligament, pterygoalar plate, septated hypoglossal canal, foramen through the anterior clinoid process, septated foramen ovale, shortened superior orbital fissure, and crista muscularis. Knowledge of individual differences in the structure of the skull may be of use to both anatomists and clinicians in the treatment of intracranial procedures as well as cranial imaging studies. Taken together, such a unique specimen is of archival value.

Anatomy and Histology of the Petrous Carotid Membrane: Application to Skull Base Surgery

INTRODUCTION

Published reports regarding the tissue types that surround the internal carotid artery (ICA) as it travels through the carotid canal vary. Reports have variably defined this membrane as periosteum, loose areolar tissue, or dura mater. With such discrepancies and realizing that knowledge of this tissue might be important for skull base surgeons who expose or mobilize the ICA at this location, the present anatomical/histological study was performed.

METHODS

In eight adult cadavers (16 sides) the contents of the carotid canal were evaluated, specifically, the membrane surrounding the petrous part of the ICA was studied and its relationship to the deeper lying artery observed. In the supine position, and using a surgical microscope, the overlying petrous part of the temporal bone was drilled away using a high-speed surgical drill. Once the overlying bone was removed, the contents of the carotid canal were exposed, and the petrous part of the ICA and its membranous envelope were removed as a single piece. These specimens were stored in formalin and submitted for histological evaluation.

RESULTS

Grossly, the membrane within the carotid canal traversed the entire carotid canal and was loosely adherent to the underlying petrous part of the ICA. Histologically, all membranes surrounding the petrous part of the ICA were consistent with dura mater. The dura mater of the carotid canal had an outer endosteal and an inner meningeal layer and in most, a clear dural border cell layer that approximated and was loosely applied to the adventitial layer of the petrous part of the ICA. Within the endosteal layer of the dura mater, which was less tightly packed than the more internally located meningeal layer, nerves and blood vessels, mostly veins, were apparent.

CONCLUSIONS

The previously noted membrane that surrounds the petrous part of the ICA is dura mater. To our knowledge, this is the first histological investigation of this structure and thus, serves to establish to true identify of this membrane and correct previous reports in the literature that have erroneously concluded that it is periosteum or loose areolar tissue.

A novel direct pathway of dural venous outflow from the basilar venous plexus via the diploic space of the clivus

INTRODUCTION

The internal jugular vein is the preeminent outflow of the dural venous sinuses in the supine position, while the vertebral venous plexus dominates venous outflow in the upright position. Emissary veins can also be an accessory pathway for this venous egress. To our knowledge, alternative dural venous sinus directly drainage via the diploic space has not been previously reported in the literature.

MATERIALS AND METHODS

Ten fresh frozen adult cadavers underwent exposure of the basilar venous plexus. The entire plexus, still adhered to the underlying clivus, was removed with its underlying bone and submitted for histological examination following decalcification (Masson Trichrome, 5μm slices).

RESULTS

All specimens were found to have direct communications between the basilar venous plexus and underlying diploic space of the clivus i.e., no intermediate clival emissary vein. These were concentrated near the midline and were more numerous over the clivus near the junction of the occipital and sphenoid bones. The endothelium of the venous sinus was continuous at the opening into the diploic space and these openings ranged in size from 500 to 750 μm (mean 650 μm).

CONCLUSION

An improved understanding of cerebral venous drainage can assist clinicians and surgeons in recognizing normal, pathologic, and variant anatomy in this region. Based on our study, direct venous sinus to diploic space drainage offers an additional pathway for venous egress from the intracranium. Therefore, removal of the dura over the clivus during various skull base procedures might be associated with increased venous bleeding from the basilar venous plexus on its deep surface where it interfaces with the clivus.

Accessory extensor pollicis longus from the extensor digitorum: a rare case report and review of the literature

PURPOSE

Variations of the extensor pollicis longus are rare. When present, these include a separate extensor pollicis longus muscle, tendon or an intertendinous connection with nearby tendons within the deep extensor compartment of the forearm. Here, we report an extremely rare variation of an accessory extensor pollicis longus originating from the extensor digitorum.

METHODS

An unusual muscle was found during the routine dissection forearm of a 71 year-old at death male cadaver.

RESULTS

This variant muscle originated from part of the extensor digitorum muscle belly that supplies the index finger. It became tendinous and entered the third extensor compartment of the wrist before joining the ulnar side of the extensor pollicis longus tendon. Traction on the muscle belly resulted in simultaneous extension of both the thumb and the index finger.

CONCLUSION

This study documents an extremely rare extensor tendon to the thumb originating from the extensor digitorum, with a unique attachment to the normal extensor pollicis tendon. There have been minimal accounts of this variation, and the present report adds to the limited literature. Furthermore, the report suggests a new subtype, 1f, be included in the existing classification system. Surgeons should be aware of this rare variant for proper evaluation, diagnosis and surgical treatment. Further anatomical studies are needed to study the prevalence of this variant.

Effects of intubation technique on intracranial pressure: a cadaveric study

Patients are at risk of increased intracranial pressure (ICP) during manipulation for endotracheal intubation. The aim of this cadaveric study was to quantify this relationship. Five fresh frozen adult cadaveric heads were used. The internal carotid artery (ICA) and internal jugular vein (IJV) were dissected bilaterally. All vessels were occluded on the right side. To mimic central venous pressures, the left IJV was cannulated and filled with water to maintain a pressure of approximately 7 cm H2O. The ICA cannula was attached to an oscillating water pump. Next, an ICP monitor was placed. Normophysiological volumes of water were infused to maintain normal ICP. Baseline ICP and IJV pressures were recorded. The heads were then placed in the sniffing position and in neutral position for nasal intubation, and finally an oral endotracheal tube was placed using standard head/neck maneuvers. The ICP was recorded. Mean baseline ICP was 13 mmHg (range 4-18 mmHg) and mean IJV pressure was 6 cm H2O. In the sniffing position, ICP increased in all specimens by a mean of 5 mmHg. In the neutral position, after intubation, the ICP increased in all specimens by a mean of 3 mmHg. Nasal intubation resulted in an increase in four of the five specimens. The mean increase in ICP with this maneuver was 2 mmHg. We present a cadaveric model of ICP measurement during neck manipulation using intracranial fluid dynamics. The ICP increased consistently. Following clinical studies, physicians involved in intubating patients with concern for raised ICP should change the technique to avoid complications.

Anatomical Variants Identified on Computed Tomography of Oropharyngeal Carcinoma Patients

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.

Anatomical characteristics and morphometric analyses of the internal carotid artery using retrospective angiographic images

PURPOSE

Anatomical variations of the internal carotid artery (ICA) can cause complications during endovascular treatments. Therefore, the aim of this study was to investigate the features of the ICAs obtained from 2D digital subtraction angiography (2D DSA).

METHODS

The morphometrics and angles of the ICA segments from 2D DSA images from a total of 100 patients (45 males and 55 females) were investigated. The lengths (L1-3), angles (A1-3), and diameters (D1-6) through the ICA measurement points (five segments: C2 [petrous], C3 [lacerum], C4 [cavernous], C5 [clinoid], C6 [ophthalmic]) were systemically recorded by two observers. All measured parameters were compared for both sexes and sides.

RESULTS

The lengths (mm) and angles of the ICA were 7.20 ± 2.22 (L1), 15.71 ± 2.32 (L2), 10.99 ± 1.66 (L3) and 109.31 ± 17.77 (A1), 107.87 ± 20.51 (A2), 80.81 ± 16.33 (A3), respectively. There were no differences in the angulations of the A1-A3 segments between the sexes (p > 0.05). The L2 (C3-C4) was significantly longer in males, but only the left side of females showed a greater length (p < 0.05). The averaged mean diameters of the ICA (D1-6) in both sexes were 4.17 ± 0.55 mm. However, the diameters of the D1-D6 from left and right sides of males except the right D6 were significantly longer than those of females (p < 0.05). Also of significance was that the right diameters of females (D1) and males (D1 and D2) were shorter compared to left sides.

CONCLUSION

This study demonstrates some differences in lengths, diameters, and angles in both sexes and sides of the normal ICA. Neurosurgeons and neurointerventionalists should be aware of such variations when operating, performing interventional procedures, and interpreting 2D DSA.

Granular Foveolae in the Groove of the Sigmoid Sinus: An Anatomical Study

Background Granular foveolae in the groove of the sigmoid sinus have rarely been reported in the literature compared to numerous published reports on the granular foveolae near the superior sagittal sinus and its sulcus on the internal aspect of the calvaria. The present study was performed to better elucidate their prevalence and locations. Materials and methods One hundred and ten adult dry skulls (220 sides) were analyzed for the presence of granular foveolae within the groove of the sigmoid sinus. The exact position of the foveolae was documented, and the diameter of the granular foveola was measured. Results Granular foveolae were found in the groove of the sigmoid sinus on 3.6% of the sides. These were at or within a mean of 1.3 cm inferior to the transverse-sigmoid junction. When a mastoid foramen was noted in the groove, it was always located inferior to the granular foveolae when present. The mean diameters of the granular foveolae of the left groove of the sigmoid sinus were 2.8 mm and 4 mm for the right grooves. The mean depth of the granular foveolae in the left groove of the sigmoid sinus was 2.7 mm and 3.5 mm for the right grooves. Granular foveolae were statistically larger and deeper on the right versus left sides (p<0.05). Conclusions Granular foveolae of the groove of the sigmoid sinus were identified most commonly on the right sides and 3.6% on all sides. If identified on medical imaging, these uncommon structures at the skull base should be considered normal anatomical variations.

Topographical study of scapular foramina and scapular nutrient foramina in dried skeletons

PURPOSE

The aim of our study is to study the prevalence and anatomy of scapular foramina (SF) and scapular nutrient foramina (SNF) in dried skeletons from the Northeastern Thai population.

METHODS

A total of 150 dried scapulae were investigated. Both SF and SNF were identified using a metal wire with a diameter of 0.36 mm. The number, locations, lengths, and diameters of SF were recorded. Subsequently, SNF were identified using the same metal wire. Their number and locations were recorded. Two observers performed the evaluations and measurements.

RESULTS

SF were present in 78.0% of scapulae. They could have up to five openings. Eighteen types were found. On average they were longer in males (21.7 ± 5.0 mm) than females (19.45 ± 4.6 mm). The mean diameters of both the superior and inferior openings were significantly greater in females (p < 0.01). SNF, in contrast, were present in 100% of scapulae. They were located in the supraspinous fossa (36.7%), subscapular fossa (31.3%), infraspinous fossa (22.8%), and peri-glenoid area (10.0%).

CONCLUSION

Unlike previous studies, the present study suggests that SF are normal anatomical findings, present in 78.0% of the scapulae investigated. Surgeons should be aware of both SNF and SF when operating or interpreting radiological findings.

Pectorobrachioepicondylaris musculoaponeurotic band: case description with evidence of median nerve compression

Upper limb muscle variations can be encountered on imaging or at surgery. We report an unusual muscle and band found during routine dissection of the arm in a cadaver. This case is described and salient literature reviewed. A band was found that traveled from the insertion of the pectoralis major tendon distally and obliquely toward the medial intermuscular septum and medical epicondyle. Fibers of the brachialis were found to interdigitate into the band. A tunnel was formed that carried the median nerve and brachial vessels. Evidence of median nerve compression was observed. We considered this an example of a pectorobrachioepicondylaris muscle. However, some can lead to clinical presentations. Although the significance of the case reported herein is not certain, signs of median nerve compression were identified. We believe that the term pectorobrachioepicondylaris bests describes the muscle reported herein and that our case represents a previously unreported variant of this muscle.

The Venous Circle of Trolard: An Anatomical Study with Application to Approaches to the Basal Brain

BACKGROUND

The arterial circle of Willis is a well-known and interconnecting set of blood vessels at the base of the brain. However, its lesser-known venous counterpart, the circle of Trolard, has had almost no attention in the extant medical literature.

METHODS

Twenty-four adult human brains underwent dissection of the circle of Trolard. When identified, its component vessels and relationships with adjacent structures were confirmed and documented with photography and measured using microcalipers.

RESULTS

A complete circle of Trolard was identified on 42% of specimens. Most (64%) incomplete circles were incomplete anteriorly with no anterior communicating vein. The anterior communicating veins joined the anterior cerebral veins superior to the optic chiasm and continued posteriorly. The anterior communicating veins had a mean diameter of 0.45 mm. The length of these veins ranged from 0.8 mm to 1.45 mm. Thirty-six percent of circles were incomplete posteriorly with lack of a posterior communicating vein. The posterior communicating veins were always larger and longer than the anterior cerebral veins. The posterior communicating veins had a mean diameter of 0.8 mm. The length of these veins ranged from 2.8 to 3.9 cm. In general, the circles of Trolard were more or less symmetrical. However, in 2 specimens, asymmetry existed.

CONCLUSIONS

A better understanding of the venous circle of Trolard might decrease iatrogenic injury during approaches to the base of the brain and improve diagnoses based on imaging of the skull base. To our knowledge, this is the first anatomical study dedicated to the circle of Trolard.

Revisiting the tentorial venous sinuses: Anatomical and histological study

Anatomical studies of the tentorial sinuses are scant and to our knowledge, histological studies of this structure, have not been reported. Therefore, we aim to better elucidate this anatomy. In 15 fresh frozen, latex injected, adult cadaveric specimens, the tentorial sinuses were evaluated with microsurgical dissection and histology. The superior layer had a mean thickness of 0.22mm and the inferior layer had a mean thickness of 0.26mm. Two types of tentorial sinuses were identified. Type 1 was a small intrinsic plexiform sinus with no obvious connections to the draining veins with gross examination. Type 2 was a larger tentorial sinus with direct connections to the bridging veins from the cerebral and cerebellar hemispheres. In general, the type 1 sinuses were located more medially than type 2 sinuses. The inferior tentorial bridging veins drained directly into the tentorial sinuses along with connections to the straight and transverse sinuses. In 53.3% of specimens, superficial and deep sinuses were seen with superior and inferior group draining the cerebrum and cerebellum, respectively. We identified novel findings for the tentorial sinuses which can be considered surgically and when diagnosing pathology involving these venous sinuses.

Direct Hemi-Hypoglossal Nerve and Hypoglossal Nerve for Suprascapular Nerve/Proximal Brachial Plexus Neurotization: A Cadaveric Feasibility Study

Introduction Partial restoration of shoulder function is important in upper brachial plexus lesions, and the suprascapular nerve is often the target for such neurotization procedures. Although there is an extensive history of peripheral nerve surgeons using the hypoglossal nerve for various local nerve transfers, some have reported using this nerve as a donor for upper brachial plexus grafting procedures. We discuss our anatomical findings for the use of a direct hypoglossal to suprascapular nerve transfer. Materials and methods Fifteen adult cadavers (30 separate sides) were dissected to reveal the hypoglossal nerve in the neck and the supraclavicular brachial plexus in the supraclavicular region. On 15 sides, the hypoglossal nerve was dissected anteriorly to the midline, cut, and transposed toward the supraclavicular region in half of the dissections. On the remaining sides, the nerve was hemisected longitudinally into two equal parts, and the cut inferior portion also swung inferiorly toward the supraclavicular region. The cut end of the hypoglossal nerve was brought toward the proximal suprascapular nerve, the fifth (C5) and sixth (C6) cervical nerve roots, and the upper trunk. Measurements included the length and diameter of the cervical portion of the hypoglossal nerve and the diameter of the suprascapular nerve. Results The mean diameter and length of the hypoglossal nerve were 2.1 millimeters (mm) and 72.8 mm, respectively. The mean diameter of the proximal suprascapular nerve was 2.7 mm. Successful, tension-free transposition to the C5 and C6 nerve roots was achieved on all sides. The average extra length of the hypoglossal nerve for a C5 root transposition was 8 mm and 5.2mm for a C6 root transposition. The distal hypoglossal nerve reached the upper trunk on all but two sides (6.7%). The distal hypoglossal nerve reached the proximal suprascapular nerve on all but four sides (13.3%). Of the 87% of sides (n=26) where the hypoglossal nerve reached the proximal suprascapular nerve, 58% of these (n=15) required some manipulation of the suprascapular nerve from its origin at the upper trunk. This technique resulted in a mean additional length to the suprascapular nerve of 35 mm. No differences were found between the completely cut hypoglossal nerves and hemisected nerves in regard to working length. Conclusions To our knowledge, the use of the hypoglossal nerve as a transpositional graft for direct suprascapular nerve neurotization has not been previously described. Based on our study, we propose that the hypoglossal nerve, or hemi-hypoglossal nerve, should be considered as a donor nerve to restore suprascapular nerve function in the majority of patients. Additionally, the hypoglossal nerve may be transferred to the C5 and C6 roots and upper trunk of the brachial plexus for direct neurotization.

Prevalence, Laterality, and Classification of Ossified Petroclival Ligaments: An Anatomical and Histological Study With Application to Skull Base Surgery

Background The petroclival ligament (PL) forms the roof of Dorello's canal (DC). In humans, partial and complete ossification of this ligament have been reported. When completely ossified, DC is transformed into a bony foramen for the abducens nerve and accompanying vascular structures. As this osteological finding might have an impact on skull base surgery, this anatomical study was performed. Methodology Using 100 adult human skulls, the presence of an ossified PL was noted and classified. The diameter of the resultant bony foramen and laterality were documented. Additionally, PL was evaluated histologically in 10 heads. Results Overall, 8% of the sides were found to have partial or complete ossification of the PL. Partial ossification (type I) was noted on 3% of the sides. Completely ossified PL was identified on 5% of the sides. Some ossified ligaments (2.5%) were seen as an ossified bridge (type II), and others (2.5%) were converted into small foramina (type III). Three skulls (3%) were found to have a completely ossified ligament bilaterally. The mean diameter of the underlying DC was 0.8 mm. Partially ossified ligaments were statistically more likely to be on the right sides, and the diameter of the underlying DC was statistically smaller in type III. Histologically, the PL was found to have bone within it on three skull sides. Conclusions An ossified ligament can be found on imaging of the skull base. Moreover, during surgical approaches to the petroclival region and, specifically, DC, skull base surgeons should be cognizant of this anatomical variation.

A Three-Headed Piriformis Muscle With Splitting of the Common Fibular Nerve

Although the division of the piriformis muscle by the sciatic nerve or its branches is fairly common, other anatomical variations of this muscle are relatively uncommon. Here, we present a cadaveric case found to have an atypical composition of the piriformis muscle. During the routine dissection of the right gluteal region in an adult male cadaver, an unusual finding of the piriformis muscle was observed. Three distinct heads of the muscle were identified. In addition, one of these heads split the common fibular nerve. The anatomy and relationships of this case are presented here. Any variation in neurovasculature and musculature can be relevant for diagnosing or surgically intervening in the gluteal region. The present case is apparently unique and of archival value.

Morphometric analysis of dry atlas vertebrae in a northeastern Thai population and possible correlation with sex

PURPOSE

The uppermost segment of the cervical vertebra or atlas (C1) is a critically important anatomical structure, housing the medulla oblongata and containing the grooves for the C1 spinal nerve and the vertebral vessels. Variations of the C1 vertebra can affect upper spine stability, and morphometric parameters have been reported to differ by population. However, there are few data regarding these parameters in Thais. The use of this bone to predict sex and age has never been reported.

METHODS

This study aimed to examine C1 morphometry and determine its ability to predict sex. Twelve diameter parameters were taken from the C1 vertebrae of identified skeletons (n = 104, males [n, 54], females [n, 50]). Correlation analysis was also performed for sex and age, which were predicted using machine learning algorithms.

RESULTS

The results showed that 8 of the 12 measured parameters were significantly longer in the male atlas (p < 0.05), while the remaining 4 (distance between both medial-most edges of the transverse foramen, transverse dimension of the superior articular surface, frontal plane passing through the canal's midpoint, and anteroposterior dimension of the inferior articular surface) did not differ significantly by sex. There was no statistically significant difference in these parameters on the lateral side. The decision stump classifier was trained on C1 parameters, and the resulting model could predict sex with 82.6% accuracy (root mean square error = 0.38).

CONCLUSION

Assertation of the morphometric parameters of the atlas is important for preoperative assessment, especially for the treatment of atlas dislocation. Our findings also highlighted the potential use of atlas measurements for sex prediction.

Anatomical Study of the Communication Between the Mental Nerve and Marginal Mandibular Branch of the Facial Nerve

Background Trigeminal-facial nerve communications have been recognized for over 100 years. More specifically, the mental nerve (MN) and marginal mandibular branch of the facial nerve (MMb) communication have been studied but the termination of these branches remains unclear. Therefore, we aim to classify the anatomical communication between the MN and MMb by its course. Methods Sixty sides from thirty adult cadaveric heads were dissected. The communicating branches were dissected and observed anatomically and histologically. Results Communication between the MN and MMb was found on all sides. Based on the course, the communication was classified into two types, superior and anterior. For the superior type, a small branch of the MN and MMb join and travel superiorly to reach the lower lip area. The communication was observed at the level of the mental foramen or above it. For the anterior type, a small branch of the MN and MMb join and travel anteriorly to reach the chin area. The termination was either in the subcutaneous tissue of the chin or in the mentalis. This communication was observed below the mental foramen. Histological observation revealed that these communications contained two or more perineuria. Conclusions Although the function of such neural communications is still unclear, this study helps better understand the anatomical variants of these unions and provides a novel classification system.

The Parasympathetic Root of the Submandibular Ganglion: A Review

The submandibular ganglion is a small fusiform-shaped cluster of cell bodies of the parasympathetic nervous system. Parasympathetic innervation of the submandibular gland is not only responsible for the secretion of saliva, but it also plays a main role in the development and regeneration of the gland. The parasympathetic root of the submandibular ganglion or the posterior branch of the lingual nerve to the submandibular ganglion is one of three roots of the submandibular ganglion. Using standard search engines (PubMed, Google), papers in English discussing the anatomy, embryology, variations, and clinical significance of the parasympathetic root of the submandibular ganglion were reviewed.

Classifications of Odontoid Process Fractures: A Systematic Review and Proposal of a New Simplified Classification System Based on Embryology

Odontoid fractures are the most common cervical spine fractures in the elderly. Although many classification systems have been developed for them, the ambiguity in various definitions can potentially lead to misunderstandings. This paper aims to review the terminologies and current classification systems of odontoid fractures and propose a new, simplified anatomical classification. Given the descriptive variability of odontoid fractures in current classifications, we systematically reviewed the literature using PRISMA guidelines querying the National Library of Medicine PubMed database. The initial literature search yielded 175 publications. A total of seven reports met the inclusion criteria and were ultimately included for a full review. The classification systems previously used to categorize fractures of the odontoid process often need to be more transparent, imprecise, and incongruous. To simplify them, a new embryologically accurate system is proposed. A new embryological and anatomically-based system, combining the former systems' specific attributes, allows a more straightforward and adaptable classification of odontoid fractures.

The Échancrure of the Uncovertebral Joint: A Forgotten Structure of the C3-C7 Cervical Vertebral Bodies

Introduction The échancrure (a French term meaning "indentation") of the cervical vertebrae is the poorly defined articular part on the inferolateral aspect of the cervical spine body, which, with the uncinate processes of the associated caudal vertebra, makes up the joints of Luschka (uncovertebral joint). With no known previous studies on the échancrure, the present anatomical study aimed to better elucidate this structure, its prevalence, and its relationships to the adjacent intervertebral foramen and uncinate process. Methods We observed 50 adult cervical spines (100 sides) for the presence of an énchancrure. When an énchancrure was identified, its morphometry was documented and photographed. Measurements included the width and height of the énchancrure. The relationship with the adjacent uncinate process was also studied. Any correlation between the size and shape of the adjacent uncinate process and the énchancrure was recorded. Results Anénchancrure was found at all levels of the cervical vertebrae except at C1 and C7 and was clearly visible on 88% of the sides. The énchancrure, more or less, conformed to the reciprocal shape of the uncinate process, which was found on all sides. The shapes were roughly arched, ovoid, or linear. These structures were always in an anterolateral position on the body of the vertebra and just outside the apophyseal ring. The mean height of the énchancrure was 2.1 mm. The length of the uncinate process correlated positively (r=0.8) to the size of the adjacent énchancrure. The height of the énchancrure was inversely related to the diameter of the adjacent intervertebral foramen. The mean width was 8.3 mm. These structures tended to be largest at C3 and C4 vertebral levels and were smallest at C5 and C6 levels. The énchancrure was most in contact with the uncinate process with lateral flexion of the cervical spine and in specimens with a longer uncinate process, e.g., C6. The énchancrure was also found to be wider in cases of cervical spine degeneration involving the body of the cervical vertebrae. Degeneration of the uncovertebral joint was most often seen at the énchancrure and not at the adjacent uncinate process. Conclusions We found that the énchancrure is found in the majority of cervical spines. These structures tended to be largest at C3 and C4 vertebral levels and were smallest at C5 and C6 levels, and they had more prominence when the adjacent uncinate process was enlarged. The énchancrure should be considered a normal feature of the inferolateral aspect of the cervical vertebrae. Future clinical studies are necessary to better elucidate their functional significance.

Angulation Between the Occipital Condyle and the Hypoglossal Canal: An Anatomical Study With Application in Transcondylar Approaches and Occipital Condyle Screw Placement

Background A detailed understanding of the relationship between the occipital condyle (OC) and the deeper-lying hypoglossal canal (HC) is necessary for surgeons who place screws into the OC or drill through or around the HC. Therefore, this anatomical study was performed. Methodology A total of 30 skulls (60 sides) underwent an analysis of the angle formed between the long axis of the OC and the HC, i.e., the OC/HC angle. Additionally, the lengths and widths of the OCs and foramen magnum (FM) of each skull were measured using a micrometer. Statistical analyses were performed between the left and right sides, and a Pearson's correlation coefficient was calculated between OC/HC angles and the sizes of the OCs and FM of the skulls. Results The OC/HC angle for the left and right sides ranged from 30 to 56 degrees (mean 46 degrees). The width of the OCs ranged from 9 to 18 mm (mean 13 mm). The length of the OCs was 18 to 31 mm (mean 24 mm). The mean length and width of the FM were 36 mm and 30 mm, respectively. There was no statistically significant difference between the OC/HC angle comparing left and right sides or male or female specimens. Additionally, no statistically significant differences were found between septated and non-septated HC. Pearson's correlation coefficient for left and right OC/HC angles and left and right OC lengths was r = 0.4056 and r = 0.2378, respectively. Pearson's correlation coefficient for left and right OC/HC angles and left and right OC width was r = 0.3035 and r = 0.3530, respectively. Pearson's correlation coefficient for left and right OC/HC angles and the width of the FM was r = 0.2178 and r = 0.2048, respectively. Pearson's correlation coefficient for left and right OC/HC angles and the length of the FM was r = 0.3319 and r = 0.2683, respectively. Conclusions The OC/HC angle as measured here was relatively consistent with no statistically significant differences between sides. We did not find a strong correlation between the width or length of the OC or the width or length of the FM and the OC/HC angles. Therefore, based on our study, surgeons can expect that this angle will range between 30 and 56 degrees (mean 46 degrees). Such knowledge might decrease patient morbidity following invasive procedures involving the OC.

The prevalence of Stafne bone cavity: A meta-analysis of 355,890 individuals

Background/purpose

A Stafne bone cavity (SBC) is an incidental depression in the lingual surface of the mandible. The aim of this study is to provide pooled estimates of the frequency of Stafne bone cavity and to correlate its presence with such variables as sex, laterality, diagnostic methods and population.

Materials and methods

Potential studies were searched through four electronic databases: Google Scholar, PubMed, Scopus, and Journal Storage. Titles, abstracts, and full texts of the articles were screened.

Results

A total of 54 studies relating to 355,890 subjects met the inclusion criteria for meta-analysis. A meta-analysis using the DerSimonian-Laird model revealed an overall prevalence of 0.17% (CI:0.14%-0.21%, I ² = 80.7%). SBC was four times more common in males than females (z = 6.94, P < 0.01), and was unilateral in almost all cases (z = 12.90, P < 0.01). Radiographic studies yielded a lower SBC prevalence at 0.12% (CI:0.09%-0.15%, I ² = 71.7%) than computed tomography studies, skeletal studies and excavation studies. Ancient populations had three times higher SBC prevalences (0.47%, CI:0.21%-0.73%, I ² = 89.5%) than the average populations today (z = 3.21, P < 0.01).

Conclusion

The prevalence of Stafne bone cavity is approximately 0.17%, and was four times more prevalent in males than females. This variant bone cavity was also present unilaterally in the majority of cases. Awareness of SBC is important for dentists, maxillofacial surgeons and other practitioners performing routine dental practices and interpreting panoramic radiographs.

Characterization, expression, and function of the pyrokinins (PKs) in the giant freshwater prawn, Macrobrachium rosenbergii

Pyrokinins (PKs) are neuropeptides that have been found to regulate a variety of physiological activities including reproduction in various insect and crustacean species. However, the reproductive roles of PKs in the giant freshwater prawn have not yet been investigated. In this study, we identified the MroPK gene from next-generation sequence resources, which encodes a MroPK precursor that shares a high degree of conservation with the C-terminal sequence of FxPRLamide in other arthropods. MroPK is expressed within most tissues, except the hepatopancreas, stomach, and gill. Within developing ovarian tissue, MroPK expression was found to be significantly higher during the early stages (stages 1-2) compared with the late stages (stages 3-4), and could be localized to the oogonia, previtellogenic, and early vitellogenic oocytes. A role for PK in M. rosenbergii reproduction was supported following experimental administration of MroPK to ovarian explant cultures, showing an increase in the productions of progesterone and estradiol and upregulation of steroidogenesis-related genes (3β-HSD and 17β-HSD) and vitellogenin (Vg) expressions. Together, these results support a role for MroPK in regulating ovarian maturation via steroidogenesis.

Incidence and Skeletal Features of Developmental Cervical and Lumbar Spinal Stenosis

STUDY DESIGN

Cross-sectional study.

PURPOSE

To report the prevalence and relationship of developmental cervical and lumbar spinal stenosis (DCSS and DLSS) with the bone parameters of the skull and extremities.

OVERVIEW OF LITERATURE

DCSS and DLSS are found occasionally in daily practice. DCSS and DLSS can cause compressive myelopathy, radiculopathy, and cauda equina syndrome; however, data on their prevalence and correlation with skull and skeletal extremity profiles is scarce.

METHODS

A cross-sectional measurement study of 293 whole-body dried-bone samples was conducted. We measured the anteroposterior (AP) and transverse diameter of the fourth to sixth cervical vertebrae (C4-C6) and third to fifth lumbar vertebrae (L3-L5). Stenosis of the cervical spine and lumbar spine was defined as an AP diameter of <12 mm and <13 mm, respectively. We also measured the skull circumference, the AP and transverse diameters of the foramen magnum, the inner and outer inter distances between the left and right orbital bones, the humerus length, and the femoral length. Kruskal-Wallis and post hoc analyses were used in the statistical analyses.

RESULTS

The age was 22-93 years. DCSS was found in 59 (20.1%) and DLSS in 28 (9.6%). Twelve samples had both DCSS and DLSS (development spinal stenosis, DSS). When compared to the "no spinal stenosis sample," DSS (-), DCSS and DSS had a significantly smaller skull circumference, the transverse diameter of the foramen magnum, and inner and outer distance between the orbital bone (p<0.05). There was no significant difference in humeral length, femoral length, or AP diameter of the foramen magnum.

CONCLUSIONS

DCSS was correlated with a small skull, a small transverse diameter of the foramen magnum, and a small orbital bone. A small skull was strongly associated with a small cervical canal. DLSS, on the other hand, was unrelated to either a small cervical canal or a small skull.