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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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, Macrobrachium rosenbergii, 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, which led to an increase in the production of progesterone and estradiol and upregulation of expression of steroidogenesis-related genes (3ß-HSD and 17ß-HSD) and vitellogenin (Vg). Together, these results support a role for MroPK in regulating ovarian maturation via steroidogenesis.