Anatomy of the lymphovenous valve of the thoracic duct in humans.

The majority of lymph generated in the body is returned to the blood circulation via the lymphovenous junction (LVJ) of the thoracic duct (TD). A lymphovenous valve (LVV) is thought to guard this junction by regulating the flow of lymph to the veins and preventing blood from entering the lymphatic system. Despite these important functions, the morphology and mechanism of this valve remains unclear. The aim of this study was to investigate the anatomy of the LVV of the TD. To do this, the TD and the great veins of the left side of the neck were harvested from 16 human cadavers. The LVJs from 12 cadavers were successfully identified and examined macroscopically, microscopically, and using microcomputed tomography. In many specimens, the TD branched before entering the veins. Thus, from 12 cadavers, 21 LVJs were examined. Valves were present at 71% of LVJs (15/21) and were absent in the remainder. The LVV, when present, was typically a bicuspid semilunar valve, although the relative size and position of its cusps were variable. Microscopically, the valve cusps comprised luminal extensions of endothelium with a thin core of collagenous extracellular matrix. This study clearly demonstrated the morphology of the human LVV. This valve may prevent blood from entering the lymphatic system, but its variability and frequent absence calls into question its utility. Further structural and functional studies are required to better define the role of the LVV in health and disease.

The effect of positioning on maternal anatomy and hemodynamics during late pregnancy.

INTRODUCTION: Supine positioning during late pregnancy causes dramatic compression of maternal abdominal vasculature and is a risk factor for stillbirth. The azygos vein has been shown to provide collateral circulation in this scenario. There are many well-known anatomical differences in abdominal vasculature between the left and right sides of the body. However, the effect of left and right positioning in pregnancy has not been well studied. MATERIALS AND METHODS: After obtaining ethics approval, 10 women with uncomplicated pregnancies between 34 and 38 weeks gestation underwent magnetic resonance imaging in the left and right lateral positions. Phase contrast images were evaluated to measure blood flow through the abdominal aorta, inferior vena cava, and azygos vein. RESULTS: No significant differences between left and right lateral positions were found in blood flow through the IVC at its formation (mean difference -0.15 L/min [CI -0.47, 0.18], p = .34) or through the azygos vein (mean difference 0.02 L/min [CI -0.22, 0.26], p = .87). Blood flow through the IVC just above the level of the renal veins was found to be reduced by 35% in the right lateral position when compared to the left (mean difference 1.01 L/min [CI 0.25, 1.43], p = .03). There were no significant differences in cardiac output or blood flow through the abdominal aorta. CONCLUSIONS: While it was noted that blood flow through the IVC immediately above the level of the renal veins was reduced in the right lateral position, this did not appear to impact significantly on maternal cardiac output or blood flow through the azygos vein.

What is a tongue tie? Defining the anatomy of the in-situ lingual frenulum.

Surgical release of the lingual frenulum (frenotomy) has become an increasingly common procedure, performed from birth through to adulthood. Surprisingly, detailed anatomy of the in-situ lingual frenulum has never been described, and no anatomical basis has been proposed for the individual variability in frenulum morphology. The lingual frenulum is frequently referred to as a "cord" or "submucosal band" of connective tissue, yet there is no evidence to support this anatomical construct. This paper aims to describe the anatomy of the in-situ lingual frenulum and its relationship to floor of mouth structures. Fresh tissue microdissection of the lingual frenulum and floor of mouth was performed on nine adult cadavers with photo-documentation and description of findings. The lingual frenulum is a dynamic structure, formed by a midline fold in a layer of fascia that inserts around the inner arc of the mandible, forming a diaphragm-like structure across the floor of mouth. This fascia is located immediately beneath the oral mucosa, fusing centrally with the connective tissue on the tongue's ventral surface. The sublingual glands and submandibular ducts are enveloped by the fascial layer and anterior genioglossus fibers are suspended beneath it. Lingual nerve branches are located superficially on the ventral surface of the tongue, immediately deep to the fascia. The lingual frenulum is not a discrete midline structure. It is formed by dynamic elevation of a midline fold in the floor of mouth fascia. With this study, the clinical concept of ankyloglossia and its surgical management warrant revision. Clin. Anat. 32:749-761, 2019. © 2019 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Pediatric central venous catheterization: The Role of the Aortic Valve in Defining the Superior Vena Cava-Right Atrium Junction.

The aortic valve (AV) has been used as a surrogate marker for the superior vena cava-right atrium (SVC-RA) junction during the placement of central venous catheters. There is a paucity of evidence to determine whether this is a consistent finding in children. Eighty-seven computed tomography scans of the thorax acquired at local children's hospitals from April 2010 to September 2011 were retrospectively collected. The distance between the SVC-RA junction and the AV was measured by dual consensus. The cranio-caudal level of the junction and the AV were referenced to the costal cartilages (CCs) and anterior intercostal spaces (ICSs). The results confirmed that the SVC-RA junction has a variable relationship to the AV. The junction was on average 3.1 mm superior to the AV. This distance increased with age. In the <1-year-old age group, the junction was on average 1.3 mm superior to the AV (range: -6 to 11 mm). In the 1-2 years old age group: 3.5 mm (range: -8 to 15 mm). In the 3-6 years old: 3.8 mm (range: -9 to 13 mm). In the >7 years old age group: 4 mm (range: -11 to 16 mm). The surface anatomy of the SVC-RA junction was variable, ranging from the second ICS to sixth CC. The SVC-RA junction has a predictable relationship to the AV, and this can be used as an adjunct marker for accurate placement of central venous catheters except in the smallest neonates. Clin. Anat. 32:778-782, 2019. © 2019 Wiley Periodicals, Inc.

The plantar calcaneal spur: a review of anatomy, histology, etiology and key associations.

The plantar calcaneal spur (PCS) is a bony outgrowth from the calcaneal tuberosity and has been studied using various methods including cadavers, radiography, histology and surgery. However, there are currently a number of discrepancies in the literature regarding the anatomical relations, histological descriptions and clinical associations of PCS. Historically, authors have described the intrinsic muscles of the foot and/or the plantar fascia as attaching to the PCS. In this article we review the relationship between the PCS and surrounding soft tissues as well as examining the histology of the PCS. We identify a number of key associations with PCS, including age, weight, gender, arthritides, plantar fasciitis and foot position; these factors may function as risk factors in PCS formation. The etiology of these spurs is a contentious issue and it has been explained through a number of theories including the degenerative, inflammatory, traction, repetitive trauma, bone-formers and vertical compression theories. We review these and finish by looking clinically at the evidence that PCS causes heel pain.

Should we abandon landmark-based technique for caudal anesthesia in neonates and infants?

BACKGROUND: Caudal anesthesia is a landmark-based technique with ultrasound guidance occasionally used in the absence of landmarks. The current surface landmark remains a popular approach due to its desirable success rate. However, incomplete ossification of the posterior vertebral elements can make this procedure for neonatal caudal anesthesia difficult. The aim of this study was to describe the anatomical relationship of the posterior superior iliac spines (PSISs) to the sacral cornua in infants using ultrasound. METHODS: A total of 26 healthy infants (17 female; mean age 13 weeks) were scanned by an experienced radiologist in the prone position with hip and knee joints flexed. The PSISs and sacral cornua were identified clinically then using ultrasound to assess whether these markings corresponded with the clinical markings. The distance between the PSISs and the distance between the tip of the PSIS and tip of the sacral cornu were measured using ultrasound. RESULTS: The PSISs were clinically identified in all babies, but the sacral cornua were not palpable in four babies (15%). The PSISs and sacral cornua were easily visualized using ultrasound in all participants. The mean distance between the two left and right PSISs was 3.4 ± 0.5 cm; the mean distance between the PSISs and cornu was 2.5 ± 0.5 cm on the left and right. CONCLUSION: This study showed that the current landmark (equilateral triangle) for infant caudal anesthesia is unreliable. Importantly, the sacral hiatus is clinically identifiable only if the sacral cornua are palpable; otherwise, using ultrasound is essential.

A review of the surface and internal anatomy of the caudal canal in children.

The anatomy of the sacral hiatus and caudal canal is prone to significant variation, yet studies assessing this in the pediatric population remain limited. Awareness of the possible anatomical variations is critical to the safety and success of caudal epidural blocks, particularly when image guidance is not employed. This systematic review analyzes the available evidence on the clinical anatomy of the caudal canal in pediatric patients, emphasizing surface anatomy and internal anatomical variations. A literature search using three electronic databases and standard pediatric and anatomy reference texts was conducted yielding 24 primary and seven secondary English-language sources. Appreciating that our current landmark-guided approaches to the caudal canal are not well studied in the pediatric population is important for both clinicians and researchers.

Differences in running biomechanics and tibiotalar cartilage T2 relaxation time between runners with and without asymptomatic tibial sesamoid bone marrow edema - clinical case series.

The impact of asymptomatic bone marrow edema (BME) in sesamoids on running biomechanics remains largely unknown, but exploring this relationship could aid early detection of forefoot-related injuries with cost-effective modalities. This study aimed to compare the running biomechanics of runners with asymptomatic BME in the tibial sesamoids with that of healthy controls. Four runners with asymptomatic BME in tibial sesamoids and four healthy runners participated. Lower extremity joint kinetics and kinematics were assessed along with plantar pressure while running at a self-selected speed. The T2 relaxation time of the tibiotalar cartilage was measured using MRI-derived T2 maps. Compared to the non-injured group, the injured group exhibited significantly lower plantar pressure under the hallux (p = 0.001), increased peak ankle rotation angles (p = 0.025), reduced ankle power generation (p = 0.049), and increased knee extension torque (p = 0.015). No significant differences in T2 values of the tibiotalar cartilage were observed. It appears that runners with asymptomatic BME adapted their running strategies by modifying their ankle biomechanics and reducing plantar pressure, even in the absence of pain. While the precise implications of these biomechanical alterations warrant further investigation, this study provides valuable insights into the relationship between asymptomatic BME and running biomechanics.

Comparison of SPAG11A gene expression in infertile men with grade 1 and 2 varicocele before and after treatment.

OBJECTIVE: Sperm Associated Antigen 11A (SPAG11A) protein is a family of the epididymis-specific secretory proteins implicated in sperm maturation and function. Varicocele might cause pathophysiological difficulties in the testis and epididymis, with a harmful effect on the environment for spermatogenesis and sperm maturation. The aim of this study was to evaluate the expression level of the SPAG11A gene and sperm parameters in infertile men with grade 1 and 2 varicocele before and after treatment. METHODS: Semen specimens were collected from 20 infertile men with varicocele pre-and post-treatment and 10 healthy volunteers. Semen analysis was conducted according to world health organization guidelines. Real time PCR (qRT-PCR) reaction was applied for determination of SPAG11A mRNA expression. RESULTS: The results showed that there was a significant difference between the concentration and normal morphology between pre- and post-treatment groups and the controls. There were significant differences between pre-treatment and control groups in terms of progressive and non-progressive mobility. SPAG11A mRNA levels were significantly lower in the pre-treatment group than in healthy control subjects (p=0.007). There was no statistically significant difference in the expression of SPAG11A as well as semen parameters in the post-treatment group compared to the pre-treatment group. CONCLUSIONS: SPAG11A gene expression and semen parameters may be affected by varicocele. Whether varicocele treatment is an effective approach to reduce the adverse effect of this disease on SPAG11A expression and semen parameters needs further investigation.

Measuring Shear Wave Velocity in Adult Skeletal Muscle with Ultrasound 2-D Shear Wave Elastography: A Scoping Review.

Ultrasound 2-D shear wave elastography (US 2D-SWE) is a non-invasive, cost-effective tool for quantifying tissue stiffness. Amidst growing interest in US 2D-SWE for musculoskeletal research, it has been recommended that shear wave velocity (SWV) should be reported instead of elastic moduli to avoid introducing unwanted error into the data. This scoping review examined the evolving use of US 2D-SWE to measure SWV in skeletal muscle and identified strengths and weaknesses to guide future research. We searched electronic databases and key review reference lists to identify articles published between January 2000 and May 2021. Two reviewers assessed the eligibility of records during title/abstract and full-text screening, and one reviewer extracted and coded the data. Sixty-six studies met the eligibility criteria, of which 58 were published in 2017 or later. We found a striking lack of consensus regarding the effects of age and sex on skeletal muscle SWV, and widely variable reliability values. Substantial differences in methodology between studies suggest a pressing need for developing standardized, validated scanning protocols. This scoping review illustrates the breadth of application for US 2D-SWE in musculoskeletal research, and the data synthesis exposed several notable inconsistencies and gaps in current literature that warrant consideration in future studies.

Toward Emulating Human Movement: Adopting a Data-Driven Bitmap-Based "Voxel" Multimaterial Workflow to Create a Flexible 3D Printed Neonatal Lower Limb.

It is increasingly common to produce physical anatomical medical models using high-fidelity multiproperty 3D printing to assist doctor-patient communication, presurgical planning, and surgical simulation. Currently, most medical models are created using image thresholding and traditional mesh-based segmentation techniques to produce mono-material boundaries (STL file formats) of anatomical features. Existing medical modeling manufacturing methods restrict shape specification to one material or density, which result in anatomically simple 3D printed medical models with no gradated material qualities. Currently, available high-resolution functionally graded multimaterial 3D printed medical models are rigid and do not represent biomechanical movement. To bypass the identified limitations of current 3D printing medical modeling workflows, we present a bitmap-based "voxel" multimaterial additive manufacturing workflow for the production of highly realistic and flexible anatomical models of the neonatal lower limb using computed tomographic ("CT") data. By interpolating and re-slicing a biomedical volumetric data set at the native 3D printer z resolution of 27 µm and using CT scan attenuation properties (Hounsfield units) to guide material mixing ratios, producing highly realistic models of the neonatal lower limb at a significantly faster rate than other manufacturing methods. The presented medical modeling workflow has considerable potential to improve medical modeling manufacturing methods by translating medical data directly into 3D printing files aiding in anatomical education and surgical simulation practices, especially in neonatal research and clinical training.

Flexible Endoscopic Evaluation of Swallowing in Breastfeeding Infants With Laryngomalacia: Observed Clinical and Endoscopic Changes With Alteration of Infant Positioning at the Breast.

OBJECTIVES: This retrospective cohort study uses endoscopic assessment of the pharyngeal phase of swallowing in infants with laryngomalacia, to ascertain the impact of infant positioning on airway compromise and fluid dynamics during breastfeeding. The study aims to identify whether modification of infant positioning at the breast may improve the possibility of safe, successful breastfeeding in infants with laryngomalacia and concurrent breastfeeding difficulty. METHODS: Twenty-three infants referred for noisy breathing and difficulty feeding were assessed with flexible endoscopic evaluation of swallowing (FEES) during breastfeeding. All had endoscopically confirmed laryngomalacia. During FEES, observations were made of clinical signs of airway compromise as well as endoscopically observable anatomical features and swallowing dynamics during breastfeeding, including tongue base position, view of laryngeal inlet and vocal folds, dynamic supraglottic soft tissue collapse, timing of milk flow into pyriform fossae/hypopharynx relative to sucking, and presence of penetration and/or aspiration. If airway and/or swallowing compromise was present, the infant's initial position at the breast was altered from supine or semi lateral decubitus position to semi-prone, with a description of the clinical and endoscopically observable changes that subsequently occurred. RESULTS: Signs of dynamic airway obstruction and/or compromised airway protection with swallowing were present in 20 of the 23 infants (87%) in their initial supine or semi lateral decubitus position. These 20 infants were repositioned to semi-prone, with improvement and/or resolution of stridor and an improved ability to maintain latch in all infants. Continued endoscopic evaluation following positional change was possible in 16 infants, identifying anterior positioning of the tongue base, reduced dynamic supraglottic tissue collapse, reduced volume of milk flow into pyriform fossae during pauses in sucking and resolution of penetration and aspiration. CONCLUSION: This study has shown how alteration of breastfeeding position to semi-prone may improve dynamic airway obstruction and reduce aspiration risk in infants with laryngomalacia.

Effect of gender and running experience on lower limb biomechanics following 5 km barefoot running.

Barefoot running has been increasing in popularity, yet there is a gap in understanding concerning the biomechanics of mid-distance barefoot running, especially between genders and runners of different running-experience levels. This study examines the effects of running-experience, gender, and their interaction on running biomechanics following 5 km barefoot running. Before and after a 5 km run, three-dimensional kinematics and kinetics of the lower limb joints and plantar pressure during barefoot running were collected from 20 participants. Participants were stratified by their running-experience levels (novice and marathon-experienced) and gender. This study revealed significant gender effects on lower limb biomechanics following a 5 km barefoot run. Increased plantar pressure under the lateral aspect of the foot was observed in the female cohort, while the male cohort exhibited reduced plantar pressure under the lateral heel. This study suggests that modified lower limb running biomechanics and modified lateral foot loading after 5 km barefoot running may create a different foot loading environment for female and male runners that should be accommodated in barefoot runningand minimalist shoe design.

The Lymphovenous Junction of the Thoracic Duct: A Systematic Review of its Structural and Functional Anatomy.

Background: The lymphovenous junction (LVJ) of the thoracic duct (TD) is the principle outlet of the lymphatic system. Interest in this junction is growing as its role in lymphatic outflow obstruction is being realized, and as minimally invasive procedures for accessing the terminal TD become more common. Despite the growing clinical significance of the LVJ, its precise form and function remain unclear. The aim of this article was to systematically review the literature surrounding the structure and function of the LVJ and its associated lymphovenous valve (LVV). Methods and Results: A systematic review of the structure and function of the LVJ and LVV was undertaken using the MEDLINE, Scopus, and Google Scholar databases. Human and animal studies up to November 2019, with no language or past date restriction, were included. Forty-six relevant articles were reviewed. The LVJ shows marked anatomical variation. A valve is frequently absent at the LVJ, but when present it displays numerous distinct morphologies. These include bicuspid semilunar, ostial, and flap-like structure. Other factors, such as functional platelet plugs, or the tangential/intramural course of the terminal TD across the vein wall, may work to prevent blood from entering the lymphatic system. Conclusions: The form and function of the LVJ remain unclear. Dedicated studies of this area in vivo are required to elucidate how this part of the body functions in both health and disease.

Imaging the breastfeeding swallow: Pilot study utilizing real-time MRI.

OBJECTIVE: Knowledge of the breastfeeding swallow is limited by practical challenges. Radiation exposure to both mother and infant and the radiolucent properties of breastmilk make videofluoroscopy an unsuitable imaging modality. Furthermore, ultrasound is not ideal for capturing the complex 3-dimensional functional anatomy of swallowing. In this study we explore the feasibility of using real-time MRI to capture the breastfeeding swallow. METHODS: Prospective observational study: Review of imaging from 12 normal infants (<5 months of age) and their mothers while breastfeeding using real-time MRI. RESULTS: Static images were successfully captured in 11 infants and dynamic images in nine infants. This imaging modality confirms the dorsal surface of the infant's tongue elevates the maternal nipple to the hard palate, closing the space around the nipple with no air visible in the oral cavity during sucking and swallowing. We obtained dynamic imaging of mandibular movement with sucking, palatal elevation and pharyngeal constriction with swallowing, diaphragm movement with breathing and milk entering the stomach. Breastmilk was easily visualized, being high intensity on T2 sequences. Technical challenges were encountered secondary to infant movement and difficulties acquiring and maintaining midsagittal orientation. The similarity in tissue densities of the lips, tongue, nipple and hard palate limited definition between these structures. CONCLUSION: Real-time MRI imaging was successful in capturing dynamic images of the breastfeeding swallow. However, technical and practical challenges make real-time MRI unlikely at present to be suitable for swallow assessment in clinical practice. Advances in technology and expertise in dynamic image capture may improve the feasibility of using MRI to understand and assess the breastfeeding swallow in the near future. LEVEL OF EVIDENCE: 4.

The prevalence of Peyronie's disease in diabetic patients -2018- Yazd.

INTRODUCTION: Peyronie's disease (PD) is the fibrous scar tissue inside the penis that causes curved and painful erections. PD is associated with, diabetes, hypertension, dyslipidemia and low testosterone. PD causes erectile dysfunction (ED). The aim of this study was to evaluate the prevalence of PD in type 2 diabetic (T2DM) patients in Yazd. METHODS: This cross-sectional study was conducted on 317 patients with T2DM referred to the Diabetes Research Center of Yazd. Inclusion Criteria were: T2DM, ages 30-65 years old, having a medical record at the Yazd diabetes research center, willingness to participate in research. Exclusin criteria contain: history of smoking and using anti-depressive drugs. Data was analyzed using with SPSS-16 and Stata software. Descriptive tables and charts were used and statistical tests such as independent sample T-test and Fisher's exact test were used. RESULTS: A total number of 317 male patients were enrolled. The prevalence of diabetes microvascular complications were as following; neuropathy 36.30% (30.97-41.38), retinopathy 24.30% (19.67-29.39), nephropathy 20.50% (16.19-25.37), and PD 3.80% (1.97-6.51). CONCLUSION: There was no difference in the prevalence of PD in our study with the global studies. But there is a higher prevalence of PD in diabetic patients than the general population.

Gait kinetics, kinematics, spatiotemporal and foot plantar pressure alteration in response to long-distance running: Systematic review.

The aim of this systematic review was to obtain an improved insight of the present state of knowledge regarding the effect of long-distance running on gait kinetics, kinematics, spatiotemporal and foot plantar pressure. Electronic databases were searched for articles relating to biomechanical modification following long-distance running, published in English between 1990 and 2016. All the studies presenting gait parameters before and after long-distance running were included. A modified Quality Index was used for assessing methodological quality. Thirteen studies met the eligibility criteria. Five of 13 studies measured plantar pressure, reporting that the loading under the metatarsal regions were shown to be the highest following long-distance running. Ten studies reported spatiotemporal changes; step and stride frequency were generally increased, while stride length and aerial time were decreased after running. Four studies measured kinetics, indicating that vertical ground reaction force (GRF) was generally decreased, whereas impact acceleration was increased. Four studies showed that the lower limb kinematics and the foot strike techniques were altered by long-distance running. Three studies performed a second follow-up, revealing that the changes were generally returned to baseline levels. This is the first systematic review to examine the effect of long-distance running on gait kinetics, kinematics, spatiotemporal and foot plantar pressure.