Neuron-Microglia Interaction is Involved in Anti-inflammatory Response by Vagus Nerve Stimulation in the Prefrontal Cortex of Rats Injected with Polyinosinic:Polycytidylic Acid.

Injection of polyinosinic:polycytidylic acid (poly(I:C)) into experimental animals induces neuroimmunological responses and thus has been used for the study of neurological disorders such as anxiety, depression, and chronic fatigue. Here, we investigated the effects of vagus nerve stimulation (VNS) on poly(I:C)-induced neuroinflammation and associated behavioral consequences in rats. The microglia in the prefrontal cortex (PFC) displayed the activated form of morphology in poly(I:C)-injected rats and changed to a normal shape after acute VNS (aVNS). Production of phospho-NF-κB, phospho-IκB, IL-1ß, and cleaved caspase 3 was elevated by poly(I:C) and downregulated by aVNS. In contrast, phospho-Akt levels were decreased by poly(I:C) and increased by aVNS. Neuronal production of fractalkine (CX3CL1) in the PFC was markedly reduced by poly(I:C), but recovered by aVNS. Fractalkine interaction with its receptor CX3CR1 was highly elevated by VNS. We further demonstrated that the pharmacological blockade of CX3CR1 activity counteracted the production of IL-1ß, phospho-Akt, and cleaved form of caspase 3 that was modulated by VNS, suggesting the anti-inflammatory effects of fractalkine-CX3CR1 signaling as a mediator of neuron-microglia interaction. Behavioral assessments of pain and temperature sensations by von Frey and hot/cold plate tests showed significant improvement by chronic VNS (cVNS) and forced swimming and marble burying tests revealed that the depressive-like behaviors caused by poly(I:C) injection were rescued by cVNS. We also found that the recognition memory which was impaired by poly(I:C) administration was improved by cVNS. This study suggests that VNS may play a role in regulating neuroinflammation and somatosensory and cognitive functions in poly(I:C)-injected animals.

A practical guide to botulinum neurotoxin treatment of teres major muscle in shoulder spasticity: Intramuscular neural distribution of teres major muscle in cadaver model.

BACKGROUND: Botulinum neurotoxin treatment typically focuses on the teres major muscle as a primary target for addressing shoulder spasticity. The muscle is located deep within a large muscle group and optimal injection locations have not been identified. OBJECTIVE: To identify the preferred location for administering botulinum toxin injections in the teres major muscle. METHODS: Teres major specimens were removed from 18 cadaveric models and stained with Sihler's method to reveal the neural distribution within the muscle. The muscles were systematically divided into equal lengths from origin to insertion. The neural density in each section was evaluated to determine the location that would be likely to increase effectiveness of the injection. RESULTS: The greatest density of intramuscular nerve endings was located in the middle 20% of the muscle. The tendinous portion was observed at the ends of the muscle. CONCLUSIONS: The results suggest that botulinum neurotoxin should be delivered in the middle 20% of the teres major muscle.

Anatomical consideration of ultrasonography-guided intraoral injection for temporal tendinitis.

Temporal tendinitis is characterized by acute inflammation often resulting from mechanical stress, such as repetitive jaw movements associated with jaw opening and closing and teeth clenching. Treatment for temporal tendinitis typically involves the administration of local anesthetic or corticosteroid injections. However, the complex anatomical structure of the coronoid process, to which the temporalis tendon attaches, located deep within the zygomatic arch, poses challenges for accurate injections. In this study, we aimed to establish guidelines for the safe and effective treatment of temporal tendinitis by using intraoral ultrasonography (US) to identify the anatomical structures surrounding the temporalis tendon and coronoid process. US was performed using an intraoral transducer on 58 volunteers without temporomandibular joint disease. The procedure involved placing the transducer below the occlusal plane of the maxillary second molar. Measurements were taken for the horizontal distance from the anterior border of the coronoid process, observed at the midpoint (MP) of the US images, and the depth of the coronoid process and temporalis muscle from the oral mucosa. The anterior border of the coronoid process was visualized on all US images and classified into three observed patterns at the MP: type A (anterior to the MP, 56.2%), type B (at the MP, 16.1%), and type C (posterior to the MP, 27.7%). The temporalis muscle was located at a mean depth of 3.12 ± 0.68 mm from the oral mucosa. The maxillary second molar is an intraoral landmark for visualizing the anterior border of the coronoid process. The new location information obtained using intraoral US could help identify the safest and most effective injection sites for the treatment of temporal tendinitis.

Ideal Injection Points for Botulinum Neurotoxin for Pectoralis Minor Syndrome: A Cadaveric Study.

Pectoralis Minor Syndrome (PMS) causes significant discomfort due to the compression of the neurovascular bundle within the retropectoralis minor space. Botulinum neurotoxin (BoNT) injections have emerged as a potential treatment method; however, their effectiveness depends on accurately locating the injection site. In this study, we aimed to identify optimal BoNT injection sites for PMS treatment. We used twenty-nine embalmed and eight non-embalmed human cadavers to determine the origin and intramuscular arborization of the pectoralis minor muscle (Pm) via manual dissection and Sihler's nerve staining techniques. Our findings showed the Pm's origin near an oblique line through the suprasternal notch, with most neural arborization within the proximal three-fourths of the Pm. Blind dye injections validated these results, effectively targeting the primary neural arborized area of the Pm at the oblique line's intersection with the second and third ribs. We propose BoNT injections at the arborized region within the Pm's proximal three-fourths, or the C region, for PMS treatment. These findings guide clinicians towards safer, more effective BoNT injections.

A standardized protocol for needle placement in the infraspinatus muscle: an anatomical perspective.

PURPOSE: This study aimed to evaluate the morphology of the three parts of the infraspinatus muscle based on surface landmarks for precise and effective access, and to propose the most effective fine-wire electrode insertion technique and sites. METHODS: Fifteen Asian fresh cadavers were used. We investigated the probability of the presence of the superior, middle, and inferior parts in each infraspinatus muscle based on surface landmarks. Based on the positional characteristics of the muscle, we determined the needle insertion method and confirmed its effectiveness by dissection. RESULTS: The superior part was mostly observed near the spine of the scapula. The middle part was broadly observed within the infraspinous fossa. The inferior part showed variable location within the infraspinous fossa. The injection accuracy of the superior, middle, and inferior parts in the infraspinatus muscle was 95.8%, 100%, and 91.7%, respectively. Targeting the superior and middle parts for injection of the infraspinatus muscle is relatively more straightforward than targeting the inferior part. Targeting the inferior part of the infraspinatus muscle in this study was more challenging than targeting the superior and middle parts. CONCLUSION: Needling for electromyography should be performed with special care to avoid unintended muscle parts, which could lead to inaccurate data acquisition and affect the conclusions about muscle function.

Ultrasound-guided Injection of the Levator Scapulae Muscle in a Cadaver Model.

BACKGROUND: Despite the advantages of ultrasound and previous anatomical data on neuromuscular junction locations, to the best of our knowledge, the feasibility and accuracy of precise ultrasound-guided injection techniques into the proposed injection site of botulinum neurotoxin for the levator scapulae muscle have not been assessed in any publication. OBJECTIVE: In the present cadaver-based study, the ultrasound-guided injection technique in the middle and distal portions of the levator scapulae muscle was evaluated to determine whether this method distributes injections properly to the target muscle in fresh cadavers. STUDY DESIGN: Cadaveric study. SETTING: A cadaver laboratory. METHODS: Twenty fresh cadavers were used. Real-time B-mode ultrasound scanning was performed interfaced with a linear array transducer. A mixture of 0.5 mL of dye and yellow filler was injected transverse in-plane with a 6 cm 21-G. needle. Each specimen was dissected to determine whether the dye was correctly targeted to the middle and distal portions of the levator scapulae muscle and to evaluate the accuracy of the injections and any complications. RESULTS: All 40 injections were successfully injected within the middle and distal portions of the levator scapulae muscle. When dissecting the cadavers, the dye spread was evenly distributed along the muscle fiber. LIMITATION: Despite successful injection into the middle and distal portions of the levator scapulae muscle, the usefulness of this technique was not verified in clinical practice. CONCLUSIONS: The ultrasound-guided injection technique presented in this study might facilitate precise visualization and localization of the levator scapulae muscle, thereby enhancing the effectiveness and safety of botulinum neurotoxin treatment in cervical dystonia.

Sonoanatomy of the platysmal bands: What causes the platysmal band?

BACKGROUND: The platysmal band is created by the platysma muscle, a thin superficial muscle that covers the entire neck and the lower part of the face. The platysmal band appears at the anterior and posterior borders of the muscle. To date, no definite pathophysiology has been established. Here, we observed a lack of knowledge of the anatomy of the platysma muscle using ultrasonography in this study. METHODS: We conducted a descriptive, prospective study observing the platysmal band in resting and contraction states to reveal muscle changes. Twenty-four participants (aged 23-57 years) with anterior and posterior neck bands underwent ultrasonography in resting and contracted states. Ten cadavers were studied aged 67-85 years to measure the thickness of the platysma muscle at 12 points: horizontally (medial, middle, lateral) and vertically (inferior mandibular margin, hyoid bone, cricoid cartilage, superior margin of clavicle). RESULTS: The anterior and posterior borders of the platysma muscle were thicker than the middle of the platysma muscle when in a contracted state, and the muscle also had a convex shape when contracted. The thickness of the platysma muscle was not significantly different over 12 points in the resting state. During contraction, the platysma muscles contracted in the medial and lateral margins of the muscle, which was more significant in the posterior bands. CONCLUSION: The anterior and posterior platysmal bands are related to muscle thickness during contraction. These observations support the change in platysmal band treatment only at the anterior and posterior border of the muscle.

Intramuscular Neural Distribution of Adductor Pollicis Muscle Spasticity in Cadaver Model Regarding Botulinum Neurotoxin Treatment.

PURPOSE: The adductor pollicis muscle is frequently targeted for botulinum neurotoxin injective treatment for spasticity. However, there are no injective guidelines for delivering injection to the muscle. MATERIALS AND METHODS: A method known as the modified Sihler's method was used to stain the adductor pollicis muscle in 16 specimens to reveal intramuscular neural distribution of the muscle. RESULTS: The most intramuscular neural distribution was located on 1/5 to 3/5 of the muscle regarding midline of 3rd metacarpal bone (0) to the base of the 1st proximal phalanx (5/5). The nerve entry point was mostly located on 0 to 1/5 of the muscle. CONCLUSION: The result suggests that botulinum neurotoxin should be delivered at the middle of second metacarpal bone via deep injection.

Intramuscular neural distribution of the teres minor muscle using Sihler's stain: application to botulinum neurotoxin injection.

The aim of this study was to elucidate the intramuscular arborization of the teres minor muslce for effective botulinum neurotoxin injection. Twelve specimens from 6 adult Korean cadavers (3 males and 3 females, age ranging from 66 to 78 years) were used in the study. The reference line between the 2/3 point of the axillary border of the scapula (0/5), where the muscle originates ant the insertion point of the greater tubercle of the humerus (5/5). The most intramuscular neural distribution was located on 1/5-3/5 of the muscle. The tendinous portion was observed in the 3/5-5/5. The result suggests the botulinum neurotoxin should be delivered in the 1/5-3/5 area of the teres minor muscle.

Anatomical analysis of the intramuscular distribution patterns of the levator scapulae and the clinical implications for pain management.

PURPOSE: The present study aimed to demonstrate the intramuscular nerve distribution of the levator scapulae muscle that is responsible for pain and to use this anatomic data to propose possible injection sites. METHODS: Twenty levator scapulae muscles were dissected from 16 Korean embalmed cadavers. The intramuscular nerve distribution of the levator scapulae muscle was identified by whole-mount nerve staining to preserve and stain the nerve fibers without damage. RESULTS: The posterior ramus of spinal nerves C3, C4, and C5 innervated the levator scapulae muscles. When the origin and insertion of the muscle were set to 0% and 100%, respectively, most of the intramuscular nerve terminals were located between 30 and 70%. This area may correspond to the cricoid cartilage of the sixth cervical vertebra. CONCLUSION: Most intramuscular nerve terminals can be found in the middle and distal portions of the levator scapulae muscle. Our findings improve our understanding of the intramuscular nerve distribution of the levator scapulae muscle and will aid in pain management in clinical practice.

Control of the Reaction Kinetics of Monodispersed InP/ZnSeS/ZnS-Based Quantum Dots Using Organophosphorus Compounds for Electroluminescent Devices.

Green emissive InP-based quantum dots (QDs) remain less developed than red QDs because of the difficulty of controlling the reactivity of small InP cores. Herein, we report the synthesis of monodispersed green InP-based QDs using tris(dimethylamino)phosphine, a considerably inexpensive and safer phosphorus source compared to conventional tris(trimethylsilyl)phosphine. An organophosphorus compound, trioctylphosphine, was used to control the reaction kinetics by slowing the progression of the nucleation process, which weakened the aggregation behavior of the clusters and improved the size distribution. The synthesized green emissive InP/ZnSeS/ZnS QDs exhibited a photoluminescence (PL) peak at 515 nm with an enhancement of the full width at half-maximum from 66 to 46 nm and the PL quantum yield from 61% to 70%. An electroluminescent device was fabricated, and the electron transport layer was optimized by changing the layer thickness. The optimized device structure improved the charge balance and increased the external quantum efficiency from 2.1% to 3.5%.

Novel anatomical guidelines for botulinum neurotoxin injection in the mentalis muscle: a review.

The mentalis muscle is a paired muscle originating from the alveolar bone of the mandible. This muscle is the main target muscle for botulinum neurotoxin (BoNT) injection therapy, which aims to treat cobblestone chin caused by mentalis hyperactivity. However, a lack of knowledge on the anatomy of the mentalis muscle and the properties of BoNT can lead to side effects, such as mouth closure insufficiency and smile asymmetry due to ptosis of the lower lip after BoNT injection procedures. Therefore, we have reviewed the anatomical properties associated with BoNT injection into the mentalis muscle. An up-to-date understanding of the localization of the BoNT injection point according to mandibular anatomy leads to better injection localization into the mentalis muscle. Optimal injection sites have been provided for the mentalis muscle and a proper injection technique has been described. We have suggested optimal injection sites based on the external anatomical landmarks of the mandible. The aim of these guidelines is to maximize the effects of BoNT therapy by minimizing the deleterious effects, which can be very useful in clinical settings.

Novel anatomical proposal for botulinum neurotoxin injection targeting depressor anguli oris for treating drooping mouth corner.

The depressor anguli oris (DAO) muscle is a thin, superficial muscle located below the corner of the mouth. It is the target for botulinum neurotoxin (BoNT) injection therapy, aimed at treating drooping mouth corners. Hyperactivity of the DAO muscle can lead to a sad, tired, or angry appearance in some patients. However, it is difficult to inject BoNT into the DAO muscle because its medial border overlaps with the depressor labii inferioris and its lateral border is adjacent to the risorius, zygomaticus major, and platysma muscles. Moreover, a lack of knowledge of the anatomy of the DAO muscle and the properties of BoNT can lead to side effects, such as asymmetrical smiles. Anatomical-based injection sites were provided for the DAO muscle, and the proper injection technique was reviewed. We proposed optimal injection sites based on the external anatomical landmarks of the face. The aim of these guidelines is to standardize the procedure and maximize the effects of BoNT injections while minimizing adverse events, all by reducing the dose unit and injection points.

Anatomical Proposal for Botulinum Neurotoxin Injection Targeting the Platysma Muscle for Treating Platysmal Band and Jawline Lifting: A Review.

The platysma muscle is a thin superficial muscle that covers the entire neck and lower part of the face. The platysma muscle is the primary target muscle for botulinum neurotoxin injection therapy aimed at treating platysmal band and lower facial lifting. In the procedure of botulinum neurotoxin injection therapy, a lack of knowledge of the anatomy of the platysma muscle and the properties of botulinum neurotoxin can lead to side effects such as dysphagia, dysphonia, and weakness of the neck muscles. Anatomically safe injection sites have been proposed for the platysma muscle, and the appropriate injection technique has been reviewed. We proposed optimal injection sites based on the external anatomical features of the mandible. The aim of these proposal was to standardize the procedure for the effective use of botulinum neurotoxin injections by minimizing the dose unit and injection points and thereby preventing adverse events.

Analysis of facial ultrasonography images based on deep learning.

Transfer learning using a pre-trained model with the ImageNet database is frequently used when obtaining large datasets in the medical imaging field is challenging. We tried to estimate the value of deep learning for facial US images by assessing the classification performance for facial US images through transfer learning using current representative deep learning models and analyzing the classification criteria. For this clinical study, we recruited 86 individuals from whom we acquired ultrasound images of nine facial regions. To classify these facial regions, 15 deep learning models were trained using augmented or non-augmented datasets and their performance was evaluated. The F-measure scores average of all models was about 93% regardless of augmentation in the dataset, and the best performing model was the classic model VGGs. The models regarded the contours of skin and bones, rather than muscles and blood vessels, as distinct features for distinguishing regions in the facial US images. The results of this study can be used as reference data for future deep learning research on facial US images and content development.

Clinical anatomy considerations on the muscular and vascular components of the midface by ultrasonographic imaging.

The first signs of face aging appear in the midface, so procedures such as botulinum toxin and filler injections are performed there. However, no guidelines based on clinical anatomy describing the muscular and vascular components in vivo have been published. The aim of this research was to describe the depths of the midface muscles and the locations of vessels using ultrasonographic (US) imaging. US was applied at 12 landmarks on the midface in 88 volunteers (49 males and 39 females; 19-36 years) to detect sex differences in the depths of muscles and the locations of the vessels. The depths of the orbicularis oculi (OOc), levator labii superioris alaeque nasi (LLSAN), and zygomaticus minor (Zmi) differed significantly with sex at P7 (p = 0.001) and P8 (p = 0.017), P1 (p = 0.028), and P4 (p = 0.035), respectively. The facial artery, facial vein, angular artery, angular vein, and perforator vessels were found at P9, P2 and P10, P1, P1 and P5, and P8, P11 and P12, respectively. The findings indicate that the depths of the OOc, LLSAN, and Zmi muscles differ between the sexes and that the vessels appear at specific landmarks. This information could help in developing anatomical guidelines for several procedures.

Correlation analysis between lower limb muscle architectures and cycling power via ultrasonography.

The primary purpose was to examine the relationship between the muscle architectural characteristics of short and long-distance cyclist-including muscle thickness, fascicle angle, and fascicle length-of the anterior thigh and posterior leg and its impact in 20-s cycling power. The secondary purpose was to clarify the muscle variables that predict the cycling power by using ultrasonography to measure the muscle architectural characteristics. Twenty-four varsity cyclists participated in this study, of whom 12 were short-distance cyclists and 12 were long-distance cyclists. B-mode ultrasonography was used to measure muscle architecture parameters. A cycle ergometer was used to measure the cycling power. The rectus femoris, vastus medialis, and medial head of gastrocnemius were significantly thicker in short-distance cyclists than in long-distance cyclists at every site (p < 0.05). Our analysis revealed that the rectus femoris fascicle length at the 30% level of the thigh was a significant independent predictor of the 20-s cycling power in short-distance cyclists, while the rectus femoris fascicle angle at the 50% level was that of the 20-s cycling power in long-distance cyclists. These findings highlight the significance of rectus femoris muscle architecture to cycling power.

Three-dimensional topography of facial soft tissues for the safer and effective threading procedures.

INTRODUCTION: To reduce complications caused by the procedure, the target layer for thread lifting should be the superficial fat or superficial musculoaponeurotic system of the face. The aim of this study was to establish the thicknesses of the facial skin and superficial fat using a 3D scanning system to provide basic clinical data for thread lifting. MATERIAL AND METHODS: Thirty fixed Korean and Thai cadavers (male: 17, female: 13) were used. The depths of the skin and superficial fat were measured using a three dimensional (3D) structured-light scanner. Facial images of both undissected and removed skin and superficial fat were taken with the 3D scanner. The paths from the temple and the front of the tragus to the infraorbital, perioral, cheek, and mental areas were displayed on the 3D image. The thickness along the path was measured by calculating the difference between the undissected and dissected 3D images. RESULTS: The means and standard deviations of thicknesses of the skin and superficial fat were 2.1 ± 0.4 mm and 5.2 ± 1.9 mm in the 11 pathways. The facial skin became thicker going toward the lower aspect of the face from temple to infraorbtial and perioral regions. The thickness of the superficial fat around the marionette line showed the biggest change. CONCLUSIONS: The present findings indicate that a 3D scanning system can yield crucial anatomical information about the thickness of the facial skin and superficial fat for use in various minimally invasive clinical procedures including thread lifting.

Guidelines for botulinum neurotoxin injections in piriformis syndrome.

BACKGROUND: The piriformis muscle is normally involved in piriformis syndrome and can be treated with botulinum neurotoxin using several different injection methods. However, definitive injection guidelines for the muscle have not been reported previously. AIMS: This study aimed to determine the ideal area for injections based on the intramuscular nerve distribution as obtained using a modified Sihler's staining technique. MATERIALS AND METHODS: A modified Sihler's method was applied to the piriformis muscle in 15 specimens. The intramuscular arborization areas were identified based on two anatomical landmarks: (a) the lateral border of the sacrum bone and (b) the greater trochanter. RESULTS: The nerve entry point for both piriformis muscles was found in the area between the lateral border of the sacrum and one-fifth of the distance toward the greater trochanter. The intramuscular nerve distribution for the piriformis muscle had the largest arborization patterns between one-fifth and two-fifths of the distance from the sacrum to the greater trochanter. The piriformis muscle was tendinous from two-fifths of the distance to the greater trochanter. DISCUSSION: This study has yielded suggested optimal injection locations for the piriformis muscle relative to external anatomical landmarks. CONCLUSION: Clinicians can use these guidelines to ensure the effectiveness of not only botulinum neurotoxin injections but also other agents such as steroids, anesthetics, and normal saline. These guidelines will also help to avoid adverse outcomes of injection treatments.

Three-Dimensional Evaluation of the Depressor Anguli Oris and Depressor Labii Inferioris for Botulinum Toxin Injections.

BACKGROUND: Botulinum toxin type A (BoNT-A) injection administered at an inappropriate site or depth can produce an unwanted change in facial animation because the depressor anguli oris (DAO) and depressor labii inferioris (DLI) muscles are partially overlapped. Therefore, simple BoNT-A injection guidelines, based on 3-dimensional (3D) facial anatomic references and landmarks, would be very useful. OBJECTIVES: The aim of this study was to establish novel BoNT-A injection guidelines that include the soft tissue thickness at the lower perioral region. Data were acquired with a 3D scanning system combined with dissections in order to obtain accurate injection sites and depths for the DAO and DLI. METHODS: 3D scans of the facial skin, superficial fat, and facial muscle surface were performed in 45 embalmed cadavers. The thicknesses of the skin and subcutaneous layer were calculated automatically from superimposed images at each of 5 reference points (P) in the perioral region. RESULTS: In every case (100%), P3 and P5 were located in the DLI and DAO areas, respectively (45/45). Therefore, we defined P3 as the "DLI point" and P5 as the "DAO point." The soft tissue thicknesses at the DLI and DAO points were 6.4 [1.7] mm and 6.7 [1.8] mm, respectively. CONCLUSIONS: The P3 and P5 described in this study are effective guidelines that only target the DLI and DAO. Clinicians, specifically, can easily use facial landmarks, such as the cheilion and pupil, to assign the DLI and DAO points without any measurement or palpation of the modiolus.