Sonoanatomy of injecting botulinum neurotoxin into the facial muscles.

INTRODUCTION: Ultrasonography (US) has become an essential tool for guiding botulinum neurotoxin (BoNT) injections in facial muscles, enhancing precision and safety. This narrative review explores the role of US in BoNT administration, particularly in complex anatomical regions, highlighting its impact on treatment customization, real-time visualization, and complication reduction. MATERIALS AND METHODS: A comprehensive literature search was conducted using PubMed, MEDLINE, Embase, and Cochrane Library for articles published from January 2018 to December 2023. Search terms included "Botulinum neurotoxin," "facial anatomy," "ultrasonography guided injection," and "facial muscle sonoanatomy." Studies focusing on US-guided BoNT injections in facial muscles were included. Data extraction and synthesis were performed independently by two reviewers, focusing on study design, ultrasonography techniques, outcomes, and conclusions. RESULTS: The review found that US guidance significantly enhances the precision of BoNT injections by providing real-time visualization of facial muscles and blood vessels, thereby reducing the risk of adverse events. US enables tailored injection strategies, ensuring symmetrical facial expressions and minimizing over-treatment. The technique also offers immediate feedback, allowing for on-the-spot adjustments to improve treatment efficacy and safety. However, the review identified limitations, including potential selection bias and variability in US techniques across different studies. CONCLUSION: US guidance for BoNT injections into facial muscles offers substantial benefits in terms of precision, safety, and treatment customization. Despite the identified limitations, the integration of US into clinical practice is poised to enhance patient outcomes in aesthetic and therapeutic procedures. Further research is needed to standardize US techniques and broaden the inclusivity of studies to validate these findings comprehensively.

Intramuscular Neural Distribution of the Gluteus Maximus Muscle: Diagnostic Electromyography and Injective Treatments.

INTRODUCTION: The purpose of this study was to investigate neural patterns within the gluteus maximus (Gmax) muscle to identify optimal EMG placement and injection sites for botulinum toxin and other injectable agents. METHODS: This study used 10 fixed and 1 non-fixed adult Korean cadavers. Intramuscular arborization patterns were confirmed in the cranial, middle, and caudal segments of 20 Gmax muscles using Sihler staining. Ultrasound images were obtained from one cadaver, and blue dye was injected using ultrasound guidance to confirm the results. RESULTS: The intramuscular innervation pattern of the Gmax was mostly in the middle part of this muscle. The nerve endings of the Gmax are mainly located in the 40-70% range in the cranial segment, the 30-60% range in the middle segment, and the 40-70% range in the caudal segment. DISCUSSION: Addressing the spasticity of the gluteus maximus requires precise, site-specific botulinum toxin injections. The use of EMG and other injection therapies should be guided by the findings of this study. We propose that these specific sites, which correspond to areas with the densest nerve branches, are the safest and most efficient locations for both botulinum toxin injections and EMG procedures.

Sihler's staining technique: How to and guidance for botulinum neurotoxin injection in human muscles.

The Sihler's stain is a whole-mount nerve staining technique that allows visualization of the nerve distribution and permits mapping of the entire nerve supply patterns of the organs, skeletal muscles, mucosa, skin, and other structures that contain myelinated nerve fibers. Unlike conventional approaches, this technique does not require extensive dissection or slide preparation. To date, the Sihler's stain is the best tool for demonstrating the precise intramuscular branching and distribution patterns of skeletal muscles. The intramuscular neural distribution is used as a guidance tool for the application of botulinum neurotoxin injections. In this review, we have identified and summarized the ideal botulinum neurotoxin injection points for several human tissues.

Novel Clinical Anatomical Consideration of the Superficial and Deep Layers of the Deep Temporal Fascia.

BACKGROUND: The deep temporal fascia provides anchoring during thread lifting, which is a minimally invasive face-lifting procedure. However, anatomical studies involving the deep temporal fascia in addition to effective and safe thread-lifting procedures are scarce. The authors clarified the anatomy of the superficial layer of the deep temporal fascia and its surrounding structure using ultrasonography, histologic sections, and cadaveric dissection to propose an effective thread-lifting procedure guideline. METHODS: The authors included 20 healthy young participants from the Republic of Korea. Real-time, two-dimensional, B-mode ultrasonography was performed. Longitudinal scanning was performed along three vertical lines: the line passing through the jugale, the anterior margin of the condylar process of the mandible, and the midpoint between the jugale and anterior margin of the condylar process. Histologic samples from three fresh adult cadavers were harvested from 2.5 cm above and below the zygomatic arch. Eighteen fresh adult hemifaces of cadavers from the Republic of Korea (six men and three women, aged 67.3 ± 7.2 years) were used to confirm the morphology of the deep temporal fascia. RESULTS: The superficial layer of the deep temporal fascia crossed the zygomatic arch and was connected to the origin of the zygomaticus major muscle at the line passing through the jugale. The superficial layer continued inferiorly to the parotidomasseteric fascia at the line passing through the midpoint and condylar process of the mandible. CONCLUSION: This study yielded the novel anatomy of the superficial layer of the deep temporal fascia, and this anatomical structure may be used for an ideal thread-lifting procedure.

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.

Does injecting small amounts of fillers prevent the development of secondary blindness?

INTRODUCTION: Inadvertent entry of filler products into the supratrochlear, supraorbital, or dorsal nasal arteries, among other branches of the ophthalmic artery, might result in an immediate and devastating loss of vision. We wanted to examine how much filler could block the ophthalmic artery. MATERIALS AND METHODS: Twenty-nine fresh cadavers were examined. We exposed the arterial supply to the opthalmic artery by dissecting the orbital area. Thereafter, 17 filler injections were introduced into the supratrochlear, supraorbital, and dorsal nasal arteries each. The amount of filler injection that completely blocked the ophthalmic artery was measured. Additionally, one of the head specimens was processed using phosphotungstic acid-based contrast enhancement micro-computed tomography to analyze each arteries to obstruct its whole ophthalmic artery. RESULTS: The supratrochlear, supraorbital, and dorsal nasal arteries had mean volumes in milliliter (mean ± standard deviation) of 0.0397 ± 0.010 mL, 0.0409 ± 0.00932 mL, and 0.0368 ± 0.00732 mL, respectively. However, the arteries did not differ significantly. CONCLUSION: Even a modest amount of filler injection can completely block the ophthalmic artery, resulting in visual loss.

Association of Bypass Surgery and Mortality in Moyamoya Disease.

Background Patients with moyamoya disease (MMD) have a high risk of stroke or death. We investigated whether extracranial to intracranial bypass surgery can reduce mortality by preventing strokes in patients with MMD. Methods and Results This nationwide retrospective cohort study encompassed patients with MMD registered under the Rare Intractable Diseases program via the Relieved Co-Payment Policy between 2006 and 2019, using the Korean National Health Insurance Service database. Following a 4-year washout period, landmark analyses were employed to assess mortality and stroke occurrence between the bypass surgery group and the nonsurgical control group at specific time points postindex date (1 month and 3, 6, 12, and 36 months). The study included 18 480 patients with MMD (mean age, 40.7 years; male to female ratio, 1:1.86) with a median follow-up of 5.6 years (interquartile range, 2.5-9.3; mean, 6.1 years [SD, 4.0 years]). During 111 775 person-years of follow-up, 265 patients in the bypass surgery group and 1144 patients in the nonsurgical control group died (incidence mortality rate of 618.1 events versus 1660.3 events, respectively, per 105 person-years). The overall adjusted hazard ratio (HR) revealed significantly lower all-cause mortality in the bypass surgery group from the 36-month landmark time point, for any stroke mortality from 3- and 6-month landmark time points, and for hemorrhagic stroke mortality from the 6-month landmark time point. Furthermore, the overall adjusted HRs for hemorrhagic stroke occurrence were beneficially maintained from all 5 landmark time points in the bypass surgery group. Conclusions Bypass surgery in patients with MMD was associated with a lower risk of all-cause and hemorrhagic stroke mortality and hemorrhagic stroke occurrence compared with nonsurgical control.

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.

Observation of Anatomical Structures in the Human Larynx Using Micro-Computed Tomography with Lugol's Solution Enhancement.

Histological and naked-eye dissections are frequently used to investigate human anatomy. However, limitations of conventional methods include tissue damage and difficulty in observing structures, rendering findings limited. Micro-computed tomography (micro-CT) allows for a three-dimensional observation with whole-mount staining for contrast enhancement. A precise anatomical understanding of the larynx is essential for both the medical and surgical fields; however, the larynx is difficult to dissect because of its minuscule and complex structures. Therefore, we aimed to clarify the detailed anatomy of the larynx using micro-CT. The study was conducted on twelve specimens of cadavers using Lugol-based-contrast micro-CT. Using Lugol-micro-CT, relevant information on human structures was obtained. Consequently, we successfully employed the Lugol-micro-CT technique in the analysis of specific human soft tissue structures that are challenging to analyze using conventional methods.

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 obturator internus muscle regarding injective treatment.

INTRODUCTION: The obturator internus muscle is frequently targeted for injective treatments such as botulinum toxin injections in the management of pain syndromes. However, there are controversies over injective method delivering injection to the muscle. METHOD: A method called modified Sihler's method was used to stain the OI muscle in 16 specimens to reveal the intramuscular neural distribution of the muscle. RESULT: The greatest intramuscular neural distribution was located on the 2/10-4/10 of the muscle in the medial edge of the obturator foramen (0/0) to the greater trochanter of the femur (10/10). CONCLUSION: The result suggests that botulinum neurotoxin should be delivered in the intrapelvic portion of the obturator internus muscle. As most of the extrapelvic portion of the obturator muscle is composed of a tendinous portion, it should be considered unsuitable as an injection site by medical professionals.

Unusual insertion of the levator scapulae muscle: a case report.

The current case report describes an uncommon insertion of the levator scapulae (LS), which broadly attaches to multiple structures, including the serratus posterior superior, ligamentum nuchae, and the 6th and 7th spinous processes of the cervical vertebrae. The most superior portion of this aponeurosis merged with the ligamentum nuchae at the C7 level. The middle and inferior portions of the head were inserted (or fused) into the tendon of the rhomboid minor as well as the fibers of the serratus posterior superior muscle. Consequently, recognizing this anatomical variation, characterized by an additional slip of the LS attaching to the 7th vertebra and other muscular structures, is crucial not only for anatomists but also for surgeons performing procedures on the posterior neck related to cervical or shoulder pain and cervical dystonia.

A three-dimensional analysis of the tibialis anterior tendon: emphasizing tendon insertion patterns for effective repair and understanding hallux valgus development.

PURPOSE: The present study aimed to evaluate the insertion site of the tibialis anterior tendon three-dimensionally. METHODS: Seventy lower limbs were dissected. The tibialis anterior tendon was dissected to verify the insertion site to the medial cuneiform and the base of the first metatarsal bone. The three-dimensional (3D) territory of the tibialis anterior tendon insertion on the medial cuneiform and the first metatarsal bones was measured on a reconstructed 3D model. RESULTS: The insertion pattern of the tibialis anterior tendon was classified into three types, the most common being Type I: a single tibialis anterior tendon dividing into two equal-sized bands to the medial cuneiform and base of the first metatarsal bone (57.1%, 40/70 of cases). The 3D territory of the tibialis anterior tendon was larger in the plantar aspect than in the medial side of both the medial cuneiform and the base of the first metatarsal bone. The width of the tendon inserted into the medial cuneiform was wider than that inserted into the first metatarsal bone. CONCLUSION: The tibialis anterior tendon was more commonly attached to the plantar part than the medial part in both the medial cuneiform and the base of the first metatarsal bone. This anatomical information will help surgeons perform anatomical reconstruction of the tibialis anterior tendon, reduce further tendon damage in the first metatarsocuneiform joint area and also provide valuable knowledge to improve understanding of hallux valgus pathogenesis.

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.

Botulinum neurotoxin injection for treating plunged nose and post-rhinoplasty: anatomical perspectives of depressor septi nasi, nasalis, leveator labii superioris alaeque nasi muscle.

Botulinum neurotoxin (BoNT) injection for the treating plunged nose, post-rhinopasty and hyaluronic filler migration is common procedures in clinical settings. However, the lack of thorough anatomical understanding makes it difficult to locate the nose region muscles. The anatomical considerations concerned with BoNT injection into the nasalis, levator labii superioris alaeque, and depressor septi nasi muscles were reviewed in this study. The injection spots have been presented for the nasalis, levator labii superioris alaeque, and depressor septi nasi muscles, with the recommended injection technique for each muscle. We have suggested the ideal injection sites in association with outer anatomical landmarks of the nose region. Moreover, these proposals would support a more accurate procedure of BoNT injection in relieving plunged nose, preventing post-rhinoplasty deviation, and migration of the hyaluronic acid filler.

Intramuscular Neural Distribution of the Gastrocnemius for Botulinum Neurotoxin Injection: Application to Cosmetic Calf Shaping.

PURPOSE: Anatomical landmarks can provide vital information on the distribution of nerves in the gastrocnemius muscle. We aimed to provide an anatomical perspective on appropriate locations for botulinum neurotoxin (BoNT) injections in the medial and lateral parts of the gastrocnemius for calf shaping. MATERIALS AND METHODS: A modified Sihler's method was applied to both the medial and lateral parts of the gastrocnemius muscles (16 specimens). Intramuscular neural distributions were revealed by dissecting along a transverse line crossing the fibular head and superior margin of the calcaneal tuberosity. RESULTS: The intramuscular neural distribution for the medial and lateral parts of the gastrocnemius had the greatest arborized patterns in the 7/10-8/10 section of the medial head and 7.5/10-8.5/10 section of the lateral part of the gastrocnemius. CONCLUSION: We propose that BoNT injections should be directed to the 7/10-8/10 section of the medial head and the 7.5/10-8.5/10 section of the lateral part of the gastrocnemius. Following our guidelines, clinicians can ensure satisfactory results with the use of minimal doses to limit adverse effects, such as gait disturbance, antibody production, and bruising, due to multiple injections. The results can also be altered and applied to electromyography.