Location of the motor entry point and intramuscular motor point of the tibialis posterior muscle: for effective motor point block

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.

Distribution of the intramuscular innervation of the triceps brachii: Clinical importance in the treatment of spasticity with botulinum neurotoxin

This study aimed to identify ideal sites for botulinum toxin injection by analyzing the intramuscular nerve patterns of the triceps brachii muscles. A modified Sihler's method was applied to the triceps brachii muscle (15 specimens), with long, medial, and lateral heads. The intramuscular arborization areas of the long, medial, and lateral heads of the triceps brachii muscle were measured as a percentage of the total distance from the midpoint of the olecranon (0%) to the anteroinferior point of the acromion (100%), by dividing the medial and lateral parts based on the line connecting the midpoint of the olecranon and the anteroinferior point of the acromion. Intramuscular arborization patterns were observed at the long head at two medial regions, proximally 30%-50% and distally 60%-70%; medial head of 30%-40%; and lateral head of 30%-60%. These results suggest that the treatment of spasticity of the triceps brachii muscles involves botulinum toxin injections in specific areas. The areas corresponding to the areas of maximum arborization are recommended as the most effective and safe points for botulinum toxin 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.

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.

Nerve entry points - The anatomy beneath trigger points

INTRODUCTION

Myofascial trigger points (MTrPs) have been the subject of considerable scientific research for almost forty years. In their seminal paper, Travell and Simons described a model based on the presence of highly irritable, palpable nodules within taut bands of muscle. Since then, a significant number of studies have increased our understanding of the phenomenon, which has, in turn, resulted in refutation of the original model. Alternative models have explained certain properties of MTrP but fail to provide an explanation of their spatial distribution. The aim of this paper was to propose a hypothesis connecting MTrPs and distinct points along the course of the nerve called nerve entry points (NEPs). A literature review was performed in order to identify studies to support hypothesis development.

METHODS

Literature search of digital databases.

RESULTS

A total of 4631 abstracts were screened; 72 were selected for further review. Four articles made a direct connection between MTrPs and NEPs. Another fifteen articles provided high-quality data regarding the distribution of NEPs, thus strengthening the hypothesis.

CONCLUSIONS

There is sufficient evidence to hypothesise that NEPs are the anatomical basis for MTrPs. This presented hypothesis addresses one of the crucial issues in diagnosing trigger points, which is the lack of repeatable and reliable diagnostic criteria. By connecting subjective phenomenon of trigger points with objective anatomy, this paper provides a novel and practical foundation for identifying and treating pain conditions associated with MTrPs.

Guidance in botulinum neurotoxin injection for lower extremity spasticity: Sihler's staining technique

Spasticity is a motor disease characterized by a velocity-dependent acceleration in muscle tone or tonic stretch reflexes linked to hypertonia. Lower limb spasticity has been successfully treated with botulinum neurotoxin; however, the injection sites have not been generalized. Sihler's stain has been used to visualize intramuscular nerve distribution to guide botulinum neurotoxin injection. Sihler staining is a whole-mount nerve staining technique that allows visualization of nerve distribution and mapping of entire nerve supply patterns in skeletal muscle with hematoxylin-stained myelinated nerve fibers. This study reviewed and summarized previous lower extremity spasticity studies to determine the ideal injection site for botulinum neurotoxin.

Teaching Essential EMG Theory to Kinesiologists and Physical Therapists Using Analogies Visual Descriptions, and Qualitative Analysis of Biophysical Concepts

Electromyography (EMG) is a multidisciplinary field that brings together allied health (kinesiology and physical therapy) and the engineering sciences (biomedical and electrical). Since the physical sciences are used in the measurement of a biological process, the presentation of the theoretical foundations of EMG is most conveniently conducted using math and physics. However, given the multidisciplinary nature of EMG, a course will most likely include students from diverse backgrounds, with varying levels of math and physics. This is a pedagogical paper that outlines an approach for teaching foundational concepts in EMG to kinesiologists and physical therapists that uses a combination of analogies, visual descriptions, and qualitative analysis of biophysical concepts to develop an intuitive understanding for those who are new to surface EMG. The approach focuses on muscle fiber action potentials (MFAPs), motor unit action potentials (MUAPs), and compound muscle action potentials (CMAPs) because changes in these waveforms are much easier to identify and describe in comparison to the surface EMG interference pattern (IP).

Nerve and Arterial Supply Pattern of the Popliteus Muscle and Clinical Implications

Introduction. The aim of this study was to investigate the nerve and artery supply and the tibial attachment of the popliteus muscle using anatomical methods. Methods. Forty-four nonembalmed and embalmed extremities were dissected for this study. To measure the attachment area of the popliteus, the most prominent points of the medial epicondyle of the femur and the medial malleolus of the tibia were identified before dissection. A line connecting these two prominent points was used as the reference line, with the most prominent point of the medial epicondyle of the femur as the starting point. This study also investigated the area where the popliteus attaches to the bone and the points where nerves and arteries enter the popliteus muscle when it is divided into three equal parts in the coronal plane. Results. The mean length of the reference line was $34.6\pm 2.1\text{cm}$ . The origin of the popliteus was found to be at a distance of 16.6% to 35.2% on the tibial bone from the proximal region. The popliteus was innervated by only the tibial nerve in 90% of the cases and by the tibial and the sciatic nerves in the remaining 10% of the cases. The inferior medial genicular artery and the posterior tibial artery supplied blood to the popliteus in 90% and 65% of the cases, respectively. When the popliteus muscle was divided into three equal parts in the coronal plane, the nerve and the artery were found to enter the muscle belly in zones II and III and zones I and II in 92% and 98% of the specimens, respectively. Discussion. The anatomical investigation of the popliteus in this study will help identify patients with clinically relevant syndromes.

Ultrasonographic Evaluation of Three Approaches for Botulinum Toxin Injection into Tibialis Posterior Muscle in Chronic Stroke Patients with Equinovarus Foot: An Observational Study

Spastic equinovarus (SEV) foot deformity is commonly observed in patients with post-stroke spasticity. Tibialis posterior (TP) is a common target for botulinum toxin type-A (BoNT-A) injection, as a first-line treatment in non-fixed SEV deformity. For this deep muscle, ultrasonographic guidance is crucial to achieving maximum accuracy for the BoNT-A injection. In current clinical practice, there are three approaches to target the TP: an anterior, a posteromedial, and a posterior. To date, previous studies have failed to identify the best approach for needle insertion into TP. To explore the ultrasonographic characteristics of these approaches, we investigated affected and unaffected legs of 25 stroke patients with SEV treated with BoNT-A. We evaluated the qualitative (echo intensity) and quantitative (muscle depth, muscle thickness, overlying muscle, subcutaneous tissue, cross-sectional area) ultrasound characteristics of the three approaches for TP injection. In our sample, we observed significant differences among almost all the parameters of the three approaches, except for the safety window. Moreover, our analysis showed significant differences in cross-sectional area between treated and untreated. Advantages and disadvantages of each approach were investigated. Our findings can thus provide a suitable reference for clinical settings, especially for novice operators.

A consensus statement on the use of botulinum toxin in pediatric patients

Botulinum toxin has been used in medicine for the past 30 years. However, there continues to be controversy about the appropriate uses and dosing, especially in the pediatric population. A panel of nine pediatric physiatrists from different regions and previous training programs in the United States were nominated based on institutional reputation and botulinum toxin (BoNT) experience. Based on a review of the current literature, the goal was to provide the rationale for recommendations on the administration of BoNT in the pediatric population. The goal was not only to review safety, dosing, and injection techniques but also to develop a consensus on the appropriate uses in the pediatric population. In addition to upper and lower limb spasticity, the consensus also provides recommendations for congenital muscular torticollis, cervical dystonia, sialorrhea, and brachial plexus palsies.

Anatomical locations of the motor endplates of sartorius muscle for botulinum toxin injections in treatment of muscle spasticity

PURPOSE

This study aimed to detect the idyllic locations for botulinum neurotoxin injection by analyzing the intramuscular neural distributions of the sartorius muscles.

METHODS

An altered Sihler's staining was conducted on sartorius muscles (15 specimens). The nerve entry points and intramuscular arborization areas were measured as a percentage of the total distance from the most prominent point of the anterior superior iliac spine (0%) to the medial femoral epicondyle (100%).

RESULTS

Intramuscular neural distribution were densely detected at 20-40% and 60-80% for the sartorius muscles. The result suggests that the treatment of sartorius muscle spasticity requires botulinum neurotoxin injections in particular locations.

CONCLUSIONS

These locations, corresponding to the locations of maximum arborization, are suggested as the most suggestive points for botulinum neurotoxin injection.

Topographic anatomical localization of the motor nerve entry points (MEPs) of the masseter muscle

PURPOSE

The masseteric nerve, which is a branch of the mandibular nerve, passes lateral to the mandibular notch and then spreads in the muscle to achieve motor innervation. The muscle entry points of these motor branches are the target points of minimally invasive interventions preferred in the treatment of masseter hypertrophy. The aim of this study was to reveal the areas where the motor entry points are concentrated in the muscle by dividing the muscle into topographic regions using reliable anatomic landmarks.

METHODS

Bilateral 20 masseter muscles (40 in total) belonging to 20 formalin-fixed cadavers (10 female and 10 male) were examined. The distribution of the nerve in the muscle and its motor entry points were demonstrated and marked on the muscle surface. The masseter muscle was divided into six areas by lines passing through reliable anatomical landmarks (Areas 1-6).

RESULTS

The total number of MEPs was 231.The mean distance of the MEPs from the Line-1 was 27.4 ± 11 mm, and the same distance from the Line-6 was 30.32 ± 7.2 mm. Most of the MEPs (123/231) were located in Area-4. Area-6 was the second (82/231) and Area-5 (19/231) was the third.

CONCLUSION

We suggest that interventions in Area-4 (especially in the middle part) may have less complications as a result of less relationship with surrounding anatomical structures and more effective with high MEP number.

Simple semi-permanent blockade against rigid varus foot in a case with spasticity: possible practical benefits in ambulatory adults

A 55-year-old ambulatory woman with hemiplegia and varus foot deformity had several problems in her daily life, including load pain and stance instability in the affected foot, easy fatigue of the non-paralysed leg, low back pain, neck stiffness and rapid shoe-rubber wear on the deformed side. We began repeated focal blockades using botulinum toxin to the tibialis posterior muscle to control varus spasticity. Distant influences presenting in the whole body were relieved soon after the first blockade, and shoe wear also stopped. Although, neither the deformed appearance nor foot contact pattern on walking changed in the initial period after beginning the blockade, the foot contact pattern revealed gradual improvement over several years. Generally, surgical correction is indicated for the treatment of deformed feet. The present case suggests that, in case of varus-deformed foot with some spastic elements, trial of focal blockade for varus spasticity may be worthwhile.

Ultrasonographic Evaluation of Botulinum Toxin Injection Site for the Medial Approach to Tibialis Posterior Muscle in Chronic Stroke Patients with Spastic Equinovarus Foot: An Observational Study

The tibialis posterior muscle is a frequent target for injection of botulinum toxin during the management of spastic equinovarus foot in adults with post-stroke spasticity. Although it is deep-seated, the needle insertion into the tibialis posterior muscle is usually performed using anatomical landmarks and safety information obtained from healthy subjects and cadavers. Our aim was to evaluate the botulinum toxin injection site for the medial approach to the tibialis posterior muscle in chronic stroke patients with spastic equinovarus foot. Forty-six patients were evaluated at the affected middle lower leg medial surface with ultrasonography according to the following parameters: tibialis posterior muscle depth, thickness, and echo intensity. As to the spastic tibialis posterior, we found a mean muscle depth of 26.5 mm and a mean muscle thickness of 10.1 mm. Furthermore we observed a median tibialis posterior muscle echo intensity of 3.00 on the Heckmatt scale. The tibialis posterior muscle thickness was found to be inversely associated with its depth (p < 0.001) and echo intensity (p = 0.006). Furthermore, tibialis posterior muscle depth was found to be directly associated with its echo intensity (p = 0.004). Our findings may usefully inform manual needle placement into the tibialis posterior for the botulinum toxin treatment of spastic equinovarus foot in chronic stroke patients.

Detailed anatomy of the abducens nerve in the lateral rectus muscle

The aims of this study were to elucidate the detailed anatomy of the abducens nerve in the lateral rectus muscle (LRM) and the intramuscular innervation pattern using Sihler staining. In this cohort study, 32 eyes of 16 cadavers were assessed. Dissection was performed from the LRM origin to its insertion. The following distances were measured: from LRM insertion to the bifurcation point of the abducens nerve, from LRM insertion to the entry site of the superior branch or inferior branch, from the upper border of the LRM to the entry site of the superior branch, from the lower border of LRM to the entry site of inferior branch, and the widths of the main trunk and superior and inferior branches. The single trunk of the abducens nerve divided into two branches 37 mm from insertion of the LRM, and 22 of 32 (68.8%) orbits showed only two superior and inferior branches with no subdivision. The superior branch entered the LRM more anteriorly (P = 0.037) and the superior branch was thinner than the inferior branch (P = 0.040). The most distally located intramuscular nerve ending was observed at 52.9 ± 3.5% of the length of each muscle. Non-overlap between the superior and inferior intramuscular arborization of the nerve was detected in 27 of 32 cases (84.4%). Five cases (15.6%) showed definite overlap of the superior and inferior zones. This study revealed the detailed anatomy of the abducens nerve in the LRM and provides helpful information to understand abducens nerve palsy. Clin. Anat. 30:873-877, 2017. © 2017 Wiley Periodicals, Inc.

Localization of nerve entry points as targets to block spasticity of the deep posterior compartment muscles of the leg

To identify the optimal body surface puncture locations and the depths of nerve entry points (NEPs) in the deep posterior compartment muscles of the leg, 60 lower limbs of thirty adult cadavers were dissected in prone position. A curved line on the skin surface joining the lateral to the medial epicondyles of the femur was taken as a horizontal reference line (H). Another curved line joining the lateral epicondyle of the femur to the lateral malleolus was designated the longitudinal reference line (L). Following dissection, the NEPs were labeled with barium sulfate and then subjected to spiral computed tomography scanning. The projection point of the NEP on the posterior skin surface of the leg was designated P, and the projection in the opposite direction across the transverse plane was designated P'. The intersections of P on H and L were identified as P_H and P_L , and their positions and the depth of the NEP on PP' were measured using the Syngo system and expressed as percentages of H, L, and PP'. The P_H points of the tibial posterior, flexor hallucis longus and flexor digitorum longus muscles were located at 38.10, 46.20, and 55.21% of H, respectively. The P_L points were located at 25.35, 41.30, and 45.39% of L, respectively. The depths of the NEPs were 49.11, 54.64, and 55.95% of PP', respectively. The accurate location of these NEPs should improve the efficacy and efficiency of chemical neurolysis for treating spasticity of the deep posterior compartment muscles of the leg. Clin. Anat. 30:855-860, 2017. © 2017 Wiley Periodicals, Inc.

Intramuscular nerve distribution of the hamstring muscles: Application to treating spasticity

The aim of this article is to elucidate the ideal sites for botulinum toxin injection by examining the intramuscular nerve distributions in the hamstring muscles. The hamstring muscles, biceps femoris, semitendinosus, and semimembranosus (10 specimens each) were stained by the modified Sihler method. The locations of the muscle origins, nerve entry points, and intramuscular arborized areas were recorded as percentages of the total distance from the line crossing the medial and lateral tibial condyles (0%) to the ischial tuberosity (100%). Intramuscular arborization patterns were observed at 15-30% and 50-60% for the biceps femoris, 25-40% and 60-80% for the semitendinosus, and 20-40% for the semimembranosus. This study suggests that botulinum toxin injection for spasticity of the hamstring muscles should be targeted to specific areas. These areas, where the arborization of intramuscular nerve branches is maximal, are recommended as the most effective and safest points for injection. Clin. Anat. 29:746-751, 2016. © 2016 Wiley Periodicals, Inc.

Intramuscular nerve distribution pattern of ankle invertor muscles in human cadaver using sihler stain

INTRODUCTION

We sought to the ideal sites for botulinum toxin injection by examining the intramuscular nerve patterns of the ankle invertors.

METHODS

A modified Sihler method was performed on the flexor hallucis longus, tibialis posterior, and flexor digitorum longus muscles (10 specimens each). The muscle origins, nerve entry points, and intramuscular arborization areas were measured as a percentage of the total distance from the most prominent point of the lateral malleolus (0%) to the fibular head (100%).

RESULTS

Intramuscular arborization patterns were observed at 20-50% for the flexor hallucis longus, 70-80% for the tibialis posterior, and 30-40% for the flexor digitorum longus.

CONCLUSIONS

These findings suggest that treatment of muscle spasticity of the ankle invertors involves botulinum toxin injections in specific areas. These areas, corresponding to the areas of maximum arborization, are recommended as the most effective and safest points for injection.

Approach for needle insertion into the tibialis posterior: An ultrasonography study

INTRODUCTION

To avoid neurovascular damage by needle electrode insertion into the tibialis posterior, we used ultrasonography to determine the proper insertion point based on anatomic landmarks.

METHODS

Using ultrasonography, the safety window, the corrected safety window, and the depth of the tibialis posterior were measured at 4 points (the upper third and midpoint of the tibia using anterior and posterior approaches) in healthy volunteers.

RESULTS

The safety window at the midpoint for the posterior approach was significantly larger than at the other points. The corrected safety window could be defined only at the upper third for the anterior approach and at the midpoint for the posterior approach.

CONCLUSIONS

Among the 4 points used for needle insertion into the tibialis posterior, the midpoint by the posterior approach may be the most favorable insertion point. The upper third may be better for the anterior approach.

Determination of injection site in flexor digitorum longus for effective and safe botulinum toxin injection

OBJECTIVE

To determine the optimal injection site in the flexor digitorum longus (FDL) muscle for effective botulinum toxin injection.

METHODS

Fourteen specimens from eight adult Korean cadavers were used in this study. The most proximal medial point of the tibia plateau was defined as the proximal reference point; the most distal tip of the medial malleolus was defined as the distal reference point. The distance of a line connecting the proximal and distal reference points was defined as the reference length. The X-coordinate was the distance from the proximal reference point to the intramuscular motor endpoint (IME), or motor entry point (MEP) on the reference line, and the Y-coordinate was the distance from the nearest point from MEP on the medial border of the tibia to the MEP. IME and MEP distances from the proximal reference point were evaluated using the raw value and the X-coordinate to reference length ratio was determined as a percentage.

RESULTS

The majority of IMEs were located within 30%-60% of the reference length from the proximal reference point. The majority of the MEPs were located within 40%-60% of the reference length from the proximal reference point.

CONCLUSION

We recommend the anatomical site for a botulinum toxin injection in the FDL to be within a region 30%-60% of the reference length from the proximal reference point.

The significance of tibial and common peroneal nerves in nerve blocks

PURPOSE

The aim of this study was to elucidate the anatomical location of tibial nerve (TN) and common peroneal nerve (CPN) in the popliteal crease for specific nerve block.

METHODS

Fifty fresh specimens from 27 adult Korean cadavers (16 males and 11 females, age 35-87 years) were investigated. Five of the 27 cadavers were used to determine the depths of nerves in cross-section.

RESULTS

Tibial nerve was located 50 % from the most lateral point of the popliteal crease and 1.4-cm deep to the surface. In 20 % of the 50 specimens, the medial sural cutaneous nerve branched out below or at the popliteal crease, whereas the CPN was located at 26 % from the most lateral point of the popliteal crease and 0.7-cm deep from the surface. Furthermore, in 6 % of specimens the lateral sural cutaneous nerve branched out below or at the popliteal crease.

CONCLUSION

The results concerning the location of the TN and CPN at the popliteal crease offer a good guide to optimal nerve block.

Effective zone of botulinum toxin a injections in hallux claw toe syndrome: an anatomical study

INTRODUCTION

The aim of this study was to determine the anatomical location of the motor points of the flexor hallucis longus (FHL) and brevis (FHB) muscles for an effective motor point block.

METHODS

Twenty cadavers were used for this study. For the FHL, we identified the line between the medial and lateral epicondyle of the femur and the line joining the prominent point on the surface of the medial malleolus of the tibia and the lateral malleolus of the fibula. For the FHB, we identified the line between the middle-lowest point of the great toe and the middle-lowest point of the sole of the foot.

RESULTS

The dense area of the motor points was located at 40-70% for the FHL and 50-70% for the FHB.

CONCLUSION

An injection area of 50-60% on the reference line for the FHL and FHB is suggested.