Intramuscular Nerve Research Articles

Muscle-tendon arrangement and intramuscular nerve distribution of flexor digitorum superficialis in the siamang (Symphalangus syndactylus), western lowland gorilla (Gorilla gorilla gorilla), western chimpanzee (Pan troglodytes verus), and Japanese macaque (Macaca fuscata).

Flexor digitorum superficialis (FDS) shows diverse muscle-tendon arrangements among primates. The intramuscular nerve distribution pattern is a criterion for discussing the homology of FDS. In this study, the muscle-tendon arrangement and intramuscular nerve distribution of FDS were examined in the siamang, western lowland gorilla, western chimpanzee, and Japanese macaques. The FDS had muscle bellies to digits II-V. FDS had proximal belly and intermediate tendon except for siamang. Distal belly to digit II (in the western lowland gorilla and western chimpanzees) or distal bellies to digits II and V (in Japanese macaque) originated from the intermediate tendon. In all specimens, nerve branches within digit III belly extended into digit IV belly, and nerve branch(es) within digit IV belly extended into digit V belly. This consistent pattern suggested that each muscle belly to digits III-V is interspecifically homologous. The digit II belly in the siamang and the distal belly to digit II in the western lowland gorilla, western chimpanzees, and Japanese macaques could be homologous based on their similar innervating patterns. The proximal belly was innervated by branches from the communicating nerve between median and ulnar nerves in the western lowland gorilla or branches from median and ulnar nerves in western chimpanzees. In the siamang and Japanese macaque, the whole FDS was innervated by median nerve. The proximal belly in the western lowland gorilla, western chimpanzees, and Japanese macaques could be classified into different groups from the other part of the FDS.

Intramuscular innervation of the tensor fascia latae: Application to total hip arthroplasty.

The aims of this study were to clarify the extra- and intramuscular branching patterns of the tensor fascia latae (TFL) with reference to surface landmarks on the thigh and to thus suggest a safe approach for total hip arthroplasty. Sixteen fixed and four fresh cadavers were dissected and subjected to the modified Sihler's staining method to reveal the extra- and intramuscular innervation patterns, and the findings were matched with surface landmarks. The landmarks were measured from the anterior superior iliac spine (ASIS) to the patella and divided into 20 parts along the total length. The average vertical length of the TFL was 15.92 ± 1.61 cm, which was 38.79 ± 2.73% when converted to a percentage. The entry point of the superior gluteal nerve (SGN) was an average of 6.87 ± 1.26 cm (16.71 ± 2.55%) from the ASIS. In all cases, the SGN entered parts 3-5 (10.1%-25%). As the intramuscular nerve branches traveled distally, they had a tendency to innervate more deeply and inferiorly. In all cases, the main SGN branches were intramuscularly distributed in parts 4 and 5 (15.1%-25%). Most tiny SGN branches were found inferiorly in parts 6 and 7 (25.1%-35%). In three of 10 cases, very tiny SGN branches were observed in part 8 (35.1%-38.79%). We did not observe SGN branches in parts 1-3 (0%-15%). When information on the extra- and intramuscular nerve distributions was combined, we found that the nerves were concentrated in parts 3-5 (10.1%-25%). We propose that damage to the SGN can be prevented if parts 3-5 (10.1%-25%) are avoided during surgical treatment, particularly during the approach and incision.

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.

Multiple nerve cords connect the arms of octopuses, providing alternative paths for inter-arm signaling

Octopuses are remarkable in their ability to use many arms together during behavior (e.g., see Levy etal., 1 Mather,2 Byrne etal.,3 and Hanlon etal.4). Arm responses and multi-arm coordination can occur without engagement of major brain regions,5 which indicates the importance of local proprioceptive responses and peripheral connections. Here, we examine the intramuscular nerve cords (INCs),6,7,8,9 the key proprioceptive anatomy in the arms. INCs are understood to include proprioceptive neurons, multipolar neurons, and motoneurons (reviewed by Graziadei10) and are thought to contribute to structuring whole-arm movement.11 There are four INCs running the full length of each arm (e.g., see Guérin-Ganivet,6 Martoja and May,8 and Graziadei9); we focused on the pair closest to the suckers, called the oral INCs. In tracking the oral INCs, we found that they extend proximally and continue beyond the arm, through the arm's base. Each oral INC bypasses two adjacent arms and is continuous with the nearer oral INC of the third arm over. As a result, an arm connects through oral INC pathways to arms that are two arms away to the right and left of it. In addition to connecting distant arms, nerve fibers project from the central region of the INCs, suggesting function in local tissues. The other two INCs, paired aboral INCs, also extend proximally beyond the arm's base with trajectories suggestive of the oral INC pattern. These data identify previously unknown regions of the INCs that linkdistant arms, creating anatomical connections. They suggest potential INC proprioceptive function in extra-arm tissues and contribute to an understanding of embodied organization for octopus behavioral control.12,13,14,15.

VARIANTS OF THE STRUCTURE, INNERVATION, AND BLOOD SUPPLY OF THE EXTENSOR CARPI RADIALIS LONGUS AND BREVIS IN THE HUMAN FETUS

In modern orthopedic practice, some diseases do not cause pronounced functional disorders in the anatomical segments of the limbs but are accompanied by persistent pain syndrome. Among such diseases is lateral epicondylitis, or «tennis elbow». The superfi cial extensor muscles of the posterior group of the forearm begin in the region of the lateral epicondyle of the humerus, in particular the extensor carpi radialis longus and brevis. The deepening of knowledge about the typical and variant structure, topography, blood supply, and innervation of the extensor carpi radialis longus and brevis in human fetuses will allow for improving the approach to carrying out existing fetal surgical techniques, as well as to creating foundation for the development of modern surgical approaches.The study aimed to determine the anatomical variability of the extensor carpi radialis longus and brevis in human fetuses.The study was conducted on preparations of the upper limbs of 36 human fetuses aged 4-10 months using macromicroscopic preparation, vascular injection, and morphometry. The topographical and anatomical features of the extensor carpi radialis longus and brevis in human fetuses are elucidated: variability and bilateral asymmetry of the external shape and size, variability of the places of origin and attachment, variants of blood supply and innervation, patterns of intramuscular distribution arteries and nerves in these muscles. It was found that the zone of the greatest concentration of intramuscular nerves and arteries is the upper and middle third of the bellies of the extensor carpi radialis longus and brevis.Despite the good blood supply of the extensor carpi radial muscles, the relatively small size of their muscle bellies and the transverse course of the intramuscular nerves result in limited opportunities for cutting out muscle fl aps from them. To cut the fl aps on the leg from these muscles, the most rational cuts are in the ascending (transverse) direction, coinciding with the course of the main intramuscular nerves and arteries. Thus, it is possible to use the extensor carpi radialis longus and brevis only for plastic fi lling of the remaining bone cavities of the upper third of the posterior- lateral surface of the radius.The movement of the extensor carpi radialis longus and brevis is also complicated by the fact that their tendons cross the abductor pollicis longus muscle, extensor carpi radialis longus and brevis, and create serious obstacles for the mobilization of these tendons.Knowledge of the classic and variant anatomy of the arteries of the upper limb, and in particular the described topographic and anatomical features of the right brachial radial artery in a 6-month-old fetus, will allow choosing the correct treatment tactics and avoiding iatrogenic injuries during manipulations, diagnostic and surgical interventions.

An exploratory study on the presence of sensory nerves in the caudal part of the trapezius

Intramuscular onabotulinumtoxinA (BTX) injections and nerve decompression surgery both aim to release compressed sensory nerves and are used in the treatment of migraine/headaches. Although for many BTX injection sites, sensory nerves and their potential entrapment sites have been established, for the trapezius this information is incomplete. A macro- and microscopic cadaveric study was performed in which the suprascapular part of the trapezius was explored for the presence of piercing or penetrating nerves and whether these nerves contained sensory nerve fibers. One side of six human cadavers were dissected to reveal trapezius-associated nerves in its suprascapular part. Schematic overview drawings were made of nerves either piercing or penetrating the trapezius in this region. Piercing or penetrating cervical nerves were resected and microscopically studied for the presence of sensory nerve fibers. For this suprascapular region, correlating potential entrapment sites of the supraclavicular nerves were detected. In all specimens, plexuslike connections between the accessory nerve and branches of the cervical plexus, varying between CII-CV, were observed to innervate the trapezius at locations that showed overlap with BTX injection sites. Moreover, all these nerves contained sensory nerve fibers as confirmed by immunohistochemical staining with the sensory nerve marker CGRP. The presence of potential entrapment sites for supraclavicular nerves and other cervical nerve branches might explain why BTX injection in the suprascapular part of the trapezius show therapeutic effectivity in the treatment of migraine/headaches

Немалиновая миопатия редкой формы (случай из практики)

Introduction Nemaline myopathies (NM) are a group of neuromuscular diseases, the distinctive histological feature of which are nemaline rods in myosymplasts. The purpose of this work is to describe the morphology of a rare form of primary nemaline myopathy that progresses in adulthood. Material and methods The surgical material of the paravertebral muscles of a 51-year-old patient with scoliotic deformity at the level of L4-S1, who was repeatedly operated on to correct spinal deformity due to neurological disorders, was studied. Paraffin sections were stained with hematoxylineosin, according to Masson, using the Ptah method, studied using a 3DHISTECH Pannoramic MIDI II BF scanning microscope to digitize preparations using Whole slide imaging technology in two modes: Single layer mode and Extended focus (3DHISTECH, Hungary). Results In the fragments of the altered muscle tissue, filamentous structures of nemaline bodies in myosymplasts were identified, which were located diffusely-dotted throughout the sarcoplasm or formed clusters of various configurations. There was an increased variability in the diameters of muscle fibers, internal nuclei, myosymplasts altered by contraction and with signs of myophagy, patterns of gradual replacement of muscle fibers by adipocytes, massive fatty degeneration of fibers, and fibrosis of the interstitial space. Intramuscular nerve trunks showed signs of complete involution; fibrous perineurium was preserved, and there were single nerve fibers; neuromuscular spindles were distinguished by an enlarged connective tissue capsule. The vessels of the arterial flow had signs of fibrosis and obliteration of the lumen; the vessels of the venous bed were tortuous. Discussion Due to a large number of genes responsible for NM, genetic search can be difficult and is effective only in 50 % of cases. It has been established that nemaline bodies can be distributed diffusely or form clusters of irregular shape, more often subsarcolemmal and characteristic of small fibers. In the presented clinical case, nemaline bodies were observed over the entire area of the fibers and were characteristic of myosymplasts of various sizes. Conclusion The histopathological study of the paravertebral muscles established the neuromuscular nature of the disease, being nemaline myopathy that progressed in adulthood and had not been diagnosed at previous stages of treatment.

O.07 TDP43 accumulates in intramuscular nerve bundles of ALS patients

Amyotrophic lateral sclerosis (ALS) shows progressive muscle weakness and atrophy caused by neuronal death associate with TAR DNA-binding protein 43 (TDP43). Meanwhile, Awaji and Gold Coast criterion include an electrophysiological aspect to support clinical findings but not a pathological aspect because myopathological findings of ALS are not considered as specific. However, the advantage of the Awaji criteria is less pronounced in patients with spinal-onset ALS. The Gold Coast criteria enables us to diagnose spinal onset ALS patients and needs to allow for a specific diagnosis including a pathological aspect. Here, we aimed to identify and characterize the histopathology of peripheral axons in muscles of ALS patients. The post-mortem study included 10 sporadic ALS (SALS) patients with TDP43 pathology and 12 patients with non-ALS disease. The muscle biopsy cohort considered 450 patients and enrolled 114 as without family history of ALS or other neuromuscular diseases and not diagnosed with muscle diseases at biopsy. They ensure clinical follow-up in minimum one year. Exclusions were as follows: 51 for not screening clinical records after biopsy, 282 diagnosed with muscular diseases, and 3 harboring known causative genes of ALS. Muscle tissues were evaluated by histochemistry and immunohistochemical analysis. Ten SALS patients exhibited axonal phosphorylated TDP43 (pTDP43)-positive accumulations in intramuscular nerve bundles; 12 non-ALS patients did not. Among the muscle biopsy cohort, 71 patients exhibited intramuscular nerve bundles; 43 did not. Of the former, 33 presenting pTDP43-positive nerve bundles were later diagnosed with ALS. The remaining 38 showed no pTDP43-positive bundles and did not develop ALS. Among those without evident nerve bundles, 3 were later diagnosed with ALS. Among ALS patients in the biopsy cohort, 9 having pTDP43-positive bundles showed only lower motor neuron symptoms at biopsy. Axonal pTDP43 accumulations might be characteristic for ALS patients. As such findings precede clinical fulfillment of the Gold Coast criteria, TDP43 in nerve bundles might be a novel diagnostic biomarker for ALS.

Localization of the nerves innervating the pelvic floor muscles: An application to pelvic pain treatment.

The aim of this study was to achieve accurate localization of the body surface position and depth of the center of the intramuscular nerve dense region (CINDR) of the pelvic floor muscles and to establish a target site for treating pelvic floor muscle spasm or weakness. Thirty-six adult cadavers were studied in the prone position. To locate the CINDR of the levator ani and coccygeus muscles, horizontal (H) and longitudinal (L) reference lines were used. Sihler's staining revealed the intramuscular nerve dense region of the pelvic floor muscles. The CINDR was labeled with barium sulfate and spiral computed tomography scanning, and three-dimensional reconstructions were obtained. The anterior and posterior CINDR projection points (P and P'), the position of point P projected on to the H and L lines (PH and PL ), and the CINDR depth were determined using the Syngo system. The PH of the CINDR of the levator ani and the coccygeus muscle were located at (24.73 ± 0.17)% and (15.93 ± 0.31)% of the H line, respectively. The PL were located at (84.30 ± 2.47)% and (6.76 ± 0.93)% of the L line. The puncture depth of the levator ani muscle was located at (5.56 ± 0.53) cm, and the depth of the coccygeus muscle at (22.08 ± 2.11)% of the PP' line. The body surface position and depth of the CINDR of the pelvic floor muscles were conducive to locating the target more efficiently and enhancing the efficacy of botulinum toxin A injection for treating pelvic floor muscle spasm and weakness with electrical stimulation or biofeedback.

Dry Needling Produces Mild Injuries Irrespective to Muscle Stiffness and Tension in Ex Vivo Mice Muscles.

Numerous studies have suggested that the myofascial trigger points are responsible for most of the myofascial pain syndrome, so it seems reasonable that its destruction is a good therapeutic solution. The effectiveness of dry needling (DN) has been confirmed in muscles with myofascial trigger points, hypertonicity, and spasticity. The objective of this study is to analyze the need of repetitive punctures on muscles in different situations. The levator auris longus (LAL) muscle and gastrocnemius muscle from adult male Swiss mice were dissected and maintained alive, while being submerged in an oxygenated Ringer's solution. DN was evaluated under four animal models, mimicking the human condition: normal healthy muscles, muscle fibers with contraction knots, muscles submerged in a depolarizing Ringer solution (KCl-CaCl2), and muscles submerged in Ringer solution with formalin. Thereafter, samples were evaluated with optical microscopy (LAL) and scanning electron microscopy (gastrocnemius). Healthy muscles allowed the penetration of needles between fibers with minimal injuries. In muscles with contraction knots, the needle separated many muscle fibers, and several others were injured, while blood vessels and intramuscular nerves were mostly not injured. Muscles submerged in a depolarizing solution inducing sustained contraction showed more injured muscular fibers and several muscle fibers separated by the needle. Finally, the muscles submerged in Ringer solution with formalin showed a few number of injured muscular fibers and abundant muscle fibers separated by the needle. Scanning electron microscopy images confirm the optical analyses. In summary, dry needling is a technique that causes mild injury irrespective of the muscle tone.

Biopsy Characteristics, Subtypes, and Prognostic Features in 107 Cases of Feline Presumed Immune-Mediated Polyneuropathy.

Inflammatory polyradiculoneuropathy (IMPN) is one of the causes of sudden onset of neuromuscular signs such as para-/tetraparesis in young cats. Even though most cases have a favorable outcome, persistent deficits, relapses, and progressive courses are occasionally seen. As clinical presentation does not always appear to predict outcome and risk of recurrence, this study was initiated to screen for prognostic biopsy findings in a large cohort of histologically confirmed IMPN cases with clinical follow-up. In total, nerve and muscle specimens of 107 cats with biopsy diagnosis of presumed autoreactive inflammatory polyneuropathy and 22 control cases were reviewed by two blinded raters for a set of 36 histological parameters. To identify patterns and subtypes of IMPN, hierarchical k-means clustering of 33 histologic variables was performed. Then, the impact of histological parameters on IMPN outcome was evaluated via an univariate analysis to identify variables for the final multivariate model. The data on immediate outcome and follow-up were collected from submitting neurologists using a purpose-designed questionnaire. Hierarchical k-means clustering sorted the tissues into 4 main categories: cluster 1 (44/129) represents a purely inflammatory IMPN picture, whereas cluster 2 (47/129) was accompanied by demyelinating features and cluster 3 (16/129) by Wallerian degeneration. Cluster 4 (22/129) reflects normal tissues from non-neuropathic control cats. Returned questionnaires provided detailed information on outcome in 63 animals. They were categorized into recovered and non-recovered. Thereby, fiber-invasive infiltrates by mononuclear cells and mild fiber loss in intramuscular nerve branches correlated with higher probabilities of recovery. Remyelination in semithin sections, on the other hand, is correlated with a less favorable outcome. Animals grouping in cluster 1 had a tendency to a higher probability of recovery compared to other clusters. In conclusion, diagnosis of feline IMPN from nerve and muscle biopsies allowed for the identification of histologic features that were positively or negatively correlated with outcome.

TDP-43 Accumulation Within Intramuscular Nerve Bundles of Patients With Amyotrophic Lateral Sclerosis

Degeneration of neuromuscular junctions and axons is considered an important aspect of the pathomechanism of amyotrophic lateral sclerosis (ALS). However, a mechanism including the role of transactive response DNA-binding protein 43 (TDP-43) in axons has not been pathologically clarified. To identify and characterize the histopathology of peripheral axons in the skeletal muscle of patients with ALS. This study comprised 2 parts: a postmortem case-control study and a retrospective population-based cohort study with a minimum of 1 year of follow-up. Patients in the cohort study were enrolled from January 1, 2004, to September 30, 2019. The postmortem study included patients with sporadic ALS (SALS) with TDP-43 pathology and control patients with non-ALS disease. The cohort study enrolled patients without a family history of ALS or other neuromuscular disease and those not diagnosed with a muscle disease at biopsy. Patients were excluded if their clinical records were not screened after biopsy, if they were diagnosed with a muscular disease, and if they were harboring known causative genes of ALS. Data were collected between September 2019 and June 2021 and analyzed in June 2021. Muscle biopsy or postmortem muscle tissue examination. Clinical information and muscle pathological characteristics. A total of 10 patients with autopsy-confirmed SALS (mean [SD] age at death, 76.1 [8.5] years; 8 men [80%]) exhibited axonal phosphorylated TDP-43 (pTDP-43)-positive accumulations in intramuscular nerve bundles; the 12 control patients without ALS did not. Among the 114 patients in the cohort study (mean [SD] age, 62.3 [16.1] years; 76 men [67%]), 71 patients (62.3%) exhibited intramuscular nerve bundles; 43 (37.7%) did not. Among those who exhibited pTDP-43-positive intramuscular nerve bundles, 33 patients (22 men [66.7%]; mean [SD] age, 65.2 [15.6] years) were later diagnosed with ALS. The other 38 patients (26 men [68.4%]; mean [SD] age, 59.3 [18.0] years) showed no pTDP-43-positive bundles and did not develop ALS. Among those without evident nerve bundles (28 men [65.1%]; mean [SD] age, 61.3 [15.3] years), 3 were later diagnosed with ALS. Among patients with ALS in the biopsy cohort, 9 with pTDP-43-positive bundles showed only lower motor neuron symptoms at biopsy. Results of this dual case-control and retrospective cohort study suggest that axonal pTDP-43 accumulations may be characteristic for patients with ALS. As such findings precede clinical fulfillment of the Gold Coast criteria, TDP-43 in nerve bundles may be a novel diagnostic biomarker for ALS.

Clinical Course and Diagnostic Findings of Biopsy Controlled Presumed Immune-Mediated Polyneuropathy in 70 European Cats.

There is a paucity of information on the clinical course and outcome of young cats with polyneuropathy. The aim of the study was to describe the clinical features, diagnostic investigations, and outcome of a large cohort of cats with inflammatory polyneuropathy from several European countries. Seventy cats with inflammatory infiltrates in intramuscular nerves and/or peripheral nerve biopsies were retrospectively included. Information from medical records and follow up were acquired via questionnaires filled by veterinary neurologists who had submitted muscle and nerve biopsies (2011–2019). Median age at onset was 10 months (range: 4–120 months). The most common breed was British short hair (25.7%), followed by Domestic short hair (24.3%), Bengal cat (11.4%), Maine Coon (8.6%) and Persian cat (5.7%), and 14 other breeds. Male cats were predominantly affected (64.3%). Clinical signs were weakness (98.6%) and tetraparesis (75.7%) in association with decreased withdrawal reflexes (83.6%) and, less commonly, cranial nerve signs (17.1%), spinal pain/hyperesthesia (12.9%), and micturition/defecation problems (14.3%). Onset was sudden (30.1%) or insidious (69.1%), and an initial progressive phase was reported in 74.3%. Characteristic findings on electrodiagnostic examination were presence of generalized spontaneous electric muscle activity (89.6%), decreased motor nerve conduction velocity (52.3%), abnormal F-wave studies (72.4%), pattern of temporal dispersion (26.1%) and unremarkable sensory tests. The clinical course was mainly described as remittent (49.2%) or remittent-relapsing (34.9%), while stagnation, progressive course or waxing and waning were less frequently reported. Relapses were common and occurred in 35.7% of the cats' population. An overall favorable outcome was reported in 79.4% of patients. In conclusion, young age at the time of diagnosis and sudden onset of clinical signs were significantly associated with recovery (p < 0.05). Clinical and electrodiagnostic features and the remittent-relapsing clinical course resembles juvenile chronic inflammatory demyelinating polyneuropathy (CIDP), as seen in human (children/adolescents), in many aspects.

Localization of the Center of the Intramuscular Nerve Dense Region of the Suboccipital Muscles: An Anatomical Study.

PurposeThis study aimed to determine the body surface puncture position and depth of the center of the intramuscular nerve dense region in the suboccipital muscle to provide morphological guidance for accurate botulinum toxin A injection to treat headaches caused by increased suboccipital muscle tension.MethodsTwenty-four cadavers aged 66.5 ± 5.3 years were studied. The curve line connecting occipital eminence or mastoid process and spinous process of the 7th cervical vertebrae was considered the longitudinal reference line (L) and horizontal reference line (H), respectively. Sihler's staining, barium sulfate labeling, and CT were employed. The body surface projection point of the center of the intramuscular nerve dense region was designated as P. The projection of the center of the intramuscular nerve dense region was in the opposite direction across the transverse plane and was recorded as P'. The intersections of the vertical line through point P and lines L and H were designated as PL and PH. The percentage position of the PH and PL points on the H and L lines and the depths of the center of intramuscular nerve dense regions were identified.ResultsSihler's staining showed one intramuscular nerve-dense region in each suboccipital muscle. The PH of the center of the intramuscular nerve dense region was located at 51.40, 45.55, 20.55, and 43.50%. The PL was located at 31.38, 30.08, 16.91, and 52.94%. The depth of the center of the intramuscular nerve dense region was at 22.26, 22.54, 13.14, and 27.30%. These percentage values are all the means.ConclusionAccurately defining the body surface position and depth of the center of intramuscular nerve dense region in suboccipital muscles will help to improve botulinum toxin A to target localization efficiency for treating tension-type headache.

Intramuscular Neural Arborization of the Latissimus Dorsi Muscle: Application of Botulinum Neurotoxin Injection in Flap Reconstruction.

Postoperative pain after breast reconstruction surgery with the latissimus dorsi flap is a common occurrence. Botulinum neurotoxin (BoNT) injection during surgery is effective in reducing postoperative pain. This study aimed to determine the most appropriate locations for BoNT injection. A modified Sihler’s method was performed on the latissimus dorsi muscles in 16 specimens. Intramuscular nerve arborization was noted under the landmark of the medial side surgical neck of the humerus to the line crossing the spinous process of T5 and the middle of the iliac crest. The latissimus dorsi muscles were divided into medial, middle, and lateral segments with 10 transverse divisions to give 10 sections (each 10%). Intramuscular nerve arborization of the latissimus dorsi muscle was the largest from the medial and lateral part of the muscle ranging from 40 to 60%, middle part from 30 to 60% and medial, middle and lateral part from 70 to 90%. The nerve entry points were at the medial and lateral part with 20–40% regarding the medial side of surgical neck of the humerus to the line crossing spinous process of T5 to the middle of iliac crest. These outcomes propose that an injection of BoNT into the latissimus dorsi muscles should be administered into specific zones.

Validation of terminal Schwann cell gene marker expression by fluorescent in situ hybridization using RNAscope

Recent RNA-seq studies have generated a new crop of putative gene markers for terminal Schwann cells (tSCs), non-myelinating glia that cap axon terminals at the vertebrate neuromuscular junction (NMJ). While compelling, these studies did not validate the expression of the novel markers using in situ hybridization techniques. Here, we use RNAscope technology to study the expression of top candidates from recent tSC and non-myelinating Schwann cell marker RNA-seq studies. Our results validate the expression of these markers at tSCs but also demonstrate that they are present at other sites in the muscle tissue, specifically, at muscle spindles and along intramuscular nerves.

VARIATIONS OF THE STRUCTURE, TOPOGRAPHY, BLOOD SUPPLY AND INNERVATION OF THE BRACHIORADIALIS IN HUMAN FETUS.

The aim of the research was to establish the features of age-related and individual anatomical variability of the brachioradialis, its blood supply, and innervation options. Materials and methods: The study of the variant anatomy of the brachioradialis and its vascular and nervous structures was carried out on 25 preparations of human fetuses of 4-7 months, 81.0-270.0 mm parietal-coccygeal length (PCL) using macromicroscopic preparation, injection vessels, and morphometry. Results: Spindle-like (56%) and round (24%) shapes of the brachioradialis were found in most of the studied fetuses; its elongated flat (12%) and triangular (8%) forms occur less often. In a fetus of 185.0 mm TKD, the right brachioradialis consisted of two separate parts: upper and lower, which were connected at the level of the middle of the forearm into a common short muscle belly. In another human fetus of 220.0 mm TKD, the right brachioradialis also consisted of two separate parts - upper and lower, triangular in shape, but separated by a pronounced horizontal gap. Conclusions: The features of the fetal anatomy of the brachioradialis are established: its variability and bilateral asymmetry of shape and size, variability of the places of origin and attachment, etc. In individual human fetuses, the brachioradialis consists of two separate parts that have special topographical relationships. The area of the greatest concentration of both extra- and intramuscular nerves and arteries is the upper and middle third of the brachioradialis. In the area of the forearm, the course of radial vascular-nerve formations is determined by the brachioradialis.

Anatomic variability of the nerves of the triceps surae in early human fetuses

Background. Establishing fetal anatomical variability of intramuscular nerves and their connections plays an important role in the search for and development of new methods for the diagnostic and treatment posterior region of the leg. Objective – to find out the topographic and anatomical features of the innervation of the triceps surae in human fetuses 4-6 months. Methods. The study was performed on 46 human fetuses 81.0-230.0 mm crown-rump length (CRL) length using macromicroscopic preparation, vascular injection, and morphometry. Results. In early human fetuses, the anatomical variability of the distribution of intramuscular nerves in the thickness of the triceps surae was established, which is due to the variability of the structure and topography of the tibial nerve, structural and functional organization of triceps surae, arterial branching and interneural connections in the thickness of the heads of the gastrocnemius and soleus in fetuses of different and the same age groups, and sometimes in the same fetus. Conclusion. The main source of innervation of the triceps surae is the tibial nerve, which can be presented by a single trunk, main and additional trunks, or several independent trunks. The nerves in the thickness of the triceps are unevenly distributed. The highest concentration of muscular branches of the tibial nerve is determined in the medial head of the gastrocnemius and the medial part of the soleus. Information on fetal topography of intramuscular nerves in the thickness of the right and left triceps surae, as well as forms of their anatomical variability, both in fetuses of different and the same age and sometimes in the same fetus, due to structural-functional organization of the components of the triceps surae, the type of branching of arteries and nerves in the thickness of the heads of the gastrocnemius and soleus. Atypical variants of the topography of the tibial nerve and common fibular nerve in early fetuses, as well as interneural connections in the thickness of the components of the triceps surae, are more common on the right lower leg.

Macro-Microscopic Features of the Leg Muscles Innervation

The purpose of the study was to disclose topographic anatomical features of the extra- and intramuscular innervation points of the leg. Materials and methods. 15 adult human subjects and one-month old baby legs at three levels were studied using such methods: cross-sections according to N.I. Pirogov technique, histotopographic sections, macro-microscopic method, histological staining with hematoxylin-eosin and Krutsay. Results. In our macro-microscopic study, the main attention was paid to the individual anatomical variability in the innervation of the lower leg muscles. Study of the nerves of the leg muscles allowed to clarify the course of the neurovascular bundle of the leg at its three levels, taking into account individual age characteristics, and also to show the myeloarchitectonics of both the main nerve trunks and their intramuscular branches. Such differences in the location of the leg muscles of an adult and of one month-old baby undoubtedly related to the fact that the child’s muscular belly is longer in relation to the tendon. The histotopography of intramuscular nerves on total transverse sections of antagonistic muscles was studied: flexor and extensor digitorum longus, longus flexor and extensor of the big toe, and also the spectrum of myelin fibers contained in these nerves in a one-month-old baby and an adult was investigated. On histotopographic sections of the extensor digitorum longus nerve in a one-month-old baby, thick-diameter myelin fibers are absent, whereas in the long finger flexor nerve, on average, they are 0.5%. The number of thin and medium is respectively 8%, 13% and 83.5%, 16%. However, we have determined individual anatomical variability in the location of the vessels in relation to the main nerve trunks, as well as differences in the topography of the nerve in the corresponding muscles. Conclusion. In the nerves of the leg muscles, features were found, both in quantitative and qualitative composition of the conductors forming them; in the nerves of the flexor muscles, the composition of the nerve fibers is more diverse (with a slight predominance of the number of medium, thick and very thick fibers), which is associated with the peculiarity of their functions; in adulthood, the % ratio in the spectrum of myelin fibers in the nerves of the lower leg changes significantly

Histomorphometric study of the soleus muscle under conditions of modeling of spinal cord contusion injury: experimental morphological study

Objective. To conduct a morphometric analysis of the soleus muscle of rats after moderate spinal cord contusion injury.Material and Methods. Experiments were performed on female Wistar rats aged 8–12 months, weighing 270–320 g. Animals of the experimental group (n = 25) underwent laminectomy at the T9 level under general anesthesia and modeling of spinal contusion injury of moderate severity. Intact rats constituted the control group (n = 10). Euthanasia was performed on the 5th, 15th, 30th, 60th, 90th, and 180th days of the experiment. Paraffin sections were stained with hematoxylin-eosin and Masson, the diameters of muscle fibers were determined by computer morphometry, and histograms of their distribution were obtained.Results. In the soleus muscle, the signs of reversible reparative processes prevailed in response to neurotrophic damage. It was evidenced by a local increase in the diversity of myocyte diameters and the loss of polygonality of their profiles, focal destruction of muscle fibers, activation of the connective tissue component, disorganization of some intramuscular nerve conductors, and vascular fibrosis of perimysium. Nevertheless, the histostructure of an intact muscle prevailed in the course of the experiment, which was confirmed by the data of morphometric analysis. All histograms of the distribution of the muscle fiber diameters are unimodal with a mode in the range of 30–41 μm. On the 180th day, the maximum myocyte diameters in the histogram of the left limb muscle belonged to the range of 21–30 μm, which was typical for histograms in the intact group.Conclusion. The nature of the plastic reorganization of the soleus muscle when neurotrophic control is impaired indicates compensatory regeneration of muscle tissue by the type of restitution, which opens up the possibility of predicting the rehabilitation period. It is advisable to take this into account when developing medical and social programs and therapeutic measures, where the most important role is played by superficial neuromuscular and functional electrical stimulation.