Accessory Muscle Research Articles

Outcome of Exacerbation of Chronic Obstructive Pulmonary Disease (COPD) in a Tertiary Care Hospital

Background: Patients with chronic obstructive pulmonary disease (COPD) may suffer from recurrent exacerbations, with a worsening of symptoms and reduction in lung function that may not be recovered in a small proportion of patients. Exacerbations of COPD are associated with increased morbidity and mortality. Objectives: The objectives of the study were to find out the in-hospital outcome of patients admitted with COPD exacerbation Methods: This prospective observational study was conducted in the Department of Medicine, Shere Bangla Medical College Hospital, Barisal during the period of January 2022 to December 2022. 42 known patients with COPD exacerbation admitted in medicine unit during the study period were enrolled in the study by convenient sampling. COPD with bronchogenic carcinoma, with bronchiectasis and with ischaemic heart disease were excluded from the study. All patients were examined regularly for cough, sputum, grading of dyspnoea, tracheal tug, prominence of accessory muscles, sleep disturbance, frequency of inhaled β-2 agonist therapy per day for 7 days. After 7 days follow up, patients were categorized into-improved, when it fulfills the following GOLD criteria or not improved. After processing all available information Statistical analysis was done using SPSS for windows version 22. Results: The mean±SD age of the patients was 66.3±10.0 years with a range of 46-85 years.There were 37(88.1%) male patients and 5(11.9%) female patients. The mean±SD duration of illness of the patients was 9.24±4.05 years with a range of 2-15 years. The median duration was 10 years. Tracheal tag, prominence of accessory muscles of respiration, sleep disturbance, cyanosis, and loss of consciousness was present in 95.2%, 95.2%, 71.4%, 28.60% and 9.5% patients respectively. X-ray chest P-A view showed that 88.1% patients had the diagnosis of only COPD, 2.4% had COPD with cardiomegaly and 2.4% had COPD with cor-pulmonale and 7.1% normal X-ray finding. ECG finding showed that 9.5% patients had Cor pulmonale with COPD, 11.9% had sinus tachycardia, 4.8% had. RVH, 2.4% had p pulmonale with sinus tachycardia. The mean±SD oxygen saturation of the patients was 92.10±5.27% with a range of 72-95%. The median saturation was 94%. The mean±SD length of hospital stay was 5.21±1.18 days with a range of 3-7 days. The median length of hospital stay was 5 days. 39(92.9%) patients were improved and discharged from the hospital and 3(7.1%) patients died. Conclusion: The mean length of hospital stay was about 5 days. 92.9% of the cases, the symptoms of exacerbations of COPD subside within 10 days with standard regimen of treatment and in-hospital mortality was 7.1%

Acute effects of manual breathing assist technique on lung volume and dyspnea in individuals with severe chronic obstructive pulmonary disease: A quasi-experimental study.

Manual breathing assist technique (MBAT) is a common physical therapy technique used to facilitate airway clearance and improve ventilation and oxygenation. The effects during and immediately after intervention in individuals with chronic obstructive pulmonary disease (COPD) are unknown. This study aimed to investigate the acute effects and potential mechanisms of MBAT on lung volume, dyspnea, and oxygenation in individuals with COPD. This non-randomized quasi-experimental pre-test/post-test study included participants from pulmonary rehabilitation programs at Tagami Hospital (COPD group) and a community exercise program (Healthy group). During a single session, MBAT was applied during the expiration of every breath for 10 minutes. Dyspnea and lung volumes (tidal volume; VT, inspiratory capacity; IC, inspiratory reserved capacity; IRV, expiratory reserve capacity; ERV) were collected at baseline and after MBAT. Pulse oximetry (SpO2), skeletal muscle oxygenation (SmO2), and oxy- and deoxy-hemoglobin (O2Hb and HHb) using near-infrared spectroscopy (NIRS) were collected at baseline, during, and after MBAT. Between-group comparisons were conducted using the Mann-Whitney U-test and chi-square analyses. Within-group changes before and after MBAT were analyzed using the Wilcoxon signed-rank test. The Kruskal-Wallis test was used to detect differences in NIRS variables in each phase and over time. Thirty participants with COPD, matched for age and sex, were included, with 15 individuals per group. The difference scores of VT, IRV, and IC were significantly higher in the Healthy group than in the COPD group, but improvements in dyspnea and SpO2 were significantly higher in the COPD group. Compared to baseline, ERV decreased significantly in both groups, with dyspnea and SpO2 improving significantly only in the COPD group. Inspiratory accessory muscle ΔO2Hb and ΔHHb were significantly higher and lower (respectively) during MBAT in the COPD group compared to the Healthy group. Additionally, only the COPD group had increased SmO2 during and after MBAT compared to baseline. MBAT in patients with COPD had acute physiological effects in reducing dyspnea by facilitating expiration and decreasing the recruitment of accessory respiratory muscles. MBAT may help individuals with COPD reduce dyspnea before exercise therapy in a pulmonary rehabilitation program.

Diaphragmatic myoclonus post cerebellar hemorrhage: a case report

BackgroundDiaphragmatic myoclonus is a rare motor disorder that affects muscle tone. It is characterized by involuntary movements of the abdominal wall and rhythmic, repetitive contractions of the accessory or respiratory muscles, all of which are innervated by the cervical nerve roots.Case descriptionWe reviewed the case of a 57-year-old male patient who underwent surgery for a left cerebellar hemorrhage. He exhibited persistent myoclonus in the palate, jaw, and thoracoabdominal region. Following treatment, there was a significant reduction in flutter amplitude in these areas.ConclusionThe clinical rarity and variability of presentations often make diagnosis challenging and delayed. It is believed that this condition stems from abnormal excitation within the central nervous system or neural pathways that involve the phrenic nerve. Another potential mechanism is the direct irritation of the diaphragm. Ultrasound, chest fluoroscopy, and electromyography (EMG) can support the diagnosis. Various pharmacological and surgical treatments have been tried, yet specific treatment guidelines are still lacking.

Muscle reoxygenation is slower after higher cycling intensity, and is faster and more reliable in locomotor than in accessory muscle sites.

Wearable near-infrared spectroscopy (NIRS) can be used during dynamic exercise to reflect the balance of muscle oxygen delivery and uptake. This study describes the behaviour and reliability of postexercise reoxygenation with NIRS as a function of exercise intensity at four muscle sites during an incremental cycling test. We discuss physiological components of faster and slower reoxygenation kinetics in the context of sport science and clinical applications. We hypothesised that reoxygenation would be slower at higher intensity, and that locomotor muscles would be faster than accessory muscles. We quantified test-retest reliability and agreement for each site. Twenty-one trained cyclists performed two trials of an incremental cycling protocol with 5-min work stages and 1-min rest between stages. NIRS was recorded from the locomotor vastus lateralis and rectus femoris muscles, and accessory lumbar paraspinal and lateral deltoid muscles. Reoxygenation time course was analysed as the half-recovery time (HRT) from the end of work to half of the peak reoxygenation amplitude during rest. Coefficient of variability (CV) between participants, standard error of the measurement (SEM) within participants, and intraclass correlation coefficient (ICC) for test-retest reliability were evaluated at 50%, 75%, and 100% peak workloads. A linear mixed-effects model was used to compare differences between workloads and muscle sites. HRT was slower with increasing workload in the VL, RF, and PS, but not DL. VL had the fastest reoxygenation (lowest HRT) across muscle sites at all workloads (HRT = 8, 12, 17s at 50%, 75%, 100% workload, respectively). VL also had the greatest reliability and agreement. HRT was sequentially slower between muscle sites in the order of VL < RF < PS < DL, and reliability was lower than for the VL. This study highlights the potential for using wearable NIRS on multiple muscle sites during exercise. Reoxygenation kinetics differ between local muscle sites with increasing intensity. Moderate-to-good reliability in the VL support its increasing use in sport science and clinical applications. Lower reliability in other muscle sites suggest they are not appropriate to be used alone, but may add information when combined to better reflect systemic intensity and fatigue during exercise at different intensities.

The accessory brachioradialis muscle: prevalence of a rare variant with possible clinical implications.

The brachioradialis muscle (BRM) belongs to the lateral group of forearm muscles and contributes to the elbow flexion. Accessory brachioradialis muscle (ABRM) or "brachioradialis accessorius" represents an uncommon BRM variant, not been enough studied. The present study investigates the prevalence of the ABRM, along with its origin, insertion, and innervation. Eighty-three upper limbs were meticulously dissected at the arm, forearm, and cubital fossa to investigate the ABRM presence. When the variant muscle was identified, morphometric measurements were obtained. The ABRM was identified in two upper limbs (2/83, 2.4%), in a male cadaver, bilaterally. Its origin was located along with the typical BRM, and its insertion was identified into the anterior surface of the radius (proximal third). The ABRM was innervated by the radial nerve, coursing posteriorly (deeply). In the current study, the variant muscle was observed in 2.4%. Radial nerve compression, at the forearm, is not an uncommon entrapment neuropathy. The relationship between the radial nerve and the ABRM could precipitate radial neuropathy.

Nasal high flow or noninvasive ventilation? navigating hypercapnic COPD exacerbation treatment: A randomized noninferiority clinical trial

BackgroundNoninvasive ventilation (NIV) has been the cornerstone for managing acute exacerbations of COPD (AECOPD) with hypercapnic respiratory failure. Nasal high flow (NHF) oxygen therapy has emerged as a potential alternative, offering a more tolerable modality with promising outcomes. The aim of the present study was to evaluate whether NHF respiratory support is noninferior to NIV with respect to treatment failure, in patients with mild-to-moderate hypercapnic AECOPD. MethodsIn this multi-center, randomized, noninferiority trial, 105 patients with AECOPD and respiratory failure type II were enrolled. Participants were randomly assigned to receive either NHF therapy or NIV. The primary endpoint was the frequency of treatment failure, defined as the need for intubation and invasive mechanical ventilation or a switch to the alternative treatment group. Secondary endpoints included changes in respiratory parameters, patient comfort indicators, and the occurrence of complications. ResultsThe findings revealed no significant difference in the primary outcome between the groups, with a treatment failure rate of 19.6 % (10 out of 51) in the NHF group and 14.8 % (8 out of 54) in the NIV group. Interestingly, NHF users reported significantly lower levels of dyspnea and discomfort at multiple follow-up points. Despite the differences in patient comfort, respiratory parameters such as respiratory rate, arterial blood gases, and use of accessory muscles of respiration showed no significant disparities between the groups throughout the study period. ConclusionsNHF therapy was similar to NIV in preventing treatment failure among patients with hypercapnic AECOPD, offering a viable alternative with enhanced comfort. Trial registrationThe study was prospectively registered in ClinicalTrials.gov (Identifier: NCT03466385) on March 15, 2018.

The brachioradialis longus: an unreported accessory form of the brachioradialis muscle.

The brachioradialis muscle (BR) belongs to the lateral forearm muscle. Typically, the radial nerve innervates it. BR morphological variability, such as split muscular belly, split tendon, or accessory BR (ABR), has been described in the current literature. A 68-year-old female donated cadaver was routinely dissected for research and educational purposes. A variant muscle was identified extending at the right arm's lateral and forearm compartments. It originated from the humerus lateral surface between the deltoid and the triceps brachii lateral head, joined the second muscular head from the brachialis muscle, and inserted into the radius styloid process. According to its origin, course, and insertion, the variant muscle probably corresponded to the BR accessory form. However, in the current literature, the ABR morphology corresponds to an accessory muscle originating adjacent to the typical BR and inserted into the radial tuberosity. At the same time, it was defined as "brachioradialis brevis." In the current case, the variant muscle differed significantly from the current literature due to the origin, insertion, length, and relationship with the typical BR; therefore, the term "brachioradialis longus" seemed adequate to describe this variant muscle.

Accessory thoracic muscles in human fetuses.

Typically, the anterior thoracic wall musculature is composed of the pectoralis major and pectoralis minor. Embryologically, these two muscles are originated from a common pectoral muscle mass; therefore, disruption of the normal development and differentiation could give rise to an aberrant or accessory muscle. The main aim of this study is to demonstrate and classify the accessory muscles of the pectoralis region in human fetuses. Fifty spontaneously aborted human fetuses (25 male and 25 female, 100 sides) aged 18-38 weeks of gestation at death, and fixed in 10% formalin solution were examined. Following parental approval, the fetuses were donated to the Medical University anatomy program. The pectoralis major and minor muscle's morphology, the possible occurrence of accessory muscles of pectoral region and its morphology, their origins, and insertions, as well as the morphometric details, were assessed. The pectoralis major and minor were bilaterally found in all fetuses (100 cases). The accessory muscles of pectoral region were found in 16 cases (16%), and four types were differentiated. The Pectoralis Quartus muscle was the most common type of accessory muscles found in this study and occurred in 8 cases. The axillary arch muscle was observed in 3 cases. The chondrocoracoideus muscle was observed in 3 cases. The sternalis muscle occurred in 2 cases, and one of them was bifurcated. The thoracic region is characterized by a large amount of morphological variations, which are observed not only in adult population, but also among human fetuses. The pectoralis quartus was the most frequent variation in this study. Accessory structures like sternalis muscle, chondrocoracoideus muscle, pectoralis quartus muscle, or axillary arch muscle may have clinical implications, and knowledge about them is very useful for clinicians, especially plastic surgeons, thoracic surgeons, and orthopedics.

An accessory head of the extensor indicis: a rare case report.

A deep knowledge of the variations of the posterior forearm musculature is crucial for assessing and diagnosing conditions in this region. Extensor indicis (EI) is one of the muscles in this region, which exhibits diverse anatomical variations. This report documents an extremely unusual form of the EI with an accessory head on the dorsum of the hand. During routine dissection, an extremely rare presentation of the EI was found in the left forearm of a 94-year-old female cadaver. This unusual EI consisted of two muscle bellies. The traditional belly originated from the distal two-thirds of the ulna. The muscle became tendinous around the carpal area, distal to the extensor retinaculum. The tendon was subsequently joined by an accessory muscle belly originating from the distal radioulnar ligament. The EI tendon inserted onto the dorsal expansion of the index finger, ulnar to that of the extensor digitorum. The posterior interosseous nerve innervated the muscle. Herein, we report an extremely rare form of the EI. To our knowledge, EI with an accessory head has only been reported rarely over the past 200 years. Moreover, our report appears to be the first case with photographic details of this anatomical variation. Clinicians should be aware of this variation for proper diagnosis and treatment.

Surgical Technique For Chronic Symptomatic Peroneal Sheath Pain in Young Patients

To present the clinical and radiographic data, emphasize our surgical technique and how it was used, and the outcome measures in a case series of patients with chronic symptomatic peroneal sheath pain. A retrospective chart and radiograph review was conducted involving 36 adolescent patients (ages 8 to 20 y) treated surgically for chronic symptomatic peroneal sheath pain from 2010 to 2020. Findings that include chief complaint, magnetic resonance imaging findings, and surgical measures were documented. The patients’ postoperative and clinic visit notes were analyzed and outcome scores (FAOS Foot &amp; Ankle Survey, AOFAS Ankle-Hindfoot Scale, and Kaikkonen Functional Scale) were calculated to determine the long-term results of the procedure. In our case series of 36 patients undergoing surgical treatment for chronic symptomatic peroneal sheath pain the procedures performed were as follows: 35 peroneal sheath repairs (97.22%), 34 ankle arthroscopies (94.44%), 27 resections of anomalous peroneus brevis muscle belly (75.00%), 2 resections of accessory peroneus quartus muscle (5.56%), 7 partial synovectomies (19.44%), 29 debridements (80.56%), and 6 Brostrom repairs (16.67%). magnetic resonance imaging findings showed 50% of our patient population had low-lying peroneus brevis muscles, and on examination during surgery, 61.11% of peroneus brevis muscles extended past the fibular tip. The average time in the cast post-operatively was 4.33 weeks. The average time from surgery to return to activity was 9.03 weeks. Twenty-two of the 36 patients (61.11%) were athletes and 100% were able to return to their sport. Outcome scores were retrospectively determined to be 99.27 for the FAOS Foot and Ankle Survey, 98.72 for the AOFAS Ankle-Hindfoot Scale, and 99.31 for the Kaikkonen Functional Scale. Complications were minimal and included 1 postoperative infection, 3 cast impingements, and 2 reported instances of post-operative pain. In our retrospective case series of 36 patients, the outcomes of surgical intervention for peroneal tendon pathology unresponsive to nonsurgical management in pediatric patients were evaluated. Our surgical method utilizes debridement, synovectomy, excision of low lying peroneus brevis muscle belly, excision of peroneus quartus if present, repair of split-tears of the tendons, and repair of the peroneal tendon sheath using “pants over vest” sutures to tighten the sheath. Our chart review shows all 36 patients were satisfied with the outcome, demonstrated improvement in relevant patient-reported outcome measures, and would elect to undergo the procedure again. Therefore, the novel surgical techniques outlined in this study appear to be viable options to treat chronic symptomatic peroneal tendon sheath pain resistant to conservative methods. Level of Evidence: Retrospective Case Series, Level IV.

A rare presentation of cubital tunnel syndrome by accessory anconeus muscle

Cubital tunnel syndrome (Cu TS) is the second most frequent upper extremity compressive neuropathy after carpal tunnel syndrome. Cu TS is idiopathic; however, it has been linked to ulnar nerve vulnerability and anconeus epitrochlearis (AE) muscle hypertrophy. Although there are few studies in the literature that reveal AE muscle as one of the causes of Cu TS, its prevalence is low. The goal of this case report is to raise awareness regarding the existence of AE muscle as a potential cause of Cu TS, as well as the imaging findings of Cu TS in magnetic resonance imaging (MRI). A 17-year-old male patient complained of intermittent pain in the medial aspect of the left elbow and paresthesia in the left hand. Examination revealed hyperextension of meta carpalphalangeal joints and flexion of proximal interphalangeal joints of the 4th and 5th digits, besides the sensory deficit along the ulnar border of the 5th digit. A nerve conduction study revealed non-stimulable sensory and motor components of the right ulnar nerve. MRI with T1-weighted fast spin echo, Fat sat proton density-weighted, and gradient echo T2*-weighted sequence showed AE - on the posteromedial aspect of the elbow. The ulnar nerve within the cubital tunnel appeared thickened and edematous with bright perineural fat signals with maintained fascicular architecture, secondary to compression by the anconeus muscle. This paper reviews imaging findings of ulnar neuropathy secondary to accessory anconeus muscle and explains the importance of MRI imaging for accurate diagnosis. Knowing MRI imaging is vital in the modern imaging era for accurate diagnosis.

The ratio of parasternal intercostal muscle-thickening fraction-to-diaphragm thickening fraction for predicting weaning failure

BackgroundDiaphragm dysfunction is associated with weaning outcomes in mechanical ventilation patients, in the case of diaphragm dysfunction, the accessory respiratory muscles would be recruited. The main purpose of this study is to explore the performance of parasternal intercostal muscle thickening fraction in relation to diaphragmatic thickening fraction ratio (TFic1/TFdi2) for predicting weaning outcomes, and compare its accuracy with D-RSBI in predicting weaning failure. Materials and methodsWe prospectively enrolled consecutive patients from 7/2022–5/2023. We measured TFic, TFdi, and diaphragmatic excursion (DE3) by ultrasound and calculated the TFic/TFdi ratio and diaphragmatic rapid shallow breathing index (D-RSBI4). Receiver-operator characteristic (ROC5) curves evaluated the accuracy of the TFic/TFdi ratio and D-RSBI in predicting weaning failure. Results161 were included in the final analysis, 114 patients (70.8%) were successfully weaned from mechanical ventilation. The TFic/TFdi ratio (AUROC = 0.887 (95% CI: 0.821–0.953)) was superior to the D-RSBI (AUROC = 0.875 (95% CI: 0.807–0.944)) for predicting weaning failure. ConclusionsThe TFic/TFdi ratio predicted weaning failure with high accuracy and outperformed the D-RSBI.

Bilateral tensor fascia suralis muscles and unilateral accessory biceps femoris muscle: a cadaveric case study

PurposeThis study reports the findings of bilateral tensor fascia suralis muscles (TFS) and a unilateral accessory muscle belly of the biceps femoris (AMBF) in a 72-year-old female. Case reportThe findings were initially identified during educational dissection of the lower extremities by medical students. The AMBF and bilateral TFS were further dissected to identify their origins and insertions. The left TFS (length, 22.83 ± 0.05 cm; width, 6.24 ± 0.14 mm) originated from the biceps femoris long head muscle (BFLH) and inserted onto the crural fascia overlying the lateral head of gastrocnemius muscle. The right TFS (length, 114.89 ± 0.62 mm; width, 9.82 ± 0.11 mm) originated from the BFLH and inserted onto the crural fascia overlying the medial head of gastrocnemius muscle. The length of the crural fascia insertion was 76.26 ± 3.00 mm (left) and 127.69 ± 1.41 mm (right). An AMBF was present in the left lower limb, originating from the greater trochanter and inserting on the distal end of the BFLH. The common peroneal nerve passed deep to the AMBF, 20.3 cm inferior to the inferior border of the piriformis. ConclusionThis data characterizes a novel finding of bilateral TFS muscles with a unilateral AMBF.

Bilateral, symmetrical, tripartite variation of the anterior belly of digastric muscle

BackgroundThe anterior and posterior bellies of digastric muscle act to facilitate components of phonation, jaw opening, and hyoid bone stabilization during swallowing. Variations in the digastric muscle within the submental triangle are well-documented in the literature. Ongoing and up-to-date reporting and knowledge of these variations is important from a clinical perspective. MethodRoutine human anatomical dissection of the anterior neck in a male donor revealed bilateral pairs of accessory muscles (n = 4) attached to and within the depth plane of right and left anterior bellies of digastric muscles. ResultsThe case presented here is of a bilateral, tripartite digastric muscle variation within the submental triangle of an anatomical donor. Attachments and relationships were noted. Variant digastric muscles were found to be innervated by the nerve to the mylohyoid muscle and supplied by the submental artery, consistent with supply to the anterior belly of the digastric muscle. ConclusionThe clinical relevance of these additional muscles primarily pertains to radiological evaluation and reconstructive surgical procedures in the submental region, as digastric muscle bellies serve as essential landmarks and potential targets. Describing anatomical variations is crucial for appropriate planning of interventions in this region.

Radiologic-Pathologic Correlation of Cardiac Tumors: Updated 2021 WHO Tumor Classification.

Cardiac tumors, although rare, carry high morbidity and mortality rates. They are commonly first identified either at echocardiography or incidentally at thoracoabdominal CT performed for noncardiac indications. Multimodality imaging often helps to determine the cause of these masses. Cardiac tumors comprise a distinct category in the World Health Organization (WHO) classification of tumors. The updated 2021 WHO classification of tumors of the heart incorporates new entities and reclassifies others. In the new classification system, papillary fibroelastoma is recognized as the most common primary cardiac neoplasm. Pseudotumors including thrombi and anatomic variants (eg, crista terminalis, accessory papillary muscles, or coumadin ridge) are the most common intracardiac masses identified at imaging. Cardiac metastases are substantially more common than primary cardiac tumors. Although echocardiography is usually the first examination, cardiac MRI is the modality of choice for the identification and characterization of cardiac masses. Cardiac CT serves as an alternative in patients who cannot tolerate MRI. PET performed with CT or MRI enables metabolic characterization of malignant cardiac masses. Imaging individualized to a particular tumor type and location is crucial for treatment planning. Tumor terminology changes as our understanding of tumor biology and behavior evolves. Familiarity with the updated classification system is important as a guide to radiologic investigation and medical or surgical management. ©RSNA, 2024 Supplemental material is available for this article.

Pterygoideus proprius muscle: stuck between the greater wing and lateral pterygoid plate.

The muscles of mastication derive from a common embryological source, and the presence of accessory muscles in the infratemporal fossa (ITF) is uncommon. Here, we present findings from postmortem dissection of the ITF revealing a unilaterally present muscle extending from the greater wing of the sphenoid to blend inferiorly with the medial and lateral pterygoid muscles before attaching to the lateral pterygoid plate. This muscle is most consistent with the pterygoideus proprius muscle initially described in 1858. Though the exact embryological origin and function of this muscle remain speculative, these topics are nonetheless worth investigating as it may provide insight regarding the ontogeny of muscles descending from the first pharyngeal arch. Additionally, presence of the pterygoideus proprius muscle may have clinical implications and impact surrounding structures such as the mandibular division of the trigeminal nerve, maxillary artery, pterygoid venous plexus, masticatory muscles, and temporomandibular joint (TMJ).

Neural Respiratory Drive During Different Dyspnea Relief Positions and Breathing Exercises in Individuals With COPD.

When the work load of the respiratory muscles increases and/or their capacity decreases in individuals with COPD, respiratory muscle activation increases to maintain gas exchange and respiratory mechanics, and perception of dyspnea occurs. The present study aimed to compare diaphragm and accessory respiratory muscle activation during normal breathing, pursed-lip breathing, and breathing control in different dyspnea relief positions, supine and side lying. A cross-sectional study design was used. Sixteen individuals with COPD age between 40-75 y were included. Pulmonary function was evaluated by spirometry, muscle activation by surface electromyography, and dyspnea by the modified Borg scale. Muscle activation was measured in the diaphragm, scalene, sternocleidomastoid, and parasternal muscles. The evaluation was made in the dyspnea relief positions (sitting leaning forward, sitting leaning forward at a table, leaning forward with back against a wall, standing leaning forward, and high lying), seated erect, supine, and side lying. There were significant differences between the 8 positions (P < .001). There was no significant difference in muscle activation between sitting leaning forward and sitting leaning forward at a table position with analyzing post hoc test results (P > .99 for each muscle). However, muscle activation was lower in these 2 positions than in the other positions (P < .001 for each muscle). Muscle activation was greater in the supine position than in the other positions (P < .001 for each muscle). No difference was observed in muscle activation between the seated erect, leaning forward with back against a wall, standing leaning forward, high-lying, or side-lying positions (P > .05 for each muscle with a minimum P value of .09). The use of sitting leaning forward and sitting leaning forward at a table positions together with breathing control may help people with COPD to achieve more effective dyspnea relief and greater energy efficiency.

An unusual configuration of two anomalies in the extensor digitorum profundus complex in a human.

The extensor digitorum profundus complex underwent degeneration of the ulnar segments during primate adaptation and evolution. This process resulted in the preservation of only the extensor pollicis longus and extensor indicis in some apes, including humans. Consequently, anatomical variations within the digitorum profundus complex in modern humans have been well-documented, with detailed reports on their frequency and patterns in previous studies. Here, we report an unusual arrangement involving two anomalies in the extensor digitorum profundus complex, identified in a 66-year-old Japanese male cadaver. In this cadaver, two accessory muscles differentiated from both the extensor pollicis longus and extensor indicis. Notably, the latter muscle featured a tendon bifurcating towards both the thumb and index fingers, referred to as the extensor pollicis et indicis communis. Under the extensor retinaculum, the tendon of the accessory extensor pollicis longus passed through an independent compartment, whereas that of the extensor pollicis et indicis communis traversed a compartment shared by the extensor indicis and the extensor digitorum communis. Both muscles were innervated by the posterior interosseous nerve. Previous studies have reported that the accessory slip of the extensor pollicis longus and extensor pollicis et indicis communis appear at frequencies of 0.6% and 0.4-1.4%, respectively. However, to the best of our knowledge, a configuration in which both appear simultaneously has not been reported. The data from this case could provide essential insights into the variations in the extensor digitorum profundus complex in humans and non-human primates.

Structure-Function Relationship of Respiratory Muscles in the mdx Mouse Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a genetic neuromuscular disorder, characterized by severe and progressive skeletal muscle weakness, which extends to the respiratory muscles. We have determined that peak inspiratory pressure-generating capacity is preserved in early dystrophic disease in the mdx mouse model of muscular dystrophy, but this early compensation is lost as disease progressesa. We sought to examine the structure-function relationship of obligatory and accessory respiratory muscles in early (4-month) and advanced (16-month) disease. Ex vivo muscle function of obligatory (diaphragm and parasternal) and accessory (sternomastoid, cleidomastoid and scalene) respiratory muscles was assessed in wild-type and mdx mice in early dystrophic disease (n = 8-15 per group). Diaphragm and scalene ex vivo muscle function was assessed in advanced dystrophic disease (n = 10-14 per group). Histology (sirius red, and haematoxylin and eosin) and immunofluorescence (laminin) were used to assess the form of obligatory (diaphragm, parasternal and intercostal) and accessory (sternomastoid, cleidomastoid, scalene and trapezius) respiratory muscles (n=6 per group). Pro-inflammatory cytokine concentrations were examined in muscle homogenates of obligatory and accessory respiratory muscles of wild-type and mdx mice in early and advanced dystrophic disease (n=10 per group). Our study revealed obligatory (diaphragm and parasternal) and accessory (sternomastoid and cleidomastoid) muscle weakness evident in early dystrophic disease. Scalene muscle function is preserved in mdx mice in early disease but is weak in mdx mice in advanced dystrophic disease. Structural remodelling by way of increased collagen deposition (fibrosis), increased central nucleation, increased area of inflammatory cell infiltrate and reduced mean minimal Feret’s diameter (relative atrophy) was evident in obligatory and accessory respiratory muscles in early dystrophic disease. The relative area of collagen deposition in obligatory and accessory respiratory muscles increased with disease progression, but interestingly the increase was most pronounced in the diaphragm muscle. Increased concentration of pro-inflammatory cytokines (IFN-γ, IL-1β, IL-6, KC/GRO, TNF-α, MCP-1, IL-33, MIP-1α, IP-10, MIP-2) was observed in mdx obligatory and accessory muscle homogenates compared to wild-type in early and advanced dystrophic disease. These data widen characterisation of the respiratory control system in mdx mice, potentially revealing novel therapeutic targets. References a O'Halloran KD, Maxwell MN, Marullo AL, Hamilton CP, Ó Murchú SC, Burns DP, Mahony CM, Slyne AD, Drummond SE (2023). Loss of compensation afforded by accessory muscles of breathing leads to respiratory system compromise in the mdx mouse model of Duchenne muscular dystrophy. J Physiol. 601(19):4441-4467. Eli Lilly &amp; Science Foundation Ireland (19/FFP/6628). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Advanced Age Impairs the Neuromuscular Control of Peak Inspiratory Performance in Mice

Respiratory muscle wasting is known to occur in ageing adults resulting in a decreased capacity for force production and an associated reduction in high-threshold respiratory performance. Dysfunction of the respiratory musculature in this manner may contribute to an increased susceptibility to respiratory complications frequently observed in older populations. The objective of the current study was to characterise the respiratory phenotype during advanced age to assess the impact of sarcopenia on the neuromuscular control of respiratory performance. Male wild type (BL10) mice were studied at 6-months and 24-months, representing young and old age cohorts, respectively. In anaesthetised animals, inspiratory pressure and contemporaneous obligatory and accessory respiratory muscle electromyography (EMG) activities were measured during baseline and sustained tracheal occlusion (n = 9 young; n = 8 old). Diaphragm muscle contractile performance was assessed ex-vivo via tissue bath preparations (n = 8 young; n = 8 old). Furthermore, diaphragm and limb muscle tissues were harvested and snap frozen for subsequent structural and molecular analyses which will assess potential differences in cross-sectional area and relative fibre type composition. Peak inspiratory pressure was significantly reduced in 24-month-old compared to 6-month-old mice (P &lt; 0.0001). Associated EMG activity was significantly lower (P &lt; 0.05) in obligatory (external intercostal; parasternal) and accessory (cleidomastoid; scalene; trapezius; sternomastoid; sternohyoid) muscles of breathing in the old group compared to the young. Diaphragm EMG amplitude was not different between the groups. No differences were observed in the force-generating capacity of the diaphragm between young and old cohorts. Our preliminary results suggest an impairment in the neuromuscular control of the respiratory system during peak performance which apparently precedes the age-related decline in diaphragm muscle force generating capacity. Our further histological and molecular analyses will provide additional insight into the nature of this respiratory phenotype in advanced age. This work was funded by the Department of Physiology, UCC. B.T. Murphy is funded by an Irish Research Council Doctoral Scholarship. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.