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Immobilization following trauma or surgery induces skeletal muscle atrophy, and improvement in the muscle atrophy is critical for successful clinical outcomes. The purpose of this study is to evaluate the effect of electrical muscle stimulation (EMS) on muscle atrophy. The study design is a controlled laboratory study. Eighty rats (56 to establish the deltoid muscle atrophy [DMA] model and 24 to evaluate the effect of EMS on the model) were used. DMA was induced by completely immobilizing the right shoulder of each rat by placing sutures between the scapula and humeral shaft, with the left shoulder as a control. After establishing the DMA model, rats were randomly assigned into three groups: low‐frequency EMS (L‐EMS, 10 Hz frequency), medium‐frequency EMS (M‐EMS, 50 Hz frequency), and control (eight rats per group). After 3 weeks, the deltoid muscles of each rat were harvested, alterations in gene expression and muscle cell size were evaluated, and immunohistochemical analysis was performed. DMA was most prominent 3 weeks after shoulder immobilization. Murf1 and Atrogin were significantly induced at the initial phase and gradually decreased at approximately 3 weeks; however, MyoD expressed an inverse relationship with Murf1 and Atrogin. IL6 expression was prominent at 1 week. The time point for the EMS effect evaluation was selected at 3 weeks, when the DMA was the most prominent with a change in relevant gene expression. The M‐EMS group cell size was significantly larger than that of L‐EMS and control group in both the immobilized and intact shoulders (all p < 0.05), without significant differences between the L‐EMS and control groups. The M‐EMS group showed significantly lower mRNA expressions of Murf1 and Atrogin and higher expressions of MyoD and Col1A1 than that of the control group (all p < 0.05). In immunohistochemical analysis, similar results were observed with lower Atrogin staining and higher MyoD and Col1A1 staining in the M‐EMS group. DMA model was established by complete shoulder immobilization, with the most prominent muscle atrophy observed at 3 weeks. M‐EMS improved DMA with changes in the expression of relevant genes. M‐EMS might be a solution for strengthening atrophied skeletal muscles and facilitating rehabilitation after trauma or surgery. [ABSTRACT FROM AUTHOR]

Background: Deltoid muscle detachment and atrophy have been reported to occur after shoulder surgery. Purpose: To investigate the 2-year changes in deltoid muscle structure and function after arthroscopic rotator cuff repair (ARCR) using magnetic resonance imaging (MRI) and electrophysical examination. Study Design: Case series; Level of evidence, 4. Methods: A total of 72 patients (72 shoulders) who underwent ARCR between 2015 and 2020 were enrolled. Whole deltoid muscle volume and regional (anterior, lateral, and posterior) muscle thicknesses were determined on T2-weighted MRI scans of both shoulders taken preoperatively and at 1, 3, 6, 12, and 24 months postoperatively, and their correlations with compound muscle action potentials (CMAPs), shoulder abduction muscle strength, and Constant scores were investigated. Comparison between groups was performed using paired or Student t tests, and the relationship between deltoid muscle volume and various factors was determined using Pearson correlation analysis. Results: The volume of the deltoid muscle on the affected side decreased from 44,369 ± 12,371 mm3 preoperatively to 38,139 ± 10,615 mm3 at 1 month postoperatively (P <.05), representing a 14% decrease. The deltoid muscle volume of the contralateral side also significantly decreased during the same time frame, from 43,278 ± 12,248 to 40,273 ± 11,464 mm3 (P <.05), representing a 7% decrease at 1 month postoperatively. Subsequently, the deltoid muscle volume on both sides recovered to preoperative levels at 12 months and was maintained at 24 months. Only the thickness of the anterior part of the deltoid was markedly decreased, from 13.9 ± 3.7 mm preoperatively to 12.0 ± 3.2 mm at 1 month postoperatively (P <.05), representing a 14% reduction. The CMAP amplitude showed a significant decrease at 1 month postoperatively; however, no significant difference was observed after 12 months when compared with the preoperative values or the values on the contralateral side. Positive correlations were found between deltoid muscle volume and CMAP amplitude at 24 months as well as between deltoid muscle volume and shoulder abduction muscle strength (R 2 = 0.698; P <.05) and Constant score (R 2 = 0.133; P <.05). Conclusion: Our study demonstrated that the early structural and functional decline of the deltoid muscle after ARCR was fully recovered within 1 year, confirming that this procedure does not negatively affect the deltoid muscle. [ABSTRACT FROM AUTHOR]

Abstract The deltoid muscle and rotator cuff tissue are structural components that maintain the dynamic stability of the shoulder joint. However, atrophy of the deltoid muscle may affect the stability of the shoulder joint, which in turn alters the mechanical distribution of rotator cuff tissue. Currently, the effect of muscle volume changes in the deltoid muscle on reducing the load on the rotator cuff tissue is still unknown. Therefore, this paper intends to analyze the mechanical changes of rotator cuff tissue by deltoid muscle atrophy through finite elements. Based on previously published finite element shoulder models, the deltoid muscle was modeled by constructing deltoid muscle models with different degrees of atrophy as, 100% deltoid muscle (Group 1), 80% deltoid muscle (Group 2), and 50% deltoid muscle (Group 3), respectively. The three models were given the same external load to simulate glenohumeral joint abduction, and the stress changes in the rotator cuff tissue were analyzed and recorded. In all three models, the stress in the rotator cuff tissue showed different degrees of increase with the increase of abduction angle, especially in the supraspinatus muscle. At 90° of glenohumeral abduction, supraspinatus stress increased by 58% and 118% in Group 2 and Group 3, respectively, compared with Group 1; In the subscapularis, the stress in Group 3 increased by 59% and 25% compared with Group 1 and Group 2, respectively. In addition, the stress of the infraspinatus muscle and teres minor muscle in Group 2 and Group 3 were higher than that in Group 1 during the abduction angle from 30° to 90°. Deltoid atrophy alters the abduction movement pattern of the glenohumeral joint. During glenohumeral abduction activity, deltoid atrophy significantly increases the stress on the rotator cuff tissue, whereas normal deltoid volume helps maintain the mechanical balance of the rotator cuff tissue.

Abstract Scapular surgery has usually been performed through the posterior Judet approach. This approach allows access to the entire posterior scapular body, but causes significant soft tissue damage and detaches the deltoid muscle. To date, there has been no clinical study of a deltoid-preserving approach to access the joint for displaced postero-inferior glenoid fractures (Ideberg type II or Ib). We describe an easy and less invasive approach to the postero-inferior glenoid fossa.

The utilization of botulinum neurotoxin in the field of body contouring is on the rise. Body contouring procedures typically focus on specific muscle groups such as the superior trapezius, deltoid, and lateral head of the triceps brachii. The authors propose identifying optimal injection sites for botulinum neurotoxin to achieve desired aesthetic contouring of the shoulders and arms. The authors conducted a modified Sihler's staining method on specimens of the superior trapezius, deltoid, and lateral head of the triceps brachii muscles, totaling 16, 14, and 16 specimens, respectively. The neural distribution exhibited the most extensive branching patterns within the horizontal section (between 1/5 and 2/5) and the vertical section (between 2/4 and 4/4) of the superior trapezius muscle. In the deltoid muscle, the areas between the anterior and posterior deltoid bellies, specifically within the range of the horizontal 1/3 to 2/3 lines, showed significant intramuscular arborization. Furthermore, the middle deltoid muscle displayed arborization patterns between 2/3 and the axillary line. Regarding the triceps brachii muscle, the lateral heads demonstrated arborization between 4/10 and 7/10. The authors recommend targeting these regions, where maximum arborization occurs, as the optimal and safest points for injecting botulinum toxin. [ABSTRACT FROM AUTHOR]

Abstract Background In minimally invasive lateral plate osteosynthesis of the humerus (MILPOH) the plate is introduced through a deltoid split proximally and advanced through the central portion of the deltoid insertion and between bone and brachial muscle to the distal aspect of the humerus. The fracture is then indirectly reduced and bridged by the plate. Whereas it has been shown that the strong anterior and posterior parts of the distal deltoid insertion remain intact with this maneuver, its impact on deltoid muscle strength and muscular morphology remains unclear. It was the aim of this study to evaluate deltoid muscle function and MR-morphology of the deltoid muscle and its distal insertion after MILPOH. Methods Six patients (median age 63 years, range 52–69 years, f/m 5/1) who had undergone MILPOH for diaphyseal humeral fractures extending into the proximal metaphysis and head (AO 12B/C(i)) between 08/2017 and 08/2020 were included. Functional testing was performed for the injured and uninjured extremity including strength measurements for 30/60/90° shoulder abduction and flexion at least one year postoperatively. Constant-Murley-Score (CMS) including an age-and gender-adjusted version, were obtained and compared to the uninjured side. Oxford Shoulder Score (OSS) and the Disability of the Arm, Shoulder and Hand (DASH) questionnaire were acquired for the affected extremity. Quality of life was measured using the EQ visual analogue scale (EQ-5D-5 L VAS). MR imaging was performed for both shoulders accordingly at the time of follow-up to assess the integrity of the distal insertion, muscle mass and fatty degeneration of the deltoid muscle. Muscle mass was determined by measuring the area of the deltoid muscle on the axial MR image at the height of the center of the humeral head. Results Median follow-up was 29 months (range 12–48 months). Median difference of abduction strength after MILPOH was + 13% for 30°, 0% for 60° and − 22% for 90°. For flexion, the difference to the uninjured side was measured 5% for 30°, -7% for 60° and − 12% for 90°. Median CMS was 75 (66–82) for the operated extremity compared to 82 (77–90) for the uninjured side. Age- and gender-adapted CMS was calculated 88 (79–99) vs. 96 (89–107). Median OSS was 47 (40–48). DASH was 26 (15–36). EQ-5D-5 L VAS ranged from 81 to 95 with a median of 90. The median difference of the deltoid muscle area on MRI was 2% (-21% to + 53%) compared to the uninjured side. No fatty degeneration of the deltoid muscle was observed. The weaker central part of the distal deltoid insertion was exclusively perforated by the plate, leaving the strong anterior and posterior parts of the insertion intact in all patients. Conclusions MILPOH was associated with good functional and subjective outcome. Minor impairment of abduction strength was observed with increasing abduction angles. The reason for this impairment is unclear since MILPOH did not affect the structural quality of the deltoid muscle and the integrity of the strong anterior and posterior parts of its insertion remained intact. Trial registration 26/05/2023: ISRCTN51786146.

The term giant melanoma was previously characterized as a significantly large melanoma, often exceeding 10 cm in diameter. The present case report presents our experience in managing a giant malignant melanoma in the deltoid region in a 79-year-old patient. Due to the size of the lesion, surgical resection with reconstruction using the pectoralis major muscle flap to cover the defect was chosen. The results showed that experimental treatment regimens and new therapeutic agents and techniques should be considered, since giant melanomas are often associated with several negative prognostic factors. Therefore, more studies are necessary for a better understanding of this pathology, which requires a multidisciplinary team for its treatment.

Background: In minimally invasive lateral plate osteosynthesis of the humerus (MILPOH) the plate is introduced through a deltoid split proximally and advanced through the central portion of the deltoid insertion and between bone and brachial muscle to the distal aspect of the humerus. The fracture is then indirectly reduced and bridged by the plate. Whereas it has been shown that the strong anterior and posterior parts of the distal deltoid insertion remain intact with this maneuver, its impact on deltoid muscle strength and muscular morphology remains unclear. It was the aim of this study to evaluate deltoid muscle function and MR-morphology of the deltoid muscle and its distal insertion after MILPOH. Methods: Six patients (median age 63 years, range 52–69 years, f/m 5/1) who had undergone MILPOH for diaphyseal humeral fractures extending into the proximal metaphysis and head (AO 12B/C(i)) between 08/2017 and 08/2020 were included. Functional testing was performed for the injured and uninjured extremity including strength measurements for 30/60/90° shoulder abduction and flexion at least one year postoperatively. Constant-Murley-Score (CMS) including an age-and gender-adjusted version, were obtained and compared to the uninjured side. Oxford Shoulder Score (OSS) and the Disability of the Arm, Shoulder and Hand (DASH) questionnaire were acquired for the affected extremity. Quality of life was measured using the EQ visual analogue scale (EQ-5D-5 L VAS). MR imaging was performed for both shoulders accordingly at the time of follow-up to assess the integrity of the distal insertion, muscle mass and fatty degeneration of the deltoid muscle. Muscle mass was determined by measuring the area of the deltoid muscle on the axial MR image at the height of the center of the humeral head. Results: Median follow-up was 29 months (range 12–48 months). Median difference of abduction strength after MILPOH was + 13% for 30°, 0% for 60° and − 22% for 90°. For flexion, the difference to the uninjured side was measured 5% for 30°, -7% for 60° and − 12% for 90°. Median CMS was 75 (66–82) for the operated extremity compared to 82 (77–90) for the uninjured side. Age- and gender-adapted CMS was calculated 88 (79–99) vs. 96 (89–107). Median OSS was 47 (40–48). DASH was 26 (15–36). EQ-5D-5 L VAS ranged from 81 to 95 with a median of 90. The median difference of the deltoid muscle area on MRI was 2% (-21% to + 53%) compared to the uninjured side. No fatty degeneration of the deltoid muscle was observed. The weaker central part of the distal deltoid insertion was exclusively perforated by the plate, leaving the strong anterior and posterior parts of the insertion intact in all patients. Conclusions: MILPOH was associated with good functional and subjective outcome. Minor impairment of abduction strength was observed with increasing abduction angles. The reason for this impairment is unclear since MILPOH did not affect the structural quality of the deltoid muscle and the integrity of the strong anterior and posterior parts of its insertion remained intact. Trial registration: 26/05/2023: ISRCTN51786146. [ABSTRACT FROM AUTHOR]

Glomus tumors originate from perivascular, temperature-regulating bodies. They are generally located at the fingertips, rarely around the shoulder girdle. This paper reports a deltoid glomus tumor larger in size than ever previously reported. The intramuscular mass, asymptomatic for 10 years, had enlarged to the extent of causing pain. Tumor size and localization suggested the presence of malignancy, indicating wide resection as appropriate surgical action. Incisional biopsy revealed benign morphology. Surgical treatment achieved complete pain relief. This is the largest glomus tumor reported to date. Marginal excision is the treatment of choice when there is no suspicion of malignancy, but due to our suspicions, we performed a wide resection of the tumor. Neither the diagnostic biopsy at the commencement of resection nor the post-surgical pathology later indicated malignancy. [ABSTRACT FROM AUTHOR]

Background: Whether vitamin D deficiency is related to rotator cuff muscle and tendon physiology is controversial. Purpose: To assess the relationship between vitamin D deficiency and various gene expression patterns in patients with rotator cuff tears. Study Design: Controlled laboratory study. Methods: During arthroscopic surgery, samples from the supraspinatus muscle, deltoid muscle, and supraspinatus tendon were acquired from 12 patients with vitamin D deficiency (serum 25-hydroxyvitamin D concentration <20 ng/dL) and 12 patients with sufficient vitamin D levels (control group, serum 25-hydroxyvitamin D concentration ≥30 ng/dL) who were matched for age, sex, and tear size. Alterations in the expression of genes and proteins associated with myogenesis, muscle atrophy, adipogenesis, inflammation, and apoptosis, as well as in vitamin D receptor expression, were assessed using quantitative reverse transcription polymerase chain reaction, Western blotting, and immunohistochemistry and were compared between the 2 groups. Results: Vitamin D receptor gene expression in the deltoid muscle was significantly lower in the vitamin D deficiency group than in the control group (P =.043). Additionally, in the deltoid muscle, myoDgene expression levels were lower and atrogin levels were higher in the vitamin D deficiency group than in the control group (P =.034 and P =.011, respectively). However, in the supraspinatus muscle, no differences were observed between groups in the expression of myogenesis- or atrophy-related genes (all P >.05). The expression of inflammation-related genes (interleukin (IL)-1β and IL-6) was significantly higher in the vitamin D deficiency group, in both the deltoid and supraspinatus muscles (all P <.05). The supraspinatus tendon tissue did not show any significant differences in any gene expression evaluated (all P >.05). A correlation between gene and protein expression was observed for atrogin and IL-1β in the deltoid muscle (P =.019 and P =.037, respectively) and for IL-6 in the supraspinatus muscle (P =.044). Conclusion: Vitamin D deficiency was not associated with the expression of myogenesis-related or muscle atrophy–related genes in the supraspinatus muscle of patients with rotator cuff tears, unlike in the deltoid muscle; rather, vitamin D deficiency was associated with increased proinflammatory cytokine expression. Clinical Relevance: In patients with rotator cuff tears, vitamin D deficiency was observed to be associated with increased levels of proinflammatory cytokines in the rotator cuff muscles, without significant changes in gene expression related to myogenesis or muscle atrophy. [ABSTRACT FROM AUTHOR]

Background and objectives: This study describes the intramuscular nerve branching of the deltoid muscle in relation to shoulder surface anatomy, with the aim of providing essential information regarding the most appropriate sites for botulinum neurotoxin injection during shoulder line contouring. Methods: The modified Sihler's method was used to stain the deltoid muscles (16 specimens). The intramuscular arborization areas of the specimens were demarcated using the marginal line of the muscle origin and the line connecting the anterior and posterior upper edges of the axillary region. Results: The intramuscular neural distribution of the deltoid muscle had the greatest arborization patterns in the area between the horizontal 1/3 and 2/3 lines of the anterior and posterior deltoid bellies, and 2/3 to axillary line in middle deltoid bellies. The greatest part of the posterior circumflex artery and axillary nerve ran below the areas with the highest aborizations. Conclusion: We propose that botulinum neurotoxin injections should be administered in the area between the 1/3 and 2/3 lines of the anterior and posterior deltoid bellies, and 2/3 to axillary line on middle deltoid bellies. Accordingly, clinicians will ensure minimal dose injections and fewer adverse effects of the botulinum neurotoxin injection. Deltoid intramuscular injections, such as vaccines and trigger point injections, should ideally be adapted according to our results. [ABSTRACT FROM AUTHOR]

Objectives: It is known that bodybuilders suffer from shoulder injuries frequently. Therefore, it is important to determine the most appropriate form of movement during shoulder exercises. For this reason, this study was carried out to determine the most accurate form of movement by examining the deltoid muscle activation of bodybuilders from different angles. Methods: The survey model, one of the quantitative research techniques, was used in this study. 53 athletes (44 men, 9 women) with an age of 25.77±9.13 years, height of 177.07±8.40 cm, body weight of 78.06±14.16 kg, and body mass index of 24.78±3.43 kg/m2 who regularly attended bodybuilding gyms were included in the study. The deltoid activations of the participants was measured, while the glenohumeral joint is at 90°, the cubital joint is in abduction at 180°, 150° and 120°. surface electromyography (sEMG) biofeedback was determined using the Neurotrac Myoplus Pro device. Joint angles were determined with a goniometer. Statistical analyses of the study were performed using the SPSS 25 package program. It was found that the data were normally distributed and the Repeated measures Anova test was applied for comparisons. Results: As a result of statistical analysis, in male participants, mean deltoid sEMG values and maximum voluntary contraction (MVC [%]) significantly decreased with decreasing angle size (p<0.05). In female participants, the average sEMG and MVC (%) values did not change at different angles (p>0.05). Conclusion: According to the research results, shoulder sEMG activations decrease in direct proportion to the angle in bodybuilders. When the glenohumeral joint is 90° and the cubital joint is 180°, the activation of the medial deltoid muscle is highest. It is suggested that bodybuilders should consider the results of our study when performing exercises to hypertrophy the deltoid muscle. [ABSTRACT FROM AUTHOR]

Currently, the literature contains few studies that describe any potential complications following arthroscopic acromioplasty. Because part of the anterior deltoid originates from the anterior acromion, there is a risk for violation and subsequent iatrogenic rupture or avulsion during this procedure. This type of injury can be a devastating problem for patients that may lead to poor function and debilitating pain. We present a patient with deltoid insufficiency following arthroscopic acromioplasty who elected to proceed with operative management with a planned arthroscopic evaluation of the shoulder followed by an open deltoid repair. At the final follow-up visit 2.5 years postoperatively, the patient reported improved pain from baseline and no residual disability and was able to perform most activities of daily living without difficulty. This case serves as an example of a surgical repair for a deltoid avulsion following arthroscopic acromioplasty. As there is still a lack of standard guidelines, our suture repair technique can be considered one method of treatment for this type of injury.

Calcific tendinitis is a potentially symptomatic disorder characterized by calcium deposits in the substance of the tendon. Although this condition can occur in any tendinous tissue throughout the human body, calcium deposition commonly occurs at tendon insertions near the bone–tendon junction. The musculotendinous junction of the deltoid muscle has peculiarly dense intramuscular tendons to which muscle fibers attach obliquely to create muscular strength. Given that the intramuscular tendons themselves, which form the consecutive part from the insertion, are subjected to unpredictable stress load or microtrauma similar to tendon insertions, it is reasonable to assume that calcific tendinitis could also occur at the intramuscular tendons. Here we report a case of chronic symptomatic calcium deposition in the lateral part of the deltoid muscle between the origin and the insertion, which was eventually surgically removed and confirmed as intramuscular calcific tendinitis. [ABSTRACT FROM AUTHOR]

The deltopectoral approach is well accepted for shoulder arthroplasty procedures. The extended deltopectoral approach with detachment of the anterior deltoid from the clavicle allows increased joint exposure and can protect the anterior deltoid from traction injury. The efficacy of this extended approach has been demonstrated in anatomic total shoulder replacement surgery. However, this has not been shown in reverse shoulder arthroplasty (RSA). The primary aim of this study was to evaluate the safety of the extended deltopectoral approach in RSA. The secondary aim was to evaluate the performance of the deltoid reflection approach in terms of complications and surgical, functional, and radiologic outcomes up to 24 months after surgery. A prospective, nonrandomized comparative study was performed between January 2012 and October 2020 including 77 patients in the deltoid reflection group and 73 patients in the comparative group. The decision for inclusion was based on patient and surgeon factors. Complications were recorded. Patients were followed up for ≥24 months to evaluate their shoulder function and undergo ultrasound evaluation. Functional outcome measures included the Oxford Shoulder Score, Disabilities of the Arm, Shoulder and Hand score, American Shoulder and Elbow Surgeons score, pain intensity (rated on visual analog scale [VAS] from 0 to 100), and range of motion (forward flexion, abduction, and external rotation). A regression analysis was performed to evaluate any factors of influence on the VAS score. There were no significant differences in the complication rate between the 2 groups (14.5% in deltoid reflection group and 13.8% in comparative group, P =.915). Ultrasound evaluation was available in 64 patients (83.1%), and no proximal detachment was observed. In addition, there were no significant differences in functional outcome measures both preoperatively and at 24 months after surgery between the groups assessed based on the mean VAS pain score, Oxford Shoulder Score, Disabilities of the Arm, Shoulder and Hand score, American Shoulder and Elbow Surgeons score, forward flexion, abduction, and external rotation. Adjustment for possible confounders in a regression model indicated that only prior surgery significantly influenced the VAS pain score after surgery (P =.031; 95% confidence interval, 0.574-11.67). Deltoid reflection (P =.068), age (P =.466), sex (P =.936), use of glenoid graft (P =.091), prosthesis manufacturer (P =.382), and preoperative VAS score (P =.362) were not of influence. The results of this study show that an extended deltopectoral approach for RSA is safe. Selected reflection of the anterior deltoid muscle improved exposure and prevented anterior deltoid muscle injury followed by reattachment. Patients had similar functional scores preoperatively and at 24 months postoperatively compared with a comparative group. Furthermore, ultrasound evaluation showed intact reattachments. [ABSTRACT FROM AUTHOR]

Abstract Background In our previous published study, we demonstrated that a qualitatively assessed elevation in deltoid muscle echogenicity on ultrasound was both sensitive for and a strong predictor of a type 2 diabetes (T2DM) diagnosis. This study aims to evaluate if a sonographic quantitative assessment of the deltoid muscle can be used to detect T2DM. Methods Deltoid muscle ultrasound images from 124 patients were stored: 31 obese T2DM, 31 non-obese T2DM, 31 obese non-T2DM and 31 non-obese non-T2DM. Images were independently reviewed by 3 musculoskeletal radiologists, blinded to the patient’s category. Each measured the grayscale pixel intensity of the deltoid muscle and humeral cortex to calculate a muscle/bone ratio for each patient. Following a 3-week delay, the 3 radiologists independently repeated measurements on a randomly selected 40 subjects. Ratios, age, gender, race, body mass index, insulin usage and hemoglobin A1c were analyzed. The difference among the 4 groups was compared using analysis of variance or chi-square tests. Both univariate and multivariate linear mixed models were performed. Multivariate mixed-effects regression models were used, adjusting for demographic and clinical variables. Post hoc comparisons were done with Bonferroni adjustments to identify any differences between groups. The sample size achieved 90% power. Sensitivity and specificity were calculated based on set threshold ratios. Both intra- and inter-radiologist variability or agreement were assessed. Results A statistically significant difference in muscle/bone ratios between the groups was identified with the average ratios as follows: obese T2DM, 0.54 (P

Giriş: Günlük yaşam sırasında ağırlık kaldırmak sıklıkla kullanılmakta olup, omuz eklemi de üst ekstremitenin hareket serbestliğinin çoğundan sorumludur. Amaç: Bu çalışmada, sağlıklı bireylerde omuz ekleminin fleksiyon ve abdüksiyon hareketleri sırasında ağırlık kaldırmanın kas aktivasyonlarına farklı açı değerlerindeki etkisinin belirlenmesi amaçlanmıştır. Yöntem: Çalışma, yaş ortalaması 22.60 ± 0.44 olan 28 sağlıklı erkek bireyin katılımı ile gerçekleştirilmiştir. Bireyler ağırlıksız ve 3 kilogramlık bir ağırlık ile omuz fleksiyon ve abdüksiyon hareketi yaptığı sırada kas aktivasyonları trapezius kası üst orta ve alt parçaları ile deltoid kasının ön ve orta parçalarından yüzeyel elektromiyografi cihazı ile kaydedilmiştir. Hareketler 0-30, 0-60, 0-90, 0-120, 0-150 ve 0-180 dereceler arasında ve metronom eşliğinde yapılmıştır. Bulgular: Ağırlıksız olarak gerçekleştirilen fleksiyon ölçümlerinde tüm hareket açıklıklarında aktivitesi en fazla olan kas ön deltoid kası iken ağırlık ile gerçekleştirilen fleksiyon ölçümlerinde ise hareketin erken açılarında en aktif kasın üst trapezius, diğer açılarda ise ön deltoid kası olduğu görülmüştür. Ağırlıksız olarak gerçekleştirilen abdüksiyon ölçümlerinde ise yine erken derecelerde en aktif kas ön deltoid iken ağırlık ile gerçekleştirilen ölçümlerde ise üst trapezius kasının aktif olduğu belirlenmiştir. Sonuç ve Öneriler: Ağırlık ile veya ağırlıksız yapılan fleksiyon ve abdüksiyon hareketlerinde çalışma grubumuzda yer alan bireylerde en fazla aktivasyon gösteren kaslar, üst trapezius ve ön deltoid kasları olmaktadır. Bu kasların aktivasyonunu düzenlemeyi hedefleyen tedavilerde omuzun dirençli fleksiyon veya abdüksiyon hareketlerinin kullanımı göz önünde bulundurulabilir.

Currently, the literature contains few studies that describe any potential complications following arthroscopic acromioplasty. Because part of the anterior deltoid originates from the anterior acromion, there is a risk for violation and subsequent iatrogenic rupture or avulsion during this procedure. This type of injury can be a devastating problem for patients that may lead to poor function and debilitating pain. We present a patient with deltoid insufficiency following arthroscopic acromioplasty who elected to proceed with operative management with a planned arthroscopic evaluation of the shoulder followed by an open deltoid repair. At the final follow-up visit 2.5 years postoperatively, the patient reported improved pain from baseline and no residual disability and was able to perform most activities of daily living without difficulty. This case serves as an example of a surgical repair for a deltoid avulsion following arthroscopic acromioplasty. As there is still a lack of standard guidelines, our suture repair technique can be considered one method of treatment for this type of injury. [ABSTRACT FROM AUTHOR]

We aimed to investigate the relationship between functional outcomes and radiological and clinical measurements (based on deltoid moment arm length measurements) of reverse total shoulder arthroplasty (RTSA) performed in patients for irreparable rotator cuff tears. Thirty-eight patients who underwent RTSA after irreparable rotator cuff tears between 2016 and 2019 were included in the study. Patients with primary osteoarthritis, rheumatoid arthritis, or post-traumatic RTSA were excluded from the study. The patients were evaluated functionally using the range of motion, Quick DASH, and Constant Scores (CS). Deltoid lengthening was measured both clinically by the difference in upper extremity length (dUEL) and radiologically by the acromiohumeral distance (AHD) and deltoid lever length (DLL). AHD was measured with true anteroposterior radiographs and ultrasound guidance. The mean age of the patients was 66.39 ± 7.92 (range, 49–83) years. Of 38 patients, 31 (81.57%) were female and 7 (18.43%) were male. The mean follow-up durations were 26.43 ± 17.05 (range, 12–58) months. The mean active anterior elevation (AAE), abduction (AAB), and external rotation (AER) increased from 57.32°, 41.25°, and 22.32° preoperatively to 149°, 110°, and 34° at the last follow-up, respectively. Preoperatively, the mean QuickDASH score was 58.04, and at the last follow-up, it was 38.19. The mean Constant Score rose from 24.75 preoperatively to 60.64 at the last follow-up. The AHD, DLL, and dUEL mean values were 2.346, 1.89, and 1.746 cm, respectively. There was a significant relation between the DLL and the AAE (P <.01). Optimizing deltoid tension plays an essential role in regaining function, and this study demonstrates that lengthening the deltoid increases the patient's ability to elevate anteriorly, likely by recreating the force-length relationship of the deltoid muscle. [ABSTRACT FROM AUTHOR]

Background: The deltoid is the muscle that forms the rounded contour of the shoulder. Anatomically, it seems to be made up of three different sets of fibers. The three anatomical portions in which the deltoid muscle are typically divided into the anterior (clavicular), the mean (acromial), and the posterior (spinal). Different variations of the deltoid muscle have been described in the literature. The analysis and knowledge of these anomalies are essential for surgeons and anatomists. Methods: A total of 21 specimens (12 women and 9 men) were used with a 10% formaldehyde solution. All specimens were dissected bilaterally (the classical dissection methodology was used). Results: In one corpse, an additional bilateral belly of the deltoid muscle was found. It was observed that this additional muscular belly was related to the fascial tissue of the deltoid muscle and its muscle fibers take origin from the middle third of the inferomedial bands of infraspinatus fascia. In addition, the belly attaches to the posterior belly of the deltoid muscle. The deltoid muscle and the additional belly were innervated by the axillar nerve, which is a lateral terminal bouquet of the posterior fascicle of the brachial plexus. Conclusions: This new variation of the deltoid muscle must be considered by surgeons, as well as abnormal conditions in terms of compartment syndrome involving the shoulder. Therefore, consideration of this variant is necessary for the correct diagnosis and treatment of trauma or other shoulder pathology that may be refractory to standard treatments. [ABSTRACT FROM AUTHOR]

Background: The deltoid muscle originates from the spine of the scapula, the lateral border of the acromion and the lateral third of the clavicle. It inserts on the deltoid tuberosity. It is divided into three parts: spinal, acromial and clavicular. Our research shows that each part of the deltoid muscle can have up to three bellies during prenatal life., Materials and Methods: The material included 80 upper limbs of spontaneously-aborted human fetuses (32 male, 48 female; Central European population), 18-38 weeks of gestation at the time of death., Results: Each part had one (Type I), two (Type II) or three (Type III) bellies. In all parts, the most common form was Type I: it was present in 81.25% of cases in the clavicular part, 73.75% in the acromial part and 57.5% in the spinal part. In contrast, Type III was the rarest form in all parts: it was present in 3.75% of cases in the clavicular part, 12.5% in the acromial part and 7.5% in the spinal part., Conclusions: The deltoid muscle is characterized by morphological variability, even in fetuses.

Background: Acromial fractures after reverse total shoulder arthroplasty (RTSA) are a common complication. Nevertheless, only a few studies have identified risk factors for acromial fractures after RTSA. High delta angle (combination of inferiorization and medialization of the center of rotation [COR]) after RTSA was identified as a risk factor in recent studies. The aim of this study was the biomechanical exploration of different delta angles and implant configurations with regard to the acromial stress., Methods: In a rigid body model of the upper extremity muscle, forces of the deltoid muscle were calculated before and after implanting RTSA in different arm and implant positions. The deltoid muscle was divided into an anterior, middle, and posterior part. Implant positions of the glenoid components were changed in the medialization, lateralization, and inferiorization of the COR as well as lateralization of the humeral component. Further, in a finite element model of the upper extremity, the stresses of the acromion in the same implant design configurations were measured., Results: Differences in acromial stress between different delta angle model configurations were observed. Lateralization (5 and 10 mm) of the glenosphere reduced the maximal acromial stress by 21% (1.5 MPa) and 31% (1.3 MPa), respectively. Inferiorization (5 and 10 mm) of the glenosphere increased the maximal acromial stress by 5% (2.0 MPa) and 15% (2.2 MPa), respectively. Changes in positioning the humeral component was found to have the highest impact in this model configuration. A 10-mm-lateralized humeral component reduced acromial stress by 37% (1.2 MPa), whereas in the 6-mm-medialized configuration, an increase in acromial stress by 83% (3.48 MPa) was observed. There was a high correlation between the delta angle and acromial stress (R 2  = 0.967)., Conclusion: Implant design configuration has an impact on the acromial stress. High delta angles correlate with an increase in acromial stress. Both lateralization of the COR and the humerus decreased the acromial stress in our study. The lateralization of the humerus has the highest impact in influencing acromial stress. Because of contrary results in the current literature, further studies with focus on the acromial stress influenced by different anatomic variants of the shoulder and the acromion are needed before a clinical recommendation can be made., (Copyright © 2024. Published by Elsevier Inc.)

Background: Plate fixation of proximal humeral fractures is usually associated with some degree of distal deltoid dissection. The purpose of this study was to quantify deltoid release with standard linear versus curvilinear plates used in the repair of proximal humeral fractures., Methods: Seven nonpaired, fresh-frozen, clavicle-to-fingertip cadaveric shoulders met the inclusion criteria for this study. Four different proximal humerus implants were tested. One of these plates was curvilinear (89 mm), and the other 3 plates were linear (85, 98, 109 mm in length). Plates were compared based on the amount of deltoid insertion released for proper plate positioning. An analysis of variance with post hoc Tukey tests was conducted to compare mean deltoid disruption across the 3 shortest plate types from each manufacturer. A linear regression analysis was conducted to analyze the effect of plate length on mean deltoid release., Results: The mean deltoid insertion length was 39.6 ± 8.6 mm (n = 7). The curvilinear plate (89 mm) required the least amount of average deltoid release at 4.1 ± 4.5 mm, or 12.1% of the deltoid insertion. Independent analysis of variance, including the 3 shortest plates from each manufacturer, found a significant effect of which plate was used on the amount of deltoid disruption that resulted (F(2, 18) = 18.0, P < 0.001, ω = 0.6). A linear regression including all 4 plates demonstrated a statistically significant direct relationship between the plate length and the mean deltoid released (y = 0.6x - 43.8, r2 = 4)., Conclusion: This study demonstrates that proximal humerus plate length has a direct relationship with the amount of deltoid released during plating. Although deltoid disruption is length dependent, plate shape (curvilinear vs. linear) could also be contributory. When comparing a curvilinear and a linear plate of similar lengths, the curvilinear plate resulted in less mean deltoid release., Competing Interests: M. McKee is a consultant for and receives royalties from Stryker, Inc. A. Shah is a consultant for and receives royalties from Arthrex, Inc. E. Lederman is a consultant for and receives royalties from Arthrex, Inc. The remaining authors report no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The mRNA COVID vaccines are only licensed for intramuscular injection but it is unclear whether successful intramuscular administration is required for immunogenicity. In this observational study, eligible adults receiving their first ComirnatyTM/BNT162b2 dose had their skin to deltoid muscle distance (SDMD) measured by ultrasound. The relationship between SDMD and height, weight, body mass index, and arm circumference was assessed. Three needle length groups were identified: 'clearly sufficient' (needle exceeding SDMD by >5 mm), 'probably sufficient' (needle exceeding SDMD by ≤ 5 mm), and 'insufficient' (needle length ≤ SDMD). Baseline and follow-up finger prick blood samples were collected and the primary outcome variable was mean spike antibody levels in the three needle length groups. Participants (n = 402) had a mean age of 34.7 years, BMI 29.1 kg/m2, arm circumference 37.5 cm, and SDMD 13.3 mm. The SDMD was >25 mm in 23/402 (5.7%) and >20 mm in 61/402 (15.2%) participants. Both arm circumference (≥40 cm) and BMI (≥33 kg/m2) were able to identify those with a SDMD of >25 mm, the length of a standard injection needle, with a sensitivity of 100% and specificities of 71.2 and 79.9%, respectively. Of 249/402 (62%) participants with paired blood samples, there was no significant difference in spike antibody titres between needle length groups. The mean (SD) spike BAU/mL was 464.5 (677.1) in 'clearly sufficient needle length' (n = 217) compared with 506.4 (265.1) in 'probably sufficient' (n = 21, p = 0.09), and 489.4 (452.3) in 'insufficient needle length' (n = 11, p = 0.65). A 25 mm needle length is likely to be inadequate to ensure vaccine deposition within the deltoid muscle in a small proportion of adults. Vaccine-induced spike antibody titres were comparable in those vaccinated with a needle of sufficient versus insufficient length suggesting deltoid muscle deposition may not be required for an adequate antibody response to mRNA vaccines. [ABSTRACT FROM AUTHOR]

Introduction: Antegrade intramedullary nailing in humeral shaft fracture allows a stable fixation with satisfactory outcomes. However, shoulder impairment remains an important complication of intramedullary nailing. The procedure involving the splitting of supraspinatus tendon to expose humeral head for nail insertion has been attributed for it, even though it is followed by the repair of the tendon. Aim: To evaluate rotator cuff integrity with Ultrasound (USG) in patients who underwent humeral fracture fixation with an intramedullary interlocking nail and to evaluate the clinical outcome of the shoulder joint in patients with and without rupture of the rotator cuff using constant murley and QuickDASH scores. Materials and Methods: This prospective interventional study was conducted in the Department of Orthopaedics of AJ Institute of Medical Sciences, Mangaluru, India, from August 2018 to September 2020 in which 20 adult patients with acute humeral shaft fractures were treated with closed intramedullary nailing in antegrade manner. Patients were followed-up for six months clinically and radiologically. The USG evaluation of rotator cuff was done at six months follow-up, along with clinical evaluation using constant Murley and QuickDASH scores. Association between variables was analysed by using Chi-square test for categorical variables. Unpaired t-test was used to compare the mean of quantitative variables. The level of significance was set at 0.05. Data were entered into Microsoft excel (Windows 7; Version 2007) and analyses were done using the Statistical Package for Social Sciences (SPSS) for Windows software (version 22.0; SPSS Inc, Chicago). Results: At six months follow-up, patients were evaluated by USG showing ruptured supraspinatus tendon in 3 (15%) of the study patients. The results by constant murley score were 76.50±12.61 for the entire series, 77.82±12.75 for patients without rotator cuff rupture, and 69±10.53 for patients with partial rupture of the rotator cuff, with no statistical difference (p=0.275). QuickDASH scores were 9.90±7.69 for the entire series, better in the group without rupture of the rotator cuff (9.41±7.92 versus 12.70±6.84) but without statistically significant difference (p=0.510). Conclusion: The functional outcome of the shoulder joint is satisfactory and is not influenced by the presence or absence of a rotator cuff tear following the procedure. [ABSTRACT FROM AUTHOR]

Background: In our previous published study, we demonstrated that a qualitatively assessed elevation in deltoid muscle echogenicity on ultrasound was both sensitive for and a strong predictor of a type 2 diabetes (T2DM) diagnosis. This study aims to evaluate if a sonographic quantitative assessment of the deltoid muscle can be used to detect T2DM. Methods: Deltoid muscle ultrasound images from 124 patients were stored: 31 obese T2DM, 31 non-obese T2DM, 31 obese non-T2DM and 31 non-obese non-T2DM. Images were independently reviewed by 3 musculoskeletal radiologists, blinded to the patient's category. Each measured the grayscale pixel intensity of the deltoid muscle and humeral cortex to calculate a muscle/bone ratio for each patient. Following a 3-week delay, the 3 radiologists independently repeated measurements on a randomly selected 40 subjects. Ratios, age, gender, race, body mass index, insulin usage and hemoglobin A1c were analyzed. The difference among the 4 groups was compared using analysis of variance or chi-square tests. Both univariate and multivariate linear mixed models were performed. Multivariate mixed-effects regression models were used, adjusting for demographic and clinical variables. Post hoc comparisons were done with Bonferroni adjustments to identify any differences between groups. The sample size achieved 90% power. Sensitivity and specificity were calculated based on set threshold ratios. Both intra- and inter-radiologist variability or agreement were assessed. Results: A statistically significant difference in muscle/bone ratios between the groups was identified with the average ratios as follows: obese T2DM, 0.54 (P < 0.001); non-obese T2DM, 0.48 (P < 0.001); obese non-T2DM, 0.42 (P = 0.03); and non-obese non-T2DM, 0.35. There was excellent inter-observer agreement (intraclass correlation coefficient 0.87) and excellent intra-observer agreements (intraclass correlation coefficient 0.92, 0.95 and 0.94). Using threshold ratios, the sensitivity for detecting T2DM was 80% (95% CI 67% to 88%) with a specificity of 63% (95% CI 50% to 75%). Conclusions: The sonographic quantitative assessment of the deltoid muscle by ultrasound is sensitive and accurate for the detection of T2DM. Following further studies, this process could translate into a dedicated, simple and noninvasive screening method to detect T2DM with the prospects of identifying even a fraction of the undiagnosed persons worldwide. This could prove especially beneficial in screening of underserved and underrepresented communities. [ABSTRACT FROM AUTHOR]

In the deltoid muscles of Pan troglodytes and Homo sapiens, we have analyzed the muscle architecture and the expression of the myosin heavy chain (MHC) isoforms. Our aim was to identify differences between the two species that could be related to their different uses of the upper limb. The deltoid muscle of six adult Pan troglodytes and six adult Homo sapiens were dissected. The muscle fascicle length (MFL) and the physiological cross‐sectional area (PCSA) of each muscle were calculated in absolute and normalized values. The expression pattern of the MHC‐I, MHC‐IIa and MHC‐IIx isoforms was analyzed in the same muscles by real‐time polymerase chain reaction. Only the acromial deltoid (AD) presented significant architectural differences between the two species, with higher MFL values in humans and higher PCSA values in chimpanzees. No significant differences in the expression pattern of the MHC isoforms were identified. The higher PCSA values in the AD of Pan troglodytes indicate a greater capacity of force generation in chimpanzees than in humans, which may be related to a greater use of the upper limb in locomotion, specifically in arboreal locomotion like vertical climbing. The functional differences between chimpanzees and humans in the deltoid muscle are more related to muscle architecture than to a differential expression of MHC isoforms. [ABSTRACT FROM AUTHOR]

Introduction: Antegrade intramedullary nailing in humeral shaft fracture allows a stable fixation with satisfactory outcomes. However, shoulder impairment remains an important complication of intramedullary nailing. The procedure involving the splitting of supraspinatus tendon to expose humeral head for nail insertion has been attributed for it, even though it is followed by the repair of the tendon. Aim: To evaluate rotator cuff integrity with Ultrasonography (USG) in patients who underwent humeral fracture fixation with an intramedullary interlocking nail and to evaluate the clinical outcome of the shoulder joint in patients with and without rupture of the rotator cuff using Constant-Murley and QuickDASH scores. Materials and Methods: This prospective interventional study was conducted in the Department of Orthopaedics of AJ Institute of Medical Sciences, Mangaluru, India, from August 2018 to September 2020 in which 20 adult patients with acute humeral shaft fractures were treated with closed intramedullary nailing in antegrade manner. Patients were followed-up for six months clinically and radiologically. The USG evaluation of rotator cuff was done at six months follow-up, along with clinical evaluation using Constant-Murley and QuickDASH scores. Association between variables was analysed by using Chi-square test for categorical variables. Unpaired t-test was used to compare the mean of quantitative variables. The level of significance was set at 0.05. Data were entered into Microsoft Excel (Windows 7; Version 2007) and analyses were done using the Statistical Package for the Social Sciences (SPSS) for Windows software (version 22.0; SPSS Inc, Chicago). Results: At six months follow-up, patients were evaluated by USG showing ruptured supraspinatus tendon in 3 (15%) of the study patients. The results by Constant-Murley score were 76.50±12.61 for the entire series, 77.82±12.75 for patients without rotator cuff rupture, and 69±10.53 for patients with partial rupture of the rotator cuff, with no statistical difference (p=0.275). QuickDASH scores were 9.90±7.69 for the entire series, better in the group without rupture of the rotator cuff (9.41±7.92 versus 12.70±6.84) but without statistically significant difference (p=0.510). Conclusion: The functional outcome of the shoulder joint was satisfactory and was not influenced by the presence or absence of a rotator cuff tear following the procedure.

Effects of low-threshold afferents from the anterior (DA), middle (DM) and posterior parts of the deltoid (DP) on the excitability of biceps brachii (BB) motoneurons in humans were studied. We evaluated the effects on individual motor units and motoneuron pool using a post-stimulus time-histogram (PSTH) and an electromyogram-averaging (EMG-A) methods, respectively, in 11 healthy human subjects. Electrical conditioning stimulation was delivered to the axillary nerve branch innervating DA (DA nerve), DM (DM nerve) and DP (DP nerve) with the intensity below the motor threshold. In the PSTH study, stimulation to the DA, DM and DP nerves produced a significant peak (facilitation) in 26/40 (65%), 28/47 (59%) and 0/32 (0%) of BB motor units, respectively. Since the central latency of the facilitation from the DA and DM nerves was 0.1 ± 0.3 and 0.1 ± 0.2 ms (mean ± S.D.) longer than that of the homonymous monosynaptic Ia facilitation of BB, respectively, the facilitation thus being compatible with monosynaptic path. In the EMG-A study, stimulation to the DA and DM nerves produced a significant peak (facilitation) for the BB motoneuron pool in all the subjects, whereas stimulation to the DP nerve produced no effect on BB. The facilitation diminished by vibration stimulation, and the suppression lasted for 30–40 min after removal of the vibration. Therefore, group Ia afferents should be responsible for the facilitation. These findings suggest that monosynaptic facilitation mediated by group Ia afferents from the DA and DM nerves to BB motoneurons exists in humans. [ABSTRACT FROM AUTHOR]

Purpose: Reactive FDG uptake in the axillary lymph nodes (ALN) and deltoid muscle (DM) after COVID-19 mRNA vaccination has been recognized, although the actual situation in the Japanese population remains unknown. To determine the incidence of reactive FDG uptake and its contributing factors, we retrospectively studied a cohort of subjects who were vaccinated at our hospital. Methods: Whole-body FDG-PET/CT examinations performed in 237 subjects out of 240 subjects with a definite history of COVID-19 vaccination (BNT162b2; BioNTech-Pfizer) were analyzed. Positivity and SUVmax of FDG uptake in the ALN and DM ipsilateral to vaccination, various subject characteristics, and the grade of the pathological FDG-PET/CT findings were evaluated using a multivariate analysis. Results: FDG uptake in the ALN and DM ipsilateral to vaccination was seen in about 60% of the subjects even soon (0–4 days) after the first vaccination, with percentages reaching 87.5% and 75.0%, respectively, after the second vaccination. DM uptake had almost disappeared at around 2 weeks, while ALN uptake persisted for 3 weeks or longer. A multivariate analysis showed that a short duration since vaccination, a younger age, a female sex, and a low FDG-PET/CT grade (minimal pathological FDG uptake) contributed significantly to positive ALN uptake, while a short duration since vaccination and a female sex were the only significant contributors to positive DM uptake. This study is the first to identify factors contributing to positive FDG uptake in ALN and DM after COVID-19 vaccination. Conclusion: A high incidence of FDG uptake in ALN and DM was observed after vaccination. ALN uptake seemed to be associated with a younger age, a female sex, and minimal pathological FDG uptake. After vaccination, an acute inflammatory reaction in DM followed by immune reaction in ALN linked to humoral immunity may be speculated. [ABSTRACT FROM AUTHOR]

Introduction: Reverse shoulder arthroplasty (RSA) leads to medialization and distalization of the centre of rotation of the shoulder joint resulting in lengthening of the deltoid muscle. Shear wave ultrasound elastography (SWE) is a reliable method for quantifying tissue stiffness. The purpose of this study was to analyse if deltoid muscle tension after RSA correlates with the patients' pain level. We hypothesized that higher deltoid muscle tension would be associated with increased pain. Material and methods: Eighteen patients treated with RSA were included. Constant score (CS) and pain level on the visual analogue scale (VAS) were analysed and SWE was performed on both shoulders. All three regions of the deltoid muscle were examined in resting position and under standardized isometric loading. Results: Average patient age was 76 (range 64–84) years and average follow-up was 15 months (range 4–48). The average CS was 66 points (range 35–89) and the average pain level on the VAS was 1.8 (range 0.5–4.7). SWE revealed statistically significant higher muscle tension in the anterior and middle deltoid muscle region in patients after RSA compared to the contralateral non-operated side. There was a statistically significant correlation between pain level and anterior deltoid muscle tension. Conclusion: SWE revealed increased tension in the anterior and middle portion of the deltoid muscle after RSA in a clinical setting. Increased tension of the anterior deltoid muscle portion significantly correlated with an increased pain level. SWE is a powerful, cost-effective, quick, dynamic, non-invasive, and radiation-free imaging technique to evaluate tissue elasticity in the shoulder with a wide range of applications. Level of evidence: Diagnostic study, Level III. [ABSTRACT FROM AUTHOR]

Background: The ball impact position during spiking in volleyball may influence the pattern of activation of shoulder girdle muscles and, therefore, could be a significant risk factor for shoulder injury. Methods: Activation of 10 muscles in the dominant shoulder was evaluated using surface electromyography (EMG) in 11 male volleyball players, during spiking in a static standing position, with the goal being to precisely control the specified ball impact positions, without a run-up or ball setting. The following 4 ball impact positions were evaluated: standard, posterior, medial, and lateral. The EMG amplitude, normalized to the maximal voluntary isometric contraction of the respective muscles, was compared for each phase of the spiking movement between the standard position and the other 3 different impact positions, using the Dunnett test. Results: The following between-position differences were noted for the deltoid muscle: increased activation of the anterior deltoid during the acceleration phase for the posterior position (P = .041), increase in the posterior deltoid during the acceleration phase for the lateral position (P = .04), and increase in the middle deltoid during the deceleration phase for the lateral position (P = .005). Conclusion: A posterior or lateral shift in the position of ball impact may cause an increase in the activity of the deltoid muscle that would cause a decrease in the centripetal force of the humeral head through the acceleration and deceleration phases. As such, neuromuscular exercises, combined with strengthening of the rotator cuff muscle, might reduce the risk of shoulder injury during performance of the volleyball spiking movement.

With the increasing demand for body contouring, botulinum toxin (BTX) injection is being widely used off‐label for muscular hypertrophy. However, to the best of our knowledge, no study has investigated the clinical efficacy of BTX type A (BTX‐A) in deltoid muscle hypertrophy. This study was conducted to evaluate the efficacy and safety of intramuscular injection of BTX in reducing deltoid muscle hypertrophy. Overall, 10 patients with bilateral deltoid muscle hypertrophy were treated with an intramuscular injection of prabotulinum toxin A, with a total of 50 units [U] administered per patient. As measured by ultrasonography, the thickness of the deltoid muscles was significantly decreased at weeks 2 and 12. In addition, the clinical assessment score by blinded investigators was improved after the treatment; however, patients' satisfaction scores were relatively low. No major complications were reported. Therefore, intramuscular injection of BTX‐A seems to be a candidate for novel treatment option for deltoid muscle hypertrophy. Further larger clinical studies are warranted to confirm the efficacy of BTX‐A. [ABSTRACT FROM AUTHOR]

Objective: To describe the MRI features of deltoid tears and to evaluate tear characteristics in patient groups based on history of trauma and rotator cuff tear (RCT). Materials and methods: The records of patients who underwent shoulder MRI at our institution between July 2007 and June 2018 were retrospectively reviewed to identify deltoid tears, and patients were divided into groups based on history of recent trauma and presence of RCT. Images were reviewed to identify the location and size of the deltoid tear; the presence or absence of RCT, muscle atrophy, tendon retraction, humeral head subluxation, soft tissue edema, and additional pathologies were also noted. Medical records were reviewed for information about history of steroid injection, previous rotator cuff surgery, and treatments used. Results: Among 69 patients with deltoid tears (45 men; mean age, 65.2 years; range, 19–89 years), patients with RCTs and no trauma had the highest frequency of deltoid tears in the middle portion (p = 0.005). Only patients with RCTs had undergone steroid injection or rotator cuff surgery. Two patients had deltoid tear without RCT and without recent trauma; these patients demonstrated evidence of calcific tendinopathy and chronic subacromial-subdeltoid bursitis. Conclusion: The middle (acromial) portion of the deltoid is more frequently affected in patients with RCTs than in those with trauma. Although deltoid tears are commonly associated with RCT, calcific tendinopathy and chronic bursitis may also be seen in patients with deltoid tears. [ABSTRACT FROM AUTHOR]

Introduction: Reverse shoulder arthroplasty (RSA) shows promising short- and mid-term results in cuff tear arthropathy. However, functional impairments are described in long-term findings. Micromorphological changes in the periarticular musculature could be in part responsible for this, but have not yet been analysed. Thus, histological changes of the deltoid muscle and their association to the functional outcome were evaluated in this study.Material and Methods: A total of 15 patients treated with RSA were included in this prospective study. Functional outcome was assessed using the Constant Score (CS) and the DASH (disabilities of the arm, shoulder and hand) Score before RSA and after a mean follow-up of 12 months. Deltoid muscle biopsies were harvested intraoperatively and 12 months postoperatively. Mean deltoid muscle fibre area (MMFA) was calculated histologically after haematoxylin-eosin staining.Results: Postoperative shoulder function significantly improved within 12 months (CS: Δ 37.4 ± 22.6, p = 0.001; DASH: Δ 27.1 ± 29.1, p = 0.006). The MMFA significantly decreased (p = 0.02), comparing the results from the intraoperative biopsy (MMFA: 8435.8 µm2, SD ± 5995.9 µm2) to the 12 months biopsy (MMFA: 5792. µm2, SD ± 3223.6 µm2). No correlation could be found between the functional score results and MMFA.Conclusion: Signs of deltoid muscle changes in terms of a reduced MMFA can be detected 1 year after RSA and thus already a long time before long-term functional impairments become apparent. Further studies with larger patient series and longer follow-up periods as well as extended histological assessments and simultaneous radiological examinations are required. [ABSTRACT FROM AUTHOR]

UnlabelledMucosal immunity is central to sexual transmission and overall pathogenesis of HIV-1 infection, but the ability of vaccines to induce immune responses in mucosal tissue compartments is poorly defined. Because macaque vaccine studies suggest that inguinal (versus limb) vaccination may better target sexually-exposed mucosa, we performed a randomized, double-blinded, placebo-controlled Phase I trial in HIV-1-uninfected volunteers, using the recombinant Canarypox (CP) vaccine vCP205 delivered by different routes. 12 persons received vaccine and 6 received placebo, divided evenly between deltoid-intramuscular (deltoid-IM) or inguinal-subcutaneous (inguinal-SC) injection routes. The most significant safety events were injection site reactions (Grade 3) in one inguinal vaccinee. CP-specific antibodies were detected in the blood of all 12 vaccinees by Day 24, while HIV-1-specific antibodies were observed in the blood and gut mucosa of 1/9 and 4/9 evaluated vaccinees respectively, with gut antibodies appearing earlier in inguinal vaccinees (24-180 versus 180-365 days). HIV-1-specific CD8(+) T lymphocytes (CTLs) were observed in 7/12 vaccinees, and blood and gut targeting were distinct. Within blood, both deltoid and inguinal responders had detectable CTL responses by 17-24 days; inguinal responders had early responses (within 10 days) while deltoid responders had later responses (24-180 days) in gut mucosa. Our results demonstrate relative safety of inguinal vaccination and qualitative or quantitative compartmentalization of immune responses between blood and gut mucosa, and highlight the importance of not only evaluating early blood responses to HIV-1 vaccines but also mucosal responses over time.Trial registrationClinicalTrials.gov NCT00076817.

Abstract Intramuscular myxoma (IM) is a rare mesenchymal neoplasm with the incidence of one per 1 000 000 people and is reported greater among women. Our case reports an IM of a deltoid muscle in a young man. Differential diagnosis with sarcoma is important. Surgery is the treatment of choice usually without recurrence.

Background This study investigates the effects of neuromuscular electrical stimulation (NMES) in preventing deltoid atrophy during the first 12 weeks after arthroscopic rotator cuff repair. Methods Eighteen patients undergoing arthroscopic repair of a medium-sized rotator cuff tear by a single surgeon, were randomized into two groups: NMES and transcutaneous electrical nerve stimulation (TENS). Each group used the respective device for 6 weeks after surgery. Pain was measured at baseline, 6, and 12 weeks postoperatively, using the visual analogue scale (VAS); range of motion (ROM), abduction strength and functional scores were measured at baseline and 12 weeks postoperatively. Deltoid thickness and cross-sectional areas were measured using magnetic resonance imaging at 12 weeks postoperatively. Results At 12 weeks post-surgery, no statistically significant difference was observed between the NMES and TENS groups in the pain VAS, the Disabilities of the Arm, Shoulder and Hand score, ROM, and abduction strength. Postoperative decrease in the thickness of the anterior, middle, and posterior deltoid, at the level just below the coracoid, was -2.5%, -0.7%, and -6.8%, respectively, in the NMES group, and -14.0%, -2.6%, and -8.2%, respectively, in the TENS group (p=0.016, p=0.677, and p=0.791, respectively). At the level of the inferior glenoid tubercle, postoperative decrease in area of the deltoid was -5.4% in the NMES group and -14.0% in the TENS group, which was significantly different (p=0.045). Conclusions NMES has the potential for reducing deltoid atrophy after arthroscopic rotator cuff repair, suggesting that NMES might help minimize postoperative atrophy after various shoulder surgeries.

The aims of this study were to compare muscle activity of the anterior deltoid, medial deltoid, and posterior deltoid in the bench press, dumbbell fly, shoulder press, and lateral raise exercises. Thirteen men experienced in strength training volunteered for the study. Muscle activation was recorded during maximum isometric voluntary contraction (MVIC) for data normalization, and during one set of 12 repetitions with the load of 60% 1RM in all exercises proposed. One-way repeated-measures ANOVA with Bonferroni's posthoc was applied using a 5% significance level. For anterior deltoid, the shoulder press (33.3% MVIC) presented a significantly higher level of activation when compared to other exercises. Also, no significant difference was found between the bench press (21.4% MVIC), lateral raise (21.2% MVIC), and dumbbell fly (18.8% MVIC). For the medial deltoid, the lateral raise (30.3% MVIC) and shoulder press (27.9% MVIC) presented a significantly higher level of activity than the bench press (5% MVIC) and dumbbell fly (3.4% MVIC). Besides, no significant difference was found between the bench press and the dumbbell fly. For the posterior deltoid, the lateral raise (24% MVIC) presented a significantly higher level of activation when compared to other exercises. For the posterior deltoid portion, the shoulder press (11.4% MVIC) was significantly more active than the bench press (3.5% MVIC) and dumbbell fly (2.5% MVIC). Moreover, no significant difference was found between the bench press and the dumbbell fly. In conclusion, the shoulder press and lateral raise exercises showed a higher level of muscle activation in the anterior deltoid and medial deltoid when compared to the bench press and dumbbell fly exercises. [ABSTRACT FROM AUTHOR]

The importance of the research came in preparing rehabilitative exercises for the deltoid muscle in the shoulder joint using exercises with different resistances and angles. The researchers believe that the problem is that the rehabilitation programs that suffer from a lack of reliance on various exercises, devices and weights, as well as angles to determine the degree of pain, which is one of the most important factors in the speed of the process Rehabilitation and symmetry of recovery Therefore, the researcher decided to prepare rehabilitative exercises for the deltoid muscle injury using some different resistance, weights and angles, and try to benefit from them to rehabilitate these injuries to return the injured to practicing sports activity in the shortest possible period. The research aims to: 1. Preparing rehabilitative exercises for the deltoid muscle injury using some different resistances, weights and angles for the subjects of the research sample. 2. Identifying the effect of rehabilitative exercises for the deltoid muscle injury by using some different resistances, weights and angles among the members of the research sample. The experimental method was used with one group and the number of injured (4) badminton was advanced in Wasit governorate for the 2018-2019 season, and the researchers concluded that the proposed rehabilitative exercises have a positive effect by restoring the normal range of motion on the muscle groups working on a joint, and it is recommended that the means should be used. Therapeutic and auxiliary means to rehabilitate muscle injury in carrying out rehabilitative exercises in line with the level of injury. [ABSTRACT FROM AUTHOR]

Introduction Acromioplasty is a widely performed procedure for various rotator cuff pathologies with good outcomes and high patient satisfaction. However, few studies have focused on its potential complications. Previous cadaveric studies have demonstrated that a considerable portion of the deltoid muscle is detached from its acromial origin following arthroscopic acromioplasty, but the clinical relevance of this muscle detachment has not been investigated. The goal of our research was to examine the influence of arthroscopic acromioplasty on abduction strength and to assess whether acromial anatomy plays a role in any potential effect. Methods From a preliminary sample of 87 individuals who were diagnosed with isolated impingement syndrome and underwent arthroscopic acromioplasty, 74 patients who met the inclusion criteria were ultimately included in the study. The patients were divided into two groups according to their acromion morphology: Bigliani type 2 (33 patients) and type 3 (41 patients). The isometric abduction strength of the two groups was measured by a handheld dynamometer (Isobex®; Cursor AG, Berne, Switzerland) at different abduction angles preoperatively and at the first, third, and sixth months following surgery and was statistically compared. Results Both groups showed reduced abduction strength postoperatively; however, the strength of abduction in the Bigliani type 3 group returned to near preoperative values in the third month. Although increased mean abduction strength was recorded at 30° abduction in the sixth month, this difference was not statistically significant (p=0.78). In the Bigliani type 2 group, compared with those in the sixth-month group, the preoperative abduction strength decreased from 8.32 kg to 6.0 kg (p = 0.047), 6.57 kg to 5.15 (p = 0.025), and 6.1 kg to 4.56 kg (p = 0.006) at 30, 60, and 90° abduction, respectively.  Conclusions Arthroscopic acromioplasty decreased isometric abduction strength in patients with a Bigliani type 2 acromion. Patients should be counseled about this loss, which might be especially important for professional athletes and heavy manual workers., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Heydar et al.)

OBJECTIVES: To find out the reasons of deltoid injection abscess in female patients and disseminate awareness in our population. METHODS: This descriptive cross-sectional study was conducted in the female Outpatient Department of surgery at Khyber Teaching Hospital, Peshawar, Pakistan from April 2017 to December 2017. All female patients with age more than 14 years who presented with deltoid injection abscesses on either arm were included and patients with diabetes, bleeding disorders, major debilitating disorders or immune-compromised conditions were excluded. All patients were interviewed regarding the Intramuscular injection technique and data was collected on a structured proforma and analyzed on SPSS 20. RESULTS: A total of fifty female patients were studied in which 56% were in the age group of 26-45years with mean age 35.5±12.93 years, 14 (28%) qualified and 36 (72%) non-qualified personnel administered the injection. It was injected over the sleeve in 41 (82%) patients while in only 9 (18%) patients the arm was exposed properly. The reasons for insignificant exposure came out to be social reasons in 9 (18%), time deficiency in 9 (18%), improper trained personnel in 19 (38%), tight sleeves in 4 (8%) patients. In 9 (18%) patients aseptic measures were used while in 41 (82%) patients no aseptic measures were taken. CONCLUSION: Mostly patients received intramuscular injection over the sleeves due to simple avoidable reasons from local practitioners due to lack of awareness.

Background: Some studies show that frozen shoulder is due to the pathologic changes in the muscles around the shoulder. Measurement of the ultrasonic thickness of a muscle is a method for measuring the muscle changes. There is no study about the reliability of measurement of the muscle’s ultrasonic thickness around the shoulder in patients with frozen shoulder. The present study aims to investigate the intra-rater reliability of the ultrasonic thickness measurement of the supraspinatus, deltoid and upper trapezius muscles in women with frozen shoulder and healthy women. Methods: This study was carried out during 4 months (June to October 2017). Twenty women consisted of 10 patients with frozen shoulder (mean age: 51.6±9.41 years) and 10 healthy subjects (mean age: 35.5±8.22 years) participated in this study. The patients from some clinics and hospitals in Tehran, and healthy subjects consisted of some personals and students in the School of Rehabilitation of Shahid Beheshti university of Medical Sciences participated in the present study. Measurements of ultrasonic thickness of the upper trapezius, supraspinatus and deltoid muscles in rest position carried out by the same rater two times in 48 hours. Ultrasonography instrument with linear probe (frequency: 7.5 MHz) were used for measurement of muscle thickness in millimeter. Results: Reliability of the ultrasonic measurements of the muscle thickness in patients and healthy subjects was respectively as follow: The upper trapezius muscle (0.81, 0.81), the supraspinatus muscle (0.90, 0.92) and the middle deltoid muscle (0.93, 0.96). The reliability of the ultrasonic measurements of the muscle thickness for the upper trapezius muscle and the supraspinatus muscle was higher in healthy subjects compared to the patients with frozen shoulder. The reliability of the ultrasonic measurements of the middle deltoid thickness for the patients and healthy subjects was similar. Conclusion: It seems that ultrasonography is a reliable method for measuring the thickness of the muscles around the shoulder in patients with frozen shoulder and healthy subjects.

Study DesignCase–control study.PurposeThe aim of the present study was to identify physical findings useful for differentiating between cervical spondylotic amyotrophy (CSA) and rotator cuff tears to prevent the misdiagnosis of CSA as a rotator cuff tear.Overview of LiteratureCSA and rotator cuff tears are often confused among patients presenting with difficulty in shoulder elevation.MethodsTwenty-five patients with CSA and 27 with rotator cuff tears were enrolled. We included five physical findings specific to CSA that were observed in both CSA and rotator cuff tear patients. The findings were as follows: (1) weakness of the deltoid muscle, (2) weakness of the biceps muscle, (3) atrophy of the deltoid muscle, (4) atrophy of the biceps muscle, and (5) swallow-tail sign (assessment of the posterior fibers of the deltoid).ResultsAmong 25 CSA patients, 10 (40.0%) were misdiagnosed with a rotator cuff tear on initial diagnosis. The sensitivity and specificity of each physical finding were as follows: (1) deltoid weakness (sensitivity, 92.0%; specificity, 55.6%), (2) biceps weakness (sensitivity, 80.0%; specificity, 100%), (3) deltoid atrophy (sensitivity, 96.0%; specificity, 77.8%), (4) biceps atrophy (sensitivity, 88.8%; specificity, 92.6%), and (5) swallow-tail sign (sensitivity, 56.0%; specificity, 74.1%). There were statistically significant differences in each physical finding.ConclusionsCSA is likely to be misdiagnosed as a rotator cuff tear; however, weakness and atrophy of the biceps are useful findings for differentiating between CSA and rotator cuff tears to prevent misdiagnosis.

• This study investigated whether muscle mass affects the waves of TcMEPs. • Muscle mass of the upper limb is associated with the amplitude of deltoid TcMEPs. • TcMEPs of the ADM are less influenced by muscle mass than those of the deltoid. To perform spinal surgery safely, it is important to understand the risk factors, including factors that negatively influence intraoperative neuromonitoring (IONM). Transcranial motor evoked potentials (TcMEPs) are important in IONM. Therefore, we aimed to investigate whether muscle mass affects the waveforms of TcMEPs to understand the risk factors influencing TcMEPs. We enrolled 48 patients with thoracolumbar spinal diseases who underwent surgery at our facility between April 2015 and March 2018. Before surgery, the body composition, including muscle mass and fat mass, of all patients was measured using bioelectrical impedance analysis (BIA). During surgery, cranial stimulation under general anesthesia was used to derive TcMEPs, enabling us to measure the amplitude, using the control wave of the TcMEPs of the deltoid muscles and the abductor digiti minimi (ADM) muscles. We found a negative correlation between the amplitude of deltoid-muscle TcMEPs and muscle mass of the upper limb. The amplitude of deltoid-muscle TcMEPs did not correlate with the skeletal muscle index (SMI), muscle mass of the lower limb, or body fat mass. The amplitude of ADM-muscle TcMEPs did not correlate with SMI, muscle mass of any limb, or body fat mass. In conclusion, a larger muscle mass of the upper limb correlated with a lower amplitude of deltoid-muscle TcMEPs. By contrast, there was no correlation between the muscle mass of the upper limb and the amplitude of ADM-muscle TcMEPs. These findings suggest that TcMEPs of the ADM are less influenced by muscle mass and are more stable than those of the deltoid. [ABSTRACT FROM AUTHOR]

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• Myositis ossificans of the deltoid muscle is extremely rare. • We present a case with unique presentation and MRI findings. • Our case had no history of trauma or surgery in the area. • Our case had MRI features mimicking myxoma. • Complete excision was curative. Myositis ossificans of the deltoid muscle is extremely rare. We present a case with unique presentation and MRI findings. A 21-year-old female presented with a 3-month history of a swelling in lateral aspect of the right arm. There was no history of trauma, injection, or surgery to the area. Examination showed a 3 × 3 cm firm mass in the deltoid muscle. MRI findings were suggestive of myxoma. Surgical excision was done and histopathology showed the classic features of myositis ossificans. There was no recurrence at the final follow-up 7 months later. Myositis ossificans of the deltoid muscle is very rare with only 6 cases previously reported in the literature. Our case is unique in presentation because it is the first case reported with no history of trauma, Injection, sickness or surgery in the area. We also review the literature for MRI features of Myositis ossificans and show that our case has a unique pattern. We report on a rare case of Myositis ossificans of the deltoid muscle and review of the literature for similar cases and MRI features of Myositis ossificans. We show that our case was unique both in presentation and MRI finding. [ABSTRACT FROM AUTHOR]