The Fate of the Shoulder Post Rotator Cuff Repair: Biomechanical Properties of the Supraspinatus Tendon and Surrounding Structures.

The study aimed to describe the changes in biomechanical properties of the supraspinatus tendon, deltoid muscle, and humeral head post arthroscopic rotator cuff repair using shear wave elastography. Shear wave velocity of the tendon, deltoid, and humeral head of 48 patients was measured at predetermined sites at 1 week, 6 weeks, 12 weeks, 6 months, and 12 months post repair. One-way ANOVA with Tukey's correction and Spearman's correlation were performed. Mean±SEM healing tendon stiffness, adjacent to tendon footprint, increased from 1 week (6.2±0.2 m/s) to 6 months (7.5±0.3 m/s) and 12 months (7.8±0.3 m/s) (P<0.001). Mean±SEM deltoid muscle stiffness was higher at 12 months (4.1±0.2 m/s) compared to 1 week (3.4±0.1 m/s) and 12 weeks (3.5±0.1 m/s) (P<0.05). Humeral head stiffness did not change. Following arthroscopic rotator cuff repair, supraspinatus tendon stiffness increased in a curvilinear fashion over 6 months. From 6 months, deltoid muscle stiffness increased, corresponding to when patients were instructed to return to normal activities.

Mutual oligosynaptic inhibition of group Ia afferents between the anterior and posterior parts of the deltoid in humans.

The anterior (DA) and posterior parts of the deltoid (DP) show alternating contraction during shoulder flexion and extension movements. It is expected that an inhibitory spinal reflex between the DA and DP exists. In this study, spinal reflexes between the DA and DP were examined in healthy human subjects using post-stimulus time histogram (PSTH) and electromyogram averaging (EMG-A). Electrical conditioning stimulation was delivered to the axillary nerve branch that innervates the DA (DA nerve) and DP (DP nerve) with the intensity below the motor threshold. In the PSTH study, the stimulation to the DA and DP nerves inhibited (decrease in the firing probability) 31 of 54 DA motor units and 31 of 51 DP motor units. The inhibition was not provoked by cutaneous stimulation. The central synaptic delay of the inhibition between the DA and DP nerves was 1.5 ± 0.5 ms and 1.4 ± 0.4 ms (mean ± SD) longer than those of the homonymous facilitation of the DA and DP, respectively. In the EMG-A study, conditioning stimulation to the DA and DP nerves inhibited the rectified and averaged EMG of the DP and DA, respectively. The inhibition diminished with tonic vibration stimulation to the DA and DP and recovered 20-30 min after vibration removal. These findings suggest that oligo(di or tri)-synaptic inhibition mediated by group Ia afferents between the DA and DP exists in humans.

Lessons in clinical reasoning - pitfalls, myths, and pearls: shoulder pain as the first and only manifestation of lung cancer.

OBJECTIVES: Lung cancer is the leading cause of cancer-related death and poses significant challenges in diagnosis and management. Although muscle metastases are exceedingly rare and typically not the initial clinical manifestation of neoplastic processes, their recognition is crucial for optimal patient care. CASE PRESENTATION: We present a case report in which we identify the unique scenario of a 60-year-old man with shoulder pain and a deltoid muscle mass, initially suggestive of an undifferentiated pleomorphic sarcoma. However, further investigations, including radiological findings and muscle biopsy, revealed an unexpected primary lung adenocarcinoma. We performed a systematic literature search to identify the incidence of SMM and reflect on how to improve and build on better diagnosis for entities as atypical as this. This atypical presentation highlights the importance of recognizing and addressing cognitive biases in clinical decision-making, as acknowledging the possibility of uncommon presentations is vital. By embracing a comprehensive approach that combines imaging studies with histopathological confirmation, healthcare providers can ensure accurate prognoses and appropriate management strategies, ultimately improving patient outcomes. CONCLUSIONS: This case serves as a reminder of the need to remain vigilant, open-minded, and aware of cognitive biases when confronted with uncommon clinical presentations, emphasizing the significance of early recognition and prompt evaluation in achieving optimal patient care.

Are glenoid retroversion, humeral subluxation, and Walch classification associated with a muscle imbalance?

BACKGROUND: The etiology of humeral posterior subluxation remains unknown, and it has been hypothesized that horizontal muscle imbalance could cause this condition. The objective of this study was to compare the ratio of anterior-to-posterior rotator cuff and deltoid muscle volume as a function of humeral subluxation and glenoid morphology when analyzed as a continuous variable in arthritic shoulders. METHODS: In total, 333 computed tomography scans of shoulders (273 arthritic shoulders and 60 healthy controls) were included in this study and were segmented automatically. For each muscle, the volume of muscle fibers without intramuscular fat was measured. The ratio between the volume of the subscapularis and the volume of the infraspinatus plus teres minor (AP ratio) and the ratio between the anterior and posterior deltoids (APdeltoid) were calculated. Statistical analyses were performed to determine whether a correlation could be found between these ratios and glenoid version, humeral subluxation, and/or glenoid type per the Walch classification. RESULTS: Within the arthritic cohort, no statistically significant difference in the AP ratio was found between type A glenoids (1.09 ± 0.22) and type B glenoids (1.03 ± 0.16, P = .09), type D glenoids (1.12 ± 0.27, P = .77), or type C glenoids (1.10 ± 0.19, P > .999). No correlation was found between the AP ratio and glenoid version (ρ = -0.0360, P = .55) or humeral subluxation (ρ = 0.076, P = .21). The APdeltoid ratio of type A glenoids (0.48 ± 0.15) was significantly greater than that of type B glenoids (0.35 ± 0.16, P < .01) and type C glenoids (0.21 ± 0.10, P < .01) but was not significantly different from that of type D glenoids (0.64 ± 0.34, P > .999). When evaluating both healthy control and arthritic shoulders, moderate correlations were found between the APdeltoid ratio and both glenoid version (ρ = 0.55, P < .01) and humeral subluxation (ρ = -0.61, P < .01). CONCLUSION: This in vitro study supports the use of software for fully automated 3-dimensional reconstruction of the 4 rotator cuff muscles and the deltoid. Compared with previous 2-dimensional computed tomography scan studies, our study did not find any correlation between the anteroposterior muscle volume ratio and glenoid parameters in arthritic shoulders. However, once deformity occurred, the observed APdeltoid ratio was lower with type B and C glenoids. These findings suggest that rotator cuff muscle imbalance may not be the precipitating etiology for the posterior humeral subluxation and secondary posterior glenoid erosion characteristic of Walch type B glenoids.

Accessory part of the deltoid muscle.

The shoulder and arm region has numerous morphological variations. The deltoid muscle usually consists of three parts: anterior, middle and posterior. This case report describes a very rare deltoid muscle variant, an addition to the spinal part that is attached proximally at the infraspinatus fascia and the spine of the scapula. The distal attachment transforms directly into the brachialis muscle. Additional parts can affect the biomechanics and function of the joints significantly.

Muscle fatigue during assisted violin performance.

Muscle fatigue is a primary risk factor in developing musculoskeletal disorders, which affect up to 93% musicians, especially violinists. Devices providing dynamic assistive support (DAS) to the violin-holding arm can lessen fatigue. The objective was to assess DAS effects on electromyography median frequency and joint kinematics during a fatiguing violin-playing task. Fifteen university-level and professional violinists were equipped with electromyography sensors and reflective markers to record upper-body muscle activity and kinematics. They played G scales with and without DAS until exhaustion. Paired t-tests assessed DAS effects on delta (final-initial) electromyography median frequencies and joint kinematics. DAS prevented the median frequency decrease of left supraspinatus, superior trapezius, and right medial deltoid, and increases in trunk rotation, left-wrist abduction, and right arm-elevation plane. DAS effects on kinematics were marginal due to retention of musical performance despite fatigue. However, DAS reduced fatigue of several muscles, which is promising for injury prevention.Practitioner summary: Violinists are greatly affected by musculoskeletal disorders. Effects of a mobility assistive device on muscle fatigue during violin playing was investigated. The assistive technology slowed down the development of fatigue for three neck/shoulder muscles, making assisted musical performance a promising avenue to prevent violinists' injuries.

Minimally invasive lateral plating for diaphyseal fractures with extension into the proximal humerus and its implications for the deltoid muscle and its distal insertion: functional analysis and MR-imaging.

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.

[Effect of critical shoulder angle on deltoid muscle strength reduction in patients with rotator cuff tears].

Objective: To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength. Methods: A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores. Results: Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05). Conclusion: Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.

Intramuscular migration of calcium deposits into the deltoid muscle: two cases of a rare complication of rotator cuff calcific tendinopathy.

Rotator cuff calcific tendinopathy is a common non-traumatic shoulder pain condition that occurs predominantly in the supraspinatus tendon. Ultrasound-guided percutaneous irrigation of calcific tendinopathy (US-PICT) is a valid treatment in the resorptive phase. A complication of calcific tendinopathy is migration of calcium deposits outside the tendon. The most common site of migration is the subacromialsubdeltoid bursa (SASD). Another, but not frequent, type of migration is the intramuscular migration which mostly affects the supraspinatus, the infraspinatus and the biceps brachii muscles. This paper reports two cases of migration of calcification from the supraspinatus tendon to the deltoid muscle. The aforementioned site of migration has so far never been described in literature. Both patients presented calcification in the resorptive phase and therefore were treated by US-PICT.

Intramuscular, extended-release naltrexone inadvertently administered in the deltoid muscle: A case report.

BACKGROUND: Extended-release, intramuscular (IM) naltrexone can be an effective and convenient medication option for alcohol use disorder. We sought to assess the clinical impact of an alternate, if inadvertent, administration of IM naltrexone in the deltoid muscle instead of the recommended gluteal muscle. CASE SUMMARY: IM naltrexone was prescribed to a hospitalized 28-year-old man with severe alcohol use disorder as part of an inpatient clinical trial. A nurse unfamiliar with naltrexone administration mistakenly administered the drug to the deltoid instead of the gluteal muscle recommended by the manufacturer. Despite concerns that injection of the large-volume suspension to the smaller muscle would potentially contribute to increased pain and higher chance of adverse events owing to faster medication absorption, the patient experienced only mild discomfort to the deltoid region, without other adverse events on immediate physical and laboratory examinations. The patient later denied additional adverse events in the period after hospitalization, but he did not endorse any anti-craving effect of the medication, resuming drinking alcohol quickly following initial discharge. PRACTICE IMPLICATIONS: This case represents a unique procedural challenge of administering a medication in the inpatient setting that is typically given in the outpatient setting. Inpatient staff members frequently rotate and may be relatively unfamiliar with IM naltrexone, so handling should be limited to personnel who have received focused training on its administration. Fortunately, in this case deltoid administration of naltrexone was well-tolerated and even deemed quite "acceptable" to the patient. Clinically, the medication was insufficiently effective, but biopsychosocial context may have made his AUD especially refractory. More research is needed to fully establish whether naltrexone given via deltoid muscle injection has comparable safety and efficacy to gluteal muscle administration.

Botulinum neurotoxin injection in the deltoid muscle: application to cosmetic shoulder contouring.

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.

Anterior deltoid muscle reflection using a deltopectoral approach is safe and does not influence outcome of reverse shoulder arthroplasty.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. DISCUSSION: 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.

Functional outcome and CEUS-assessed deltoid muscle vitality after fracture-specific versus standard prosthetic design in reverse shoulder arthroplasty for trauma.

Functional outcome after reverse-shoulder-arthroplasty (RSA) in proximal humerus fractures (PHF) depends on deltoid muscle integrity and successful reattachment of the tuberosities for best possible recovery of rotator-cuff function. In this monocentric, prospective, randomized, controlled trial we investigated whether a reverse-fracture-prosthesis (RFP) with a metaphyseal fenestrated stem achieved superior shoulder and muscle function compared to a common reverse-prosthesis (RP) design for patients with PHF. Our hypothesis was that patients with RFP may achieve a superior healing rate of the greater tuberosity (GT) compared to patients receiving RP, which translates to significantly higher clinical outcome and functional scores as well as differences in deltoid muscle microperfusion. Forty-four patients with PHF were randomized preoperatively to one of the prosthesis types in RSA between 2018 and 2020 (22 with RFP and 22 with RP) and prospectively assessed 6 months after surgery. We assessed osteointegration of the GT with radiographs 1 day and 6 months postoperatively and examined shoulder function and patient satisfaction by using established shoulder scores. A contrast-enhanced ultrasound (CEUS) examination of both shoulders was performed to quantify intramuscular blood flow and evaluate vitality of the deltoid muscle. None of the functional and psychosocial scores or radiographs and ultrasound examinations showed significant differences between the RSA designs. The constant-Murley score (p = 0.384) and active anterior-elevation-abduction, and external rotation were comparable between the RFP and RP group. Similar healing rates of the GT were observed (p = 0.655). CEUS-assessed deltoid microperfusion revealed equivalent muscle vitality for both groups (p = 0.312). Level of evidence: Level II; Randomized Controlled Trial; Treatment Study. Clinical significance: The radiographic evaluation for the investigation of the GT healing rate indicates that the proclaimed benefits of the fracture prosthesis with fenestration design might not be as great as expected.

Chronic intramuscular calcific tendinitis of the deltoid muscle.

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.

Effect of critical shoulder angle on deltoid muscle strength reduction in patients with rotator cuff tears / 中国修复重建外科杂志

OBJECTIVE@#To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength.@*METHODS@#A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores.@*RESULTS@#Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05).@*CONCLUSION@#Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.

Thickness of the Deltoid Muscle and Location of the Anterior Branch of the Axillary Nerve and the Posterior Circumflex Humeral Artery for Deltoid Injections.

This study investigated the thickness of the deltoid muscle and the location of the anterior branch of the axillary nerve (AAN) and posterior circumflex humeral artery (PCHA), with the goal of maximizing the effectiveness of deltoid injections. Forty specimens from 22 adult Korean cadavers were used. A reference line was identified, connecting the anterior point of the deltoid muscle (AP) and the posterior point of the deltoid muscle (PP) on the surface. The midpoint between the AP and PP was used as the origin point (OP). The line connecting the OP and the lowest point of the deltoid tuberosity (DP) was used as the y-axis. The mean distance of the reference line from the AP to PP was 4.7 ± 0.7 cm. The vertical mean length of the deltoid muscle from the OP and DP was 16.1 ± 1.0 cm. At the 3, 5, and 7 cm sites, the thickness of the deltoid muscle was 0.62 ± 0.9, 0.73 ± 0.7, and 1.3 ± 1.1 cm, respectively. Most of the branches of the axillary nerve were concentrated in the third section (4-6 cm, 51%), while the branches of the PCHA were predominantly found in the fourth section (6-8 cm, 69%). The peripheral branches of the AAN entering the muscle were distributed between 2.2 and 9.8 cm from the acromion. The mean number of the peripheral branches of the AAN was 9.6 ± 3.4. In the deltoid muscle, the mean number of peripheral branches of the PCHA was 8.2 ± 2.8. Administering deltoid injections 5-6 cm below the OP is recommended to avoid axillary nerve injury.

Covid-19: Vacina boa é a aplicada de forma adequada / Covid-19: Vacina boa é a aplicada de forma adequada

Na atualidade, fotografar ou gravar o instante da imunização contra a Covid-19 se tornou rotina compartilhada nas redes sociais. Essa exposição instigou a observação de uma questão relevante: a técnica de aplicação está correta? Com a veiculação de imagens, é possível visualizar as vacinas sendo administradas em diferentes áreas do músculo deltoide, o que pode acarretar efeitos adversos. A otimização da qualificação técnica e pedagógica dos profissionais que elaboram e ministram as capacitações, bem como o envolvimento efetivo dos vacinadores nos treinamentos para injeção intramuscular é uma necessidade constante para evitar mais danos à saúde da população

Currently, photographing or recording the instant of immunization against Covid-19 has become a shared routine on social networks. This exposition prompted the observation of a relevant question: is the application technique correct? With the transmission of images, it is possible to visualize the vaccines being administered in different areas of the deltoid muscle, which can cause adverse effects. The optimization of the technical and pedagogical qualification of the professionals who design and deliver the training, as well as the effective involvement of vaccinators in training for intramuscular injection, is a constant need to avoid further damage to the health of the population