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.
Male ; Female ; Humans ; Adult ; Middle Aged ; Aged ; Shoulder ; Rotator Cuff Injuries/surgery* ; Shoulder Joint/diagnostic imaging* ; Rotator Cuff/surgery* ; Muscle Strength ; Deltoid Muscle

Amputees ; Deltoid Muscle/surgery* ; Humans ; Muscle, Skeletal ; Nerve Transfer ; Quality Control ; Upper Extremity/surgery*

The aim of this study was to evaluate and compare the reorganization of corticospinal pathways innervating upper extremity muscles in patients with spastic hemiplegic cerebral palsy (CP). Thirty-2 patients (17 male, 15 female) with spastic hemiplegic CP were enrolled. The average age (mean ± standard deviation) was 7.5 ± 4.6 (range: 2–17) years. Transcranial magnetic stimulation (TMS) was applied to the unaffected and affected motor cortices in turn, and bilateral electromyographic recordings were made from the first dorsal interossei (FDI), the biceps brachii (BB), and the deltoid muscles during rest. The onset latency, central motor conduction time, and peak-to-peak amplitude of motor evoked potentials (MEPs) were measured for each muscle bilaterally. Whilst TMS of both affected and unaffected hemispheres elicited contralateral MEPs in all muscles, the number of MEPs evoked from the affected hemisphere was less than from the unaffected hemisphere for FDI and BB. TMS responses to stimulation of the affected side showed prolonged latency and reduced amplitude. The amplitudes of MEPs increased with age whereas the latencies were relatively constant. These results suggest that the corticospinal pathways to the proximal and distal muscles of the upper extremity undergo sequential maturation and reorganization patterns.
Cerebral Palsy ; Child ; Deltoid Muscle ; Evoked Potentials, Motor ; Humans ; Male ; Muscle Spasticity ; Muscles ; Pyramidal Tracts ; Transcranial Magnetic Stimulation ; Upper Extremity

Several authors have made efforts to define the position of the axillary nerve within deltoid muscle and to calculate the so called safe area for this nerve but it still remains a matter of debate. The primary aim of the study was to investigate the acromio-axillary (AA) distance and its correlation with upper arm length. The secondary aim was to re-define the safe area for axillary nerve within deltoid muscle. Sixty shoulders of thirty adult human cadavers were dissected using standard methods. The distance from the anterior and posterior edge of acromion to the upper border of the course of the axillary nerve was measured and recorded as anterior and posterior AA distance respectively. Correlation analysis was done between the upper arm length and AA distance for each limb. The ratios between anterior and posterior AA distance and upper arm length were calculated and mentioned as anterior index and posterior index, respectively. The mean of anterior and posterior AA distance was 5.22 cm and 4.17 cm, respectively. The mean of upper arm length was 29.30 cm. The means of anterior index and posterior indices were 0.18 and 0.14, respectively. There was a significant correlation between upper arm length and both the anterior and posterior AA distance. The axillary nerve was found to lie at variable distance from the acromion. The minimum AA distance was found to be 3.50 cm. So this should be considered as the maximum permissible length of the deltoid split. Upper arm length has strong correlation with both anterior and posterior AA distances. The ideal safe area for the axillary nerve was found to be a quadrangular area above it and the size of which depends on the length of the upper arm.
Acromion ; Adult ; Arm ; Cadaver* ; Deltoid Muscle* ; Extremities ; Humans ; Shoulder

PURPOSE: The objective of this study was to examine the effect of vibration exercises generated from an XCO® trainer on supraspinatus, infraspinatus, teres minor, and deltoid muscle thickness. METHODS: Thirty subjects were evenly divided into two groups. Muscle thickness was measured by a sonogram prior to the study, and at three and six weeks after the intervention. Changes in muscle thickness were analyzed using a repeated measure analysis of variance (ANOVA). The significance level for the statistical test was set at α=0.05. RESULTS: A statistically significant differences in timing, interactions between timing and the groups, and between-group changes were demonstrated for supraspinatus muscle thickness (p < 0.05). A similar finding was reported for infraspinatus, teres minor, and deltoid muscles with regard to the interactions between timing and the groups (p < 0.05), although the between-group change did not reach statistical significance (p>0.05). CONCLUSION: Significant changes were observed in the thickness of the supraspinatus, infraspinatus, teres minor, and deltoid muscles, owing to the use of vibration exercises generated from an XCO® trainer. These findings can be used as a foundation for future studies on rehabilitation training.
Deltoid Muscle ; Exercise* ; Rehabilitation ; Shoulder* ; Vibration*

OBJECTIVE: To investigate the association between the magnetic resonance imaging (MRI) findings of adhesive capsulitis and shoulder muscle fat percentages using a multi-echo Dixon method. MATERIALS AND METHODS: Twenty-four patients with clinical diagnoses of adhesive capsulitis and either intact rotator cuffs or Ellman grade 1 partial tears as indicated by MRI scans were included. Two radiologists independently evaluated MRI scans of adhesive capsulitis as follows: presence or absence of axillary recess capsular and extracapsular hyperintensities; thickness of the coracohumeral ligament; thickness of abnormal rotator interval soft tissue; and thickness of glenoidal/humeral axillary recess capsules. Fat quantifications of the supraspinatus, infraspinatus, teres minor, subscapularis, teres major and posterior deltoid muscles were performed using multi-echo Dixon imaging at three locations. Inter-rater agreement was assessed. Differences in fat percentages were assessed and correlations between fat percentages and quantitative measurements were evaluated. RESULTS: The fat percentage of the supraspinatus was significantly higher in patients with extracapsular hyperintensity (present, 3.00 ± 1.74%; absent, 1.81 ± 0.80%; p = 0.022). There were positive correlations between the fat percentage of the teres minor and the thicknesses of the abnormal rotator interval soft tissue (r = 0.494, p = 0.014) and the glenoidal axillary recess capsule (r = 0.475, p = 0.019). After controlling for the effects of age, sex and clinical stage, the relationship between the teres minor fat percentage and the thickness of the abnormal rotator interval soft tissue was statistically significant (r = 0.384, p = 0.048). Inter-rater agreement was almost perfect for fat quantification (intraclass correlation coefficients [ICC] > 0.9) and qualitative analyses (k = 0.824), but were variable for quantitative measurements (ICC, 0.170–0.606). CONCLUSION: Several MRI findings of adhesive capsulitis were significantly related to higher fat percentages of shoulder muscles.
Adhesives ; Bursitis ; Capsules ; Deltoid Muscle ; Diagnosis ; Humans ; Ligaments ; Magnetic Resonance Imaging ; Methods ; Muscles ; Rotator Cuff ; Shoulder ; Tears

Inflammatory myositis as an extra-intestinal manifestation of inflammatory bowel disease (IBD) is rare. Coexistence of immuno-mediated diseases in patients with IBD and myositis suggests a common etiopathogenic mechanism underlying these conditions. The current report refers to a rare case of a 45-year-old Korean female with ulcerative colitis (UC) who developed dermatomyositis. She presented with skin rash and proximal muscle weakness, and her disease activity of UC was in remission state. Electromyography, magnetic resonance imaging, and deltoid muscle biopsy were performed. She was diagnosed with dermatomyositis associated with UC and treatment with glucocorticoids and azathioprine resulted in improvement in muscle power and skin rash. Clinicians should be aware of this unusual extra-intestinal manifestation.
Azathioprine ; Biopsy ; Colitis, Ulcerative* ; Deltoid Muscle ; Dermatomyositis* ; Electromyography ; Exanthema ; Female ; Glucocorticoids ; Glycogen Storage Disease Type VI ; Humans ; Inflammatory Bowel Diseases ; Magnetic Resonance Imaging ; Middle Aged ; Muscle Weakness ; Myositis ; Polymyositis ; Ulcer*

In evaluating patients complaining of shoulder pain, ultrasonography is an emerging imaging tool due to convenience, low cost, high sensitivity and specificity. However, normative values of ultrasound dimensions of the shoulder to be compared with pathologic findings in Korean adults are not provided yet. We evaluated the ultrasound dimensions of the rotator cuff, long head of biceps tendon, deltoid muscle and acromioclavicular joint in Korean healthy adults. Shoulder ultrasonography was performed on 200 shoulders from 100 healthy adults. The dimensions of the thickness of rotator cuff (supraspinatus, infraspinatus, subscapularis tendon), deltoid muscle, long head of biceps tendon, subacromial subdeltoid bursa, and acromioclavicular joint interval were measured in a standardized manner. Differences in measurements among sex, age, and dominant arms were compared. The thickness of rotator cuff tendons (supraspinatus, infraspinatus, subscapularis) and deltoid muscle were significantly different between men and women. The thickness of subacromial subdeltoid bursa was significantly different between men and women for non-dominant side. In rotator cuff tendon measurements, the differences between dominant and non-dominant shoulders were not significant, which means the asymptomatic contralateral shoulder can be used to estimate the normal reference values. When stratified by age divided by 10 years, the measurements of supraspinatus, subscapularis and deltoid thickness showed tendency of increase with the age. The acromioclavicular joint interval, on the other hand, revealed decreasing tendency. This report suggests normative values of ultrasound dimensions of healthy Korean population with varying age, and can be useful as reference values in evaluating shoulder pathology, especially in rotator cuff tendon pathology.
Acromioclavicular Joint ; Adult* ; Arm ; Deltoid Muscle ; Female ; Hand ; Head ; Humans ; Male ; Pathology ; Reference Values ; Rotator Cuff* ; Sensitivity and Specificity ; Shoulder ; Shoulder Pain ; Tendons ; Ultrasonography*

OBJECTIVETo compare the safety of haemophilus influenzae type b (Hib) vaccine vaccination on vastus lateralis muscle and deltoid muscle of infant.

METHODSA total of 408 3-4 months old infants were divided into vastus lateralis muscle group and deltoid muscle group in Beijing, 2014. They were divided into the vastus lateralis muscle group (204) and deltoid muscle group (204) by extracting random number. Each observation object was given 3 doses of Hib vaccine according to the program. Collected systemic and local reactions after vaccination and calculated the incidence of adverse reactions.

RESULTSA total of 61 infants were quitted during the study, 1 132 doses were observed. The total reactions incidence of Vastus lateralis muscle group and Deltoid muscle group were 33.0% (186/564) and 27.6% (157/568) with no statistical differences (χ² = 3.818, P = 0.059). The two groups incidence at the same day of vaccination (day 0) which the highest were 23.2% (131/564) and 20.6% (117/568), then declined with time (linear trend test vastus lateralis muscle group χ² = 36.600, P < 0.001,deltoid muscle group χ² = 29.947, P < 0.001), day 1 were 20.4% (115/564) and 17.6% (100/568), day 2 were 16.0% (90/564) and 13.4% (76/568), day 3 were 10.3% (58/564) and 10.6% (60/568), day 4-7 were 11.2% (63/564) and 11.3% (64/568). No serious adverse events (SAE) were reported during the study. The local reactions incidence of two groups were 7.1% (40/564) and 7.7% (44/568)with no statistical differences (χ² = 0.176, P = 0.675). The systemic reactions incidence of two groups were 25.9% (146/564) and 20.6% (117/568) with obvious statistical differences (χ² = 4.437, P = 0.035). The fever incidence of vastus lateralis muscle group (11.5% (65/564)) was higher than Deltoid muscle group (4.4% (25/568)) with obvious statistical differences (χ² = 4.868, P = 0.027). The 1st dose incidence of fever and abnormal crying of vastus lateralis muscle group (fever 11.3% (23/204), abnormal crying 19.1% (39/204)) was higher than deltoid muscle group (fever 4.4% (9/204), abnormal crying 11.8% (24/204)) and the 2nd dose of diarrhea of deltoid muscle group (11.6% (22/190)) was higher than vastus lateralis muscle group (5.9% (11/187)) with obvious statistical differences (fever χ² = 15.288, P < 0.001, abnormal crying χ² = 4.224, P = 0.040, diarrhea χ² = 3.829, P = 0.046).

CONCLUSIONBoth vastus lateralis muscle group and deltoid muscle group had lower incidence of adverse reactions after vaccination. No serious adverse events were associated with vaccination. Vastus lateralis muscle vaccination as well as deltoid muscle vaccination demonstrated safe.

Bacterial Capsules ; China ; Deltoid Muscle ; Fever ; Haemophilus Vaccines ; Haemophilus influenzae type b ; Humans ; Incidence ; Infant ; Quadriceps Muscle ; Vaccination

The brachiocephalic muscle in domestic mammals is formed as a homology of the sternocleidomastoid muscle and the clavicular part of the deltoid muscle since it results from reduction of the clavicle as a clavicular intersection. The cranial insertions of the brachiocephalic muscle vary among species in domestic mammals. In the dog, the brachiocephalic muscle comprises three parts, which arise from the clavicular intersection and insert at the humerus, the dorsal cervical raphe, and the mastoid process of the temporal bone. These three parts are named the cleidobrachial muscle, the cervical part of the cleidocephalic muscle, and the mastoid part of the cleidocephalic muscle, respectively. This complexity could confuse veterinarians and complicate surgical procedures in this area. Information about the normal structure of this muscle, and any variation therein, would help to avoid such situations. During dissections of a male cross-breed dog, we found that the brachiocephalic muscle had two bellies located on the mastoid part of the cleidocephalic muscle that extended from the clavicular intersection to the wing of the atlas and the mastoid process of the temporal bone. They were innervated by the accessory nerve and the ventral branches of the second, third, and fifth cervical nerves, and they were supplied by the ascending branch of the superficial cervical artery. These bellies were considered to be a rare variation of the muscle. This is the second report of a brachiocephalic muscle variation in a dog, in which the mastoid part of the cleidocephalic muscle was made of two bellies inserted independently. Such variations should be considered during anatomical dissections and surgical procedures.
Accessory Nerve ; Animals ; Arteries ; Clavicle ; Deltoid Muscle ; Dogs* ; Humans ; Humerus ; Male ; Mammals ; Mastoid ; Temporal Bone ; Veterinarians