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Intraosseous pneumatocysts are benign, gas-filled cystic structures of bone, typically asymptomatic and discovered incidentally on imaging. Their precise aetiology remains unclear, with the prevailing hypothesis being that they result from air accumulation within the bone due to a vacuum phenomenon, typically linked to an adjacent joint space or intervertebral disc. We report the case of a 37-year-old man with an incidental intraosseous pneumatocyst of the scapula, which was evaluated with CT and MRI. Using thin-slice CT, we are able to detect a tiny cortical breach suggestive of a communication between the lesion and the adjacent glenohumeral joint, lending support to the aforementioned aetiological hypothesis.
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BACKGROUND: Spontaneous infections involving muscles in the shoulder girdle are uncommon conditions rarely reported in the literature. The large musculature of shoulder girdle, complex communicating spaces into the periscapular region, and late glenohumeral joint involvement can cause delay in diagnosis of infections involving muscular portion of rotator cuff. The method of surgical drainage with involvement of scapulothoracic and subscapular spaces and prognosis can be challenging. METHODOLOGY: In this descriptive study, we included patients with shoulder girdle muscle abscess and analyzed the spread in the shoulder girdle and arm through various pathways radiologically. Debridement of the abscess in the subscapular muscle and adnexa was done through the dual approach, one with deltopectoral approach for the shoulder girdle and another incision anterior to the latissimus dorsi muscle for inferior subscapular spaces and gravity-dependent drainage of collection. RESULTS: The causative organism Staphylococcus aureus was isolated only in two patients out of four cases. In repeated collections, axillary and suprascapular nerve palsies were commonly encountered. Adequate debridement, antibiotic cover with vancomycin and clindamycin for six weeks, and rehabilitation restored normal functions of the shoulder in three patients. CONCLUSION: Unsuspecting nature of the subscapular abscess and similarities with common shoulder conditions at initial presentation often led to extensive shoulder girdle involvement via subscapular space, subcoracoid recess, and scapulothoracic space to adjacent areas. The dual approach provides adequate access to drain the collections in subscapularis muscle, subscapular spaces, and shoulder girdle. LEVEL OF STUDY: V.
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Despite residual functional deficits clinically observed in conservatively treated mid-shaft clavicle fractures, no study has reported a quantitative assessment of the treatment effects on the kinematics of the shoulder complex during functional movement. Using computerised motion analysis, the current study quantified the 3D residual kinematic deviations or strategies of the shoulder complex bones during multi-plane elevations in fifteen patients with conservatively treated mid-shaft clavicle fractures and fifteen healthy controls. Despite residual clavicular malunion, the patients recovered normal shoulder kinematics for arm elevations up to 60° in all three tested planes. For elevations beyond 60°, normal clavicle kinematics but significantly increased scapular posterior tilt relative to the trunk was observed in the patient group, leading to significantly increased clavicular protraction and posterior tilt relative to the scapula (i.e., AC joint). Slightly different changes were found in the sagittal plane, showing additional changes of increased scapular upward rotations at 90° and 120° elevations. Similar kinematic changes were also found on the unaffected side, indicating a trend of symmetrical bilateral adaptation. The current results suggest that shoulder kinematics in multi-plane arm elevations should be monitored for any compromised integrated motions of the individual bones following conservative treatment. Rehabilitation strategies, including muscle strengthening and synergy stability training, should also consider compensatory kinematic changes on the unaffected side to improve the bilateral movement control of the shoulder complex during humeral elevation.
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Scapula shape is highly variable across humans and appears to be sexually dimorphic-differing significantly between biological males and females. However, previous investigations of sexual dimorphism in scapula shape have not considered the effects of allometry (the relationship between size and shape). Disentangling allometry from sexual dimorphism is necessary because apparent sex-based differences in shape could be due to inherent differences in body size. This study aimed to investigate sexual dimorphism in scapula shape and examine the role of allometry in sex-based variation. We used three-dimensional geometric morphometrics with Procrustes ANOVA to quantify scapula shape variation associated with sex and size in 125 scapulae. Scapula shape significantly differed between males and females, and males tended to have larger scapulae than females for the same body height. We found that males and females exhibited distinct allometric relationships, and sexually dimorphic shape changes did not align with male- or female-specific allometry. A secondary test revealed that sexual dimorphism in scapula shape persisted between males and females of similar body heights. Overall, our findings indicate that there are sex-based differences in scapula shape that cannot be attributed to size-shape relationships. Our results shed light on the potential role of sexual selection in human shoulder evolution, present new hypotheses for biomechanical differences in shoulder function between sexes, and identify relevant traits for improving sex classification accuracy in forensic analyses.
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INTRODUCTION: Pathologies of the scapulothoracic articulation may lead to painful symptoms such as crepitus and bursitis. While conservative treatments are preferred, persistent symptoms may require image-guided injections. This study aims to determine the optimal hand positioning during ultrasound to maximize the distance between the scapula and thoracic wall, and improve its accessibility during injections. METHODS: This cross-sectional observational study included ten healthy adult volunteers without scapulothoracic issues or history of trauma/surgery. Two musculoskeletal radiologists independently measured the scapulothoracic distance on Ultrasound in three hand positions: 1. Hands under the head; 2. Hands by the side of the trunk; and 3. Hands hanging by the side of the couch. Data was analyzed using SPSS 24.0. Continuous variables were described using mean and standard deviation (SD), with significance set at p < 0.05. RESULTS: Measurements on 20 scapulothoracic articulations (10 volunteers) showed the following findings: Position 1: Baseline value of 1. Position 2: Distance increased by 1.515 mm ± 3.617 (95% CI [- 0.0178, 3.208]. Position 3: Distance increased by 2.175 mm ± 0.66 (95% CI [0.793, 3.557]. Statistical analysis indicated no significant difference (p = 0.39) between positions. However, both radiologists subjectively noted that positions 2 and 3 provided better access for interventions. CONCLUSION: This study highlights the importance of hand positioning in optimizing the scapulothoracic distance for therapeutic interventions. While no significant statistical differences were found, the results suggest potential benefits for clinical practice. Further research with larger samples is needed to establish evidence-based guidelines for scapulothoracic injections.
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Background: Both scapular dynamics and static scapular position are important in the treatment of shoulder dysfunction. This study aimed to create an index that can evaluate scapular position on plain radiographs and evaluate the relation between scapular position and posture accurately. Methods: Using four fresh frozen cadavers, we developed a glenoid angle grade based on the degree of overlap between the shadow of the coracoid inflection point and the upper edge of the scapula on frontal plain radiographs: grade 1, no overlap; grade 2, overlaps by less than half of the shadow; grade 3, overlaps by more than half. We then performed a retrospective cohort study that included 329 shoulders of 329 patients who underwent spine surgery. Spine alignment parameters (SPAPs), including cervical lordosis (CL), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence, pelvic tilt, sacral slope, and sagittal vertical axis were measured on standing lateral plain radiographs. Glenoid anterior tilt (GAT) and glenoid anteversion angle (GAVA) were calculated on frontal radiographs and three-dimensional computed tomography scans. Correlations between SPAPs and each angle were investigated, and independent influencing factors were sought in multivariate analysis. Individual factors, GAT, GAVA, and SPAPs were compared among the grades. Results: SPAPs associated with GAT were sagittal vertical axis (R = 0.14, P = .011), TK (R = 0.12, P = .026), and LL (R = -0.11, P = .046). Multivariate analysis identified TK and LL as independent influencing factors (TK, P = .001; LL, P = .008). SPAPs associated with GAVA were CL (R = 0.17, P = .002), TK (R = 0.29, P < .001), and LL (R = 0.25, P < .001). Multivariate analysis identified CL, TK, and LL as independent influencing factors (CL, P = .01; TK, P = .03; LL, P = .03). There were 183, 127, and 19 cases categorized as grades 1, 2, and 3. GAT (grade 1, 24.0 ± 7.8; 2, 32.4 ± 7.0; 3, 41.0 ± 7.8), GAVA (1, 29.3 ± 7.6; 2, 33.7 ± 9.5; 3, 31.5 ± 8.3), and TK (1, 30.6 ± 13.6; 2, 35.1 ± 14.2; 3, 43.1 ± 20.4) differed significantly according to grade. Conclusion: We identified factors that influence scapular position and demonstrated that scapular position can be estimated by a grading system using plain radiographs.
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Introduction: Osteochondromas are a unique group of benign bone tumors that are characterized by bony outgrowth covered by Cartilage. It has a peculiar micro-architecture as its cortices are extensions of those of parent bone and there is a continuity of medullary cavity; this is akin to branching in plants, rightly earning the name "Exostosis." Case Report: We report a case of a 21-year-old male who presented with complaints of swelling on the upper back associated with mild discomfort. Examination confirmed a bony mass on the dorsal aspect of the scapula without any restricted range of motion of the shoulder joint. On the confirmation of diagnosis, en bloc excision was performed. Conclusion: In conclusion, dorsal scapular osteochondromas are a rarity, and excision of the lesion is an effective management for symptomatic lesions.
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Introduction: Osteochondromas are benign bone tumors common in metaphyseal ends of long bones like distal femur and are relatively uncommon in flat bones such as scapula. Patients usually present with either a visual deformity requiring treatment for cosmetic reason or present with mechanical symptoms hindering activities of daily living. The tumor is mostly benign and malignant transformation is rarely seen. Treatment usually involves surgical excision of the lesion with minimal chances of recurrence if complete excision of the lesion is done. Case Report: Here, we present the case of a 12-year-old boy presenting with a symptomatic dorsal scapular osteochondroma who underwent successful surgical excision without any recurrence. Conclusion: Osteochondroma can be seen on flat bones and should be kept in the differential. Treatment is by excision and usually has good long-term outcomes.
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AIMS: The hypothesis is that the scapula spine can provide a graft of suitable dimensions for use in cases of shoulder instability with critical bone loss. We aimed to investigate its utility with grafts of differing sizes. METHODS: The scapula spine was measured on CT scans of 50 patients who had undergone anterior stabilization. The theoretical ability to harvest a graft of either 2x1x1cm or 2x0.8x0.8cm was analyzed. RESULTS: Using the 2 x 1 x 1cm threshold, 36% of the scapulae had at least one zone from which a suitable graft could be obtained. 61% had only one zone from which a suitable graft could be obtained. Using the 2 x 0.8 x 0.8cm threshold, 72% had at least one zone from which a graft could be obtained. 47% met the threshold in one zone only. CONCLUSION: The scapula spine can be used as a source of autograft. Grafts up to 2 x 1 x 1cm can be harvested in some individuals, however the anatomy is very variable. TAKE HOME MESSAGE: The scapula spine can be used but we recommend that individualized preoperative planning is undertaken to ensure that a suitable graft can be harvested from the spine and to identify the exact location.
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Background: The morphology of the suprascapular notch (SSN) and the ossification of the superior transverse suprascapular ligament (STSL) are risk factors for injury of the suprascapular nerve (SN) during arthroscopic shoulder procedures. The purpose of the current study was to compare preoperative clinical and radiologic characteristics between patients with and without STSL ossification and to evaluate SSN morphology in patients who underwent arthroscopic rotator cuff repair using a 3-dimensional (3D) reconstructed model. Methods: Patients who underwent arthroscopic rotator cuff repair and were given a computed tomography (CT) scan from March 2018 to August 2019 were included in this study. Patients were divided into 2 groups: those without STSL ossification (group I) and those with STSL ossification (group II). Tear size of the rotator cuff and fatty infiltration of rotator cuff muscles were assessed in preoperative magnetic resonance imaging. The morphology of the SSN was classified following Rengachary's classification. The transverse and vertical diameters of the SSN and the distances from anatomical landmarks to the STSL were measured. All measurements were completed using a 3D CT reconstructed scapula model. Results: A total of 200 patients were included in this study. One hundred seventy-eight patients (89.0%) without STSL ossification were included in group I, and 22 patients (11.0%) with STSL ossification were included in group II. Group II showed a significantly advanced age (61.0 ± 7.4 vs. 71.0 ± 7.3 years, p < 0.001) and a shorter transverse diameter of SSN (10.7 ± 3.1 mm vs. 6.1 ± 3.7 mm, p < 0.001) than group I. In the logistic regression analysis, age was an independent prognostic factor for STSL ossification (odds ratio, 1.201; 95% confidence interval, 1.112-1.296; p < 0.001). Patients in type VI showed significantly shorter transverse diameters than other types (p < 0.001). The patient with type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than those with other types (p < 0.001). Conclusions: In the 3D morphological analysis, age was the independent factor associated with STSL ossification in patients who underwent arthroscopic rotator cuff repair. Type VI showed significantly shorter transverse diameters than other types. Type I showed a significantly shorter distance from the articular surface of the glenoid to the SSN than other types.
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Artroscopía , Imagenología Tridimensional , Lesiones del Manguito de los Rotadores , Tomografía Computarizada por Rayos X , Humanos , Artroscopía/métodos , Femenino , Masculino , Persona de Mediana Edad , Lesiones del Manguito de los Rotadores/cirugía , Lesiones del Manguito de los Rotadores/diagnóstico por imagen , Anciano , Estudios Retrospectivos , Osificación Heterotópica/diagnóstico por imagen , Osificación Heterotópica/cirugía , Manguito de los Rotadores/cirugía , Manguito de los Rotadores/diagnóstico por imagen , Escápula/diagnóstico por imagen , Escápula/cirugía , Ligamentos Articulares/cirugía , Ligamentos Articulares/diagnóstico por imagen , AdultoRESUMEN
Objectives: Axillary radiographs enable the measurement of glenoid retroversion, which is associated with worsened clinical outcomes and glenoid loosening following total shoulder arthroplasty. Due to the variability in radiographic technique, this study aims to determine if the accuracy of retroversion measured by axillary radiograph is affected by 1) scapular rotation and/or 2) proper visualization of the medial scapula. Methods: Using five cadaveric scapulae, investigators obtained axillary radiographs in true neutral position as well as in 10° and 20° of anterior and posterior rotation. For each radiograph, two fellowship trained shoulder surgeons measured glenoid retroversion with complete visualization of the scapula (Technique 1) and with visualization limited to the lateral half of scapula (Technique 2). The observers also measured glenoid retroversion by CT scan to use as a gold standard technique. Spearman's Rho was used to assess agreement between measurements. Results: Average glenoid retroversion of the five scapulae assessed by CT scan was 3.8° (R: 1.5-6.9). Measurements obtained using Technique 1 demonstrated improved levels of interobserver agreement (ICC: 0.412) compared to measurements obtained with Technique 2, which demonstrated no agreement (ICC: 0.103). Scapular rotation was inconsistently associated with agreement using both techniques. Conclusion: The reliability of glenoid retroversion measurements was limited by incomplete visualization of the medial scapular spine. When measuring retroversion to the base of the scapular spine, improved agreement and accuracy were seen with various degrees of scapular rotation.
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The nutritive arteries of bones may be injured due to fracture or surgical procedures. Therefore, there are some studies focused on the location of the nutrient foramen (NF) of bones. Rats are the most preferred animals in experimental studies. The purpose of this study is to expose the locational variations of the NF on the rat (Sprague Dawley) scapula. A total of 60 adult rat scapulae (from 16 male and 14 female rats) were used. The diameters of NFs were measured. The length, width, and distances of the NF to the proximal and cranial edges were measured. Foraminal indices were also calculated. It was determined that the average number of NF per scapula was 1.8. The location of the NFs was 52% on the medial aspect and 48% on the lateral aspect. On the medial aspect of the scapula, NFs were frequently found ventrally, on the neck region of the scapula. Laterally, 40 NFs were found in the ventral region of the infraspinatus fossa and only 12 in the ventral region of the supraspinatus fossa. Longitudinal foraminal index 95% confidence intervals were 74.25-79.18 (lateral) and 71.70-75.97 (medial). Transversal foraminal index 95% confidence intervals were 40.98-45.02 (lateral) and 42.91-46.07 (medial). Diameter of the NF 95% confidence interval was 0.21-0.39 mm. The locational knowledge of the NF can be utilized in anatomical or experimental surgery studies. The cranial and proximal edges of the rat scapula may be palpable; surgeons may palpate these regions and easily evaluate the location of the NFs.
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Ratas Sprague-Dawley , Escápula , Animales , Escápula/anatomía & histología , Masculino , Ratas/anatomía & histología , Femenino , Ratas Sprague-Dawley/anatomía & histologíaRESUMEN
The current bone report describes multiple openings identified in a dried scapula of a subject of unknown age and gender. Multiple openings (twelve) were identified in the subscapular fossa and were apparent at the infraspinatus fossa. These openings coexisted with a suprascapular foramen and an osteophyte at the inferomedial border of the foramen. In the current literature, two uncommon variants of the scapula were described: foramina and defects. It is still unclear how these two structures are differentiating. Both of them are results of abnormal ossification of the scapula. Clinicians should be aware of these variants because they may lead to misdiagnosis of malignancies, while the variants are benign entities.
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BACKGROUND: Fractures of the acromion and spine can have a major impact on the outcome of reverse shoulder arthroplasty (RSA) with respect to pain, motion, and function. Reports on internal fixation for these fractures are isolated to small series or case reports with variable outcomes. The purpose of this study was to report on the outcome of open reduction and internal fixation (ORIF) of acromion or spine fractures encountered before or after RSA and describes our evolution of fixation techniques. METHODS: Between 2011 and 2023, 22 fractures or nonunions of the acromion or spine of the scapula underwent ORIF at a single institution and were followed for a minimum of 1 year. In 16 shoulders, fractures occurred after RSA, whereas 5 shoulders underwent ORIF prior to RSA. One shoulder had undergone prior failed ORIF elsewhere and revision ORIF was performed at our institution. There were 10 males and 12 females with a mean age of 67 (SD = 15.1) years. Fixation strategies included single (n = 11) and double plate fixation (n = 11). Kruskal-Wallis one-way analyses of variance were used to analyze continuous variables and Chi-square tests employed for categorical variables. RESULTS: Of the 5 fractures treated with ORIF pre-RSA, 1 shoulder suffered an additional fracture medial to the hardware and 1 required additional bone grafting for incomplete union at the time of RSA. These 5 shoulders all underwent RSA uneventfully, but 1 fracture experienced late displacement of the scapular spine nonunion, leading to plate removal. Of the 16 post-RSA ORIF shoulders, radiographic union was confirmed in 14 and substantial residual inferior angulation identified in 3. New fractures occurred after ORIF in 5 shoulders. For patients who underwent ORIF after RSA, pain scores improved from a mean of 8 to 1.9 points, with more modest elevation gains (58.2°-91.3° pre and postoperatively, respectively). CONCLUSIONS: ORIF of acromion and scapular spine fractures or nonunions in the setting of RSA have the potential to lead to union. When these fractures and nonunions are encountered prior to RSA, ORIF allows for uneventful RSA implantation, but secondary displacement may occur. ORIF seems to lead to improvements in pain, but more modest improvements in motion and function. Our fixation strategy has evolved to (1) dual plating, (2) spanning the whole length of the spine with 1 of the plates, (3) use of hook features under the acromion or os trigonum if possible, and (4) liberal use of bone graft.
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PURPOSE: To determine the short-term complication rates following open reduction and internal fixation of scapula fractures, factors affecting the development of adverse events, and complication rates based on the anatomic location of the fracture. METHODS: Thirty-day complication rates for patients who underwent open reduction and internal fixation of the scapula were compared between glenoid, body, coracoid, and acromion fracture locations, as identified by International Classification of Disease codes. Possible adverse events included postoperative surgical site infection, renal insufficiency, intubation, pneumonia, deep vein thrombosis, pulmonary embolism, urinary tract infection, wound dehiscence, stroke, and blood transfusion. RESULTS: A total of 251 scapula fractures were identified, with 161 having known fracture locations: 105 glenoid, 20 body, 9 coracoid, and 27 acromial fractures. The rate of any adverse event for all scapular fractures was 2.0%, with no significant difference between anatomic locations (p = 0.79). The overall rates of transfusion, surgical site infection, and return to OR were 0.4%, 0.8%, and 3.98%. Steroid use associated with a significantly increased risk of any adverse event (OR: 55.57, p = 0.038) and outpatient status demonstrated a protective effect on reoperation (OR: 0.11, p = 0.014). There were no significant differences in the rates between groups [transfusion (p = 0.91); surgical site infection (p = 0.17); reoperation (p = 0.85)]. CONCLUSION: Complication rates within thirty days of ORIF for scapula fracture were low. Reoperation was the most common complication, followed by surgical site infection, wound dehiscence, stroke, transfusion, and pneumonia. Steroid use was a risk factor for developing any adverse event, and outpatient status was protective against reoperation. The 30-day complication profile of glenoid, body, coracoid, and acromial fractures was not significantly different. The low complication rates support the relative short-term safety of operative intervention with internal fixation. LEVEL OF EVIDENCE: Level III.
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Fijación Interna de Fracturas , Fracturas Óseas , Reducción Abierta , Complicaciones Posoperatorias , Escápula , Humanos , Fijación Interna de Fracturas/efectos adversos , Fijación Interna de Fracturas/métodos , Fracturas Óseas/cirugía , Escápula/lesiones , Masculino , Factores de Riesgo , Femenino , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Reducción Abierta/efectos adversos , Reducción Abierta/métodos , Persona de Mediana Edad , Adulto , Infección de la Herida Quirúrgica/epidemiología , Infección de la Herida Quirúrgica/etiología , Incidencia , Anciano , Estudios Retrospectivos , Transfusión Sanguínea/estadística & datos numéricos , Neumonía/etiología , Neumonía/epidemiología , Dehiscencia de la Herida Operatoria/etiología , Dehiscencia de la Herida Operatoria/epidemiologíaRESUMEN
Acromion fractures, particularly isolated cases, are uncommon but significant in shoulder injuries. There is no universally accepted treatment protocol, but the classification of the fracture helps to guide clinical decisions. We present a case report aiming to contribute to the understanding of treatment options for acromion fractures. A 22-year-old male sustained a left shoulder injury during a wrestling match, resulting in a type 2 acromion fracture. Conservative treatment was initiated with regular follow-ups. Serial imaging showed no further displacement. Gradual rehabilitation exercises were introduced based on healing progress. The rarity of isolated acromion fractures complicates their management. Conservative management, coupled with rehabilitation exercises, yielded positive outcomes in our case, suggesting its efficacy as a primary treatment option for isolated displaced acromion fractures. Further research is needed to establish standardized protocols for managing such fractures, but until then, conservative care remains a viable approach, potentially preferred over surgical intervention.
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BACKGROUND: This study validated the accuracy of the acromion marker cluster (AMC) and scapula spinal marker cluster (SSMC) methods compared with upright four-dimensional computed tomography (4DCT) analysis. METHODS: Sixteen shoulders of eight healthy males underwent AMC and SSMC assessments. Active shoulder elevation was tracked using upright 4DCT and optical motion capture system. The scapulothoracic and glenohumeral rotation angles calculated from AMC and SSMC were compared with 4DCT. Additionally, the motion of these marker clusters on the skin with shoulder elevation was evaluated. RESULTS: The average differences between AMC and 4DCT during 10°-140° of humerothoracic elevation were - 2.2° ± 7.5° in scapulothoracic upward rotation, 14.0° ± 7.4° in internal rotation, 6.5° ± 7.5° in posterior tilting, 3.7° ± 8.1° in glenohumeral elevation, - 8.3° ± 10.7° in external rotation, and - 8.6° ± 8.9° in anterior plane of elevation. The difference between AMC and 4DCT was significant at 120° of humerothoracic elevation in scapulothoracic upward rotation, 50° in internal rotation, 90° in posterior tilting, 120° in glenohumeral elevation, 100° in external rotation, and 100° in anterior plane of elevation. However, the average differences between SSMC and 4DCT were - 7.5 ± 7.7° in scapulothoracic upward rotation, 2.0° ± 7.0° in internal rotation, 2.3° ± 7.2° in posterior tilting, 8.8° ± 7.9° in glenohumeral elevation, 2.0° ± 9.1° in external rotation, and 1.9° ± 10.1° in anterior plane of elevation. The difference between SSMC and 4DCT was significant at 50° of humerothoracic elevation in scapulothoracic upward rotation and 60° in glenohumeral elevation, with no significant differences observed in other rotations. Skin motion was significantly smaller in AMC (28.7 ± 4.0 mm) than SSMC (38.6 ± 5.8 mm). Although there was smaller skin motion in AMC, SSMC exhibited smaller differences in scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation compared to 4DCT. CONCLUSION: This study demonstrates that AMC is more accurate for assessing scapulothoracic upward rotation and glenohumeral elevation, while SSMC is preferable for evaluating scapulothoracic internal rotation, posterior tilting, glenohumeral external rotation, and anterior plane of elevation, with smaller differences compared to 4DCT.