Critical Angle Research Articles

Talus-derived reference coordinate system for 3D calcaneal assessment: A novel approach to improve morphological measurements.

In 3D-analysis of the calcaneus, a consistent coordinate system aligned with the original anatomical directions is crucial for pre- and postoperativeanalysis. This importance stems from the calcaneus's key role in weight-bearing and biomechanical alignment. However, defining a reliable coordinate system based solely on fractured or surgically reconstructed calcanei presents significant challenges. Given its anatomical prominence and consistent orientation, the talus offers a potential solution to this challenge. Our work explores the feasibility of talus-derived coordinate systems for 3D-modeling of the calcaneus across its various conditions. Four methods were tested on nonfractured, fractured and surgically reconstructed calcanei, utilizing Principal Component Analysis, anatomical landmarks, bounding box, and an atlas-based approach. The methods were compared with a self-defined calcaneus reference coordinate system. Additionally, the impact of deviation of the coordinate system on morphological measurements was investigated. Among methods for constructing nonfractured calcanei coordinate systems, the atlas-based method displayed the lowest Root Mean Square value in comparison with the reference coordinate system. For morphological measures like Böhler's Angle and the Critical angle of Gissane, the atlas talus-based system closely aligned with ground truth, yielding differences of 0.6° and 1.2°, respectively, compared to larger deviations seen in other talus-based coordinate systems. In conclusion, all tested methods were feasible for creating a talus derived coordinate system. A talus derived coordinate system showed potential, offering benefits for morphological measurements and clinical scenarios involving fractured and surgically reconstructed calcanei. Further research is recommended to assess the impact of these coordinate systems on surgical planning and outcomes.

Stress-dependent reflection and transmission of elastic waves under confining, uniaxial, and pure shear prestresses

Insights into the reflection and transmission (R/T) of waves at a prestressed interface are important in geophysical applications, such as evaluating the angle-dependent elastic properties for monitoring geopressure and tectonic stress using sonic logging data or seismic data. Although many studies deal with wave propagation in prestressed media, the angle-dependent R/T of waves at an interface subject to different prestress loading modes remains largely unaddressed. We address this issue by applying the theory of acoustoelasticity with third-order acoustoelastic constants to study the R/T coefficients at the interface between two prestressed media. Stress-induced elastic deformations are assumed to be locally homogeneous without boundary dislocations caused by stress concentration so that the static boundary conditions can be applied. We consider three typical prestress modes (confining, uniaxial, and pure shear), each of which takes into account the incidence of upgoing and downgoing P and S waves. The Knott equations under different types of prestresses are derived, followed by the estimation of angle-dependent R/T coefficients. The energy conservation at the interface and the acoustoelastic finite-difference simulation of predicted P and S modes verify the correctness of the angle-dependent R/T coefficients under confining prestress. Comparisons with the elastic case (prestress [Formula: see text]) indicate the important influence of prestresses on the energy distribution of reflected and transmitted waves, including stress-dependent critical angles, converted waves, and R/T energy ratios. Such acoustoelastic effects mainly occur around/after the critical angle. For small-angle incidence, prestresses mainly affect the gradient of R/T coefficients. The type and magnitude of prestress are closely related to the angle-dependent R/T coefficients and must be considered for amplitude-variation-with-offset analysis in prestressed media.

Travel for women rights: social movements and the construction of travel as activism in social media

ABSTRACT Globalized social movements often require travel, but travel as a symbolic form of transnational activism has only been examined in certain instances. This paper employs the notion of political travel and, through a qualitative content analysis of social media posts during the 2018 pro-choice Irish referendum campaign, it shows how travel can be approached as a form of activism and resistance from a critical feminist angle in the context of a global campaign mediated by social media. Inspired by assemblage theory [De Landa, M. (2016). Assemblage theory. Edinburgh University Press.], our findings show how different elements; people, spaces, objects are assembled to construct the framing and narrative of a social movement that fights for women rights. The individual accounts of travel experiences in social media contributed to the overall ‘aestheticization’ of the social movement. Also, the study offered insights into the meanings that, predominantly female, travellers, assign to their political travel, which are in turn shaped by personal and historical concerns.

Damage evolution of tunnel lining under creep action considering interlayer effect in gently inclined layered surrounding rock

The anisotropy and creep characteristics of layered sandstone mudstone with different structural inclinations have a significant impact on the safety of tunnel construction and operation. we conducted research of the layered sand-mudstone of the Yunding Tunnel on the Dazhou-Chengdu line, based on the mechanical response mechanism of layered surrounding rock and employing a numerical coupling analysis method, established a creep damage mechanical model of layered rock to study the progressive failure characteristics of layered rock and the failure mechanism of tunnel lining. The results indicate that:(1) The response mechanism of layered rock mechanics based on the delamination effect can well reflect the progressive fracture of the layered rock and distinguish the failure mode of layered rock; (2) The established layered rock mechanics contact model can effectively characterize the anisotropic macroscopic mechanical properties of layered sand-mudstone in biaxial test and triaxial creep test; (3) The fracture characteristics of the layered surrounding rock matrix change significantly with the change of the dip angle of the structural plane, the cracks mainly appear in the direction perpendicular to the structural plane. And it can be determined that the critical angle of sliding failure of layered sand mudstone is α1 = 28.77°, α2 = 65.47° (4) The damage evolution of lining can be divided into four states: 1. elastic state 2. injury working state 3. ultimate bearing state 4. damage state. With the increase of the dip angle of the structural plane, the time for the lining to enter the ultimate bearing state is gradually delayed, and the delayed rate shows the characteristics of ’slower-faster-slower’. This research achievement can provide a certain foundation for the analysis of the failure mode and the failure mechanism of tunnel lining.

Predictability and functional impact of lateral acromioplasty using preoperative 2D planning on the correction of the critical shoulder angle (CSA) in patients with rotator cuff repair

Rotator cuff tears are highly prevalent, and their association with critical shoulder angle (CSA) has been reported. There is controversy regarding whether the morphology of the acromion influences its incidence, as well as whether acromioplasty would impact the results of a rotator cuff repair. Lateral acromioplasty does not play a decompressive role; rather, it aims to correct the deltoid vector. According to some publications, this would achieve less loading on the repaired rotator cuff, a lower retear rate, and better function. CSA correction with lateral acromioplasty can be planned with radiography (2-dimensional [2D]), but its predictability has not been fully studied. The primary objective of this study is to evaluate the predictability of 2D planning with radiography in CSA correction in patients with rotator cuff repair. The secondary objective is to analyze the association between the correction of the CSA and the functional outcomes. This single-center, prospective, observational, analytical study included candidates for arthroscopic repair of a rotator cuff tear with a CSA > 35°. Lateral acromioplasty was performed as planned with preoperative radiography (2D) to achieve a CSA of 35°. The degrees to be corrected were calculated. CSA was recalculated with a postoperative radiography; and the error in the planned grades to be corrected was calculated. At the end of follow-up, Visual Analog Scale, Subjective Shoulder Value (SSV), and Quick-Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) scores were evaluated. Forty one cases were included, 43.9% were men, and the mean age was 55.5±8.6 years. The mean preoperative and postoperative CSA were 39.6°±1.9° and 35.7°±2.3°, respectively; 41.5% achieved a postoperative CSA ≤ 35°. The mean CSA planned correction error was 45.7±28.8%. At the end of the follow-up, 33 (78.6%) had a functional evaluation, with an average follow-up of 41±6.8 months. The mean Visual Analog Scale, Quick-DASH, and SSV were 0.9±1.6, 5.3±7.5, and 92.7±10.6, respectively. There was a significant difference in Quick-DASH (P=.01) and SSV (P=.02) according to whether a postoperative CSA ≤ 35° was achieved. In lateral acromioplasty, planning of CSA correction with radiography (2D) is imprecise. Reaching a CSA ≤ 35° positively influences functional results.

Secular evolution of resonant planets in the coplanar case

Aims. We study the secular evolution of two planets in mutual deep mean-motion resonance (MMR) in the planar elliptic three-body problem framework for different mass ratios. We do not consider any restriction in the eccentricity of the inner planet e1 or in the eccentricity of the outer planet e2. Methods. The method we used is based on a semi-analytical model that consists of calculating the averaged resonant disturbing function numerically. It is assumed for this that all the orbital elements (except for the mean longitudes) of both planets are constant on the resonant timescale. In order to obtain the secular evolution inside the MMR, we make use of the adiabatic invariance principle, assuming a zero-amplitude resonant libration. We constructed two phase portraits, called the ℋ1 and ℋ2 surfaces, in the three-dimensional spaces (e1, Δϖ, σ) and (e2, Δϖ, σ), where Δϖ is the difference between the planetary longitude of perihelia and σ is the critical angle. These surfaces, which are related through the angular moment conservation, allow us to find the apsidal corotation resonances (ACRs) and to predict the secular evolution of e1, e2, Δϖ, and σ (libration center). Results. While studying the 1:1, 2:1, 3:1, and 3:2 MMR, we found that large excursions in eccentricity can exist in some particular cases. We compared the secular variations of e1, e2, Δϖ, and σ predicted by the model with a numerical integration of the exact equations of motion for different mass ratios. We obtained good matches. Finally, the model was applied to study the secular evolution of the resonant exoplanet systems HD 73526 and HD 31527. They both have a pair of planets and are very close to the deep MMR condition. In the first system, we found that the pair of planets that constitutes the system evolves in a symmetrical ACR, whereas in the second system, we found that planets c and d, which are in an unusual 16:3 MMR, are close to an ACR, but outside its dynamical region, where Δϖ circulates.

Analysis of the impact of different branching angles on the coronary flow field based on fluid-structure interaction

The bifurcation angle of the coronary artery can have an impact on blood flow velocity, especially in the narrow region, where the flow velocity becomes more pronounced, leading to further deterioration of the stenosis in that area. In order to investigate the effect of bifurcation angle on the coronary blood flow field, four bifurcation angle models were established in Solidworks, and a bidirectional fluid-solid coupling method was used to numerically simulate the blood distribution. The changes in the blood flow field at different periods were analyzed. The results showed that the blood flow velocity distribution was similar in the same model at different periods, with high flow velocity mainly concentrated in the coronary artery trunk and smooth branching flow velocity. The flow velocity was different at various periods, resulting in a large difference in the WSS range, which was most obvious during the peak diastolic period. The bifurcation angle had the most significant effect on TAWSS, and as the bifurcation angle increased, the area of the high TAWSS region continued to expand. A small amount of vortex at the bifurcation ridge affected the shear stress direction, resulting in a high OSI (>0.3) region in that area. In conclusion, the bifurcation angle has a significant effect on TAWSS, with the most significant fluctuation in the 37.5° to 42.5° range, and there may be a critical angle causing the fluctuation in between.

Non‐coalescence of nonidentical droplets in oil under a DC electric field

AbstractExcessive electric field strength causes the droplets to contact but not coalesce, severely deteriorating the oil–water separation efficiency. The investigation of the non‐coalescence of nonidentical droplets in oil under a DC electric field is conducted using high‐speed photography. The effects of droplet volume ratio and interfacial tension ratio on the characteristics and critical parameters for droplet non‐coalescence are systematically explored. The results show the critical electrocapillary number for the non‐coalescence of nonidentical droplets and critical contact cone angle decreases as the volume sum increases or the interfacial tension ratio decreases, which is related to the competition between the resultant electric field force and the interfacial tension force. These results contribute to optimizing the operating parameters of the electric coalescer and improving the oil–water separation efficiency.

Corrosion effects on axial pile capacity

Increase in surface roughness by corrosion processes has long been neglected as potential factor influencing pile setup. However, recently there has been an increasing number of studies who referred pile setups largely or solely to corrosion and sand incrustation. Only limited research has been conducted to assess the potential impacts of corrosion directly on pile capacity development. Therefore, we sampled steel and crust surfaces from a steel monopile having been aged for ∼four years in sand. Surface roughness measurements and interface direct shear testing were performed to quantify changes for friction angles. The impact of friction angle changes on pile capacity were calculated using ICP-05 and UWA-05 for a large- and small-diameter geometry and referenced by field data. We can show that corrosion can significantly contribute to temporal pile capacity gains. Evidence have been found that the maximum and critical interface friction angles evolve differently considering the same changes in roughness. Also, differences in shearing behavior to literature were observed, being potentially a result of the naturally corroded surfaces sheared in our study. A strong, maybe exaggerated sensitivity of the capacity prediction approaches to pile diameter was observed. Effects causing an increase in surface roughness, should be reconsidered as an important factor influencing pile setup.

Buckling analysis of a helical extension spring under combined loading

A new formula is introduced to analytically determine the critical torsional load or angle of rotation that confers instability in a tension spring under combined tension and torsion load using the theoretical framework of Greenhill's problem applied to an elastic bar as a starting point. The formula's effectiveness is evaluated with experimental torsion tests and finite element method simulations in Abaqus. The results demonstrate the formula's accuracy in predicting instability within specific stretched operating ranges, and achieving a relative error in correlation below 10 % for most operating points. The study underscores the significance of preload and pre-stretching in enhancing the spring's resistance to buckling.

Numerical study on the influence of riblet yaw-angle on drag reduction rate with different immersion heights

This paper uses the Large-eddy simulation method to investigate the influence of riblet yaw angle on drag reduction rate with different immersion heights, revealing that the vortex structure is gradually transformed from riblet-tip vortex pairs to boundary vortex forms with the increase of yaw angle, and analyzing the influence mechanism of immersion height on the critical yaw angle. The result shows that the drag-reduction rate of riblets decreases as the yaw angle increases, and the critical angle of the riblet varies with the different immersion heights. When the immersion height is 0.7, 0.5, and 0.3, the critical yaw angle is close to 30, 40, and 50°, respectively. As the immersion height increases, the cross-flow velocity at the riblet tip is more accessible to reach the critical velocity at which a boundary vortex can be formed, resulting in a smaller critical yaw angle for larger immersion heights. Furthermore, with the yaw angle increases, the normal diffusivity of normal vorticity and spanwise vorticity increase and decrease, respectively, which indicates that the lateral flow fluctuations decrease beyond a critical yaw angle, while the Reynolds stress component due to energy dissipation induced by the streamwise velocity decreases. Meanwhile, with the formation of a boundary vortex, the ability of the riblet to reduce viscous shear stresses increases due to the reduction of near-wall velocity gradient, and the emergence of a high-pressure region on the windward side of the riblet and a low-pressure region on the leeward side, consequently augmenting the differential pressure drag. This work provides valuable insights for designing riblets with heightened effectiveness at larger yaw angles, thereby extending their applicability under diverse flow conditions.

A comprehensive analysis of the ‘coming and going’ phenomenon of the projectile motion of a sphere under air resistance

We have analyzed the ‘coming and going’ phenomenon of the projectile motion of a sphere using experimental data correlations that span the entire range of Reynolds numbers. We have modeled the drag force using an analytical expression for the drag coefficient and performed a numerical analysis to compute the critical angle as a function of the sphere’s initial speed, radius, and mass. Our results indicate that the critical angle behaves analogously to the drag coefficient as a function of the Reynolds number. This study is significant as it deals with a drag force not limited to any specific flow regime and may help undergraduate students and science instructors delve deeper into the subject.

Coupling Effect of Structural Lubrication and Thermal Excitation on Phononic Friction.

This work investigates the coupling effect of structural lubrication and thermal excitation on phononic friction between black phosphorus (BP) layers. As the rotation angle increases from commensurate to incommensurate states, the friction gradually decreases at any temperature. However, the role of temperature in friction depends on commensurability. For a rotation angle less than 10°, increasing temperature leads to a decrease in friction due to thermal excitation. Conversely, when the rotation angle exceeds 10°, elevated temperature results in an increase in friction due to the effect of thermal collision. At a critical rotation angle of 10°, higher temperatures lead to reduced friction through thermal lubrication at low speeds, and at large speeds, the thermal excitation duration becomes so short that the role of thermal lubrication is weakened, and instead thermal collision dominates. Further research reveals that BP's ability to withstand different maximum speeds is also determined by commensurability. Finally, a method to measure the sliding period length of a rotated tip through an unrotated substrate potential energy topography is proposed and simply verified by using the phonon spectrum.

Experimental Study on Shear Strength of Roof–Snow Interfaces for Prediction of Roof Snow Sliding

The sliding of roof snow may result in surcharges of snow load on lower roofs or the injury of pedestrians on the ground. It is therefore of great significance to study the mechanism of roof snow sliding, such that prevention or control measures can be developed to manage the risk. Considering four commonly used roofing materials, glass, steel, membrane, and concrete, two types of experiments were carried out in this study to possibly reveal the influence of roofing materials on the shear strength of the roof–snow interface: one is the critical angle tests where the angle at which the snow starts to slide off from the roof is tested, and the other is the shearing tests which aim to test the shear strength of the roof–snow interfaces at specific temperatures. The results showed that the critical angle for roof snow sliding, as well as the shear strength of the roof–snow interface for the four considered roofing materials, show a U-shape trend with the increase in surface roughness and that the shear strength of the roof–snow surface ranges from 0.15 kPa to 2 kPa for the cases considered, while the strength reaches its maximum at certain temperatures near −5 °C for a specific roofing material and snow thickness. These findings could be a useful reference for future experimental or simulation studies on roof snow sliding.

Can coracoacromial ligament degeneration be evaluated with preoperative MRI?

Subacromial impingement syndrome is one of the most common causes of painful shoulder in the middle-aged and elderly population. Coracoacromial ligament (CAL) degeneration is a well-known indicator for subacromial impingement. To examine the relationship between CAL thickness on preoperative magnetic resonance imaging (MRI), arthroscopic CAL degeneration and types of rotator cuff tears. Video records of patients who underwent arthroscopic shoulder surgery between 2015 and 2021 were retrospectively scanned through the hospital information record system. In total, 560 patients were included in this study. Video records of the surgery were used to evaluate the grade of coracoacromial ligament degeneration and the type of cuff tear. Preoperative MRI was used to measure CAL thickness, acromiohumeral distance, critical shoulder angle, acromial index, and acromion angulation. Significant differences were observed between grades of CAL degeneration in terms of CAL thickness (P < 0.001). As CAL degeneration increases, the mean of CAL thickness decreases. According to the results of post-hoc analysis, the mean CAL thickness of normal patients was significantly higher than those of patients with full-thickness tears (P = 0.024) and massive tears (P <0.001). Patients with articular-side, bursal-side, and full-thickness tears had significantly higher CAL thickness averages than patients with massive tears. This study showed that the CAL thickness decreases on MRI as arthroscopic CAL degeneration increases. High-grade CAL degeneration and therefore subacromial impingement syndrome can be predicted by looking at the CAL thickness in MRI, which is a non-invasive method.

The significance of subjective mechanical symptoms in rotator cuff pathology

BackgroundThe presence of subjective mechanical symptoms, such as clicking or popping, is common in patients presenting for shoulder pain and dysfunction, with unclear clinical significance. The primary objective of this study was to assess whether subjective mechanical symptoms in the affected shoulder were associated with full-thickness rotator cuff tearing in a consecutive, prospective cohort of patients undergoing shoulder magnetic resonance imaging (MRI) for suspected rotator cuff pathology. MethodsA prospective cohort study was performed of 100 consecutive patients with suspected rotator cuff tendinopathy and/or tearing who underwent shoulder MRI. The presence of subjective shoulder mechanical symptoms, including clicking or popping, was documented prior to MRI. Indications for MRI included weakness on isolated testing of rotator cuff muscle(s) or symptoms refractory to conservative treatment including at least a 6-week course of physical therapy. The primary outcome variable was the presence of full-thickness rotator cuff tearing; secondary outcome variables included any (full-thickness or partial-thickness) rotator cuff tearing and biceps long head subluxation. Radiographic parameters, including critical shoulder angle, Goutallier grade, tear retraction, and tear size were quantified. One patient was lost to follow-up, and 99 patients completed MRI imaging. ResultsIn our cohort, 60% of patients reported subjective mechanical symptoms in the affected shoulder. Full-thickness rotator cuff tearing was identified in 42% of patients, any rotator cuff tearing in 69% of patients, and biceps long head subluxation in 14% of patients. Subjective mechanical symptoms were not associated with full-thickness rotator cuff tearing, any rotator cuff tearing, biceps long head subluxation, critical shoulder angle, Goutallier grade, tear size, or tear retraction. Older age was associated with full-thickness and any rotator cuff tearing. As a diagnostic test for full-thickness rotator cuff tearing, subjective shoulder mechanical symptoms has a sensitivity of 64%, a specificity of 44%, and Youden’s index of 0.08, consistent with poor diagnostic accuracy. ConclusionsSubjective mechanical symptoms in the affected shoulder are a common complaint in patients with suspected rotator cuff pathology. Patients may be reassured that a sensation of clicking or popping alone does not necessarily entail structural shoulder derangement.

Preliminary Implications of Viscoelastic Ray Theory for Anelastic Seismic Tomography Models

ABSTRACT The recent developments in general viscoelastic ray theory provide a rigorous mathematical framework for anelastic seismic tomography. They provide closed-form solutions of forward ray-tracing and simple inverse problems for anelastic horizontal and spherical layered media with material gradients. They provide ray-tracing computation algorithms valid for all angles of incidence that account for changes in wave speed, attenuation, and trajectory of anelastic P and S body waves induced by anelastic boundaries. They account for theoretical predictions that seismic waves refract as inhomogeneous waves across anelastic boundaries for all angles of incidence, which in turn accounts for energy carried by plane waves along seismic boundaries at head wave critical angles and wide-angle refracted (WAR) ray paths that are not predicted by elastic models. Exact viscoelastic ray-tracing numerical results for various models provide examples that illustrate the effects of anelastic boundaries on the travel times and amplitudes of seismic waves. They show the effects are strongly dependent on angle of incidence. For near-critical and wide angles of incidence the anelastic effects on travel times and amplitudes can be large and are not explained by elastic ray theory, but the effects on travel times can be relatively small and difficult to distinguish from those for elastic media for pre-near-critical angles of incidence. The results for some models indicate that reflected anelastic WAR waves may be observable at the surface and possibly account for some prominent seismic arrivals not explained by elasticity. These preliminary results suggest that the application of exact viscoelastic ray-tracing computation algorithms to exploration and teleseismic data sets can reveal new insights regarding the properties and distribution of anelastic materials in the Earth.

Effect of repetitive nano-cutting tool parameters on surface quality and subsurface damage of γ-TiAl alloy

In this paper, the molecular dynamics simulation of the repeated nano-cutting of single crystal γ-Tial alloy was carried out by selecting different geometric parameters of the second cutting tool by single factor experiment. The cutting force, friction coefficient, subsurface defects, dislocation evolution and surface roughness of the second cutting were analyzed systematically. The results show that when the tool rake angle is 15°, the surface roughness is lower and the surface quality is better. The influence of different second cutting tool rake angle on the surface roughness is not strong. When the rake angle of the second cutting tool and the radius of edge are constant, the average normal cutting force decreases with the increase of the clearance angle of the tool. Under the machining parameters in this paper, the critical clearance angle of the second cutting of single crystal γ-TiAl alloy is between 10° and 15°. When the tool clearance angle is greater than the critical clearance angle, the average cutting force and the machined-surface roughness no longer change significantly. With the increase of the radius of the second cutting tool, the chip decreases, the subsurface defect increases, and the surface roughness of the machined surface also increases with strong regularity.

A model for thermocapillary driven motion of liquid drops on an inclined plane

Thermocapillary drop migration is driven by surface tension gradient. On an inclined plane, gravity acts as an additional force that can have a promoting or resisting effect depending on the thermal gradient direction. The present 2-D model extends Brochard and Chebbi models for thermocapillary migration of small drops on horizontal plates by accounting for Marangoni and Poiseuille flow components, while including the effect of gravity, acting in the case of inclines. The present treatment is based on fundamentals of conservation of mass and momentum transport, and uses the lubrication approximation and extended boundary conditions at the receding and advancing contact lines. A model for the dynamics of migration is provided, and an analytical solution is derived for drop migration dynamics and the critical angle of inclination.

Lower trapezius and latissimus dorsi transfer relieve teres minor activity into the physiological range in Collin D irreparable posterosuperior massive rotator cuff tears: a biomechanical analysis

Tendon transfers are established techniques to regain external rotation mobility in patients suffering from an irreparable, posterosuperior massive rotator cuff tear (MRCT). Posterosuperior MRCT with intact teres minor (Type D MRCT) can lead to excessive teres minor loading to maintain external rotation. We hypothesize that tendon transfers are effective in relieving teres minor loading in Type D MRCTs. Our aim was to biomechanically assess muscle synergism with latissimus dorsi (LD-Transfer) and lower trapezius (LT-Transfer) tendon transfer during external rotation at different abduction heights. Using musculoskeletal modeling, we analyzed and compared the moment arm, muscle torque and muscle activity between a healthy and Type D MRCT pathological model with and without the LD- or LT-Transfer at infraspinatus and teres minor insertion sites. Output measures were analyzed during external rotation at different abduction angles and 10 to 50N resistance against external rotation. We assessed its impact on teres minor loading in a Type D MRCT. Morphological variations were parameterized using the critical shoulder angle and the acromiohumeral distance to address variations among patients. Both transfer types reduced teres minor torque and activity significantly, reaching physiological state at 40N external resistance (p<0.001), with insertion to infraspinatus site being more effective than teres minor site (p<0.001). External rotation moment arms of LD-Transfer were larger than LT-Transfer at 90° abduction (25.1±0.8mm vs. 21.2±0.6mm, p<0.001) and vice versa at 0° abduction (17.4±0.5mm vs. 24.0±0.2mm, p<0.001). While the healthy infraspinatus was the main external rotator in all abduction angles (50-70% torque), a Type D MRCT resulted in a 70-90% increase of teres minor torque and an up to sevenfold increase in its activity leading to excessive loadings beyond 10N resistance against external rotation. Varying the critical shoulder angle and the acromiohumeral distance led to minor variations in muscle moment arm and muscle activity. We identified biomechanical efficacy of both tendon transfers in Type D MRCT regarding teres minor load relieve and superior performance of the transfers at the infraspinatus insertion site.