Effects of Tear-Associated Scapula Shape on the Stabilizing Potential of Glenohumeral Muscles
Bibliographic record
Abstract
Glenohumeral muscles stabilize the humerus by providing compressive forces directed into the glenoid or by resisting opposing forces from larger muscles like the deltoid. Scapula shape is correlated to rotator cuff tear likelihood and previous research found that tear-associated shapes shift the supraspinatus’ line-of-action (LOA) anteriorly, potentially inhibiting its stabilizing potential. We predicted that the tear-associated scapula shape would cause an anterior shift in all glenohumeral muscles’ LOA. We expanded previous finite element models and computational scripts to compute the stability ratios of the teres major, teres minor, infraspinatus, supraspinatus and subscapularis on tear-associated and non-tear control scapulas. We identified insertion and attachment points for each muscle and created respective straight muscle meshes in Matlab. Then, we wrapped those meshes around the scapula and humerus surfaces and simulated an arm-raising motion in the open-source modelling package, Artisynth. In Matlab, we computed the muscle LOAs and their anterior-posterior (AP) and superior-inferior (SI) stability ratios, which describe how muscles tend to pull on the humerus relative to the glenoid. We found that the mean AP stability ratios of all five glenohumeral muscles were higher in the tear-associated scapula shape compared to the control shape, indicating an anterior shift in the muscles’ LOA. Aside from the teres minor, all other muscles exhibited slightly larger SI ratios for the tear-associated scapula shape, indicating a shift superiorly in their LOA. The tear-associated scapula shape may impact certain glenohumeral muscles’ ability to stabilize the humerus, placing higher demand on posterior fibres, subscapularis and teres major to maintain anterior stability. These findings indicate a potential injury mechanism caused by scapula shape and may help to inform rotator cuff tear prevention and rehabilitation. This method can also be applied to in vivo measurements of shoulder motions and bones to provide precise, patient-specific information on rotator cuff stabilizing potential.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.005 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".