The arthroscopic view of the glenohumeral ligaments compared with anatomy: fold or fact?

In a morphologic cadaveric study with observational arthroscopy in living subjects, we tried to resolve the contradiction in the literature with regard to the nature of the glenohumeral ligaments and the difference in observation of the folds during arthroscopic and open surgery. Observation of morphology and functional anatomy of the glenohumeral capsule was performed in 200 non-embalmed cadavers through open dissection (100 specimens) and by arthroscopy (50 specimens) or both (50 specimens), as well as in 100 living subjects undergoing shoulder arthroscopy. In the resting arm position, folds and bands can be observed on the inside of the anteroinferior capsule. When the arm is moved into full abduction and external rotation, however, all bands progressively disappear from sight. The bands generally observed in the shoulder capsule during arthroscopy appear at the site of histologic reinforcements of the capsule but are not the capsular ligaments themselves, as they seem to disappear in certain positions of the humerus. Arthroscopically, it is, therefore, not possible to discern the exact limits of these ligaments. This may give rise to a certain amount of confusion when comparing clinical with anatomic and physiologic studies. On the other hand, their presence or absence in arthroscopic surgery might be of clinical relevance in evaluating capsular tension.