[Significance of the limbus glenoidalis for the stability of the shoulder joint].

Besides the osseous structures and the muscular elements, the capsular and ligamentous apparatus, including the limbus genoidalis, is of utmost importance for the stability of the shoulder-joint. In the literature the limbus glenoidalis (L.G.) is generally described as a fibrocartilagineous structure comparable to the menisci of the knee-joint. Basically, the cause of a primary foreful shoulder-dislocation may be either a direct or an indirect trauma. The lesions during luxation concern the joint's capsula, the L.G. and the head of the humerus. However, in the literature one finds many different explanations as to which of those lesions is responsible for the subsequent development of recurring shoulder dislocation. The variability of concepts is reflected by the large number of operative procedures that are advised as treatment of a recurring dislocation. Assuming that the L.G. substantially contributes to the stability of the shoulder joint, we have investigated structure, blood-perfusion and anatomical connections of the L.G. The mechanism of the primary shoulder dislocation was simulated in mechanical strain-experiments, carried out on human corpse specimens. The occurring lesions were analysed. The following investigations were undertaken in alltogether 182 fresh specimens of human shoulder joints: measurement and calculation of the joint-surfaces of scapula and humeral head, dye-injection of the arteria axillaris, in order to demonstrate the vascular supply of the limbus glenoidalis, histological examination of the structure of the limbus glenoidalis, mechanical strain-experiments, that simulate the dislocation mechanism of the shoulder-joint. The calculations of joint-surfaces showed a relative decrease of the scapular joint-surface with growing age. The relation of the scapular joint-surface (always plus limbus glenoidalis) to the joint-surface of the humeral head is 1: 2.25 +/- 0.38 in men and 1: 2.20 +/- 0.11 in women (age-group: 20 to 49 years). In the age-group of 70 to 89 years the respective numbers are 1: 2.90 +/- 0.35 and 1: 2.99 +/- 1.04. The differences in the relations of surfaces between the different age-groups are statistically significant for both sexes (p less than 0.01; Student-t-test). The dye-injection showed that the main artery supplying the limbus glenoidalis is a branch of the arteria circumflexa scapulae. This branch is connected by several anastomoses with the arteriae circumflexa humeri anterior and posterior. These macroscopical observations were confirmed by histological and microangiographic examinations.(ABSTRACT TRUNCATED AT 400 WORDS)